NCD986175644_19980716_Davis Park Road TCE Site_FRBCERCLA FS_Feasibility Study Report Rev. 1-OCR

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Document Control No. 4400-71-AHQM
Revision 1
FEASIBILITY STUDY REPORT
DA VIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
Work Assignment No. 71-4LPN
JULY 1998
REGION IV
U.S. EPA CONTRACT NO. 68-W9-0057
Roy F. Weston, Inc.
Suite 200
5405 l\1etric Place
Norcross, C'..eorgia 30092
WESTON W.0. No. 04400-071-095-0008-08
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Document Control No. 4400-71-AHQM
Revision 1
FEASIBILITY STUDY REPORT
DA VIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
Work Assignment No. 71-4LPN
JULY 1998
REGION IV
U.S. EPA CONTRACT NO. 68-W9-0057
Roy F. Weston, Inc.
Suite 200
5405 Metric Place
Norcross, Georgia 30092
WESTON W.0. No. 04400-071-095-0008-08
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Prepared by:
FEASIBILITY STUDY REPORT
REVISION 1
DA VIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
U.S. EPA Contract No. 68-W9-0057
Work Assignn1ent No. 71-4LPN
Document Control No. 4400-71-AHQM
JULY 1998
7l!Jd/4,.1Z Date 7 U& /<t/ __ _,,_,_, ~'--,le--'-~--
WESTON Work Assignment Manager
Technical Review // // ,(? /Jf/c#
Perfonned by: __,/'----"'--'l(z:,"b-4/4:/'---"--~f_,__ .. ~//14--+,fl •-=-~~-Date: ___,,__,7,,__/;(~/2~7,Y_
Approved by:
Approved by:
Approved by:
Ralph P. McKeen_ P.E.
WESTON TeclmicaJ Manager
William R. Doyle
WESTON Region IV P
Jennifer Wendel
U.S. EPA Remedial Project Manager
Roben P. Stern
U.S. EPA Regional Project Officer
Date: -~?_-~/=~--~9 ~S ___ _
Date: --------
Date: _______ _
WESTON W.O. No. 04400-071-095-0008-08
I NOR/KIWPI04400\071\FSDDN001.DOC
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Section
1
TABLE OF CONTENTS
Title
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
INTRODUCTION ..................................................................... 1-1
I.I
1.2
1.3
1.4
Purpose of This Report ........................................................................ 1-1
Site Information .................................................................................... 1-2
1.2.1 Site Location and History ............................................................... 1-2
Site Investigations ................................................................................. I-7
1.3.1 Previous Investigations .................................................................... 1-7
1.3.1.1
1.3 .1.2
1.3.1.3
Phase I Site Screening Investigation, October 1992 .............. 1-7
Site Inspection Addendum, May 1993 ................................ 1-10
Expanded Site Investigation (ES!), May 1994 .................... 1-11
1.3.2 Remedial Investigation Conducted by EPA and WESTON ............ 1-12
Physical Characteristics of the Study Area ........................................... 1-13
1.4.1
1.4.2
1.4.3
1.4.4
Surface Features ............................................................................ 1-13
Meteorology .................................................................................. 1-14
Surface Water Hydrology .............................................................. 1-16
Geology ........................................................................................ 1-17
1.4.4.l
1.4.4.2
Fracture Trace Survey Results ........................................... 1-21
Downhole Geophysical Testing Results .............................. 1-23
1.4.5 Soils ............................................................................................. 1-34
1.4.6 Hydrogeology ............................................................................... 1-34
1.4.7 Demography and Land Use ........................................................... 1-47
1.4.8 Ecology ......................................................................................... 1-47
NOR/K:\WP\04400\071\FSDDN001.DOC
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Section
2
3
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
Page
NATURE AND EXTENT OF CONTAMINATION ............................ 2-1
2.1
2.2
2.3
2.4
2.5
2.6
2.7
May 1996 Preliminary Investigation . . .. . .... .. . .. . .. . . . .. . ...... 2-1
October 1996 Preliminary Investigation ................................................. 2-6
1997 /1998 Investigation ...................................................................... 2-10
2.3.1 Overburden Aquifer Sample Analysis Results ................................ 2-10
2.3.2 Bedrock Aquifer Sample Results ................................................... 2-14
2.3.3 Soil Boring-Groundwater Sample Results ...................................... 2-19
Summary of RI Groundwater Sample Data .......................................... 2-24
Data Gaps ........................................................................................... 2-25
Risk Assessment .................................................................................. 2-26
Summary ............................................................................................ 2-27
APPLICABLE OR RELEVANT AND APPROPRIATE
ENVIRONMENTAL AND PUBLIC HEALTH REQUIREMENTS
(ARARS) ................................................................................. 3-1
3.1
3.2
3.3
Introduction .......................................................................................... 3-1
Identification Of ARARs ....................................................................... 3-2
Federal ARARs ..................................................................................... 3-5
3.3.1 Resource Conservation and Recovery Act (RCRA) ....................... 3-15
3.3.1.]
3.3.1.2
Location-Specific Requirements ......................................... 3-15
Action-Specific Requirements ............................................ 3-16
3.3.2 Clean Water Act ........................................................................... 3-l9
3.3.2.1
3.3.2.2
Chemical-Specific Requirements ........................................ 3-19
Action-Specific Requirements ........................................... 3-20
NOR.IK:\WP\04400\071\FSDDN001.DOC II
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Section
3.4
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: i
Date: July 1998
TABLE OF CONTENTS (Continued)
Page
3.3.3 Safe Drinking Water Act .............................................................. 3-22
3.3.3.1
3.3.3.2
Chemical-Specific Requirements ........................................ 3-22
Action-Specific Requirements........................... 3-25
3 .3 .4 Clean Air Act .............................................................. . .3-27
3.3.4.1
3.3.4.2·
National Ambient Air Quality Standards (NAAQS) ............ 3-28
National Emission Standards for Hazardous Air Pollutants
3.3.5
3.3.6
3.3.7
3.3.8
3.3.9
3.3.10
3.3.11
(NESHAP) Standards ........................................................ 3-28
Occupational Safety and Health Act .............................................. 3-30
Hazardous Materials Transportation Act ....................................... 3-33
Protection of Wetlands .................................................................. 3-33
Floodplain Management ................................................................ 3-34
Regulations Protecting of Landmarks, Historical, and
Archeological Sites ........................................................................ 3-34
Endangered Species Act ................................................................ 3-35
Fish and Wildlife Conservation Act ................................................ 3-36
State ARARs ...................................................................................... 3-36
3.4.1 North Carolina Water and Air Resources Act ................................ 3-36
3.4.2 North Carolina Drinking Water Act.. ............................................. 3-37
3.4.3 North Carolina Water Pollution Control Regulations ..................... 3-37
3.4.4 North Carolina Drinking Water and Groundwater Standards .......... 3-38
3.4.4.1 Groundwater Classification ................................ . .. 3-38
3.4.5 North Carolina Surface Water Quality Standards ........................... 3-43
3.4.5.1
3.4.5.2
Surface Water Standards Based on the Receiving Water
Body .................................................................................. 3-43
Technology-Based Effluent Limitations and Standards ....... 3-55
NOR/K:\WP\04400\071 \FSDDN001.DOC Ill
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Section
44
55
3.4.6
3.4.7
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
Title Page
North Carolina Well Construction Standards ................................. 3-55
North Carolina Air Pollution Control Regulations ......................... 3-55
3.5 Summary Of Groundwater And Surface Water Standards Applicable
To The Davis Park Road TCE Site ..................................................... 3-56
SITE-SPECIFIC REMEDIAL OBJECTIVES/GOALS ........................ 4-1
4.1
4.2
4.3
4.4
Contaminants Of Concern ..................................................................... 4-1
Regulatory Requirements ...................................................................... 4-2
Groundwater Remediation Goals ........................................................... 4-2
Groundwater Treatment Standards ....................................................... .4-4
4.4.1 Receptor-Based Treatment Standards ............................................. .4-4
4.4.2 Technology-Based Eflluent Limitations .......................................... .4-4
4.5 Summary Of Groundwater Remediation Goals/Treatment Standards .... .4-5
IDENTIFICATION AND SCREENING OF REMEDIAL
TECHNOLOGIES ..................................................................... 5-1
5.1 Identification of General Response Actions ........................................... 5-I
5.2 Remedial Action Technology Identification ........................................... 5-2
5 .3 Initial Screening Phase .......................................................................... 5-4
5.4 Screening of Remedial Technology Process Options .............................. 5-5
5.5 Final Evaluation Screening .................................................................. 5-14
5.5.1 No Action ..................................................................................... 5-19
5.5.2 Institutional Controls .................................................................... 5-19
5.5.2.1
5.5.2.2
5.5.2.3
Alternate Water Supply ...................................................... 5-20
Access Restrictions ............................................................ 5-20
Point-of-Use-Treatment ................... , ................................ 5-21
NOR/K.:\WP\04400\0711FSDDN001.DOC IV
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. Jt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Section
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
5.5.2.4
5.5.2.5
Title
Groundwater Monitoring.... . ....... 5-21
Natural Attenuation ........................................................... 5-22
' 5.5.3 Collection/Removal Technologies .................................................. 5-25
5.5.3.1
5.5.3.2
5.5.3.3
Vertical Extraction Wells ................................................... 5-25
Horizontal Extraction Wells ............................................... 5-26
Dual Phase Extraction ........................................................ 5-28
5.5.4 Discharge after Collection ............................................................. 5-29
5.5.5 Physical Treatment Technologies ................................................... 5-30
5.5.5.1
5.5.5.2
5.5.5.3
5.5.5.4
5.5.5.5
Filtration ............................................................................ 5-30
Carbon Adsorption ............................................................ 5-31
Air Stripping ...................................................................... 5-32
In-Well Vapor Stripping (NoVOCs®) ............................... 5-34
Hydraulic and Pneumatic Fracturing ................................... 5-3 5
5.5.6 Chemical Treatment Technologies ................................................. 5-37
5.5.6.1
5.5.6.2
5.5.6.3
In-Situ Chemical Oxidation ................................................ 5-37
Surfactants/Cosolvents ....................................................... 5-3 8
UV/Oxidation Treatment ................................................... 5-39
5.5. 7 Biological Treatment Technologies ................................................ 5-41
5.5.7.1
5.5.7.2
5.5.7.3
5.5. 7.4
5.5.7.5
I
In-Situ Biodegradation ....................................................... 5-41
Fluidized Bed Aerobic Treatment. ...................................... 5-43
Conventional Aerobic Biological Treatment ...................... 5-44
Anaerobic Biological Treatment ......................................... 5-45
Phytoremediation ............................................................... 5-46
5.5.8 Discharge Options ......................................................................... 5-47
NOR/K:\WP\04400\071\FSOON001.DOC V
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. ll shall not be disclosed, ln whole or in part, without the express
written permission of EPA.
Section
6
7
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
Title Page
5.5.8.1
5.5.8.2
On-Site Options...... . ...... 5-48
Off-Site Options ................................................................ 5-50
5.5.9 Residuals Management .................................................................. 5-50
5.5.9.1
5.5.9.2
Offgas Treatment ............................................................... 5-50
Spent Granular Activated Carbon ....................................... 5-5 I
5.6 Summary ............................................................................................. 5-52
DEVELOPMENT OF REMEDIAL ACTION ALTERNATIVES ........... 6-1
6.1 Introduction .......................................................................................... 6-1
6.2 Summary Of Remedial Goals ................................................................. 6-2
6.2.1 Groundwater Cleanup Goals ........................................................... 6-2
6.3 Development of Remedial Alternatives ................................................. 6-3
6.3. I Alternative I -No Action ................................................................ 6-4
6.3.2
6.3.3
Alternative 2 -Institutional Controls ............................................... 6-4
Alternative 3 -Monitored Natural Attenuation with Exposure
Abatement ....................................................................................... 6-4
6.3.4 Alternative 4-Reduction of Groundwater Exposure and
Groundwater Treatment .................................................................. 6-5
6.3.5 Alternative 5 -Reduction of Groundwater Exposure and Pump
and Treat ......................................................................................... 6-6
6.4 Limitations ............................................................................................ 6-7
DETAILED EVALUATION OF REMEDIAL ALTERNATIVES ........... 7-1
7.1 Introduction And Evaluation Criteria ..................................................... 7-1
7.2 Alternative I -No Action .................................. : .................................. 7-3
NOR/K:\WPU)4400\071\FSDDN001.DOC VI
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Section
7.3
7.4
7.2.1
7.2.2
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
Page
Description ...................................................................................... 7-3
Detailed Evaluation ......................................................................... 7-4
7.2.2.1
7.2.2.2
7.2.2.3
7.2.2.4
7.2.2.5
Overall Protection of Human Health and the Environment.. .. 7-4
Compliance with ARARs ..................................................... 7-4
Short-Tenn Effectiveness ..................................................... 7-4
Long-Tenn Effectiveness and Permanence .......................... 7-5
Reduction of Toxicity, Mobility, or Volume of
Contaminants ....................................................................... 7-5
7.2.2.6
7.2.2.7
Implementability .................................................................. 7-5
Con ..................................................................................... 7-5
Alternative 2 -Institutional Controls ..................................................... 7-7
7.3.1
7.3.2
7.3.3
7.3.4
7.3.5
7.3.6
7.3.7
7.3.8
Description ...................................................................................... 7-7
Overall Protection of Human Health and the Environment ............... 7-9
Compliance with ARARs ................................................................. 7-9
Short-Tenn Effectiveness ................................................................ 7-9
Long-Tenn Effectiveness and Permanence ..................................... 7-10
Reduction of Toxicity, Mobility, or Volume .................................. 7-10
Implementability ............................................................................ 7-1 O
Cost .............................................................................................. 7-11
Alternative 3 -Monitored Natural Attenuation with Exposure
Abatement........................ . ............................................................ 7-11
7.4.1 Description .................................................................................... 7-l l
7.4.1.1
7.4.1.2
Historical Data Review for Natural Attenuation Processes. 7-14
Natural Attenuation Evaluation ......................................... 7-17
7.4.2
7.4.3
Overall Protection of Human Health and the Environment ............. 7-32
Compliance with ARARs ............................................................... 7-32
NOR/K:\WP\04400\071 \FSDDN001. DOC VII
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Section
8
7.5
7.6
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
Title Page
7.4.4 Short-Tenn Effectiveness .............................................................. 7-33
7.4.5 Long-Tenn Effectiveness and Permanence ..................................... 7-33
7.4.6 Reduction of Toxicity, Mobility, and Volume ................................ 7-33
7.4.7 Implementability ............................................................................ 7-34
7.4.8 Cost .............................................................................................. 7-34
Alternative 4 -Reduction of Groundwater Exposure and Groundwater
Treatment ........................................................................................... 7-37
7.5.1 Overall Protection of Human Health and the Environment ............. 7-38
7.5.2 Compliance with ARARs ............................................................... 7-38
7.5.3 Short-Tenn Effectiveness .............................................................. 7-38
7.5.4 Long-Tenn Effectiveness and Permanence ..................................... 7-39
7.5.5 Reduction of Toxicity, Mobility and Volume ................................. 7-39
7.5.6 Implementability ............................................................................ 7-39
7.5. 7 Cost .............................................................................................. 7-39
Alternative 5 -Reduction of Groundwater Exposure and
Groundwater Pump and Treat ............................................................ 7-42
7.6.1 Overall Protection of Human Health and the Environment ............. 7-42
7.6.2 Compliance with ARARs ............................................................... 7-43
7.6.3 Short-Tenn Effectiveness .............................................................. 7-43
7.6.4 Long-Tenn Effectiveness and Pennanence ..................................... 7-43
7.6.5 Reduction of Toxicity, Mobility and Volume ................................. 7-43
7.6.6 Implementability ............................................................................ 7-44
7.6.7 Cost .............................................................................................. 7-44
SUMMARY AND COMPARISON OF ALTERNATIVES .................... 8-1
8.1
8.2
Non-Cost Comparative Analysis ............................................................ 8-1
Cost Comparative Analysis .................................................................... 8-7
NOR/K:IWP\04400\071 \FSDDN001.DOC Vlll
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
LIST OF APPENDICES
APPENDIX A -Historical Sampling Analysis Graphs
Figure
Figure 1-1
Figure 1-2
Figure 1-3
Figure 1-4
Figure 1-5
Figure 1-6
LIST OF FIGURES
Page
Davis Park Road TCE Site Map ...................................................................... 1-3
Topographic Map of Site .................................................................................. 1-4
Cross Section Base Map .................................................................................. 1-l 8
Photolineation and Fracture Trace Survey Map ............................................... 1-22
Rose Diagram from Photolineations ................................................................ 1-24
Rose Diagram of Field Measured Fracture Orientations ................................... 1-26
Figure 1-7 Potentiometric Contour Map, Top-of-Bedrock Aquifer, January 1998 ............. 1-38
Figure 1-8 Potentiometric Contour Map, Top-of-Bedrock Aquifer, February 1998 ........... 1-39
Figure 1-9 Potentiometric Contour Map, Bedrock Aquifer, January 1998 ......................... l-40
Figure 1-10 Potentiometric Contour Map, Bedrock Aquifer, February 1998 ....................... 1-41
Figure 2-1 Monitor Well Locations-May 1996 Preliminary Investigation .......................... 2-4
Figure 2-2 Residential Well Locations-May 1996 Preliminary Investigation ...................... 2-5
Figure 2-3 Temporary Monitor Well Locations -October 1996 Preliminary Investigation .. 2-9
Figure 2-4 TCE Concentration Isopleth Map -October 1996 Preliminary Field
Investigation ....................... 2-12
NOR/K:\WP\04400\071\FSDDNOOt.DOC IX
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Figure
Figure 2-5
Figure 2-6
Figure 2-7
Figure 7-1
Figure 7-2
Figure 7-3
Figure 7-4
Figure 7-5
Figure 7-6
Table
Table 1-1
Table 1-2
Table 1-3
Table 1-4
Table 1-5
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
LIST OF FIGURES (Continued)
Page
PCE Concentration Isopleth Map -October 1996 Preliminary Field
Investigation ........ :· ......................................................................................... 2-13
PCE Concentration Isopleth Map - I 997 /1998 Field Investigation .................. 2-20
TCE Concentration Isopleth Map -1997 /1998 Field Investigation .................. 2-21
Monitor Well Location Map .............................................................................. 7-8
BIOSCREEN Natural Attenuation Decision Support System .......................... 7-23
Dissolved Concentration Along Plume Centerline(! I years) ............................ 7-24
Dissolved Concentration Along Plume Centerline (13 years) ............................ 7-25
Dissolved Concentration Along Plume Centerline (15 years) ............................ 7-26
Dissolved Concentration Along Plume Centerline (20 years) ............................ 7-27
LIST OF TABLES
Title
Azimuth Orientations, Field Data (Fracture Planes in Local Bedrock) .............. 1-25
Summary of Logging Anomalies ...................................................................... 1-28
Summary of Fracture Sets Identified from ATV Logs ...................................... 1-30
Details of Fracture Orientations ....................................................................... 1-32
Summary of Possible and Probable Water-Bearing Zones· ................................ 1-33
NOR/K:IWP\04400\071 \FSODN001. DOC X
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table
Table 1-6
Table 1-7
Table 1-8
Table 2-1
Table 2-2
Table 2-3
Table 2-4
Table 2-5
Table 2-6
Table 3-1
Table 3-2
Table 3-3
Table 3-4
Table 3-5
Table 3-6
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
LIST OF TABLES (Continued)
Page
Groundwater Elevations -Monitor, Residential, and Converted Wells,
January 16, 1998, and February 11, 1998 ........................................................ 1-36
Comparison of Water Level Elevations in Monitor Well Pairs .......................... 1-44
Slug Test Results ............................................................................................ 1-46
Summary of Field Investigations Conducted Prior to RI Activities ..................... 2-2
Residential Well Analytical Data Summary -May 1996 Preliminary
Investigation ..................................................................................................... 2-7
Temporary Well Analytical Data Summary -October I 996 Preliminary
Investigation ................................................................................................... 2-11
Groundwater Samples -Overburden Aquifer, Analytical Summary .................. 2-15
Groundwater Samples -Bedrock Aquifer, Analytical Summary ....................... 2-17
Soil Boring Groundwater Sample Analysis Results .......................................... 2-22
Summary of ARAR Sources Evaluated .............................................................. 3-4
Analysis of Potential Federal ARARs ................................................................ 3-6
Analysis of Potential North Carolina ARARs ........... · ........................................ 3-12
Summary ofNational Maximum Concentration Levels (MCLs) for Drinking
Water .............................................................................................................. 3-23
Current and Proposed Federal Safe Drinking Water Act Standards for
Identified Compounds of Concern ................................................................... 3-26
National Ambient Air Quality Standards (NAAQS) ......................................... 3-29
NOR/K.:IWP\04400\071\FSODNOOt.DOC XI
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table
Table 3-7
Table 3-8
Table 3-9
Table 4-1
Table 5-1
Table 5-2
Table 5-3
Table 5-4
Table 7-1
Table 7-2
Table 7-3
Table 7-4
Table 7-5
Table 7-6
Table 7-7
Table 7-8
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
LIST OF TABLES (Continued)
Title Page
North Carolina Groundwater Quality Standards for Class GA ......................... 3-40
North Carolina Surface Water (Freshwater) Quality Standards ........................ 3-52
Summary of Groundwater and Surface Water Standards Applicable to
Groundwater Objectives .................................................................................. 3-57
Summary of Groundwater Remediation Goals and Treatment Standards ........... .4-6
Groundwater Response Actions and Remedial Technologies ............................. 5-3
Initial Screening of Technologies and Process Options ...................................... 5-6
Technologies and Process Options Passing Initial Screening ............................ 5-13
Evaluation of Process Options ......................................................................... 5-15
Costs for Alternative 1 -No Action .................................................................. 7-6
Costs for Alternative 2-Institutional Controls ................................................. 7-12
Parameters Used for BIOSCREEN Model... .................................................... 7-21
Comparison of Measured Well Concentrations with First Order Decay Models
for TCE .......................................................................................................... 7-28
Comparison of Measured Well Concentrations with First Order Decay Models7-31
Capital Costs for Alternative 3 -Reduction of Groundwater Exposure ............ 7-35
Present Worth Costs for Alternative 3 -Reduction of Groundwater Exposure 7-36
Estimate of Capital Costs for Alternative 4, Reduction of Groundwater
Exposure and Groundwater Treatment ............................................................ 7-40
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table
Table 7-9
Table 8-1
Table 8-2
Feasibility Study Report
Davis Park Road TCE Site
Section: Table of Contents
Revision: 1
Date: July 1998
TABLE OF CONTENTS (Continued)
LIST OF TABLES (Continued)
Title
Estimate of Annual Operating and Maintenance Costs for Alternative 4,
Page
Reduction of Groundwater Exposure and Groundwater Treatment.. ................ 7-41
Summary of Non-Cost Comparison of Remedial Alternatives ............................ 8-2
Summary of Cost Comparison of Remedial Alternatives .................................... 8-8
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
EXECUTIVE SUMMARY
Feasibility Study Report
Davis Park Road TCE Site
Section: Executive Summary
Revision: 1
Date: July 1998
This Feasibility Study (FS) report for the Davis Park Road TCE site has been prepared by Roy F.
Weston, Inc., (WESTON<!>) for the U.S. Environmental Protection Agency (EPA) under Work
Assignment No. 71-4LPN of Contract No. 68-W9-0057, in accordance with the Revision I
Remedial Investigation/Feasibility Study (RI/FS) Project Assistance Work Plan prepared by
WESTON dated October I 997. The purpose of this report is to address the groundwater
contaminant plume caused by the release of volatile organic compounds (VOCs) from the
suspected source area -the Davis Park Auto Repair facility.
The Davis Park Road site is located in Gastonia, Gaston County, North Carolina. The suspected
source area has been occupied by various industries; however, the principal operation in the
building at 2307 Davis Park Road has been the repair and reconditioning of automobiles. At some
point in the operating history of the suspected source area, chlorinated solvents were released to
the environment. Reportedly, the release is a result of dumping parts cleaner into a drain within
the building that led to a drainpipe, which exited the rear of the building. The drainpipe emptied
onto the ground surface. Several field investigations have taken place at the site as a result of the
discovery of chlorinated solvents, principally trichloroethene (TCE) and tetrachloroethene (PCE),
in residential water supply wells. Based on soil and groundwater samples collected around the
property at 2307 Davis Park Road (currently known as the Davis Park Auto Repair facility), this
site has been suspected as the source area; however, this has not been confirmed due to the lack
of TCE and PCE and/or degradation products in recent soil and groundwater samples collected
adjacent to the facility. Currently, TCE and PCE are contaminants of concern in the bedrock
aquifer based on observed concentrations greater than the federal and State MCLs in bedrock
aquifer groundwater samples. Methyl-tert-butyl-ether (MTBE) is a contaminant of concern in the
NORJK:\WP\04400\071 \FSDDN001. DOC ES-I
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: Executive Summary
Revision: 1
Date: July 1998
overburden aquifer based on observed concentrations greater than State MCLs in overburden
aquifer groundwater samples. For the purposes of this FS, the contaminants of concern at the
Davis Park Road site are TCE and PCE.
WESTON has reviewed the applicability of several technologies for potential remediation and for
supplying alternative sources of water to the affected residents. The technologies were evaluated
based on their effectiveness, implementability, and relative cost, and the most viable were retained
for development of remedial alternatives. Since residents in the site area are currently using
contaminated groundwater as their water supply within the site area, the most efficient method of
removing the immediate threat would be to connect all current users of groundwater to the City
of Gastonia public water supply system. However, because the site area is not currently within the
Gastonia City Limits, resistance from some property owners is expected. Therefore, WESTON
has reviewed available technologies to find the most non-intrusive, yet immediately effective
remedies. Alternatives evaluated in addition to connection to the city water system include
treatment of groundwater at the residential wellhead, in-situ groundwater treatment, pump and
treatment of groundwater, and/or examination of natural attenuation processes.
Groundwater remediation goals have been developed and are based on applicable regulatory
standards. The groundwater treatment goals were based on the capability of technologies that are
considered to be Best Available Technology (BAT) economically achievable. For treatment of
groundwater contaminated with VOCs at the Davis Park Road site, in-situ air stripping is the
accepted BAT. Although performance expectations vary from state to state, a conservatively low
effluent criteria of I micrograms per liter was suggested for each of the contaminants of concern.
This is also the analytical method detection limit for the most widely used analytical methods.
NORJK ·\WP\04400\071 \FSDDN001 .DOC ES-2
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: Executive Summaiy
Revision: 1
Date: July 1998
The following five remedial alternatives were developed for the detailed analysis:
• Alternative 1 -No Action
• Alternative 2 -Institutional Controls
• Alternative 3 -Groundwater Exposure Abatement and Monitored Natural Attenuation
• Alternative 4 -Reduction of Groundwater Exposure in Addition to Groundwater
Treatment
• Alternative 5 -Reduction of Groundwater Exposure and Groundwater Pump and Treat
Alternative I does not address the groundwater contamination at Davis Park Road. This
alternative serves only as a baseline alternative for comparison with active remedial alternatives.
Alternative 2 is designed to prevent exposure to contaminated groundwater but does not include
measures to actively remediate groundwater. Alternative 3 also does not include measures to
remediate groundwater but does provide for removal of the threat of contaminated groundwater
from residences. This alternative also provides for the examination of natural attenuation
processes, which, as modeled within this FS, have been predicted to effectively reduce
groundwater contaminant levels below current Federal MCLs within approximately seven years.
Alternative 4 includes measures to provide alternate sources of water to residences of the Davis
Park Road site area as well as remediate the groundwater. Alternative 5 is similar to Alternative 4,
except for the inclusion of a different method of remediating groundwater.
As noted in Sections 7 and 8, the total cost for Alternative 4 is higher than Alternative 5.
Although both alternatives call for active groundwater remediation methods, the difference in
costs is a result of more expensive materials being used within the system of Alternative 4 and
higher design and construction costs.
NORIK:\WP\04400\071 \FSDDN001 . DOC ES-3
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: Executive Summary
Revision: 1
Date: July 1998
Data gaps have been identified at the Davis Park Road site. In an effort to fill these gaps, a pre-
design study has been proposed that includes installation of an additional bedrock aquifer monitor
well at the southern end of the site, and an investigation into the number of and total depth of
residential wells at the site that are installed into the bedrock aquifer, some of which have not yet
been sampled.
NOR/K:IWP\044001071 \FSDDND01. DOC ES-4
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
SECTION 1
INTRODUCTION
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
The Feasibility Study report for the Davis Park Road TCE site has been prepared by Roy F.
Weston, Inc., (WESTON,) for the U.S. Environmental Protection Agency (EPA) under Work
Assignment No. 71-4LPN of Contract No. 68-W9-0057, in accordance with the Revision 1
Remedial Investigation/Feasibility Study (RI/FS) Project Assistance Work Plan, prepared by
WESTON in October 1997. This document conforms to the requirements of the National
Contingency Plan (NCP) as amended by the Superfund Amendment and Reauthorization Act of I 1986 (SARA) and "EPA Guidance for Conducting Remedial Investigations and Feasibility Studies
Under CERCLA, Interim Final" (October 1988).
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In October 1997, WESTON was assigned the responsibility of completing an RI/FS to define the
source and areal extent of migration of contaminants underlying the Davis Park Road site, under
the U.S. EPA Region IV Alternative Remedial Contract Strategy (ARCS) contract. The results of
the RI activities conducted at the site are contained in the Final RI report submitted to EPA in
May 1998. This FS is based on the results of the RI.
1.1 PURPOSE OF THIS REPORT
The purpose of this report is to address the remediation of the groundwater contaminant plume
caused by the release of VO Cs from activities at the suspected source area, the Davis Park Auto
Repair facility.
NOR/K:\WP\04400\071 \FSDDN001. DOC 1-1
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
1.2 SITE INFORMATION
This section describes the site location and the site history.
1.2.1 Site Location and History
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
The Davis Park Road TCE site is located within the Gastonia Extra Territorial Jurisdiction area
along Davis Park Road, south of Hudson Boulevard and north of Blackwood Creek in the
southwestern portion of Gastonia, Gaston County, North Carolina. The site consists of an area of
reportedly contaminated soil behind a building that is occupied by the Davis Park Auto Repair
shop (formerly known as Moore's Transmission Shop) at 2307 Davis Park Road, and a plume of
contaminated groundwater that emanates from this property and extends south along Davis Park
Road to Blackwood Creek. The site also includes the Cedar Oak Park Subdivision located on the
east side of Davis Park Road within the confines of Cedar Oak Circle as well as areas along the
western side of Davis Park Road. The Davis Park Road TCE site is located at latitude 35° 13' 56"
N and longitude 8 IO 13' 08" W on the Gastonia South, North Carolina United States Geological
Survey (USGS) Quadrangle Map. Figure 1-1 presents a site map for the Davis Park Road TCE
site. Figure 1-2 is a topographic map of the site vicinity.
The site, situated on approximately 20 acres, includes private businesses and residential homes. I The topography of the area is slightly sloped to the west toward Crowders Creek and to the east
and south towards Blackwood Creek. Both creeks are receiving streams for groundwater in this I area. One potential source of the contaminated groundwater is an area of formerly contaminated
soil located behind the Davis Park Auto Repair shop in the vicinity of a drain line that exited the I service bay in the facility.
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FIGURE 1-1
SITE MAP
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0 " " □
0
e
DAVIS PARK ROAD TCE SITE
GASTONIA, NORTH CAROLINA
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•
□
□
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0 8 ,!J
0
0
CJ
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GASlONIA CITY l .... TS
El El
RICHLAND AVENUE
0
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Approximate
Scale In Feet
600
---
1200
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PROJECT nnE:
DAVIS PARK ROAD SITE
GASTON COUNlY, NORTH CAROLINA
SITE TOPOGRAPHIC MAP
FIGURE 1-2
LEGEND
TOPOGRN'HIC CONTOUR INTERVALS .. 5 FEET
♦ 1NEll LOCATIONS (APPROXIMATE) • -RESIDENCE
-700-INDEX CONTOUR
DRAWN: DA TE:
M. SNEED 5/18/98
CHECKED: DATE: APPROVED:
W.O.NO.:
04400--071--095
CAD FILE NAME:
TOPOMAP.DWG
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
The property and building at 2307 Davis Park Road has been owned by Carl Bell (now deceased)
and Douglas Bell of Gastonia and Charlotte, respectively, since 1960. Carl Bell leased the
property to Acme Petroleum and Fuel Company (ACME) of Gastonia in 1966. ACME held this
lease until 1981. During the lease period, the property was subleased to various service station
and transmission repair shops. Also during this lease-hold, ACME installed service bays, a drain
and drainpipe, and, reportedly, a partially aboveground storage tank to hold liquids poured down
the drain. Subsequent lease holders have contested the existence of the tank.
According to a July 1992 document from the State of North Carolina Department of Justice, the
history of subleasing of the property at 2307 Davis Park Road by ACME and of lessee
housekeeping practices is as follows:
• In 1966, ACME subleased the property to Mr. Bryson Welch of Gastonia for a period of
ten (I 0) years. Mr. Welch has admitted pouring crankcase oil down the drain, but denies
any solvent release. Mr. Welch has produced several workers who, during deposition,
stated that no tank was ever installed in back of the station.
• Mr. Reeves McAllister subleased the site from 1976 to 1978. No further information is
available concerning his tenancy. Attempts to locate Mr. McAllister by North Carolina
Department of Environment, Health, and Natural Resources (NCDEHNR) employees
have not been successful.
• Mr. James Clark subleased the site from 1978 to 1980, during which time he operated a
transmission shop. Mr. Clark indicated that oil was on the ground in back of the station in
1978 when he subleased the facility.
• Mr. Roy Moore of Gastonia subleased the site from ACME from 1980 to 1981. From
1981 to approximately 1996, Mr. Moore leased the property directly from the estate of
Carl Bell. Although there is no direct evidence of a release of chlorinated solvents during
Mr. Moore's tenancy, he has been cited for kerosene spills at the site and has admitted
dumping water from a parts cleaner on the ground.
NOR/K:\WP\04400\071 \FSDON001.DOC 1-5
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Sile
Section:·1
Revision: 1
Date: July 1998
During a March 1995 preliminary industrial survey of the Davis Park Road TCE site conducted by
EPA, City of Gastonia records were consulted to identify businesses operating from 2307 Davis
Park Road -the site of Davis Park Auto Repair. Accordingly, the following dates of operation
and names of businesses were found:
1956tol957
1958
1959 to 1960
1961 to 1965
1965 to 1970
1971 to 1972
1973 to 1975
1976 to 1979
1980 to 1982
1983 to 1987
1988 to 1996
(approx.)
No business located on this property.
Burch's Grocery
Johnny's Food Store/John A. Kersey
Gastonia Food-O-Mart
Davis Park Suprette
Davis Park Suprette and Tim's Sports Cars (used cars)
Davis Park Shell Station, Davis Park Suprette, and Tim's Sports
Cars
Davis Park Shell Station and Davis Park Suprette
Clark's Transmission and Wrecker Service
Moore's Transmission and General Mechanics
Moore's Automatic Transmission and General Mechanics
Recently (late 1996 or early 1997), the name of the business on the building at 2307 Davis Park
Road was changed to the Davis Park Auto Repair.
The results of the investigation conducted by the Superfund Section of the North Carolina
Department of Environment, Health, and Natural Resources (NCDEHNR) confirmed that at some
NOR/K:\WP\04400\071\FSDDN001.00C 1-6
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
time during the operation of the site as a service station or transmission and auto repair facility,
tetrachloroethene (PCE) and possibly trichloroethene (TCE) were released through a drain line
installed in the service bay area of the building. According to NCDEHNR, these contaminants
were detected on site in the soil around the drain pipe that exited the Moore's facility, and may
have migrated into the groundwater. PCE and TCE have been detected in groundwater sampled
from a community well and several private wells in the site vicinity at levels above the Maximum
Contaminant Levels (MCLs) established by the State of North Carolina and the U. S. EPA.
1.3 SITE INVESTIGATIONS
This section provides background information regarding previous investigations, including the RI.
1.3.1 Previous Investigations
To date, three investigations have been conducted at the Davis Park Road site:
• Phase I Site Screening Investigation, Greenhorne & O'Mara, Inc., for the NCDEHNR,
October 1992;
• Site Inspection Addendum, NCDEHNR, May I 993;
• Expanded Site Investigation (ES!), NCDEHNR May 1994.
1.3.1.1 Phase I Site Screening Investigation, October 1992
The Phase I Site Screening Investigation prepared by Greenhorne & O'Mara, Inc. in October
1992 included a review of EPA and State file material regarding permits and regulatory history for
the site, a summary of analytical data available from previous sampling activities for the site and
site vicinity, and an investigation of observed or reported releases at the site or in the site vicinity.
NOR/K:\WP\04400\071 \FSDDN001. DOC 1-7
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Dale: July 1998
The Site Screening Investigation (SSI) report summarizes the site history with respect to alleged
on-site releases and suspected sources for contamination.
According to the SSI report, on March 3 I, 1990, a groundwater sample was collected by Gaston
County Environmental Health representatives from a supply well within the Cedar Oak Park
subdivision as part of a routine sampling procedure in accordance with "Community Well Rules."
Analysis of the sample revealed concentrations of TCE (34.9 micrograms per liter [µg/L]), PCE
(23.7 µg/L), and chloroform (9.2 µg/L). A confirmation sample was collected from this well on
April I 7, I 990, and analytical results were similar to the original sample. Groundwater samples
subsequently collected from three nearby private wells by the Gaston County Health Department
before May I 990 indicated that the groundwater was contaminated with TCE. The highest
concentration of TCE (101.4 µg/L) was detected in a sample collected from the private well
located at 2419 Davis Park Rd., 200 feet south of Moore's Transmission Shop. The current EPA
Drinking Water Maximum Contaminant Levels (MCLs) for TCE and PCE are 5 µg/L. Current
NCDEHNR MCLs for TCE and PCE are 2.8 µg/L and 0.7 µg/L, respectively.
Groundwater samples were collected from the contaminated wells along Davis Park Road and
within the Cedar Oak Park subdivision by the Environmental Services Division of EPA on July 6,
1990. TCE was detected at concentrations of 82 and 81 µg/L in groundwater sampled from the
private well located at 2419 Davis Park Rd. and Cedar Oak Park subdivision wells, respectively.
In July I 990, a site inspection of the Davis Park Auto Repair location was conducted by staff
from the Groundwater Section of the North Carolina Department of Environmental Management
(NCDEM) (Mooresville Regional Office) and the Gaston County Health Department. During the
inspection, Mr. Roy Moore, manager of the transmission shop, stated that the type of work
performed at the facility consisted of the repair and restoration of automobile transmissions only.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
Mr. Moore stated that he did not use solvents in the parts cleaning process. Waste transmission
fluid and oil were stored in 55-gallon metal drums, which were staged on asphalt in the front part
of the property. The waste material was recycled and used for heating the building in the winter.
Mr. Moore knew nothing of the facility when it was a service station.
On February 18, 1991, the underground storage tanks (USTs) at Moore's Transmission and Auto
Repair Shop were removed by ACME Petroleum, Inc. of Gastonia. At the time of removal, one
tank was reported to have 5 to 7 inches of product and the other 3 to 4 inches of product. The
product reportedly had a paint thinner-like odor. Upon removal of the tank, soils in the vicinity of
the tanks were tested for contamination. Results showed no contamination present in the soils in
this area.
According to the SSI report, during the removal of the USTs, a NCDEM representative
discovered a drainpipe exiting the building. The representative collected one soil sample "at the
pipe's discharge point." The sample was analyzed for VOC content and revealed concentrations
ofTCE and PCE at 700 micrograms per kilogram (µg/kg) and 3,000 µg/kg, respectively.
1.3.1.1.1 Hazard Ranking System (HRS) Score, January 1993
The Hazard Ranking System (HRS) score is a numerically based screening system used by the
EPA to assess the relative threat associated with actual or potential releases of hazardous
substances to groundwater, surface water, soil, and air based on information from initial limited
investigations, such as preliminary assessments and site inspections. Sites are scored by assigning
numerical values to factors that relate to risk-based conditions at the site. After scores are ii calculated, they are combined using a root-mean-square equation to determine the overall site
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I NOR/K:IWP\04400\071 \FSDDN001.00C 1-9
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
score. Sites are then rated as high, intermediate, or low priority. An "A" rating indicates high
priority; "B" indicates intermediate priority; and "C," "D," or "E" indicate low priority sites.
Based on the Hazard Ranking System analysis, and with the approval of the State of North
Carolina, the Davis Park Road TCE site will be proposed for inclusion on the NPL.
1.3.1.2 Site Inspection Addendum, May 1993
At EPA's request, a Site Inspection Addendum (SIA) report to the Phase ISSI was prepared by
NCDEHNR to address items considered to be omitted from the original report. Additional
sampling data was presented along with information concerning potential sources of
contamination other than Moore's Transmission and Auto Repair Shop.
From May 1990 to August 1992, NCDEM and the Gaston County Environmental Health
Department sampled 22 private wells in the vicinity of the site. Fourteen of the samples contained
a detectable amount of either TCE or PCE or both. Also during this period, several soil samples
were collected from behind the Moore's operation adjacent to the drain line that exited the rear of
the building. The samples were found to be contaminated with PCE and two breakdown products
of this compound, TCE and cis-1,2 Dichloroethene (DCE). The drain line was reportedly installed
when ACME Petroleum installed service bays in the shop portion of the service station. Table I of
the SIA report details the levels of VOCs detected in soil and groundwater samples.
Potential sources of contamination other than the Davis Park Auto Repair location, as identified
within the SIA report, include the Homelite Division of Textron, Inc. plant located southeast of
the site, and the New Haven Drive TCE site located south of the site. According to the report,
however, the shortest distance from known contamination at the Homelite site to the closest
contaminated well on the Davis Park Road TCE site is 1.325 miles, groundwater flow direction is
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
to the southeast away from the Davis Park Road TCE site, and an uncontaminated well is located
between these two areas. Based on these data, the SIA report concluded that the Homelite plant
is not a potential source of contamination for the Davis Park Road TCE site. Additionally, several
uncontaminated wells were located between the New Haven Drive TCE site and the Davis Park
Road TCE site, and groundwater flow direction was to the west, away from the Davis Park Road
TCE site. The SIA report concluded, therefore, that the New Haven Drive TCE site was also not
a potential source of the contamination for the Davis Park Road site.
1.3.1.3 Expanded Site Investigation (ESI), May 1994
The May 1994 ES!, prepared by NCDEHNR, included results from soil and groundwater
sampling conducted to establish private and community well contamination using EPA Contract
Laboratory Program (CLP) protocols. Five of the closest private and community wells that had
shown contamination during previous investigations, were resampled. Analytical data confirmed a
release of hazardous contaminants to the groundwater and the contamination of private wells and
a community well above state and federal MCLs using US EPA CLP protocol.
Soil samples collected within a two-foot circumference of the drainpipe that exited the Davis Park
Auto Repair building contained TCE at levels between 3 8 micrograms per kilogram (µg/kg) and
260 µg/kg and 1,2-DCE at levels between 4 and 20 µg/kg. In addition, petroleum-type
compounds (toluene, ethylbenzene, total xylenes) were detected in the soil samples.
Based on VOC concentrations and information from previous investigations, the Superfund
Section of NCDEHNR reported that the site did not pose a significant threat to human health and
the environment via surface water, air, or soil pathways.
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This document was prepared by Roy f. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
Based on data collected during the ES! and previous investigations, NCDEHNR concluded that at
some time during the operation of the site as a service station or transmission and auto repair
facility, PCE and/or TCE was released through a drain line installed in the service bay area of the
building, and had migrated into the groundwater. The Superfund Section of NCDEHNR
recommended within the ES! that the Davis Park Road TCE site proceed with the preparation of
a Hazard Ranking System package for inclusion of this site on the National Priorities List.
1.3.2 Remedial Investigation Conducted by EPA and WESTON
The objectives of the RI conducted at the Davis Park Road site were to identify the source and
extent of groundwater contamination, the pathways of possible migration or releases to the
environment related to groundwater contamination, and the extent of potential human or other
environmental exposure to groundwater contamination. To meet the objectives of the RI, EPA
and WESTON developed and executed a multi-task field program. The tasks included:
• Conducting an existing water supply well inventory and creation of a property owner list
spreadsheet;
• Completion of a fracture trace survey for the site and surrounding areas;
• Review of public records to determine potential sources of the groundwater
contamination;
• Collection of soil samples at points within and surrounding the Davis Park Auto Repair
facility;
• Collection of groundwater samples from private residential supply wells;
• Installing temporary monitor wells in the overburden aquifer;
• Installing and surveying monitor wells in the overburden and bedrock aquifers underlying
the site;
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This document was prepared by Roy F. Weston, lnc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
• Converting and surveying of former residential supply wells into monitor wells;
• Collecting and analyzing groundwater samples and obtaining water level measurements
from the shallow and deep monitoring wells, and converted monitor wells;
• Collecting surface water samples to determine potential contaminant discharge to local
streams;
• Conducting geophysical borehole logging in six bedrock aquifer monitor wells;
• Conducting aquifer testing in overburden and bedrock aquifer monitor wells.
The results of the RJ were submitted to EPA in May 1998.
1.4 PHYSICAL CHARACTERISTICS OF THE STUDY AREA
This section provides background information regarding:
• Surface features;
• Meteorology;
• Surface water hydrology;
• Geology;
• Soils;
• Hydrogeology;
• Demography and land use;
• Ecology.
1.4. l Surface Features
Gaston County and the Gastonia area, including the Davis Park Road TCE site, lie within the
Piedmont Physiographic Province. The land surface is composed of low, broad ridges accentuated
by numerous small stream valleys. In general, the topographic changes are gradual, except for
NORJK·\WP\04400\071 \FSDDN001.DOC 1-13
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
occasional steep-sided stream valleys. The average elevation in Gastonia is 825 feet above sea
level.
The elevation at the Davis Park Road site ranges from 675 feet above sea level at Blackwood
Creek to 770 feet above sea level at the Davis Park Auto Repair shop. The Davis Park Auto
Repair shop is located approximately 2,550 feet north of Blackwood Creek. Elevations decline
gradually to the southeast, south, southwest, and west of this location. Figure 1-2 provides a
topographic map view of this area.
The suspected source area, the Davis Park Auto Repair location, is bounded by Davis Park Road
to the east, and by private residences to the north and south. The western portion of the Davis
Park Auto Repair location is bounded by vacant lots. The area surrounding the building is paved
on the eastern and southern portions. The western portion of the site is covered by areas of
grasses, weeds and trees intermixed with the discarded equipment from the current (and possibly
former) commercial operations at the facility. The northern portion of the suspected source area is
covered by grasses and trees. The distance from the building to the residential property north of
the building is approximately fifteen feet.
1.4,2 Meteorology
Meteorological information for Gaston County is based on data collected from the
Charlotte/Douglas International Airport located in Charlotte, North Carolina approximately 15
miles east of Gastonia. Similar meteorological conditions to those reported for the Charlotte area
can be expected in the vicinity of the Davis Park Road TCE site. Meteorological data for the I station is published in an annual summary by the National Oceanic and Atmospheric
Administration.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA. :
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Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Dale: July 1998
The climate in Charlotte, North Carolina area is moderate, characterized by cool winters and
warm summers. Rainfall is typically evenly distributed throughout the year. Snow is infrequent,
and appreciable accumulation is rare. The average freeze-free period for the area is 216 days.
Total precipitation at the Charlotte/Douglas International Airport was 40.15 inches in 1996 (the
most recent annual survey available). The largest amount of precipitation in 1996 fell in August,
while the driest month in 1996 was May (2. l 3 inches total precipitation). The mean number of
days per year with precipitation greater than 0.01 inches for 1996 was 110.9. The mean number of
days per year with precipitation greater than 1.0 inches for 1996 was I 1.3. Total annual
precipitation from 1990 through 1996 was between 35.81 (1993) and 53.73 (1992).
The average temperature in Charlotte, North Carolin~, in 1996 was 60 degrees Fahrenheit (°F).
The average monthly temperatures ranged from 39.3 °Fin January to 78.9 °Fin July. The coldest
temperature in 1996 was 7 °F in February and the hottest temperature in 1996 was 95 °F in July.
Temperatures between 32 °F and 90 °F were recorded on 266 days of the year, and below 32 °F
were recorded on 67 days. Since 1990, the average temperature per year was between 60 °F in
1996 and 64 °Fin 1990.
Snowfall greater than 1.0 inches was recorded on only one day in 1996. Since 1990, the average
snowfall was between trace precipitation (1991-92; 1995-96) and 3.0 inches (1996). Heavy fog
was recorded on 27 days. Thunderstorms were recorded on 47 days during 1996. At the
Charlotte/Douglas airport, prevailing wind speed for 1996 was 1.1 miles per hour (mph), with
maximum gusts reaching 68 mph to the northwest.
The site can be expected to expenence similar meteorological conditions to those previously
described. There are no site-specific meteorological data available.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall nofbe disclosed, in whole or in part, without the express
written permission of EPA.
1.4.3 Surface Water Hydrology
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
Gaston County is drained by various streams and creeks that flow south, southeast, and east
towards Lake Wylie. Crowders Creek is a major drainage area for the southern portion of the city
of Gastonia. Crowders Creek flows south southeast into South Carolina, and approximately 15
miles downstream from that point into Lake Wylie.
According to the Preliminary R1 report, dated September 1996, Crowders Creek is not used for
recreational purposes except for very limited bridge fishing several miles downstream of the site.
As Crowders Creek nears Lake Wylie, however, recreational activities include fishing, canoeing,
and swimming. Crowders Creek has been designated as suitable for Class C uses, which includes
fishing and wildlife propagation, secondary recreation, and agriculture. No public water supply
surface water intakes are located within 15 miles of the Davis Park Road site.
Surface runoff from the Davis Park Road site flows overland into ditches and/or culverts on the
edges of the various roads that cross the site or into small streams within the numerous residential
properties located throughout the site. Overland flow travels either south southeast towards
Blackwood Creek (a tributary to Crowders Creek) or west southwest into smaller, unnamed
streams and eventually into Crowders Creek. The distance from the suspected source area to
Crowders Creek is approximately 3,500 feet. The change in elevation over this horizontal distance I is approximately 110 feet. According to the Preliminary Remedial Investigation report (September
1996), the change in slope over the terrain from suspected source area to Crowders Creek is I estimated at 3. 7 percent (Preliminary RJ, September 1996).
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
1.4.4 Geology
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
According to the 1988 Geologic Map of the Charlotte IO x 2° Quadrangle, the Davis Park Road
site is directly underlain by the Pennsylvanian Age High Shoals Granite Formation. This formation
is described as being very light gray, coarse-grained, porphyritic, well foliated, commonly
gneissoid biotite granite. This formation has been zircon age dated at 317 million years old
(Horton and Stern, 1983), and may be cogenitic with the Churchland Pluton, which lies to the
northeast of the site and underlies the northern portion of the City of Gastonia.
The High Shoals Granite and Churchland Plutonic Suite are labeled as the High Shoals Pluton by
Goldsmith et al., 1988. The High Shoals Pluton is a linear shaped body of granitic material that
trends northeast-southwest. The High Shoals Pluton is surrounded by quartz sericite schists and
metavolcanic rocks of the Battleground Formation. In the Gastonia area, the pluton is bordered
on the west by the South Fork Antiform and on the east by the Boogertown Shear Zone. Flow
foliation in these rocks is either vertical or is greater on average than 75°, and typically trends
northeast to southwest. The High Shoals Pluton is considered to have originated after a regional
metamorphic phase in the Late Paleozoic Age.
Geology underlying the Davis Park Road site is described based on data generated from monitor
well installations and the soil boring adjacent to the Davis Park Auto Repair location. Figure 1-3
presents a cross section base map, and Figures 1-3A and l-3B show the cross sectional views of
the site. Geologic data from the soil borings for the monitor wells extend to the top of the
bedrock zone, as determined by the drilling equipment used for the RI work. The average
maximum depth to the top of bedrock is approximately 80 feet below ground surface (bgs).
NOR/K ·\WP\04400\071 IF SDDN001 . DOC 1-17
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6)
CW-2 A MW lO
t.lW JS$
DAVIS PARK
AUTO REPAIR
r w w "' r u,
0 0 0 3' " z ii'
~ u,
>-z z w
N ,. 546,704.186'
E ,. 1,3.37,678.168'
ELEV .• no.1,f
GLENRAVEN AVENUE
C AR OAK CIRCLE
-·
MW-556) /
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MW-15 $ B'
MW-10
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\ MW-2S
MW-20
((
\ -1--
LEGEND
lw!W-1 S MONITOR WELL LOCATIONS
' CROSS-SECTION A-A
B-B 'CROSS-SECTION
COMBINED FACTOR = 0.9998411 (NAD 83)
POINT NORTI-1ING EASTING
100 545544.652 1338740.388
101 545495.204 1338846.893
102 545674.010 1338358. 61 0
103 544827.129" 1338881.108
104 544846.945 1338868.067
105 544510.539 1338455.456
106 544881.886 1338621.461
107 545319.342 1337914.911
108 546610.771 1337145.070
109 546676.623 1337132. 994
110 546139.528 1338513.369
111 545175.589 1337035.677
112 546474.476 1337682.514
113 546568.657 1337641.640
141 546888.586 1337295. 709
128 546827.885 1336850. 318 129 547139.622 1336707.806
136 546854.891 1337483.389
137 546857.745 1337485.094
ELEVATION ELEVATION ELEVATION
TOP PIPE TOP PLATE GROUND
688.27 MW-1S 688.85 688.85
687.50 MW-1D 687.80 687.81
707.21 CW-5 706.61
684.60 MW-2D 684.89 684.88
684.60 MW-2S 685.04 684.99
677.26 MW-5S 677.52 677.52
687.57 PW-1 686.15
716.12 MW-4S 716.65 716.68
743.74 MW-3S 744.42 744.37
746.29 MW-30 746.75 746.75
705.76 CW-6 705.21
739.97 MW-4D 740.44 740.45
764.35 PW-2 764.09
768.75 CW-4 766.78 761.18 CW-3 761.41 761.41 757.79 CW-2 758.62 758.59 761.69 CW-1 760.88 771.21 EMW-1 771.19 769.78 771.86 EMW-2 773.00 770.22
BENCH MARK USED WAS Tl-1E CITY OF GASTONIA BENCH MARK, QUADRANT 3, BENCH MARK
No. 41, LOCATED AT Tl-1E INTERSECTION OF DA"1S PARK ROAD AND STAGE COACH ROAD.
ELEVATION = 731.05'
--eLAC;--WOOo cREEK
PROJECT TITLE1
DAVIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
GEOLOGICAL CROSS-SECTION BASE MAP DRA\JN1 DATE• DATE1 \J.0, N0,1
I M. SNEED 3 16 04400-071-095
' CHECKED1 DATE• APPROVED1 ATE• CAD FILE NAME,
L---------------------------------------------1---------F-IG_U_R_E_l _-_3 ________ __.L....----....JL.----L-------L-----'-,:;:C:.:,R:;:.0;:.SS;:.E:;,;C::..T:.:.·::.DW=G_,
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NORTHEAST
A
750-
FOR MSL
700-
650-
600-
0 U1 nn
I I 3 3
2 2 GRou
VERTICAL EXAGGERATION 1 OX
S □UTH\.JEST
A'
U1
~ 0 I ~ CJ1(f)O 3 t{)NN
PROJECT TITLE1
I I I 333
679.60
669.60
·A.ccJ-663.60
DAVIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
GEOLOGICAL CROSS-SECTION A TO A'
LEGEND
SAPROLITE/PARTIALLY WEATHERED ROCK: D SANDY CLAY
~ SANDY SLIT/SILTY SAND
l\_:I SILTY SAND WITH GRAVEL
BEDROCK
GRANITIC GNEISS
TOP OF BEDROCK WELLS
~ SCREEN ELEVATION IN FEET MSL
-679.60 TOP OF SCREEN
-669.60 BOTTOM OF SCREEN
BEDROCK WELLS
~-663.60 BOTTOM
~-630.60 BOTTOM
OF CASING
OF BOREHOLE
l'. WATER LEVEL ELEVATION FEET MSL
-·-·-·-·-·-·-WATER TABLE SURFACE
........ •POTENTIOMETRIC SURFACE
BEDROCK WELLS
DRA\JN1 DATE• DATE1 IJ.O. N□.,
M. SNEED 3 16 04400-071-095 II CHECKED• DAT£, APPROVED, ATE, CAD FILE NAME•
IJ L-----------------------------------'--------FI_G_uR_E_1-_3_A _______ ..,__ ____ .J..-__ _._ _____ ..,__ __ __,__..:;:A=_A::::..'.:.::-D:.:;W.;;G___,
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wEST EAST
B --------------------B'
0 -st
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750 -3:
2
650 -
600 -
(J)
-st
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2
VERTICAL EXAGGERATION 5X
l[)
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PROJECT TITLE•
DAVIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
GEOLOGICAL CROSS-SECTION 8 TO 8'
FIGURE 1-38
LEGEND
SAPROLITE/PARTIALLY WEATHERED ROCK:
D SANDY CLAY
[777J// ~ SILTY SAND
~ SILTY SAND WITH GRAVEL
BEDROCK
GRANITIC GNEISS
TOP OF BEDROCK WELLS
I
SCREEN ELEVATION IN FEET MSL
-668.27 TOP OF SCREEN
-658.27 BOTTOM OF SCREEN
BEDROCK WELLS
~-647.00 BOTTOM
-612.50 BOTTOM
OF CASING
OF BOREHOLE
~ WATER LEVEL ELEVATION FEET MSL
-·-·-·-WATER TABLE SURFACE
•----POTENTIOMETRIC SURF ACE
BEDROCK WELLS
DRA\JN• DATE• DES. ENG.,
M. SNEED 3 16 98
DATE, APPROVE Di ATE•
\J.0. N□.•
04400-071-095
CAD FILE NAME•
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This document was prepared by Roy F. Westoo, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
The geologic profile varied somewhat across the site during WESTON's field activities, but
generally consisted of a saprolite layer, followed by a partially weathered rock zone and the
underlying fractured crystalline bedrock. The saprolite was a silty, clay-rich, residual material
derived from in-place weathering of bedrock. Typically, the saprolite was silty clay near the
surface. With increasing depth, the amount of mica, silt, and fine-grained sand and gravel tended
to increase. Remnant fracture planes identified by quartz infilling occurred in this section of the
soil profile. The saprolite zone was observed to be thickest (approximately 80 feet) near the ridge
crest along the northern edge of the site, thinning towards the lower elevations or stream valleys
to approximately 20 feet in thickness.
Underlying the saprolite is a partially weathered rock layer derived from the weathering of
bedrock, that ranges in thickness from approximately 5 to 25 feet This layer is composed of
saprolite and fragments of weathered bedrock. Particle sizes in this zone range from silts and clays
to large boulders of unweathered bedrock. The weathering typically occurs in bedrock zones less
resistant to physical and chemical degradation (i.e., fault zones, stress relief fractures, and
mineralogic zones).
The predominant rock type observed by WESTON, based on rock samples obtained during
bedrock monitor well drilling is a metamorphosed brownish-grey to light grey, quartz biotite
granite or granitic gneiss. The bedrock appears fractured These fractures contain quartz stringers
that remain unweathered in the overlying saprolite.
1.4.4.1 Fracture Trace Survey Results
Figure 1-4 presents the photolineations identified during the examination of aerial photographs
and topographic maps of the site. The azimuths of fracture traces shown on Figure 1-4 were
NOR/K:\WP\04400\071 \FSDDN001. DOC 1-21
.~, ct~~w-L=~,\~~~~~(JJ«;IB£~~3<~ .. '-"'1Y.~~,,..~-~
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FIGURE 1-4
FRACTURE TRACE SURVEY
AUGUST 1997
DAVIS PARK ROAD TCE SITE
-••■WESTON Survey (1997)
---EPA Survey (1991)
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
plotted on a rose diagram to assess the preferred orientations for fracture traces in the site area
(Figure l-5). The azimuths of the traces were measured and tallied for each 20° arc of the
compass. The total number of traces for each arc is represented by the distance of the shading
from the center of the circle.
In order to confirm the orientations of the photolineations, WESTON personnel located and
walked the features to identify whether each feature was cultural (man-made) or natural. All
photolineations found on Figure l-4 were found to be natural features. As shown in Figure l-5,
two general sets of fractures are dominant, based on the greatest number of traces observed. The
primary set trends N20°E to N30°E, and the secondary set trends N20°W to N20°E.
During this field review, WESTON also measured the orientations of fracture planes found in
rock outcroppings along Blackwood Creek in order to provide additional verification of the
photolineations. Table 1-l presents the azimuth orientations of field data collected by WESTON.
The data were plotted on a rose diagram (Figure 1-6) to assess the preferred orientations. The
rose diagram of Figure 1-6 indicates that the dominant orientation is between N20°E and N30°E.
The photolineations and the field data appear to be in agreement for the general trend of fracture
planes across the site.
I.4.4.2 Downhole Geophysical Testing Results
Six monitor wells (EMW-l, MW-ID, -2D, -3D, and -4D, and converted monitor well CW-5)
were examined as a part of the geophysical logging portion of the I 997/ I 998 field investigation.
Within each well, potential water-producing (or hydraulically active) fracture zones were
identified based on prominent anomalies (marked deviations from a predictably patterned
background) detected with a logging suite, including acoustic televiewer, gamma ray, sonic
NOR/K: IWP\04400\071 \FSODNOO 1. DOC l-23
-- -- ------- - --
Colculot1on Method
Closs Interval
FI I ter Ing
M1n1mum Azimuth
Maximum Azimuth
Doto Type
Rotation /\mount
Population
Maximum Percentage
Mean Percentage
Standard Oev1ot1on
Vector Mean
Confidence Interval
R-mog
- -
Frequency
lD Degrees
Activated
DD Degrees
]E,0 D Degrees
B1d1rect1onol
0 0 Degrees
125
12 7 Percent
5 'l Percent
2 'l"l Percent
58 3'1 Degrees
118 08 Degrees
DOE,
NOTE: NUMBER OF FRACTURE TRACES WITHIN A 10 • ARC
- --
~ t--------------------------------------r--------------------------1.
FIGURE 1-5
ROSE DIAGRAM FROM PHOTOLINEATIONS
1
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I DAVIS PARK ROAD TCE SITE I
GASTONIA, NORTH CAROLINA W. o. NO. rtNG. NO.
'--------------------------------------L-_..;;0::,4;:::40::_:0::...-0::..:7..:.l..::-0:.::.9::.5 ______ L_..:.F.:.clG::...3::...-.:.:4·c:::C:::D.:.:Rc__ ____ _j.,
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
K:\WP\04400\071\Fs-tbls Table 1-1
Table 1-1
Azimuth Orientations, Field Data
(Fracture Planes in Local Bedrock)
Davis Park Road TCE Site
May 1998
Location
East of Davis Park
Road; north
oriented section
of Blackwood
Creek
East of Davis Park
Road: east-west
oriented section of
Blackwood Creek
Notes:
N = North
E = East
S = South
W = West
NE = Northeast
Orientation and Dip and
Strike Direction Dip Direction
{de~rees) (de~rees)
N7E 90
NI0E
N60E
Nl2W
S53W
N52W
N22E 75NW
N66W 90
NSW 90
N85E 90
N54E 90
N89E 79NW
N3W
N34E
N30E
N35E 90
N27W 90
N4W
N4W
N47E
N50E
N27E
N24E
Nl90E
N28E
N82E
N29E
N67W
N4W
1-25
-------------------
Colculot,on Method
C·I ass Intervo I
F, lter,ng
M,n,mum Azimuth
Maximum Azimuth
Doto Type
Rotot,on /\mount
Population
Maximum Percentage
Mean Percentage
Standard Dev,ot,on
Vector Mean
Conr,dence Interval
R-rnog
Frequency
lD Degrees
/\ct,voted
DD Degrees
350 D Degrees
81d1rect1onol
DD Degrees
125
12 7 Percent
5 'l Percent
2 '1'1 Percent
58 3'1 Degrees
118 08 Degrees
D 05
NOTE: NUMBER OF FRACTURE TRACES WITHIN A 10• ARC
~ • r----------------------------------,------------------------1! • FIGURE 1-6
ROSE DIAGRAM FROM PHOTOLINEATIONS
DAVIS PARK ROAD TCE SITE
GASTONIA, NORTH CAROLINA
§
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04400-071-095 FIG3-4.CDR z
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
caliper, and temperature. These geophysical tools are discussed in Section 3.3.4 of the RJ.
Hydraulically active fractures are those that appear to be contributing water to the water column
under static well conditions and these hydraulically active fractures may potentially act as
contaminant transport pathways.
A logging suite incorporating caliper, resistivity, acoustic velocity, self potential, natural gamma,
fluid temperature, conductivity and acoustic televiewer (ATV) data as log parameters was used to
indicate water-bearing fractures in bedrock. Logs of each parameter were studied for features
which might indicate anomalies related to water-filled fractures. Temperature/conductivity, self
potential, and natural gamma logs were of limited use and showed few anomalies. Resistivity,
acoustic velocity, caliper, and the ATV provided logs with more prominent anomalies, which
appeared to be related to water-filled fractures as indicated in Table 1-2.
The fractured bedrock aquifer typical of the site region is characterized by fracture sets having
high dip angles intersecting fracture sets with medium to low dip angles. Dip angle refers to the
angle that the fracture plane makes to the horizontal plane, or, in this case, the assumed local
ground surface. Fractures with higher dip angles provide gravity induced drainage from the
overlying surface and surface soil cover. As fractures with high dip angle intersect lower angle
fractures, lateral transport occurs.
A TV data was processed to determine orientation of fractures in each borehole. Dominant
fracture orientations and frequency of occurrence of different structural trends were calculated
based on this data. Table 1-3 presents a summary of fracture sets identified from A TV logs. Low
(less than 10 degree dip) and high (between 58 and 89 degree dip) angle fracture sets were
identified in each of the observed wells, though the location of these fractures varied within each
borehole. Approximately 57 percent of the total fractures reported dipped less than IO degrees.
NOR/K:\WP\04400\071 \FSDDN001. DOC 1-27
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This document was prepared by Roy F. Weston, Inc., expressly for EPA It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Depth Range l-\noma1y
Well No. Depth (ft bgs) (ft bgs)
MW-10 0-38 0-38
38-43.8 38-39
38-42.9
39.4-43.8
40
50.6-52 50.6-51.8
52
65.6-67.5 65.6-66.8
66
66.5-67.5
69-70 69
69.3-70
MW-2D 0-20 0-20
20-33 20-33
20-22
20.5-22.2
23-23.2
29
40-44 40-44
40.5-44
43-44
43.4-43.5
MW-3D 0-83 0-83
83-100 83-100
83-85.5
84
83-88.5
87.8
89.2-90
91-97.8
92.6-94
107.8 107.8
108.1-145 109-145
109
119.2
108.1-111.5
114-114.2
117.4-117.6
119-120.5
124-127. 1
129.4-129.8
131-132
139.9-141.7
144.5-145
MW-4D 0-126 0-126
124-142 124-142
124-126
126-126.8
128.7
129.1
130-142
K:\WP\04400\071\Fs-tbls Table 1-2
Table 1-2
Sununary of Lo~ging Anomalies
Da,is Park Road TCF. Site
Gastonia, North Carolina
Elevation Log Response
(ft msl)
687.5-649.5 --
649.5-648.5 Acoustic Velocity Increase
649.5-644.6 ATV Several fractures
648.1-643.7 Caliper Increased diameter
647.5 Resistivity Decrease
636.9-635.7 Acoustic Increased travel time
635.5 Resistivity Decrease
621.9-620.7 ATV Flat and steep fractures
621.5 Resistivity Decrease
621-620 Caliper Increased diameter
618.5 Resistivity Reduced response
618.2-617.5 ATV Flat structure
684.6-664.6 --
664.6-651.6 Resistivity Decrease
664.6 Acoustic Increase travel time
664. 1-662.4 ATV Flat structure
661.6-661.4 ATV Flat structure
655.6 Acoustic Increase travel time
655.6-640.6 Resistivity Decreased response
644.1-640.6 SP Strong negative
641.6-640.6 Acoustic Increase travel time
641.2-641.1 ATV Flat structure
746.29-663.2 --
663.29-646.2 Resistivity Decreased response
663.29-660.7 Acoustic Increase travel time
662.29 Caliper Increased diameter
1663.29-657.7 ATV
658.49 Acoustic Increase travel time
t,57.09-656.2 ATV Numerous structures
1655.29-648.4 ATV
~53.69-652.2 Acoustic
638.49 ATV Flat structure
1637.29-601.2 Resistivity Numerous lows
637.29 Acoustic Increase travel time
627.09 Acoustic Increase travel time
638.19-634.7 ATV
632.29-632.0 ATV Flat structure
628.89-628.6 ATV Flat structure
627.29-625.7 ATV
622.29-619.1 ATV
616.89-616.4 ATV Flat structure
615.29-614.2 ATV
606.39-604.5 ATV Flat structure ~o 1.79-601.2 ATV Flat structure
739.97-613.9 --
1615.97-597.9 Caliper Numerous small deviations
~15.97-613.9 Acoustic Increase travel time
Fracture
1613.97-613.1 ATV
611.27 ATV Fracture
610.87 ATV Fracture
09.97-597.9 ATV Numerous small fractures
1-28
Comments
Casing
Probable water zone
Possible water zone
Probable water zone
Possible water zone
Casing
Probable water zone
Probable water zone
Contamination?
Casing
Probable water zone
Probably tight
Probable water zone
Casing
Probable productive zone
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in Whole or in part, without the express written permission of EPA.
Well No. Depth Range
(ft bgs)
CW-5 0-68
69.5
82-82.5
96.8-97
100-103.2
EMW-1 0-48
55-61
56-72.5
70-73
95.5-101
119-122
141.1
154-155
A TV = acoustic televiewer
SP = self potential
Anoma,y
Depth
(ft bgs)
0-68
69.5
82.5
82.0
96.8
97
100-103.2
100-102.5
100.6-103
0-48
55-59
57.4-60.2
57.5-59.7
57.5-59.7
56-72.5
70-73
72-73
71.2-72.8
72-72.6
95.5-101
98-100
97-100
98-99.7
119-122
121-121.7
121-122
141.1
154.2-155
154-155
154
ft bgs = feet below ground surface
ft msl = meet above mean sea level
K:\WP\04400\071\Fs-lbls Table 1-2
Table 1-2 (Continued)
Summary of Logging Anomalies
Davis Park Road TCE Site
Gastonia, North Carolina
Elevation Log Response
(ft msl)
~07.21-639.2 --
637.71 ATV Weak, flat structure
Caliper Increased diameter
624.71 Caliper
625.21 Resistivity
610.41 ATV Weak, shallow-dip structure
610.21 Caliper
bo1.21-604.o Acoustic Increase travel time
~07.21-604.7 Resistivity
~06.61-604.2 ATV Shallow-dip fractures
0 71.21-723.2 --
~16.21-712.2 Resistivity Sharp decrease
~13.81-711.0 ATV Flat fractures
t713.71-7I 1.5 Caliper Increased diameter
t713.7l-7I 1.5 Acoustic Increase travel time
~15.21-698.7 Gamma Decreased response
ro1 .21-698.2 Resistivity Sharp decrease
b99.2 l-698.2 Caliper Increased diameter
~00.01-698.4 Acoustic Increase travel time
~99.21-698.6 ATV Flat structure
~75.71-670.2 Resistivity Weak decrease
~73.21-671.2 Caliper Increased diameter
674.21-671.2 Acoustic Increase travel time
673.21-671.5 ATV Flat structures
652.21-649.2 Resistivity Slight decrease
650.21-649.5 ATV Flat fracture
~50.21-649.2 Acoustic Increase travel time
630.11 ATV Weak fracture
617.01-616.2 ATV Flat structure
017.21-616.2 Acoustic Increase travel time
617.21 Resistivity Slight decrease
1-29
Comments
Casing
Probably tight
Possible water zone
Probable water zone
Casing
Probable water
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Lithology?
Probable water
Possible water
Possible water
Probably tight
Possible water
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
Table 1-3
Summary of Fracture Sets Identified from ATV Logs
Davis Park Road TCE Site
Gastonia, North Carolina
Fracture Set Orientation Wells Observed Number of Fractures
Less than 1 O degree dip All 110
Less than 15 degree dip MW-10 19
N42-76: 58-66 SE MW-1D 36
MW-2D
MW-3D
MW-4D
N253-284: 58-89 N-NE MW-1D 17
CW-5
N347-357: 76-78 E MW-2D 11
MW-3D
EMW-1
K:IWP\04400\071 \Fs-tbls Table 1-3 1-30
Percent 01
Total Fractures
57
10
18
9
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. JI shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
Steeply dipping fracture sets accounted for 33 percent of total fractures reported. The majority of
the steep fractures dipped in an easterly direction (i.e., towards Blackwood Creek). A summary of
fracture orientations by individual well is presented in Table 1-4.
Potential water-producing zones within each well were identified based on the correlation of
multiple observed log anomalies. The majority of the interpreted water-bearing zones occurred in
borehole sections with flat dipping fractures or fracture sets. The borehole log for monitor well
EMW-1, located southwest of the Davis Park Auto Repair facility, contained the greatest number
of possible and probable water-bearing zones.
The lateral and vertical extent of hydraulically active or potentially active fractures was not
determined via this borehole logging investigation. However, when depth to fracture planes were
converted to feet above mean sea level (ft ms!) for each of the boring log suites, two potential
water producing fracture zones were identified. Table 1-5 presents the elevations of potential
water-bearing fracture zones for each borehole. One fracture zone was identified in monitor wells
EMW-1, MW-ID, MW-2D, and MW-3D between 645 and 665 ft msl. Flat fractures were I recorded in monitor wells EMW-1 and MW-2D within this fracture zone. This fracture zone
could not be observed in monitor wells CW-5 or MW-4D due to depth of well casing. A second I fracture zone was observed between 598 and 637 ft msl. This fracture zone was observed in
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monitor wells EMW-1, MW-ID, MW-3D, MW-4D, and CW-5. Monitor well MW-2D did not
extend below 629.10 ft msl. Shallow dip fractures were observed in monitor wells EMW-1, MW-
I D, MW-2D, MW-3D, and CW-5. Both shallow and steeply dipping fractures were observed in
monitor well MW-ID.
Based upon the detection of contaminants during groundwater sampling activities, the correlation
of fracture zones between select monitor wells, and the number of water-bearing shallow dipping
NORIK:\WP\044001071 IF SDDN001, DOC 1-3 I
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
Well No.
MW-1D
MW-2D
MW-3D
MW-4D
CW-5
EMW-1
K:IWP\04400\071\Fs-tbls Table 1-4
Table 1-4
Details of Fracture Orientations
D:wis Park Road TCE Site
Gastonia, North Carolina
Footage No. Fractures Bearing
34.7-54 5 N162
4 N42
3 N297
54-73 14 N210
2 N44
3 N284
20-49 17 N43
4 N76
5 N347
83-102 8 N342
15 N68
2 N349
126-143 23 N127
11 N55
67-86 14 N285
13 N271
86-110 17 N200
1 N253
53-171 28 N112
4 N357
1-32
Dip
16NE
58NW
3W
14NW
55SE
58NE
2SE
66SE
77E
7E
63SE
78E
6SW
55SE
3N
62N
5NW
89N
flat
55SE
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This document was prepared by Roy F. Weston, lnc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of
EPA.
Table 1-5
Summary of Possible and Probable Water-Bearing Zones
Davis Park Road TCE Site
Well No. Units
MW-ID (ft bgs) 38-43 50.6-52'
(ft msl 649.5-644.5 636.9-635.5
MW-2D (fl bgs) 20-33 40-44
(fl msl 664.6-651.6 644.6-640.6
MW-3D (ft bgs) 83-100 109-145
(fl msl 663.29-646.2
MW-4D (fl bgs) 126-142
fl msl 613.97-597.9
CW-5 (fl bgs) 82-82.5
(fl msl 626.21-624.71 607.21-604.
EMW-1 (fl bgs) 55-61 70-73
(fl msl) 716.21-710.21 701.21-698.
ft bgs = feet below ground surface
ft ms! -feet above mean sea level
Gastonia, North Carolina
•=zones with possible rather than probable water-bearing fractures
K:\WP\04400\071\Fs-tbls Table 1-5 1-33
Comments
flat
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
structures and steeply dipping fractures primarily to the east, the spread of contamination within
the bedrock aquifer may be attributed to the interconnection of bedrock fractures.
1.4.5 Soils
The soils of Gaston County have been grouped into soil series based upon similarity in color,
texture, structure, and drainage conditions. A variety of soil types is formed by weathering of the
various rock types underlying the Gaston County area. There are five predominant soil types in
the Davis Park Road site area. These include Appling sandy loam, Cecil-Urban land complex,
Helena-Urban land complex, Pacolet sandy loam, and Wedowee sandy loam (USDA, 1989).
The area surrounding the Davis Park Road TCE site is dominated by the Cecil-Urban land
complex soils, except for areas within the flood plain of Blackwood Creek. The flood plain is
composed of Quaternary age alluvium, consisting of fine to medium grained sands intermixed with
zones of clay to silty clay. Organic material from the decomposition of rooted and transported
plants and trees also contributes greatly to this soil horizon. Below the surficial layers, soils
become more saprolitic, consisting of silty clay with varying amounts of sand. Moving deeper into
the soil profile, sand content increases while clay content decreases.
1.4.6 Hydrogeology
Metamorphosed and fractured quartz-sericite schist, metavolcanic rocks, and granitic rocks in
varying proportions and thicknesses comprise the aquifer system represented by the water bearing
units that underlie the Davis Park Road site and surrounding areas. Geologic structures that
produce high-yielding wells include contact zones of multilayered rock units, zones of fracture
concentration, and stress-relief fracture zones. According to data collected by LeGrand and
Mundorff(l952), wells in Gaston County that are set within granite have an average depth of 165
NOR/K:IWP\04400\071 \FSDDN001. DOC 1-34
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
feet bgs and have an average yield of 18 gallons per minute. Within the Davis Park area, the data
collected by LeGrand and Mundorff indicate that well depths range from 80 to over 250 feet bgs
and that well yields range from 2.5 to 116 gallons per minute. Wells located on a hill typically
have lower yields.
Site-Specific Hydrogeology
Efforts to characterize the hydrogeology at the site include lithologic sampling during the monitor
well installation program, collection of water level data from monitor wells, and hydraulic testing
of all newly installed monitor wells.
In the Davis Park Road TCE site area, the water table is typically found in the saprolite and
generally mimics the overlying land surface topography. The saprolite and partially weathered
rock comprise an overburden aquifer, which has a thickness that ranges from approximately 10 to
80 feet below ground surface. A fractured bedrock aquifer underlies the overburden. The fracture
frequency generally decreases with depth. Figures l-3A and 1-3B present cross sectional views of
the overburden and bedrock aquifers. The depth to water across the area ranges from
approximately 3 to 45 feet. Table 1-6 presents groundwater elevations collected in January and
February I 998 by WESTON referenced to elevation above mean sea level. The greatest depth to
water is found along the ridge line on the northeast portion of the site, which is also the location
of the Davis Park Auto Repair facility.
Based on groundwater elevations collected in January and February 1998 and potentiometric
maps drawn from these groundwater elevations, groundwater within the overburden and bedrock
NOR/K:\WP\04400\071 IF SDDN001. DOC 1-35
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. Jt shall not be disclosed, in whole or in part, without the express written
permission of EPA
Table 1-6
Groundwater Elevations -Monitor, Residential, and Converted Wells
January 16, 1998, and February 11, 1998
Davis Park Road TCE Site
Ma)' 1998
Januarv 16, 1998 February II, 1998
Well Aquifer Top of Casing
ID Monitoring Elevation
EMW-1 Bedrock
EMW-2 TOB
MW-1S TOB
MW-ID Bedrock
MW-2S TOB
MW-2D Bedrock
MW-3S TOB
MW-3D Bedrock
MW-4S TOB
MW-4D Bedrock
MW-5S TOB
CW-1 Bedrock
CW-2 TOB
CW-3 TOB
CW-4 TOB
CW-5 Bedrock
PW-2 Bedrock
TOB = Top of bedrock
•· = Not measured
EMW = Existing monitor well
CW= Converted monitor well
PW = Private residential well
(ft msl)
771.21
771.86
688.27
687.50
684.60
684.60
743.74
746.29
716.12
739.97
677.26
761.69
757.79
758.63
768.75
707.21
687.57
ft msl = feet above mean sea level
K:\WP\04400\071\Fs-tbls Table 1-6
Depth to Groundwater Depth to Groundwater
Water Elevation Water Elevation
(ft) (ft msl) (ft) (ft msl)
45.61 725.60 44.98 726.23
44.84 727.02 44.23 727.63
2,10 686.17 2.07 686.20
4.00 683.50 3.91 683.59
4.02 680.58 3.94 680.66
4.01 680.59 3.92 680.68
22.03 721.71 21.03 722. 71
23.83 722.46 22.54 723.75
.. .. 17.81 698.31
33,90 706.07 32.96 707.01
4.67 672.59 3.32 673.94
40.59 721.10 40.29 721.40
36.42 721.37 36,21 721.58
35.28 723.35 34,10 724.53
.. .. 45.34 723.41
14.40 692.81 12.55 694,66
.. .. 42.68 644.89
1-36
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
aquifers generally flows to the southeast to south across the site. Figures I-7, 1-8, 1-9, and 1-I 0
present potentiometric maps for the overburden and bedrock aquifers for the data collected in
January and February 1998, respectively.
Based upon the potentiometric contours, the Davis Park Auto Repair property appears to be
located within a localized groundwater high area. Potentiometric contours emanate in a semi-
circular pattern from this area.
Water level elevations and local topographic contour maps for monitor wells MW-ID, MW-2S,
MW-2D, and MW-5S, suggest that groundwater discharges from the overburden and possibly the
bedrock aquifers into Blackwood Creek along the eastern and southeastern edge of the site;
however, fractures present in the partially weathered rock and bedrock may differentially affect
the direction of groundwater flow, and relict fractures present in the saprolite may also control
groundwater flow directions. According to Harned (I 989), while working in the Piedmont
Province of Guilford and Mecklenburg Counties of North Carolina, the majority of the natural
flow in the bedrock system is probably confined to the upper 30 feet of bedrock, where fractures
are concentrated, and the overlying partially weathered rock zone, which appears to have the
highest hydraulic conductivity of any part of the hydrogeologic system.
Groundwater Elevations
WESTON collected two rounds of water levels (on January 16 and February 11, 1998) from the
top-of-bedrock and bedrock monitor wells as well as converted monitor wells. The depth to water
data were converted to water level elevations, and potentiometric maps were developed from this
data (Table 1-2). Figures 1-7 and 1-8 present the overburden aquifer potentiometric su1face for
NOR/K:IWP\04400\071\FSDDN001.00C 1-37
RICi'il,'.NO ... vo<UE
•
j
/ i i
'"
PROJECT TITLE• DAVIS PARK ROAD TCE SITE
GASTON COUNTY
GASTONIA, NORTH CAROLINA
POTENTIOMETRIC CONTOUR MAP
TOP OF BEDROCK AQUIFER -FEBUARY, 1998
FIGURE 1-7
DRA\,,'Ni
M. SNEED
DATE•
5/22/98
DAT[,
LEGEND
POTENTIOI.IETRIC CONTOUR (POTENTIOI.IETRIC CONTOUR INTERVALS "" 5 FEET)
(680.12)
(Ni,j)
GROUNDWATER El£VATION IN FEET MSL
NOT MEASURED
WELL LOCATIONS
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APPROVE Di ATE,
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04400--071--095
CAD FILE NAME•
98JA16WT.DWG
1...------------------------------r---------,
LEGEND
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""' --,~ (1UJ.5i" (727.IJ) 'Ii,$
DAVIS PARK AUTO REPAIR
RICHLAND AV[NU[
"""""""""'""'" -= ro-a••'"" N -5,4.f,,~.1&8' E • l,JJ7,17LIIIII'
[UV, ,. 770.14'
GL[NRAVEN AVENUE
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PROJECT TITLE• DAVIS PARK ROAD TCE SITE
GASTON COUN""TY
GASTONIA, NORTH CAROLINA
POTENTIOMETRIC CONTOUR MAP
TOP OF BEDROCK AQUIFER -FEBRUARY, 1998
FIGURE 1-8
680
675
i.-•-
DRA\IN1
M.SNEED
CHECKED1
DATE1
5/22198
POTENTIOMETRIC CONTOUR (POTENTIOMETRIC CONTOUR ll'ffi:RVAI. "" 5 FEIT)
MW-1 e TOP OF BEDROCK WELL LOCATIONS
(723.31) GROUNDWATER ELEVATION IN FEET MSL
~r,c;rc,..-0.-11(11,a~ --~ ~ ~ ~ ~--om -·-·--~ _,. ~ ~
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04400---071-095
CAD FILE NAME•
98FE11WT.DWG
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PROJECT TITLE• DAVIS PARK ROAD TCE SITE
GASTON COUNTY
GASTONIA, NORTH CAROLINA
POTENTIOMETRIC CONTOUR MAP
BEDROCK AQUIFER -JANUARY, 1998
LEGEND
POTENTIOMCTRIC CONTOUR (POTENTIOMETRIC CONTOUR INTERVALS - 5 FEET)
(692.87)
{NM)
MW-1 &
GROUNDWATER E1.£VATION IN FEET MSL
NOT I.IE.A.SURED
WELL LOCATIONS
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DRA\JN1 DATE1 DES, DATE1 \1.0. ND.•
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PROJECT TITLE1 DAVIS PARK ROAD TCE SITE
GASTON COUNTY
GASTONIA, NORTH CAROLINA
POTENTIOMETRIC CONTOUR MAP
BEDROCK AQUIFER -FEBUARY, 1998
FIGURE 1-10
DRA\JN1
M.SNEED
CHECKED•
DATE,
5/22/98
LEGEND
POTENTIOMETRIC CONTOUR (POTENTIOMETRIC CONTOUR INTERVAL - 5 FEET)
(72.D~) GROUNDWATER ELEVATION IN FEET MSL
1.1w-1 ~ WEU. LOCATIONS
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GRAPHIC SCALE
500' 1,000'
1" = 500 FEET
ATE,
\J.O. N□,1
0440~71-{)95
CAD FILE NAME•
98FE11WL.DWG
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This document was prepared by Roy F. Weston, Jnc., expressly for EPA. JI shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibillty Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
the above dates. Figures 1-9 and 1-10 present the potentiometric surface for the bedrock aquifer
for the above dates, respectively.
The overburden potentiometric surface (Figures 1-7 and 1-8) indicates groundwater flow toward
Blackwood Creek. The highest elevations are observed in the northeastern corner of the site at
monitor well EMW-2. However, all measured potentiometric elevations at the site are higher
across the northern region of the site. The lowest elevations were recorded in wells located along
Blackwood Creek. The potentiometric surfaces also indicate that groundwater at the top of
bedrock is generally flowing from the northwest to the southeast toward Blackwood Creek.
The potentiometric surfaces of the overburden groundwater have been used to estimate the
magnitude of the hydraulic gradient in the overburden aquifer. For the January 16, 1998,
potentiometric maps, a line formed between monitor well CW-3 and MW-2S is nearly parallel to
the direction of groundwater flow. The gradient magnitude is then estimated as the elevation
difference between the two monitor wells, (723.35 feet above MSL at CW-3 minus 680.58 feet
above MSL at MW-25) divided by the distance between the two locations (estimated at 2,580
feet), yielding 0.017 ft/ft. The gradient for the February 14, 1998, date, estimated using the same
locations, was determined to be 0.017 ft/ft.
The potentiometric maps for the bedrock aquifer also reveal a consistency in the groundwater
surface for the two dates water level measurements were recorded. The highest groundwater
elevation in the bedrock aquifer was observed at monitor well EMW-1 in the northeast corner of
the site. Groundwater elevations decrease to the south, southeast, and east reaching a minimum at
monitor well MW-2D. The groundwater flow direction in the bedrock aquifer appears to range
from south to east across the site, but the strongest component of flow appears to be to the
southeast.
NOR/K:\WP\0<!400\071 \FSDDN001. DOC 1-42
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
The magnitude of the hydraulic gradient in the bedrock aquifer was calculated in the same manner
as that for the overburden aquifer. For both water level collection dates, the line from monitor
wells MW-I to MW-2D was used because this line would nearly parallel the predicted direction
of groundwater flow. The distance between these two locations is estimated at 2,460 feet. For
January 16, 1998, the groundwater elevations (in feet above MSL) for EMW-1 and MW-2D were
725.60 and 680.59, respectively, representing a gradient magnitude of 0.018 ft/ft. For February
11, 1998, the groundwater elevations (in feet above MSL) for EMW-1 and MW-2D were 726.23
and 680.68, respectively, representing a gradient magnitude of 0.018.
During the WESTON study, a measurable difference was found in groundwater levels between
the bedrock and overburden aquifers, suggesting a vertical hydraulic gradient exists between the
two aquifers. However, for the two measuring dates, the difference in water level elevations was
at a maximum of 2.67 feet in the MW-IS/ID well pair, and a minimum of 1.40 feet in the
EMW-1/EMW-2 well pair (Table 1-7). For MW-2S and MW-2D and MW-3S and MW-3D, the
bedrock was found to have a higher groundwater elevation. At the MW-2S/2D location, this
difference is probably related to levels of water in nearby Blackwood Creek and upwelling and
discharge of bedrock aquifer groundwater into the stream. At the MW-3S/3D location, the higher
elevation in the bedrock aquifer may be a result of proximity of these wells within or adjacent to a
major fracture zone.
At the Davis Park Road site, groundwater elevation differences in well pairs, although variable,
exist across the site. However, no single geologic structure was identified during the investigation
that is capable of acting alone as an aquitard between the top-of-bedrock and bedrock aquifers.
The most plausible explanation for the differences in elevation is that the porosity in the granitic
bedrock aquifer is significantly lower than the overburden overlying the bedrock. The flow of
groundwater in the bedrock aquifer is principally controlled by fractures. The vertical hydraulic
NOR/K: \WP\04400\071 \FSDDN001. DOC 1-43
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
Well/ Piezometer
Pair
EMW-1 /EMW-2
MW-IS/MW-ID
MW-2S / MW-2D
MW-3S I MW-3D
Notes:
Table 1-7
Comparison of Water Level Elevations
in Monitor Well Pairs
Davis Park Road TCE Site
May 1998
Difference in
Water Level Water Level Water Level
Elevations for Elevations for Elevations for
1/16/98 1/16/98 2/11/98
725.60 / 727.02 1.42 726.23 / 727.63
686.17 / 683.50 2.67 686.20 / 683.59
680.58 / 680.59 -0.01 680.66 / 680.68
721.71 / 722.46 -0.75 722.71 / 723.75
All elevations are in feet above MSL.
Difference in
Water Level
Elevations for
2/11/98
1.4
2.61
-0.02
-1.04
Difference computed by subtraction of bedrock data from top-of-bedrock data.
K:\WP\04400\071 \Fs-tbls Table 1-7 1-44
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
gradient may therefore indicate that water from the saprolite/partially weathered rock aquifer is
moving into and downward through the fractures in the bedrock aquifer.
Hydraulic (Slug) Testing
To evaluate movement of groundwater in the overburden and bedrock aquifers, hydraulic
conductivity was calculated through the use of slug tests. From January 15 through January 17,
1998, slug tests were conducted in all nine of the recently installed monitor wells. Since the water
levels were well above the screened zone of the top-of-bedrock wells and the open borehole
section of the bedrock wells, both rising head and falling head slug tests were used to obtain the
most accurate evaluation. The rising head test values are used in this section of the report.
Equipment utilized during the test included a slug (3-inch diameter by 3 foot large solid PVC
cylinder) and an electronic data logger for recording water level changes in the wells.
The Bouwer and Rice (I 976) method was used to interpret the raw rising head slug test data for
interpretation of the hydraulic conductivity for both the overburden and bedrock aquifers. Rising
head tests in overburden wells, installed to the top of bedrock, ranged from 1.90 feet per day
(ft/day) at MW-4S to 0.02 ft/day at MW-2S. The average value is 0.72. Table 1-8 presents the
calculated results of all the slug tests.
Hydraulic conductivity values for the bedrock wells were also calculated using rising head tests.
Hydraulic conductivity values calculated from rising head tests ranged from of 0.02 ft/day (MW-1 20) to 1.51 ft/day (MW-ID). The average value for the slug tests in the bedrock wells 0.55 feet
per day.
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I NOR/K:IWP\04400\071 \FSDDN001. DOC 1-45
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
K:\WP\04400\071 \Fs-tbls Table 1-8
Table 1-8
Slug Test Results
Da,is Park Road TCE Site
May 1998
Monitor Well K K
I.D. (cm/sec) (ft/dav)
Top-of-Bedrock Wells:
MW-1S 1.30E-04 0.36855
MW-2S 6.22E-06 0.01763
MW-3S 2.79E-05 0.07910
MW-4S 6.69E-04 1.89662
MW-5S 4.44E-04 1.25874
Averaee 2.55E-04 0.724127
Bedrock Wells:
MW-lD 5.33E-04 1.51106
MW-2D 6.00E-06 0.01701
MW-3D l.33E-04 0.37706
MW-4D l.04E-04 0.29484
Averaee l.94E-04 0.54999
K = hydrattlic conductivity
cm/sec = centimeters per second
ft/day = feet per day
1-46
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
1.4.7 Demography and Land Use
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
According to 1995 estimates by the North Carolina Department of Reserve and Budget, Gaston
County's population was approximately 178,442. With increasing growth around the Charlotte
area, the population of Gaston County is expected to increase with each year. Gaston County
covers 357.3 square miles and has 15 municipalities within the county. The largest of these is
Gastonia with a 1990 population of 54,732. The 1990 U.S. Census found the population density
of Gaston County to be 490.06 persons per square mile. Between the years 1980 and 1990, the
county experienced an overall increase in population of 15.3 percent.
The site is bounded by Hudson Boulevard to the north, Blackwood Creek to the east and south,
and Crowders Creek to the west. Though outside Gastonia city limits, the site is located in an
Extra Territorial Jurisdiction (ETJ) community, and is therefore under city jurisdiction.
The site is located in an area zoned for single family residences (R-1 ). Two of the larger
neighborhoods include the Cedar Oak Park subdivision and the Hedgewood Circle area. There are
two commercial operations within the site boundary including Davis Park Auto Repair and
Godwin Refrigeration. These facilities may be considered a nonconforming use of property in this I zone. Were either facility to go out of business for any length of time, the property would likely
be converted to residential use, according to the Planning Department of the City of Gastonia. I There are no plans for future re-zoning of this area in the foreseeable future. The Taylor Memorial
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Baptist Church is also located within the site boundary.
1.4.8 Ecology
As a result of extensive development, there are no known critical habitats or federally listed I endangered species in the immediate vicinity of the site. The site includes commercial and residential
I NOR/K:\WP\04400\071 \FSDON001. DOC 1-47
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 1
Revision: 1
Date: July 1998
buildings, paved roads and paved parking areas, and open areas of maintained vegetation. There
are limited areas of woodlands within the immediate site vicinity; however, the woodlands are
more extensive along the southeastern, southern, and western perimeter of the site.
The May 1993 SIA report indicated that soil types in the valley of Crowders Creek (for the nine
miles that it runs through North Carolina) are almost totally Chewacla loam (CH) or Conagree
loam (Co), both of which are listed as hydric soils capable of supporting wetlands. However, the
five predominant soil types in the immediate Davis Park Road site area, Appling sandy loam,
Cecil-Urban land complex, Helena-Urban land complex, Pacolet sandy loam, and Wedowee sandy
loam, are not listed as hydric soils. The 1993 SIA stated further that there appear to be no
wetlands in the area of the site based on soils maps, soil classification, and USGS maps.
Threatened and Endangered Plant and Animal Species
The October 1992 SI and the September 1996 Preliminary RI reports indicated that there are no
known critical habitats of federally listed endangered species in the vicinity of the site. However,
both reports state that the Indiana Bat, Bald Eagle, Arctic Peregrine Falcon, and Eastern Cougar
are endangered and threatened species identified in the vicinity of the site. Additionally, the May
1993 SIA reported that several sensitive environments, several species of millipedes listed as state
endangered, threatened or of special concern, the Bear Oak (listed as significantly rare), and
Crowders Mountain State Park are located in the site vicinity.
NOR/K\WP\04400\071 IF SDDN001.00C 1-48
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. ti shall not be disclosed, in whole or in part, without the express
written permission of EPA.
SECTION 2
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
NATURE AND EXTENT OF CONTAMINATION
Since 1995, several field investigations have been conducted at the Davis Park Road site to
determine the nature and extent of contamination. A summary of the field investigations
conducted prior to RI activities is presented in Table 2-1. This section discusses the results of the
RI in detail.
This FS is primarily based on groundwater sampling tasks conducted by EPA and WESTON as
pan of the RI activities. These tasks included:
• Residential supply well sampling (September 1996);
• Groundwater sampling using temporary wells (October 1996);
• Overburden and bedrock aquifer monitor well sampling, convened monitor well sampling,
and residential well sampling (January, February, and March 1998).
Based upon the RI data evaluation and the Risk Assessment results, only voes are considered as
site-related contaminants. Therefore, voe analytical results are discussed in this section.
Analytical results for the sampling tasks and a discussion of their significance to the site are
presented in Subsections 2.1 through 2.4.
2.1 MAY 1996 PRELIMINARY INVESTIGATION
Groundwater samples were collected from the two permanent monitor wells located on the Davis
Park Auto Repair shop propeny, and from twenty-nine residential wells in the nearby vicinity.
NOR/K:\WP\04400\071\FSDDN001.DOC 2-1
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This document was prepared by Roy F. Weston, lnc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Conducted By
Greenhorne &
O'Mara, Inc.,
October 1992.
NCDHENR, May
1993.
NCDHENR, May
1994.
Table 2-1
Summary of Field Im·cstigations Conducted Prior to RJ Activities
Davis Park Road TCE Site
May 1998
Description/Purpose Location Conclusions
Review of EPA and State At Davis Park Various sampling efJons prior to
file material of history of Road site, submittal of repol1 had revealed
site; summary of anal,1ical including concentrations of PCE and TCE in
data from previous surrounding water of residential supply wells at
sampling efJons; residential areas. levels as high as 101.4 11g/L.
investigation of releases of Concentrations of PCE and TCE were
chemicals at the site and detected in soil samples collected by
site vicinity. NCDEM representatives from the
back of the Davis Park Auto Repair
facility.
Addressed items Reviewed Davis Reponed that previous groundwater
considered to be omitted Park Road site sampling effort by NCDEM and
from the Greenhorne & and off-site Gaston County representatives had
O'Mara 1992 Site locations shown that 14 of 22 private
Screening Investigation surrounding this residential wells contained detectable
repon. site. amounts ofTCE or PCE or both. Also
indicated that, after reviewing other
potential sources, the contamination
at Davis Park Road is due to activities
at Davis Park Auto Repair facility.
Conducted soil and Residential areas Five residential supply wells closest
groundwater sampling to within the Davis to the Da,is Park Auto Repair facility
establish private and Park Road site. continued to be contaminated by
community well hazardous constituents above State
contamination using EPA and federal MCLs. The report
Contract Laboratory recommended inclusion of the site on
Protocols. the National Priorities List.
NORIK:IWP\044001071\FS-TBLS.OOC 2-2
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
One duplicate sample was collected for sample 131. Monitor well and residential well locations
are included in Figures 2-1 and 2-2, respectively.
Groundwater Samples -Private Wells
All groundwater samples were analyzed for VOCs. PCE and TCE were detected at levels above
state and federal MCLs in water sampled from residential wells. Chloroform was detected above
the state MCL in one residential well sample. Concentrations of TCE above the State MCL were
detected in samples collected from five residential wells located at 2419 Davis Park Road, 2719
Davis Park Road, 2816 Davis Park Road, 2329 Skyland Drive, and Residence 13 I, respectively.
PCE was detected above the State MCL in water sampled from three residential wells located at
2723 Davis Park Road, 2719 Davis Park Road, and 2816 Davis Park Road, respectively.
Compounds detected below MCLs included 1, 1-dichloroethane, I, 1-dichloroethene,
cis-1,2-dichloroethene, 1, 1, ]-trichloroethane, chloroform, bromodichloromethane,
dibromochloromethane, methoxymethylpropane, and carbon disulfide.
Groundwater sampled from the residential wells located at 2241 Cedar Oak Cr., 2510 Briar Oak
Dr., 28 I 6 Davis Park Road, and 2634 Skyland Drive were analyzed for extractable organic
compounds, pesticides/PCBs, and metals, in addition to VOCs. The presumptive evidence of four
extractable organic compounds ( chlorocyclohexanol, dichlorohexane, bromocyclohexanol,
chloromethylbenzofuran) was detected in the groundwater sampled from the residential well
located at 2241 Cedar Oak Cr. According to EPA, these compounds are most likely the result of
methylene chloride extraction of chlorinated water.
Groundwater sampled from the residential well located at 3 8 I 6 Davis Park Rd. contained gamma-
chlordane and the presumptive evidence of trans-nonachlor and alpha-chlordane. No other
NOR/K:\WP\04400\071 \FSDDN001. DOC 2-3
--~----------------
• MW-1
MW-2 e
--:;c -HOLES IN WALL
DAVIS PARK AUTO REPAIR
• MONITORING WELL LOCATION
OAVIS PARK ROAO
~
FIGURE 2-1 APPROXIMATE SCALE
MONITOR WELL LOCATION MAP 25 ? 1~.S '·' DAVIS PARK ROAD TCE SITE '
~EPA GASTONIA, NORTH CAROLINA ( IN FEET)
1 Inch = 25 Ft.
-- -- -
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"' \ 0 ' ,: I ,.;
~ ' ~ ( z ~ < ' ~ \ &EPA ;:: ~ ' ~ ' 9 "'
- -
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FIGURE 2-2
-
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-
RESIDENTIAL WELL LOCATIONS-MAY 1996 PRELIMINARY INVESTIGATION
DAVIS PARK ROAD TCE SITE
GASTONIA, NORTH CAROLINA
- -
0
- - -
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&11
• POTABLE WELL LOCATION
Approximate
Scale In Feet
600 1200
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
pesticides and no PCBs were identified in these four groundwater samples. A variety of metals
was detected in all four residential well samples, including barium, copper, strontium, vanadium,
zinc, calcium, magnesium, iron, sodium, and potassium. The concentrations were below any
specified primary or secondary MCLs. Table 2-2 presents the analytical summary.
Groundwater Samples Monitor Wells
The two permanent monitor wells located on the Davis Park Auto Repair property were sampled
and analyzed for volatile and semi-volatile organic compounds, pesticides, PCBs, and metals.
No volatile orgamc compounds, pesticides, or PCBs were detected in either monitor well.
Monitor well MW-I contained the presumptive evidence of petroleum product. A variety of
metals was detected in the samples collected from both monitor wells, including barium,
strontium, titanium, zinc, aluminum, manganese, calcium, magnesium, iron, sodium, and
potassium.
2.2 OCTOBER 1996 PRELCMINARY lNVESTIGATION
Groundwater samples were collected from temporary monitor wells placed at three locations on
the Davis Park Auto Repair facility property and one location southeast of the property in the
vicinity of Blackwood Creek. The samples were analyzed for VOCs. Locations of the temporary
wells are presented in Figure 2-3. Analyses were conducted in the field using a Sentex Plus II Gas
Chromatograph and in accordance with the U.S. EPA Region IV, Science and Ecosystem
Support Division, Laboratory Operations and Quality Control Manual, September, 1990.
An estimated quantity of TCE (0.84 J µg/L) was detected in the groundwater sample collected
from temporary well TW-1 located on the Davis Park Auto Repair property southwest of the
NOR/K\WP\04400\071 \FSDDN001. DOC 2-6
----- -- --- -- -
This document was prepared by Roy F. Weston, Inc., expressly for EPA It shall not be disclosed, in whole or in part. without the express written permission of EPA
Tobie 2-2
Ih-sidcntial Well Anal)1ical Data Summary -l\lny 1996 Preliminary Innstigation
Da,·is Park Road TCE Site
Well ID: 054 096
Date Sam ll led: sn/96 snJ96
\'olalile OrPanlc Compounds MCL1 l\.ICr} Uj!;/L ug/L
I, 1-Dichloroethene 7 7 --
I, 1-Dichloroethane 700 5 --
cis 1,2-Dichloroethcne 70 70 --
Trichloroelhene 2.8 5 --
T etrachloroethene 0.7 5 --
Chloroform 0.19 100 \'lj/At --
I, I, 1-Trichloroethane 200 200 ---
Bromodichloromcthane NL 100 5.M -
Dibromochloromethane NL 100 0.58AJ -
Carbon Disulfide NL NL --
l\letho,';,methylpropane NL NL --
Well ID 217 221
Date Sampled: 5/7/96 5nl96
Volatile Oreanic Compounds MCL1 l\.lCL1 ug/L ug/L
1, 1-Dichloroethenc 7 7 --
1, 1-Dichlorocthane 700 5 ---
cis 1,2-Dichloroethene 70 70 --
Trichloroethene 2.8 5 --
Tctrachloroethene 0.7 5 ---
Chloroform 0.19 100 ---
1, I, 1-Trichloroethane 200 200 ----
Bromodichloromethane NL 100 --
Dibromochloromethane NL 100 ---
Carbon Disulfide NL NL ---
Methm,1methylpropane NL NL ----
Notes.
1North Carolina Administrative Code, Subchapter 2L Maximum Contaminant LcYCI
2Safe Drinking Water Act Maximum Contaminant Leu:]
A• Awrage Value
J "' estimated 1·11.lue
N • presumptfrc c1idence of presence of m<11erial
--9 m.,1er-ial w,u 11nalyzcd rm-but not detected
NL• not listed
Shaded \'alues indicate 1iolation of stale t..lCL
ug1L ~ micrograms per liter
K.\WP\04400\071\Fs-tbls Table 2-2
Gastonia, North Carolina
l00 108 121 122 131 150 170 172
5n/96 5n/96 511196 5/6/96 5n/96 517/96 5n/96 5/7/96
u2/L ugn~ u2/L ug/L 112/L u2/L ug/L ug/L
-------1.6 ---------0.57} ---1.6A ----- ----:))ij/k[ 0.92AJ i~!Mt ------
0.66.-\J ---------------------------------------
--------------I.SJ -----2.41 ------------
230 232 236 239 252 267 275 285
5/6/96 5/6/96 5/6/96 517/96 5/6/96 5/6/96 517/96 5/6/96
ug/L ug/L ugn., ugn., ug/L ug/L ug/L ugn.,
---3.8 ---0.66AJ
0.52,V -------------------------}&IN,,
0.62..-V @MW!/ -0.521 ----N~¥1W ---------------7.8 ----1.2A ----------
----------------------------40.JN -- ---
2-7
- - -- --
177 181 187 195 211
snt96 snt96 5/7/96 snt96 snt96
ug/L ug/L ug/L ug/L ugn~
--------------1.7...\ ---
--WISN',' 2.6.-\ ----
-----------------------
----------------
1.3 -----------
300 332 334 34R
5n/96 5nt96 517/96 5/7/96
ug/L ug/L ug/L ug/L
---------
----------------------------------------------2.2J ---
------
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of
EPA.
Table 2-2 (Continued)
Residential Well Analytical Data Summary-May 1996 Preliminary Investigation
Davis Park Road TCE Site
Gastonia, North Carolina
Well ID: 150 267 285
Date Sampled: 5/7/96 5/6/97 5/6/97
Semi-Volatile Organic Comnounds MCL1 MCL2 ug/L ug/L ug/L
Chlorocyclohexanol NL NL I000JN --
Dichlorohexanc NL NL IO00JN ---
Bromocyclohexanol NL NL 20JN --
Chloromethvlbenzofuran NL NL 20JN
Pesticide/PCB Comnounds MCL' MCL2 ug/L ug/L ug/L
Gamma-Chlordane NL 70 --0.0073)
Trans-Nonachlor NL NL -.. 0.004JN
Aloha-Chlordane NL 70 --0.0097JN
Metals MCL1 MCL2 ug/L ug/L ug/L
Barium 2000 2000 20 21 14
Copper IO00 NL 12 3.4 -
Strontium NL NL 190 130 200
Vanadiwn NL NL -4.2 -
Zinc 2100 (5000) 4.4 5.0 7.3
Metals MCL1 MCL2 mg/L mg/L mg/L
Calcium NL NL 8.0 6.2 II
Magnesium NL NL 1.2 I. I 2.4
Iron 0.3 (30) 0.014 --0.026
Sodiwn NL NL 10 8.3 8.8
Potassiwn NL NL 1.5 2.2 1.4
Notes:
1North Carolina Administrative Code, Subchapter 2L Maximum Contaminant Level
2Safe Drinking Water Act Maximum Contaminant Level. Numbers in parentheses are secondary MCLs.
J = estimated value
N = preswnptive evidence of presence of material
- = material was analyzed for but not detected
NL = not listed
ug/L = micrograms per liter
mg/L = milligrams per liter
K:\WP\04400\071 \Fs-tbls Table 2-2 (p.2) 2-8
300
5/6/97
ug/L
-
..
-
..
ug/L
-
--
..
ug/L
14
..
140
5.9
4.6
mg/L
9.6
3.7
-
9.1
2.5
-11111 - - - - - - - - - - - - - - - - -
~ ~
§
ii' z ~ !
I
~
i °'C~"' 11
I@
~
AU:r\) REPAIR
' • ,.e'( ! '1.,)2:,_
:: 15. 'fJI,
'' '' , 1 •2 ' '' '' '' '' ' '' " " " " ' ;:
' '' , , , , ,
.SEPA
• TEMPORARY MONITOR
WELL LOCATIONS
11¥.!$½1 l~t~I It.~! 11\ffi!l\ lf!&'lfilli
RICHLAND AVENUE
~\!11/,1 ja.c,,MI 1-•1 1~;:.ffi\ /.'V~,~, ~
GLENRAVEN AVENUE
FIGURE 2-3
TEMPORARY MONITOR WELL LOCATIONS
OCTOBER 1996 PRELIMINARY INVESTIGATIONS
DAVIS PARK ROAD TCE SITE
GASTONIA, NORTH CAROLINA
~
£ii}
/ii~~~)
= ~ ~ ~
D R
0
0 )>
;:,;;
0
Approximate
Scale In Feet
200 400
~ ~,__ ___________________________________ __J
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
building. The groundwater sampled from TW-2, located on the Davis Park Auto Repair property
southeast of the building, contained estimated concentrations of toluene, and presumptive
evidence of propene and butene. Table 2-3 presents the analytical results.
Using groundwater sample analytical data from the May 1996 and October 1996 investigations,
EPA generated contoured plots of the potential TCE and PCE contaminant plumes underlying the
Davis Park Road site. The plots are presented as Figures 2-4 and 2-5. Review of the plots
indicates that the contaminant plume is primarily in the southeastern quadrant of the site, but is
not defined at the extreme southern and southeastern edges of the site. The plots also indicate that
the higher levels of contamination are present in the southern portion of the overall plume.
2.3 1997/1998 INVESTIGATION
Monitor wells installed during the 1997/1998 WESTON investigation were intended to provide
groundwater quality information in locations other than private wells, establish monitoring points
across the site, and determine the extent of groundwater contamination in the overburden and
bedrock aquifers. In addition to monitorwells, five former residential supply wells were converted
to monitor wells and were expected to provide additional information concerning groundwater I contamination. Private residential wells throughout the site also provide important groundwater
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quality data.
2.3.l Overburden Aquifer Sample Analysis Results
Monitor wells EMW-2, :MW-IS, -2S, -3S, -4S, and -5S, and converted monitor wells CW-2, -3,
and -4 were sampled for VOC analysis using EPA Method 8260 -Level 4 QA/QC during the
NOR/K-IWP\04400\071 \FSDON001. DOC 2-10
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
Table 2-3
TemJ)orary Well Anal)·tical Data Summary -October 1996 Preliminary Investigation
Davis Park Road TCE Site
Gastonia, North Carolina
Well ID: 1-GW 2-GW
Date SamJ)led: 10/8/96 10/8/96
Volatile Or2anic Comnounds MCL1 MCL' ug/L ug/L
Trichloroethene 2.8 5 0.84J --
Toluene 1000 IOOO --0,60]
Propene NL NL --20JN
Butene NL NL --9JN
1North Carolina Administrative Code, Chapter 2L Maximum Contaminant Level
2Safe Drinking Water Act Maximum Contaminant Level
J = estimated value
N = presumptive evidence of presence of material
--= material was analyzed for but not detected
NL = not listed
K:\WP\04400\071 \Fs-tbls Table 2-3 2-I I
5-GW
10/8/96
ug/L
--
----
--
15-GW
10/8/96
ug/L
--
--
--
--
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0
0 0
◊
DC'.J
0
t~
0
0 □ DD D D
O □'0 o D
G ' '
.
Z5Z-PW9D
0
0 ~e 275-PW ,,-..._
0
□
[?
0
0
0
Q p
cl8 0 0
bc:i □c::J □O C f<P.OWE>,'il.\lE
□ □ □ Oo ,p
□
CJooc 0
' -
0
□ D D o D
0
CJ D
0 D
I:\ [?
cl 0
0 0 D D
ug/L
30.00
26.00
22.00
18.00
14.00
9 POTABLE WELL LOCATIONS 1000
6.00
APPROXIMATE SCALE
2.00
700 0 350 700
~ -· 1--1-~I ( IN FEET)
1 Inch = 700 Ft.
'ilL---------------------------------------------------------------------------------~
~EPA
FIGURE 2-4
TCE CONCENTRATION ISOPLETH MAP
OCTOBER 1996 PRELIMINARY FIELD INVESTIGATION
DAVIS PARK ROAD TCE SITE
GASTONIA, NORTH CAROLINA
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0
0
0 0
◊
0
(~
0
96-PW
~c::i ~~o ,· ,._, g □
,o
GW-
1ZZ-~
Z5Z-PW9D e
Q
,"' 0 0
ooo_o_~o~~~ O 0D~
Q o Cl 0 • 1 -PW
0
'9 275-PW
0
□
,
.
u
oo 0
0
~ O O o ., -
p~lUU_ f ~G D ~ Q \)I;] \l D
D □ D
:,-;;;;;: 'iJ = ===-□ 0 D D D 1::1 I?
D D cl D
0 0 0
1J o D D
0
D
0 0
e POTABLE WELL LOCATIONS
APPROXIMATE SCALE
700 0 350
( IN FEET)
1 Inch = 700 Ft.
700
ug/L
1000
9.00
8.00
7.00
6.00
5.00
• 4.00
iii 3.00
2.00
1.00
'ii ''--------------------------------------------------------------------------------'
&EPA
FIGURE 2-5
PCE CONCENTRATION ISOPLETH MAP
OCTOBER 1996 PRELIMINARY FIELD INVESTIGATION
DAVIS PARK ROAD TCE SITE
GASTONIA, NORTH CAROLINA
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
investigation into the extent of contamination with the top-of-bedrock aquifer. Table 2-4 presents
the results of the sample analysis.
Only three compounds were detected in the analyses, including acetone at 91 micrograms per liter
(µg/L) in the sample from CW-4, carbon disulfide at 7 µg/L in the sample from MW-IS, and
methyl tert-butyl ether (MTBE) at 790 µg/L in the sample from CW-2. Of these compounds, only
MTBE was detected above the State MCL of200 µg/L.
The acetone detection may have originated from isopropanol residue from purging and sampling
equipment. The origin of the carbon disulfide and MTBE is unknown; however, as discussed
below in Section 2.3.2, carbon disulfide was detected in several samples from bedrock monitor
wells.
2.3.2 Bedrock Aquifer Sample Results
Monitor wells EMW-1, MW-ID, MW-2D, -3D, and -4D, converted monitor wells CW-I and
CW-5, and private residential wells PW-I through PW-3 and CW-6 were sampled for VOC
analysis using EPA Method 8260 -Level 4 QA/QC as part of the investigation into the extent of
bedrock aquifer contamination. Table 2-5 presents the results of sample analysis.
Five compounds were detected in the groundwater samples from the bedrock aquifer. Of
significant note are the detections of PCE and TCE in monitor well MW-2D, converted monitor
well CW-5, and residential wells PW-I through PW-3. The highest detection of PCE was in
CW-5 at 14 µg/L. The highest detection of TCE was in PW-3 at 34 µg/L. All of the detections
are greater than the respective State MCLs for PCE (0 7 µg/L) and TCE (2.8 µg/L).
NOR/K:IWP\04400\071 IFSDDN001.DOC 2-14
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Thts document was p1epared by Roy F. Weston. Jnc., expressly lor EPA It shall not be d1Sclosed, In whole or in part, Without the express wrmen permission of EPA
Volatile Organics (JJ.g/1) :-.1CL1 MCLZ
EPA Method 8260
Acetone 700 NL
Acrylonitrile NL ,'L
Ally! Chloride NL ''L
Benzene l 5
Bromobenzene NL NL
Bromochloromethanc NL NL'
Bromodichloromethanc ''L so-
Bromoform 0.19 80'
Bromometh:mc ,'L ''L
2-Butanonc NL NL
N-Butylbcnzcnc NL NL
Sec-Bu1ylbcnzcnc NL ,'L
T ert-Butylbrnzcne NL ''L
Carbon Disulfide NL ''L
Carbon Tctr3chloride 0.3 5
Chlorobenzene 50 80'
Chlorodibromomcthane NL 80'
Chlorocthane NL >-'L
2-Chlorocthyl Vinyl Ell1cr NL NL
Chloroform 0.19 80'
Chloromethanc NL NL
2-Chlorololuene NL NL
4-Chlorotolucne ''L NL
1,2-Dibromo--3-Chloropropanc 0.025 0.2
1,2-Dibromoethanc NL ''L Dibron1omethane NL NL
1,2-Dichlorobcnzene 620 600
1,3-Dichlorobenzene 620 600
1,4-Dichlorobcnzcnc 75 75
Dichlorodifluoromcthanc 1400 ,'L
I, 1-Dichlorocthanc 700 NL
1,2-Dichlorocthanc 0.38 5
1, 1-Dichlorocthcnc 7 7
cis 1,2-Dichlorocthcnc 70 70
trans J,2-Dichlorocthcnc 70 80'
1,2-Dichloropropane 0.56 5
1,3-Dichloropropane NL ''L
2, 2-Dichloropropanc NL NL
I, 1-Dichloropropcnc NL ,'L
cis l ,3-Dichloropropcne NL NL
trans J ,3-Dichloropropcne ''L ''L
cis l,4-Dichloro-2-Butcnc NL NL
trans I,4-Dichloro-2-Butene NL ''L
Ethytbenzcne 29 700
Ethyl Meth:icl)tlte NL ''L
Hexachlorobutadiene NL NL
2-Hcxanone NL NL
Iodomethanc NL NL
lsopropylbenzene NL NL
p-lsopropyltoluene NL NL
Meth:icrylonitrilc NL ''L Methylene Chloride 5 5
Methyl Methacl)·late NL NL
4-},.•1ethyl-2-Pcnt.tnone NL 1''1.
Methyl terl-Bulyl Ether 200 ''L Naphthalene 21 ,'L
Pentachloroetl1ane NL NL
n-Propylbenzene NL ''L
S~TCnc 100 80'
I, I, 1,2· Tetrachloroethane ''L ''L
1, 1,2,2• Tetrachloroethane NL NL
Tetrachloroetl1eno;: 0.7 5
K:IWP\04400\071\Fs-tbls Table 2-4
Table 2-4
Groundwater Samples. On-rburdcn Aquifer
Anal)11cal Summary
MW-IS
1/13/98
..
---..
..
-------
7 .. .. ..
..
..
-.. ---..
..
..
---..
..
..
..
..
..
..
..
--.. ..
---.. -----..
---.. ..
-.. .. ..
-
Davis Park Road TCE Site
Gastonia, North Carolina
:-.tW-2S MW-3S ~fW-4S
1/14/98 1/13/98 1/15/98
-.. ---..
--

-
-.. ..
-

-
.. -

-
---

-
--

-
-.. --.. --.. --.. --

-
--

-

-
.. .. .. .. .. ..
-.. ..
-

-

-
-

-
..
-.. ..
-.. --

-

-
-

-

-
-

-

-
.. .. ..
-.. -.. -..
-

-
--

-

-
--..
-.. -.. ---.. -.. .. --.. -.. .. .. -

-
..
--

-
--

-
-

-

-
-.. ..
-----

-
-

-

-
-

-

-
-.. --.. ..
--

-
--

-
-

-
-.. .. ..
-.. ---

-
--

-
.. -.. -.. ..
.. ----..
--

-
-

-

-
.. .. -.. .. ..
2-15
MW-5S
1/14/98
---------..
----..
----------..
--------..
..
--------------..
-..
-..
-..
..
--. .
-
CW-2 CW-3 CW-4 EMW-2
1113198 1/14/98 1/16/98 2/10/98
.. -91 -.. -.. -----.. .. -.. --.. .. -.. --.. -

-
.. -

-

-

-
-

-
.. --.. .. .. .. .. .. .. --.. .. --

-
--

-
--.. .. . . . . .. -. . .. -.. --.. ---.. -

-
.. .. .. .. .. -

-
.. ..
-

-

-
--

-
--.. -.. ..
-

-
.. .. .. .. --.. -.. ..
-

-
-..
-

-

-
---

-
-.. -.. .. -.. .. .. ------.. -.. .. . . .. .. .. . . ..
-

-
-..
--

-
---

-
--

-
.. .. .. .. .. . . -

-
----

-
--

-

-
.. -

-

-
-.. -

-
.. .. .. .. .. -

-
---

-

-
--

-

-
-. . -.. .. -

-

-
--

-
.. ..
--.. -lpi?9@,: .. .. .. .. -

-
.. -

-

-
--.. .. .. --

-
--

-

-
-.. .. . . -.. .. .. ..
Detection
Limit
50
5
5
5
5
5
5
5
10
10
5
5
5
5
5
5
5
10
10
5
10
5
5
5
5
5
5
5
5
10
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
10
5
5
5
5
10
5
10
5
5
5
5
5
5
5
5
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Thts document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be dtscloscd, In whole or In part, without 1h11 express wrmen pcrminion ol EPA
Volatile Organics (µg/1) J\1CL1 MCL1
EPA Method 8260
Toluene 1,000 so•
1,2,3-Trichlorobenzene NL NL
1,2,4-Trichlorobenzene NL 70
1, 1, I-Trichloroethane 200 200
I, 1,2-Trichloroeth::me NL s
Trichlorocthene 2.8 s
Trichlorofluoromethane 2l00 NL
1,2,3-Trichloropropane NL NL
1,2,4-Trimcthylbenzc:nc NL NL
1,3, 5-Trimethylbenzene NL NL
Vinyl Acct.ate NL NL
Vinyl Chloride 0.015 2
Xylene (Tota.I) 530 so•
Table 2-4 (Continued)
Groundwater Samples -Overburden Aquifrr
Anal)tlcal Summary
MW-1S
1/13/98
---------------
Davis Park Road TCE Site
Gastonia, North Carolina
MW-2S MW-3S MW-4S
1/14/98 1/13/98 1/15/98
-------------------------------------------
MW-5S
1/14198
-----------------
1North Caro\in3 Administntive Code, Subchapter 2L Maximum Contaminant Level
1Safe Drinking Water Acl Maximum Contaminant Level
CW-2
1/13/98
-----------------
so• indicates 1994 proposed rule: toul for a.II trihalomethanes combined cannot e.xceed the 80 µg/1 level
MW -Monitor well sample
CW • Converted residential well sample
DW • ln\lCStigati\.t derived waste sample
K:\WP\04400\071\Fs-tbls Table 2-4 2-16
CW-3 CW-t EMW-2
1/14/98 1/16198 2/10/98
--------------------------------------------
Dl'trctlon
Limit
s
s
s
s
s
s
s
s
5
s
10
10 s
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Volatile Organics (µg/1) MCL1 J\1CL2 :-.1w-1D
EPA Method 8260 1/13/98
Acetone 700 NL ..
Acrylonitrile NL NL ..
AHyl Chloride NL NL -
Benzene 1 5 ..
Bromobenzene NL NL -
Bromochloromctl1.lne NL NL ..
Bromodichloromethane NL so• ..
Bromofonn 0.19 so• -
Bromomcthane NL NL ..
2-Buunone NL NL ..
N-Butylbenzene NL NL ..
Scc-Buty]bcnzcnc NL NL ..
Tert-Butylbcnzcnc NL NL -
Carbon Disulfide NL NL ..
Carbon Tetrachloride 0.3 5 ..
Chlorobenzcnc 50 so• -
Ch.lorodibromomellunc NL so--
Chloroclh:mc NL NL ..
2-ChlorocU,yl Vinyl EUier NL NL ..
Chlorofom1 0.19 so• ..
Chloromclh:me NL NL ..
2-Chlorololucnc NL NL ..
4--Chlorololucnc NL NL ..
I . 2-Dibromo-3--Chloropropanc 0.025 0.2 ..
1,2-Dibromoclhanc NL NL ..
Dibromomclhanc NL NL ..
l ,2-Dichlorobcnzenc 620 600 ..
1,3-Dichlorobcnzenc 620 600 ..
l.4-Dichlorobenzenc 75 75 ..
Dichlorodifluoromelhanc 1400 NL ..
I, l•Dichloroclhanc 700 NL -
1,2-Dichloroclhane 0.38 5 ..
l, 1-Dichloroclhcnc 7 7 ..
cis 1,2-Dichloroclhcnc 70 70 ..
trans 1,2-Dichloroclhenc 70 80' ..
1,2-Dichloroprop:me 0.56 5 ..
1,3-Dichloroprop:mc NL NL ..
2.2-Dichloropropanc NL NL ..
1.1-Dichloropropenc NL NL ..
cis 1,3-Dichloropropcnc NL NL ..
trans 1.3-Dichloropropcnc NL NL ..
cis l,4-Dichloro-2-Butcnc NL NL ..
trans 1,4-Dichloro-2-Butcnc NL NL -
Ethylbenzcne 29 700 -
Ethyl Methacrylatc NL NL -
H e.xa chi orobutad iene NL NL ..
2-Hcxanonc NL NL -
lodomethanc NL NL ..
lsopropylbcnzenc NL NL ..
p-lsopropyltoluenc NL NL ..
l\.lelhacl')'ionilrile NL NL ..
l\.lethylenc Chloride 5 5 ..
Methyl Methacrylate NL NL ..
4-l\.fclhyl-2-Penl,:monc NL NL ..
r-.kU1yl tcrt-Butyl EU1cr 200 NL ..
Naphthalene 21 NL ..
Pent.achlorocl.hanc NL NL ..
n-Proovlbenzene NL NL ..
K\044001071\Fs•tbls Table 2.5
Tabll' 2-5
Groundwalcr Samples -Bedrock Aquifer
Analytical Summary
Davis Park Road TCE Site
Gastonia, North Carolina
J\1\\'-2D J\'1\V-3D MW-4D CW-I CW-5
1/14/98 1/13/98 1/15198 1/1-1/98 1114/98
83 -.. --.. -.. --.. ---..
---.. .. ---.. -----.. .. .. .. .. .. .. .. --..
-----.. ---------.. ----
•· .. .. -..
-.. .. --.. --.. ---.. ------------.. .. -.. .. .. .. .. -..
--.. -..
--.. -..
-.. --------.. ---------.. .. .. .. ..
-.. --.. .. ----.. ----------.. .. ----.. .. ..
.. .. .. .. ..
.. .. -.. ..
--.. --.. ----.. --.. -.. --.. --.. .. .. .. .. -.. .. ..
.. ---..
--------.. --------.. ----.. --.. .. .. .. .. .. .. -.. ---.. --.. -.. --.. .. .. . . .. .. .. .. .. ..
.. .. .. .. ..
.. 42 .. 14 .. .. -.. .. .. .. .. -.. .. .. -.. -..
2-17
C\\'-6 PW-I PW-2 PW-3
1/16/98 2/10/98 2/10/98 2/25/98
-.. ------.. .. -..
.. --..
.. .. -.. .. .. -..
.. .. .. ..
.. ---.. --..
.. .. -..
-.. --.. .. .. ..
.. --..
.. ·• -.. .. .. -..
---..
-----------..
.. --.. .. .. .. .. -.. -..
.. ---.. ------..
.. --.. .. .. .. ..
.. .. .. ..
.. .. -..
--------
.. .. .. ..
.. .. .. ..
-.. .. ..
----.. .. -..
---.. -.. ---.. .. ..
.. -.. .. .. .. -.. -.. -..
------.. -
--------.. -.. ..
-.. .. ..
.. .. . . ..
.. .. ----.. ..
-.. -..
. . -.. .. . . .. .. .. .. .. . . .. . . -.. ..
-.. . . ..
.. .. -..
EMW-1 Dl'tcction
2/10/98 Limit
-50
-5 -5 .. 5 .. 5 .. 5 .. 5 -5 . . 10 . . 10 .. 5 .. 5 .. 5 -5 .. 5
.. 5 -5 -10
-10 -5 .. 10
. . 5 -5 -5
. . 5
. . 5 . . 5 . . 5 -5 -10 -5 . . 5
. . 5 . . 5 -5 .. 5 . . 5
.. 5
.. 5 . . 5
. . 5 . . 5 .. 5 .. 5 -5
-5
. . 10
. . 5
.. 5
.. 5 . . 5
. . 10 . . 5 . . 10 . . 5 -5
. . 5
5
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This document was p1epared by Roy F. Weston, Inc., expressly 101 EPA. It shall not be disclosed, in whole or in part, without the express written pe1mission of EPA.
Table 2-5 (Continued)
Groundwater Samples• Bedrock Aquifer
Anal)1ical Summa!')'
Dnis Park Road TCE Site
Galtonia, Nor1h Carolina
Volatile Organics (J.1gn)
EPA Method 8260
T\·1CL1 J\1CL2 MW-10 MW-2D MW-JD MW-4D CW-I CW-5 CW-6 PW-1 PW-2 PW-3
1/13/98 l/14/98 1/13/98 1/15/98 1/14/98 1/14/98 1/16/98 2/10/98 2/10/98 2/25/98
Sl)TCne
1.1, l ,2-Tetr:ach]orocth:me
I, 1,2.2-Tctrachloroeth~ne
T etrachlorocthcnc
Toluene
1.2,3-Trichloroberu:cnc
1.2,4-T richlorohenzcne
I, 1.1-Trichloroeth:me
l, l ,2-T richlorocthanc
Trichloroethene
Trichloronuoromcthane
1,2.3· Trichloroprop:tne
l ,2,4-Trimethylbcnzcne
1,3,5-Trimethylbcnzcne
Vinyl Acetate
Vinyl Chloride
Xylene (fotal)
100
NL
NL
0.7
1.000
NL
NL
200
NL
2.8
2100
NL
NL
NL
NL
0.015
530
80'
NL
NL
5
80'
NL
70
200
5
NL
NL
NL
NL
NL
2
80'
1North Carolina Administriltivc: Code:, Subchaptc:r 2L Maximum Contaminant Lc:vc:l
1Safc: Drinking Water Act Maximum Contaminant L~c:1
80• indicates 1994 proposed rule: tot.al for all trihalomc:th:tnes combined cannot exceed the 80 µg/1 level
MW -Monitor well s;imple
CW -Converted residential well sample
OW· Investigative derived waste sample
Shaded values indicate excc:c:dc:ncc of state MCL
K"\04400\071\Fl-tbls Table 2-5 2-18
8
EMW-1
2/l0/98
Detection
Limit
5
5
5
5
5
5
5
5
10
10
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. fl shall not be disclosed, in whole or in part, without the express
written permission or EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
Other VOCs detected in the samples include MTBE and acetone. MTBE was detected in samples
from MW-3D and CW-1 at concentrations of42 and 14 µg/L, respectively. Acetone was detected
at 83 µg/L in the sample from MW-2D. Detected concentrations of MTBE and acetone were
below the State MCLs of200 µg/L and 700 µg/L, respectively.
Private wells or former private wells exhibited the highest concentrations of TCE and also PCE
(see Table 2-4). Concentrations ofTCE in the samples from the residential wells ranged from 8 to
34 µg/L. All other detections also occurred in sampling points south to southeast or downgradient
from the suspected source area; the furthest (PW-1) is approximately 1,150 feet downgradient.
The sampling point nearest to the suspected source area is the residential well located at 2419
Davis Park Rd., approximately 200 feet south, or downgradient.
Figures 2-6 and 2-7 present estimated areal extent maps for PCE and TCE in the bedrock aquifer.
A comparison of PCE and TCE isopleth maps generated by EPA in the Phase II RI report
(Figures 2-4 and 2-5) with Figures 2-6 and 2-7 show good agreement between the two data sets.
The contours have changed as a result of the most recent sampling effort; however, the
contaminant plumes appear to be better characterized.
2.3.3 Soil Boring-Groundwater Sample Results
Groundwater was sampled from boring SPG-3, located adjacent to the Davis Park Auto Repair
building, on April 9, 1998. The groundwater sample was analyzed for VOCs using EPA Method
8260. No VOCs were detected in the sample. Table 2-6 summarizes analytical results.
NOR/K:IWP\044001071 IFSDDN001.OOC 2-19
sr,w-<O ND)
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DAVIS PARK /
AU TO REPAIR SHOP
(OFF MAP)
0c"" '< "
:,..
2 2 w
CEDAR OAK CIRCLE
PROJECT TITLE•
$~W-1D (ND)
DAVIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
PCE CONCENTRATION ISOPLETH MAP
1997 /1998 FIELD INVESTIGATION
FIGURE 2-6
LEGEND ---ESTit.lATED AREAL EXTENT Of PCE (5ug/l) IN BEDROCK AQUIFER.
(J2) TETRACHLOROElHENE CONCENTRATIONS IN UG;L
WW-1 • -...Ell. LOCATIONS.
(NO) NOT DETECTED.
COMBINED FACTOR -0.9998411 (NAO BJ)
POINT NORTHING EASTING ELEVATION ELEVATION a.tVAllOH
TOP PIPE TOP PL.ATE GROUND
100 5455+4.652 1338740.388 688.27 MW-1S 688.85 688.85
IOI 5-45495.20-4 13388-46.893 687.50 MW-1D 687.80 687.81
102 545674.010 1338358.610 707.21 CW-5 706.61
10, 544827.129 13J8881.108 88-4-.80 MW-20 684.89 68-4.88
104 5~.945 1338868.067 68-4.60 MW-25 685.04 684.99
105 5«510.539 1338-455.456 677.28 MW-5S 677.52 677.52
106 54-4881.886 1338621.461 687.57 PW-1 688.15
107 5-45319.342 1337914.911 716.12 MW-4S 716.65 716.68
108 546610.771 1337145.070 HJ.74 MW-JS H-4.42 7«.37
109 5.(.6676.623 1337132.994 746.29 MW-30 746.75 746.75
110 546139.528 13J8513.369 705.76 CW-6 705.21
111 545175.589 1337035.677 739.97 MW--40 740.« 740.<45 112 546474.<476 1337682.51<4 764-.35 PW-2 764.09 "' 546568.657 1337641.640 768. 75 cw-• 766. 78 141 546888.586 1337295.709 761.18 cw-, 761.41 761.4-1 128 546827.885 1336850.318 757. 79 CW-2 758.62 758.59 129 547139.622 1336707.606 761.69 CW-1 760.88 "' 54685<4.891 1337483.389 771.21 EMW-1 771.19 769.78 m 546857.745 13374-85.094 771.86 EMW-2 773.00 770.22
BENOi MARK USED WAS THE aTY or GASTONIA BENOi MARK, QUADRANT 3, BENOi MARK
No. 41, LOCATED AT THE INTERSECTION or 0Av1S PARK ROAD AND STAGE COACH ROAD.
El.£VATlON • 731,05'
DRA'w'N1 DATE1 \1.0. N□.,
04400-071-095 M. SNEED 5 18 98
CHECKED• DATE1 APPROVE Di CAD FILE NAME•
DAVISPCE.DWG
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DAVIS PARK / _,,,---.-----
1\U lO REPAIR SHOP ,/ r:i-2 S ',.._
(OFF MAP) / ',,
/ ' Sug/L '
$MW-4D (ND)
I ',
I '
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0 ' I« ,~
10 I §! I w ,~
~ \
/, \ II , ,_
\ ~
\ ~ \ en
\ 0
\ 0
\, ~ ', ~ ,0-
"' ' "i-l, ,'<-'--" ~: ____ _
CEDAR OAK CIRCLE
$ CW-5 (32)
$<:W-6
(ND)
rN"{,)5S$ /
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(ND)
_.l----
-. -. <;R[EK . BL~CKWODD
LEGEND
----5----ESTIMATED AREAL EXTENT OF TCE (Sug/L) IN BEDROCK AQUIFER.
(32) TRICHLOROETHENE CONCENTRATIONS IN UG/L
t.lW-1 $ MONITOR ¥,£LL LOCATIONS.
(ND) NOT DETECTED.
COMBINED FACTOR ,.. 0.9998411 (NAO 83)
POINT NORTHING EASTING ELEVATION EL£VA TlON El£VATION
TOP PIPE TOP PLAT£ GROUND
100 54554-4..652 1338740.368 688.27 MW-15 688.85 688.85
101 545495.204 13388.«i.893 687.50 MW-10 687.80 687.81
102 545674.010 1338358.610 707.21 CW-5 706.61
103 5+4827.129 1338881.108 684.60 t.CW-20 684.89 68-4.88
104 5-4-4846.945 1336868.067 68-l..60 MW-2S 685.04 684.99
105 54-4510.539 1338455.456 677.26 MW-5S 677.52 677.52
106 544681.886 1338621.461 667.57 PW-1 686.15
107 545319.342 1337914.911 716.12 MW-4S 716.65 716.68
108 546610.771 1337145.070 743.74 MW-3S 74--4.42 744.37
109 546676.623 1337132.994 746.29 MW-JD 746.75 746.75
110 546139.528 13J8513.J69 705.76 CW-6 705.21
111 545175.589 1337035.677 7J9.97 MW-40 74-0.44 740.45 112 546474.476 1337682.514 764.35 PW-2 764.09 113 54-6568.657 1JJ7641.640 768.75 CW-4 766.78 141 546888.586 1337295.709 761.18 CW-3 761.41 761.41 128 546827.885 tJ36850.J18 757.79 CW-2 758.62 758.59 129 547139.622 1336707.806 761.69 CW-1 760.SB 136 546854.891 1337483.389 771.21 EMW-1 771.19 769.78 1J7 546857.745 1337485.094 771.86 EMW-2 77J.OO 770.22
BENCH t.4ARK USED WAS THE CITY OF GASTONIA BENCH MARK, QUADRANT 3, BENCH MARK
No. 41, LOCATED AT THE INTERSECTION OF DAVlS PARK ROAD ANO STAGE COACH ROAD.
ELEVA llON -731.05'
I .---...i..;.--------------r----------=,,.,,..,,--:=~..,,,,,.-----------1 PROJECT TITLE•
DAVIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
TCE CONCENTRATION ISOPLETH MAP DRA'w'N• DATE, DES. 'JD. NO.•
1997 /1998 FIELD INVESTIGATIONS M. SNEED 5 18 98 04400-071-095
I CHECKED• DATE• APPROVED• CAD FILE NAME•
._ _________________________________________ _.. _________ FI_G_U_R_E_2-_7 ________ ~~----~---~------~~---.._ ... D __ A_V_IS_T_C_E_.D_W_G~
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
Table 2-6
Groundwater Sample -Soil Borings
Analytical Summary
Volatile Organics (ug/kg)
EPA Method 8260
Acetone
Acrylonilrile
Allyl Chloride
Benzene
Bromobenzene
Bromochloromethane
Bromodichloromethane
Bromofonn
Bromomethane
2-Butanone
N-Butylbenzene
Sec-Butylbenzene
Tert-Butylbenzene
Carbon Disulfide
Carbon Tetrachloride
Chlorobenzene
Chlorodibromomethane
Chloroethane
2-Chloroetliyl Vinyl Ether
Chlorofom1
Chloromethane
2-Chlorotoluene
4-Chlorotoluene
Davis Park Road TCE Site
Gastonia, North Carolina
ID: GP3
Depth (ft hgs): 35-36
Date: 4/9/98
--
--
----
--
--
--
--
----
----
--
--
--
--
----
------
--
--
1,2-Dibromo-3-Chloropropane --
1,2-Dibromoethane --
Dibromomethane --
1,2-Dichlorobenzene --
1,3-Dichlorobenzene --
1,4-Dichlorobenzenc --
Dichlorodifluoromcthane --
I, 1-Dichloroethane --
1,2-Dichloroethane --
I, 1-Dichloroethene --
cis-1,2-Dichloroethenc --
trans-1,2-Dichloroethene --
1,2-Dichloropropane --
1,3-Dichloropropanc --
2,2-Dichloropropane --
I, 1-Dichloropropene --
cis-1,3-Dichloropropene --
trans-1,3-Dichloropropene --
K:IWP\04400\071 \Fs-tbls Table 2-6 2-22
Trip
Blank Detection
4/10/98 Limit
--5 --5
--5
--5
--5
--10 --5
--5
--5 --5
--5 --10
--5
--10
--2
--2
--10
--5
--5
--5 --5
--5
--10
--5
--5
--5
--5
--5 --5
--5
--5
--5 --5
--5
--5
--5
--5
--5
--5
--5
--5
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
Table 2-6 (Continued)
Groundwater Sample -Soil Borings
Analytical Summary
Davis Park Road TCE Site
Gastonia, North Carolina
· Volatile Organics (ug/kg) ID:
EPA Method 8260 Depth (ft bgs):
Date:
cis-1, 4-Dichloro-2-Butene
trans-1,4-Dichloro-2-Butene
Ethylbenzene
Ethyl Methacrylate
Hexachlorobutadiene
2-Hexanone
IodomeUiane
Isopropylbenzene
P-Isopropyltoluene
Methacrylonitrile
MeU1ylene Chloride
MeU1yl MeUiacrylate
4-Methyl-2-Pentanone
Methyl-ten-Butyl Ether
Naphthalene
Pentachloroethane
N-Propylbenzene
Styrene
1,1,1,2-Tetrachloroethane
I, l ,2,2-TetrachloroeU1ane
Tetrachloroethene
Toluene
1,2,3-Trichlorobenzene
1,2,4-Trichlorobenzene
I, I, I -Trichloroethane
I, 1,2-Trichloroethane
TrichloroeU1ene
Trichlofluoromethane
1,2,3-Trichloropropane
1,2,4-Trimethylbenzene
1,3,5-Trimethylbenzene
Vinyl Acetate
Vinyl Chloride
Xylene (Total)
--= Malena! was analyzed for but not detected
ft bgs = feet below ground surface
K:\WP\04400\071 \Fs-tbls Table 2-6 2-23
GP3
35-36
4/9/98
--
--
--
--
--
--
--
----
--
--
--
--
6
--
--
--
--
--
--
--
--
--
--
--
--
----
--
--
--
--
--
--
Trip
Blank Detection
4/10/98 Limit
--5
--5
--5
--5
--5 --5
--5
--5
--IO --5
--5
--5
--10
--5
--5
--5
--5
--50
--IO --50
--5
--IO
--IO
--IO
--5 --5
--5 --5
--5
--5 --5
--IO
--10 --5
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
2.4 SUMMARY OF RI GROUNDWATER SAMPLE DATA
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
Although many of the residential supply wells surrounding the site have been sampled during the
R1 and previous investigations, the total depths of many of these wells, and subsequently the
aquifer in which the wells are set, remains unknown. Therefore, there has been no conclusion as
to whether the overburden aquifer or bedrock aquifer or both aquifers are contaminated.
However, based upon information gained from the conversion of residential wells to monitor
wells, discussions between WESTON personnel and private well owners, and measurements
collected from actual residential wells, several of the residential wells that have been sampled are
set within the bedrock aquifec In addition, all of the groundwater samples collected during the
1997/1998 investigation and found to be contaminated were from wells set into the bedrock
aquifer. Therefore, based upon data collected from all three phases of the RJ, the overburden
aquifer does not appear to be contaminated by the TCE and PCE detected in groundwater
samples from the site; rather the bedrock aquifer appears to continue to be contaminated by
voes.
Using Tables 2-2 and 2-5 to compare bedrock aquifer sample analytical data (where PW-I is the
same well as that of Well ID No. 285, PW-2 is the same as Well ID No. 121, and CW-5 is the
same as Well ID No. 239), the contaminant plume concentration appears to be decreasing along
the northern edge while increasing slightly to the south. In the central portion of the plume (at
monitor well CW-5/Well 239), the concentrations of TCE and PCE appear to have remained
steady over an approximate two-year period (the time between the two investigative phases). An
exception to the decrease of contaminant plume concentration along the northern edge can be
found at the residential well PW-3. The sample from this well contained the highest concentration
ofTCE encountered during the 1997/1998 investigation at 34 µg/L.
NOR/K:\WP\04400\071\FSODN001.DOC 2-24
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
Based on the I 997 / I 998 investigation sample data, the plume appears to be concentrated in the
bedrock aquifer in the area underlying Davis Park Road. The southeastern and southern edge of
the plume remains undefined. The furthest downgradient bedrock monitor well on site, MW-2D,
was contaminated with concentrations similar to concentrations detected in the sample from the
nearby residential well, PW-I.
2.5 DAT A GAPS
By analyzing all available groundwater VOC data, additional groundwater investigation activities
are necessary due to the following reasons:
• Insufficient data are available to accurately delineate the plume boundary between interior
and plume boundary wells along the southeastern and southern perimeter of the site.
Contamination has been detected in monitor well MW-2D, which is located along the
southeastern edge of the site. There is no monitor well between MW-2D and MW-4D,
located at the western perimeter of the site. Therefore, the southern perimeter of the
plume cannot be accurately defined at this time.
• Total depths of many of the residential supply wells are unknown. Based on the
groundwater sample analytical data from the 1997 /I 998 investigation, the bedrock aquifer
appears to be the aquifer underlying the Davis Park Road site that is contaminated. This
aquifer continues to be used by local residents; however, the total depths of many of the
residential wells is unknown and, as a result, the number of wells pulling groundwater
from the bedrock aquifer is also unknown.
Recommendations for filling the data gaps are as follows:
NOR/K:\WP\044001071 \FSDDND01. DOC 2-25
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. (t shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Dale: July 1998
• Installing a single bedrock aquifer monitor well at the southern perimeter of the site will
allow for the southern boundary of the plume to be defined.
• Conducting a door-to-door information search in the neighborhoods surrounding the
present plume boundary to determine if well owners know the total depth of their water
supply well and to request permission to tag the bottom of the well if the depth is
unknown.
In an effort to fill these data gaps, a Pre-Design Study will be conducted prior to completing the
final remedial design.
2.6 RISK ASSESSMENT
A Baseline Risk Assessment was performed for the site to evaluate the potential adverse human
health and ecological effects due to the presence of chemicals in the groundwater resulting from
past or present activities at the Davis Park Road site. The two components of the risk assessment
are:
• Human Health Risk Assessment -Based on future residential development.
• Ecological Risk Assessment -Based on threatened and endangered species in the area.
A Baseline Risk Assessment Report was prepared by WESTON and submitted under separate
cover. The following risk assessment conclusions have been made:
NORIK:IWP\04400\071 \FSDDN001. DOC 2-26
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt sha!I not be disclosed, in whole or in part, without the express
written permission of EPA.
Human Health Risk Assessment:
Feasibility Study Report
Davis Park Road TCE Site
Section: 2
Revision: 1
Date: July 1998
• Current residential well data was not used to calculate quantitative risk calculations.
However, State and federal standards are exceeded by levels of TCE and PCE in drinking
water.
• Levels of MTBE in the overburden aquifer, albeit at only one location, are in the range of
non-cancer risks for both children and adults if water from the aquifer were used for
drinking and showering.
• No cancer risks were generated for future residents for the overburden aquifer.
• Cancer risks from the bedrock aquifer for future residents is due primarily to chloroform,
I, 1-dichloroethene, and PCE.
Ecological Risk Assessment:
• According to the data collected during the RI, there are no endangered species within the
site. Therefore, exposure to contaminated groundwater would not pose an additional
threat.
2.7 SUMMARY
Based on groundwater data available at the Davis Park Road site and the ongms of the
contaminants detected in groundwater, the contaminants of concern at the site are TCE and PCE.
By examining the contaminant concentrations and contours in Figures 2-6 and 2-7, the plume with
the largest surface area is the bedrock aquifer TCE plume. TCE is also the contaminant with the
highest detected concentration in the groundwater. Therefore, the bedrock aquifer TCE
contaminant plume in Figure 2-7 will be used to define the outer boundary of the plume of the
contaminants of concern.
NOR/K:IWP\04400\071 \FSDDN001. DOC 2-27
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
SECTION 3
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
APPLICABLE OR RELEVANT AND APPROPRIATE ENVffiONMENTAL AND
PUBLIC HEALTH REQUrnEMENTS (ARARS)
3.1 INTRODUCTION
The Comprehensive Environmental Response, Compensation and Liability Act of 1980
(CERCLA), 42 USC §9601 et seq .. as amended, and the National Contingency Plan (NCP), 40
CFR 300, requires that the development and evaluation of remedial actions under CERCLA,
commonly known as Superfund, include a comparison of alternative site responses to applicable
or relevant and appropriate Federal and State environmental and public health requirements
(ARARs).
ln accordance with the requirements of the NCP, the remedial action selected must meet all
ARARs unless a waiver from specific requirements can be granted by EPA or by the State.
According to CERCLA Section 12l(d)(4), 42 USC §962l(d)(4), and the NCP, 40 CFR 300.430,
a waiver may be granted for one or more of the following conditions:
• The remedial action under consideration is only an interim remedy and is not the final or
permanent remedy selected for the site.
• Compliance with the ARARs would create greater risks to public health than benefits.
• Compliance with such standards is technically impractical.
• A different remedy exists that provides public health protection equivalent to the preferred
cleanup standard.
• With respect to a State requirement, a more stringent state standard which would
otherwise be applicable has not been consistently applied to other sites in the state.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. rt sha!I not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• The cost of the remedy is too expensive, considering the other demands on the fund.
3,2 IDENTIFICATION OF ARARS
Identification of ARARs must be performed on a site-specific basis. The NCP and CERCLA do
not provide across-the-board standards for evaluating whether a particular remedial action will
produce an adequate remedy at a particular site. Rather, the process recognizes that each site will
have unique characteristics that must be evaluated and compared to those applicable or relevant
and appropriate requirements that apply under the given circumstances. ARARs are defined as
follows:
• Applicable requirements are those cleanup standards, standards of control, and other
substantive environmental protection requirements, criteria, or limitations promulgated
under Federal, state, or local law that specifically address a hazardous substance,
pollutant, contaminant, remedial action, location, or other circumstance_ found at a
CERCLA site. Only those state standards that are identified by a state in a timely manner
and that are more stringent than federal requirements may be applicable. Applicable
requirements are defined in the NCP, 40 CFR 300.5 Definitions.
• Relevant and appropriate requirements are those cleanup standards, standards of control,
and other substantive environmental protection requirements, criteria, or limitations
promulgated under Federal, state, or local law that, while not "applicable" to a hazardous
substance, pollutant, contaminant, remedial action, location, or other circumstance at a
CERCLA site, address problems or situations sufficiently similar to those encountered at a
CERCLA site. Only those state standards that are identified by a state in a timely manner
and that are more stringent than federal requirements may be applicable. Applicable
requirements are defined in the NCP, 40 CFR 300.5 Definitions. ·
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
It should be noted that the Davis Park Road TCE site has not been classified as a National
Priorities List (NPL) site under CERCLA, but has been scored on the Hazard Ranking System by
the State of North Carolina and is under consideration for the NPL.
For remedial actions performed under CERCLA, permits for compliance with relevant and
appropriate regulations for on-site removal actions are not required; however, CERCLA does
require that the selected alternative meet relevant and appropriate regulatory standards or
performance levels where possible.
ARARs may be divided into the following three categories:
• Chemical-specific requirements are health-or risk-based concentration limits or ranges in
various environmental media for specific hazardous substances, pollutants, or
contaminants. These limits may take the form of action levels or discharge levels.
• Location-specific requirements are restrictions on activities that are based on · the
characteristics of a site or its immediate environment. An example would be restrictions on
wetlands development.
• Action-specific requirements are controls or restrictions on particular types of activities in
related areas such as hazardous waste management or wastewater treatment. An example
would be RCRA incineration standards. Such requirements are triggered by the particular
remedial alternative action considered and the Feasibility Study (FS).
Based on discussions with U.S. EPA-Region IV and North Carolina Department of
Environmental, Health and Natural Resources (NCDEHNR) and review of appropriate guidance
documents (EPA 1988c, EPA I 989c), Federal, state, and local ARAR sources were identified as
listed in Table 3-1.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
FEDERAL
STATE
Table 3-1
Summary of ARAR Sources Evaluated
Davis Park Road TCE Site
May 1998
Resource Conservation and Recovery Act (RCRA)
Clean Water Act (CWA)
Safe Drinking Water Act (SDWA)
Clean Air Act (CAA)
Occupational Safety and Health Act (OSHA)
Hazardous Materials Transportation Act
Protection of Wetlands (Executive Order 11990)
Floodplain Management (Executive Order 11988)
Regulations Protecting Landmarks, Historical, and Archeological Sites
Endangered Species Act
Fish and Wildlife Conservation Act
North Carolina Water and Air Resources Act
North Carolina Drinking Water Act
North Carolina Water Pollution Control Regulations
Nortl1 Carolina Drinking Water and Groundwater Standards
Nortl1 Carolina Surface Water Quality Standards
North Carolina Well Construction Standards
North Carolina Air Pollution Control Regulations
North Carolina Hazardous Waste Management Rules
Nortl1 Carolina Solid Waste Management Rules
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Sile
Section: 3
Revision: 1
Date: July 1998
Tables 3-2 and 3-3 summarize Federal and State ARARs, respectively, presenting the following
information:
• Standard, requirement, criteria, or limitation
• Regulatory citation
• Description
• Applicability of the ARAR (yes or no)
• Justification Comments
Subsections 3.3 and 3.4 further discuss the potential Federal and State ARARs m terms of
associated requirements.
3.3 FEDERAL ARARS
This section discusses the Federal ARAR sources found to be potentially applicable to the site.
ARAR sources include:
• Resource Conservation and Recovery Act (RCRA)
• Clean Water Act (CW A)
• Safe Drinking Water Act (SOWA)
• Clean Air Act (CAA)
• Occupational Safety and Health Act (OSHA)
• Hazardous Materials Transportation Act
• Protection of Wetlands (Executive Order 11990)
• Floodplain Management (Executive Order I 1988)
• Regulations Protecting Landmarks, Historical, and Archeological Sites
• Endangered Species Act
• Fish and Wildlife Conservation Act
NOR/K:\WP\04-400\071\FSDDN001.DOC 3-5
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Standard, Requirement, Regulatory Citation
Criteria, or Limitation
Resource Conscn·ation and Recovery Act
Location-Specific ARARs
Seismic considerations 40 CFR 264.18(a)
Floodplains 40 CFR 264.18(b)
Action-Specific ARARs
Requirements for hazardous 40 CFR Part 262
waste generators
Requirements for 40 CFR Part 263
transporters of hazardous
waste
Requirements for owners 40 CFR Pan 264
and operators of hazardous
waste treatment, storage, and
disposal (TSD) facilities
NOR/K:\WP\044001071\FS-TBLS.OOC
Table 3-2
Analysis of Potential Federal ARARs
Davis Park Road TCE Site
May 1998
Description
Restricts location ofTSD facilities within 200 fl
of a fault that has had a displacement within
Holocene time.
Requires TSD facility located within a I 00-year
flood plain to be designed, constructed, operated,
and maintained to prevent washout of any
hazardous wastes by a I 00-ycar nood.
Establishes standards for generators of
hazardous wastes.
Establishes standards which apply to
transporters of hazardous waste within the
United States if the transportation requires a
manifest under 40 CFR Part 262.
Establishes minimum national standards which
define the acceptable management of hazardous
wastes for owners and operators of facilities
which treat, store, or dispose of hazardous
wastes.
3-6
Applicability Justification Comments
(Yes/No)
No No known acth·c faults within or in the
vicinity of the site.
No The site or the remedial actions are not
located in the l00-year flood plain.
Yes Potentially applicable to remedial
actions involving removal of hazardous
waste (e.g. spent carbon from carbon
adsorption process).
Yes Potentially applicable to remedial
actions im·olving removal of hazardous
waste (e.g. spent carbon from carbon
adsorption process).
Yes Potentially applicable to remedial
actions involving removal of hazardous
waste (e.g. spent carbon from carbon
adsorption process).
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express written permission of EPA.
Standard, Requirement, Regulatory Citation
Criteria, or Limitation
Clean Water Act (CWA)
Chemical-Specific ARARs
Water quality criteria CWA Part 303
40 CFR Part 131
Action-Specific ARARs
National Pollutant Discharge CWA Part 402
Elimination System 40 CFR Part 122
(NPDES) requirements
Emuent guidelines and 40 CFR Part 40 I
standards for the point source
category
National pretreatment CWA Part 307(b)
standard for indirect 40 CFR Part 403
discharge to a POTW
Technology-based effluent CWA Part 30l(b)
limitations
NOR/I< \WP\04400\071\FS-TBLS.OOC
Table 3-2 (Continued)
Analysis of Potential Federal ARARs
Da,-is Park Road TCE Site
May 1998
Description
Establishes water quality criteria based on the
protection of human health and aquatic life.
Requires pennit for emuent discharge from any
point source into surface waters of the United
States.
Requires specific effluent characteristics for
discharge through NPDES system.
Establishes standards to control pollutants which
pass through or interfere with treatment
processes in public treatment works which may
contaminate sewage sludge.
Establishes guidelines to detennine effluent
standards based on the Best Available
Technology (BAT) economically achievable.
3-7
Applicability Justification Comments
(Yes/No)
Yes Potentially applicable to remedial
actions inYolYing discharge of treated
groundwater to a surface water body.
Yes Potentially applicable to remedial
actions involving discharges to surface
waters.
No No categorical standards established for
hazardous waste sites.
Yes Potentially applicable to current
discharge of groundwater into local
POTWs.
Yes Potentially applicable to groundwater
remediation at Davis Park Road site.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Standard, Requirement, Regulatory Citation
Criteria, or Limitation
Safe Drinking Water Act (SDWA)
Chemical-Specific ARARs
National Primary Drinking 40 CFR Part 141
Water Standards
National Secondary 40 CFR Part 143
Drinking Water Standards •
Maximum Contaminant 40 CFR Part 14 I
Le,·el Goals •
Action-Specific ARARs
Underground Injection 40 CFR Parts 144-147
Control (UIC) Regulations
Table 3-2 (Continued)
Analysis of Potential Federal ARARs
Davis Park Road TCE Site
May 1998
Dcscri11tion
Establishes health-based enforceable standards
for public water systems (maximum contaminant
levels (M CLs)).
Establishes aesthetic-based, non-enforceable
guidelines for public water systems (secondary
maximum contaminant levels) (SMCLs).
Establishes non-enforceable drinking water
quality goals (MCLGs) set at levels of no known
or anticipated adverse health effects with an
adequate margin of safety without consideration
of available treatment technology or cost.
Provides for protection of underground sources
of drinking water.
Applicabilit~· Justification Comments
(Yes/No)
Relevant and Current limited use and future potential
Appropriate use of groundwater as a potable water
supply.
Relevant and Current limited use and future potential
Appropriate use of groundwater as a potable water
supply.
Rc1cYant and Current limited use and future potential
Appropriate use of groundwater as a potable water
supply.
Yes Potentially applicable to groundwater
remediation if re-injection of
groundwater or injection is selected as
a discharge technologv.
* The Drinking Water Standards are only applicable for public water systems having at least 15 service connections or serving an average of at least 25 year round
residents.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Standard, Requirement, Regulatory Citation
Criteria, or Limitation
Clean Air Act (CAA) 1
Chemical-Specific ARARs
National Primary and 40 CFR Part 50
Secondary Ambient Air
Quality Standards (NAAQS)
National Emission Standards 40 CFR Part 61
for Hazardous Air Pollutants
(NESHAP)
Occupational Safety and Health Act
Action-Specific ARARs
Safety of workers 29 USC 651-678
29CFRl910
Hazardous Materials Transportation Act
Action-Specific ARARs
Hazardous Materials 49 USC 1801-1813
Transportation Regulations 49 CFR 107, 171-177
Table 3-2 (Continued)
Analysis of Potential Federal ARA Rs
Da,·is Park Road TCE Site
May 1998
Description
Establishes ambient air quality standards for
seven classes of pollutants -carbon monoxide,
lead, nitrogen dioxide, particulate matter, ozone,
and sulfur oxides. Standards do not apply
directly to source-specific emissions, but are
ambient concentration limitations.
Establishes emission standards for seven
contaminants -benzene, mercury, arsenic,
asbestos, beryllium, vinyl chloride, and
radionuclides.
Regulates workers' health and safety
Regulates transportation of Department lo
Transportation (DOD-defined hazardous
materials.
1 The State of North Carolina does not currently have CAA requirements for air stripping.
NOR/K:\WP,04400\071 \FS.. TBLS. DOC 3-9
Applicability Justification Comments
(Yes/No)
No Only "major sources" (emissions
exceeding I 00-250 tons per year of
regulated pollutants) arc subject lo
N AAQS attainment requirements.
No Nol applicable to the site as benzene
and Yinyl chloride are not produced as
a result of manufacturing operations.
Yes Applicable lo remedial actions at the
site.
Yes Applicable lo remedial action invol\·ing
transportation of DOT-defined
hazardous materials off-site.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permJssion of EPA.
Standard, Requirement, Regulatory Citation
Criteria, or Limitation
Protection of Wetlands (Executive Order 11990)
Location-Specific ARARs
Regulations to protect Executive Order No.
wetlands 11990
40 CFR 6.302(a) and
Appendix A.
Floodplain Management (Executive Order I 1988)
Location-Specific ARARs
Regulations to protect Executive Order No.
floodplains 11988
40 CFR 6.302,
Appendix A
Table 3-2 (Continued)
Analysis of Potential Federal ARA Rs
Davis Park Road TCE Site
May 1998
Description
Requires consideration of the adverse impacts
associated with the destruction or loss of
wetlands and to avoid support of new
construction in wetlands if a practical alternative
exists.
Requires evaluation of the potential efTccts of
actions which may be taken in a floodplain to
avoid the adverse impacts associated with direct
and indirect development of a floodplain.
Regulations Protecting Landmarks, Historical, and Archeological Sites
Location-Specific ARARs
National natural landmarks Historic Sites Act of Establishes regulations to protect national
1935, 16 USC-161, 40 natural landmarks during remedial actions.
CFR 6.30l(a)
Historic, architectural, National Historic Establishes regulations to protect historic,
archcological, and cultural Preservation Acl of architectural, archeological, and cultural sites
sites 1966, 16 USC -170, 36 during remedial actions.
CFR800
Executive order 11593
40 CFR 6.30l(b)
NOR/K: \WP\04400\071 \FS-TBLS. DOC 3-10
Applicabilit)' Justification Comments
(Yes/No)
No Site is not located in a wetland area.
No Site is not located in the 100-year
floodplain.
No Site is not located in an area with
natural landmarks.
No Site is not located in an area with
historic, architectural, archeological or
cultural sites.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express written permission of EPA.
Standard, Requirement, Regulatory Citation
Criteria, or Limitation
Table 3-2 (Continued)
Analysis of Potential Federal ARARs
DaYis Park Road TCE Site
May 1998
Description
Regulations Protecting Landmarks, Historical, and Archeological Sites (Continued)
Historic, prehistoric and Archeological Establishes regulations to protect historic,
archcological data Preservation Act of prehistoric, and archcological data during
1974, 16 use 469 et remedial actions.
seq.
Executive Order 11593
40 CFR 6.30 I (c)
Endangered Species Act
Action-Specific ARARs
Protection of endangered 16 USC 1531 Requires action to conserve endangered species
species 50 CFR Part 200 and/or critical habitats upon which endangered
50 CFR Part 402 species depend.
Fish and Wildlife Conservation Act
Action-Specific ARARs
Protection of fish and 16 USC 2901 et seq. Requires adequate provision for protection of
wildlife due to any fish and wildlife resources when any
modifications modification of any stream or other water body
is proposed.
NOR/K\WP,04400\071 \FS-TBLS. DOC 3-l l
Applicability Justification Comments
(Yes/No)
No Site is not located in an area with
prehistoric or archcological data.
No Not applicable as endangered and
threatened species have not been
identified within or surrounding site
boundary.
Yes Potentially applicable. Confirmation
with the responsible State agency
regarding the site being located in one
of these significant habitats.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Standard, Requirement, Citation
Criteria, or Limitation
No1ih Carolina Water and Air Resources Act
Action-Specific ARARs
Laws to achieve and to General Statutes,
maintain a total environment Chapter 143 Article
with superior quality. 21B
North Carolina Drinking Water Act
Action-Specific ARARs
Regulations on drinking General Statutes
water Chapter 130A, Article
IO
North Carolina Water Pollution Control Regulations
Action-Specific ARARs
Requirements for wastewater NCAC Title 15
discharge to surface water Chapter 2, Subchapter
2H
Wastewater Treatment NCAC Title I 5,
Requirements Chapter 2, Subchaptcr
2H.OIOO
Table 3-3
Anal~·sis of Potential State of North Carolina ARARs
Da,·is Park Road TCE Site
May 1998
Description Applicability
(Yes/No)
State equivalent of the Federal CW A and CAA Yes
Establishes criteria for protection of state public Yes
water supplies.
Requires permit for discharge of emuent from Yes
point sources into surface waters. State-level
version of federal NPDES program.
Establishes basic wastewater treatment Yes
requirements for effiucnt discharge.
North Carolina Drinking Water and Groundwater Standards
Chemical-Specific ARARs
Groundwater Classifications NCAC Title 15, Establishes groundwater and drinking water Yes and Standards Chapter 2, Subchapter standards based on the usage.
2L.0200 and 0.0201
NOR/K:\WP\04400\071\FS-TBLS.DOC 3-12
Justification Comments
Potentially applicable for remedial
action involving cleanup of groundwater
and emissions to the atmosphere.
Current limited use and potential future
use of groundwater as a potable water
supply.
Potentially applicable to remedial
actions involving point source
discharges to surface waters.
Potentially applicable to remedial
actions involving point source
discharges.
Potentially applirnblc to groundwater
remediation based on anticipated usage
of water in the future.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express written permission of EPA.
Standard, Requirement, Citation
Criteria, or Limitation
North Carolina Surface Water Quality Standards
Chemical-Specific ARARs
Classification and water NCAC Title 15A,
quality standards applicable Chapter 2,
to surface water Subchapters 2L.0 l00
and 2L.0200
Technology-based effiuent NCAC Title 15A,
limitations Subchapter 2B.0400
North Carolina Well Construction Standards
Action-Specific ARARs
Administrath·e and NCAC Title 15A
construction requirements Subchapter 2C
for injection wells
North Carolina Air Pollution Control Regulations
Chemical/Action-Specific ARARs
Permit requirements for NCACTitle 15A
voe emissions from air Chapter 143
strippers Subchapter 2D.0518
NOR/K:\WP\04400\071\FS-TBLS.DOC
Table 3-3 (Continued)
Analysis of Potential State of No11h Carolina ARARs
Davis Park Road TCE Site
May 1998
Description Aflplicahilit~·
(Yes/No)
Establishes a series of classifications and water Yes
quality standards for surface waters.
Establishes guidelines for effiuenl limitations Yes
based on BAT economically achievable.
Establishes classes of injection wells and set forth Yes
requirements and procedures for pcnnitting,
construction, operation, etc.
If the VOC emissio-ns from an air stripper exceeds Yes
40 lbs/day, an air permit is required prior 10
operation. If the VOC emissions are less than ~0
lbs/day, no air permit is required, however,
information detailing emissions and operations
must be submitted to NCDEHNR.
3-13
Justification Comments
Potentially applicable to groundwater
remediation involving discharge of
treated water to a surface water body.
Potentially applicable to groundwater
treatment.
Potentially applicable if injection of
treated water is selected as a remedial
technology.
Polcntially applicable if air SI ripping is
used as a treatment technology.
... <1!11 --
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Standard, Requirement, Citation
Criteria, or Limitation
North Carolina Hazardous Waste Management Rules
Regulations dealing \\1th NCAC Title 15A,
management of hazardous Subchapler BA
materials
North Carolina Solid Waste Management Rules
Regulations mandated lo NCAC Tille 15A,
control flow and handling of Subchapter 138
solid waste materials
NOR/K:\WP\04400\071\FS-TBLS.DOC
Table 3-3 (Continued)
Analysis of Potential State of North Carolina ARARs
Davis Park Road TCE Site
Ma~· 1998
Description
Location requirements for hazardous waste
lreatmen 1/sloragc/disposal facili tics.
Applicability
(Yes/No)
Yes
Siting requirements for solid waste disposal units Yes
3-14
Justification Comments
May be applicable 10 hazardous waste
exca\·atcd, stored, and treated on site.
May be rcic,·anl and appropriate 10 non-
hazardous waste disposed of on site.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
3.3.1 Resource Conservation and Recovery Act (RCRA)
RCRA, 42 USC 6901 et seq., mandated that EPA:
• Establish a comprehensive regulatory program to control
(Subtitle C).
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
and manage hazardous waste
• Promulgate regulations contammg guidelines to assist in the development and
implementation of state non-hazardous solid waste management plans (Subtitle 0).
In general, RCRA regulations apply to the management of RCRA hazardous wastes and RCRA
waste management (treatment, storage and disposal [TSO]) facilities subsequent to the effective
date of RCRA regulations. Wastes that are removed from closed facilities may be subject to
RCRA waste classificat:;on and must meet RCRA standards with respect to proper management,
treatment, and disposal of the wastes.
Regulations promulgated under RCRA generally provide the basis for management of hazardous
waste and establish techn,J!ogy-based requirements for hazardous waste facilities. RCRA facility
design standards may also be consulted for other wastes containing significant concentrations of
hazardous constituents.
3.3.1.l Location-Specific Requirements
Location-specific ARARs within RCRA included the location standards detailed under
40 CFR 264.18. These stand.~rds potentially apply to the siting of a new on-site TSO unit for
managing RCRA hazardous wastes generated as part of a remedial alternative.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
These location standards are as follows:
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Seismic considerations restrict TSO facilities within 200 feet of a fault that has had a
displacement within Holocene time. As the site is not located in the political jurisdictions
listed in Appendix VI of 40 CFR 264, the site would -be in compliance with this
requirement as per 40 CFR 270.14(b)(l 1).
• Floodplain considerations require TSO facilities located within a I 00-year floodplain to be
designed, constructed, operated, and maintained to prevent the movement of hazardous
waste from the active portion of the facility as a result of flooding. Since the Davis Park
Road site is not within a I 00-year floodplain as established by the Federal Emergency
Management Agency (FEMA), an on-site facility would be in compliance with this
requirement.
3.3.1.2 Action-Specific Requirements
ARARs for management of hazardous waste under RCRA include:
• Generator requirements
• Transporter requirements
• TSO Facility requirements
Each action-specific ARAR is addressed in the following subsections.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
3.3.1.2.1 Generator Requirements
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
Generator requirements under RCRA apply to operations that accumulate RCRA-defined
hazardous wastes generated on-site in containers or tanks for less than 90 days prior to transport
to another facility for proper treatment/disposal. Generators that accumulate RCRA hazardous
waste beyond 90 days operate a RCRA storage facility subject to TSO facility requirements as
discussed under Subsection 3 .3 .1.3 .3. Generator requirements ( 40 CFR 262) are potential ARARs
to the site for remedial actions involving removal/accumulation of materials qualifying as RCRA
hazardous waste for subsequent off-site treatment/disposal. This regulation may be relevant to the
Davis Park Road site depending on the technologies to be used in the remedial actions, for
example, activated carbon adsorption process produces spent carbon, a hazardous waste, which
would be transported off site for treatment or disposal. Specific RCRA generator requirements
include the following:
• Use of the manifest system (Subpart B) to continuously track hazardous waste.
• Pre-transport requirements (Subpart C) including proper packaging, labeling, marking,
placarding, and proper accumulation requirements for containers and/or tanks.
• Recordkeeping and reporting requirements (Subpart D).
3.3.1.2.2 Transporter Requirements
As remedial actions considered for the site include potential transport of RCRA-defined
hazardous waste off-site, RCRA transporter requirements specified under 40 CFR 263 are
potential ARARs.
NOR/K \WP\04400\071 \FSDDN001. DOC 3-17
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written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
The main provision identified under RCRA is compliance with the manifest system (Subpart B).
Other transportation requirements addressed by DOT are discussed under Subsection 3.3.6.
3.3.1.2.3 Treatment, Storage, and Disposal Facility Requirements
Treatment, storage, and disposal (TSO) facility requirements under RCRA apply to facilities
which treat, dispose, or store (for greater than 90 days) RCRA hazardous waste. TSO
requirements ( 40 CFR 264) are potential ARARs to the site for remedial actions involving TSO of
on-site materials qualifying as RCRA hazardous wastes. Specific requirements include:
• General facility standards (Subpart B) including those for waste analysis, security,
inspections, and personnel training.
• Preparedness and prevention standards (Subpart C) addressing facility design and
operation, required equipment, testing and maintenance of required equipment,
communication/alarm systems, and aisle space for container storage.
• Contingency plan and emergency procedures (Subpart D).
• Manifest system, recordkeeping, and reporting (Subpart E) to track hazardous waste
continuously.
• Groundwater monitoring (Subpart F) for new landfill, land treatment, and waste pile units.
• Air emission standards for process vents (Subpart AA) which set standards for process
vents associated with distillation, fractionation, thin-film evaporation, solvent extraction,
or air/steam stripping operations involving RCRA hazardous wastes with organic
concentrations of at least IO ppm (weight basis).
• Air emission standards for equipment leaks (Subpart BB) which sets standards for
equipment that contains or contacts RCRA hazardous waste with organic concentrations
of at least IO ppm (weight basis).
NOR/K:IWP\04400\0711FSDDN001.DOC 3-18
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
TSD regulations are applicable only if the remedial actions include generation of hazardous waste,
for example, spent carbon from carbon adsorption process.
3.3.2 Clean Water Act
The Clean Water Act (CW A), 33 USC 1251, et seq., formerly known as the Water Pollution
Control Act, mandated EPA to establish regulations to protect the quality of surface waters
across the nation. As such, it can be applied as an ARAR to the site based on the potential
discharge of the pretreated groundwater to either surface water or the local publicly owned
treatment works (POTW).
Under the CW A, two interrelated areas were identified for regulation:
• Establishment of water quality standards.
• Establishment of effluent standards (discharge limitations).
Water quality standards represent chemical-specific requirements, while effluent standards are
action-based requirements. Each requirement is addressed separately in this section. No action-
specific requirements were identified.
3.3.2.1 Chemical-Specific Requirements
Under Section 303 of the CWA, the State of North Carolina is mandated to establish a stream
classification system and corresponding set of water quality standards for each classification. To
aid in development of this system, Federal water quality criteria documents have been published
for 65 pollutants listed as toxic under the CW A.
NOR/K:IWP\04400\071 \FSODN001. DOC 3-19
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This document was prepared by Roy F. Weston, lnc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission or EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
The Federal water quality criteria specified under 40 CFR 131 are generally represented in
categories that are aligned with different surface water use designations. Different water quality
criteria have been developed based upon:
• Protection of human health, with consideration of two scenarios:
Water and fish ingestion by humans
Fish ingestion only
• Protection of aquatic life (both freshwater and marine) against acute toxicity and chronic
toxicity effects.
These Federal criteria are unenforceable guidelines that may be used by states to set surface water
quality standards based on designated use of the specific surface water. Although these criteria
were intended to represent a reasonable estimate of pollutant concentrations consistent with the
maintenance of designated water uses, states can appropriately modify these values to reflect local
conditions. The State of North Carolina has used those Federal guidelines to establish surface
water quality standards.
3.3.2.2 Action-Specific Requirements
CW A regulations establish effluent standards for point source discharges as follows:
• Direct discharge to a surface water is governed by the National Pollutant Discharge
Elimination System (NPDES) permitting requirements (Section 402 of the CWA). Specific
permitting requirements are contained under 40 CFR 125, while specific effluent
guidelines and standards are given in 40 CFR 40 I. It should be noted that no categorical
effluent guidelines or standards have been established for hazardous waste sites.
NOR/K:\WP\04400\071 \FSDDNOO 1. DOC 3-20
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written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Indirect discharge to a POTW is governed by pretreatment regulations (Section 307(b) of
the CWA). National pretreatment standards are addressed under 40 CFR 403. The
standards specifically prohibit discharge of the following (40 CFR 403.5):
Ignitable or explosive wastewater
Reactive or toxic fume-generating wastewaters
Used oil
Solvent waste
Pollutants that pass through the POTW without treatment, interfere with POTW
operations, contaminate POTW sludge, or endanger the health or safety of POTW
. workers
Technology-Based Guidelines and Standards
The standards of control for direct discharges are derived from Title III of the CW A. Section
301(b) of the CWA requires all direct dischargers to meet technology-based requirements. These
requirements include, for conventional pollutants, application of the best conventional pollutant
control technology (BCT), and for toxic and unconventional pollutants, the best available
technology economically available (BAT). EPA has determined the technology-based
requirements through effluent limitations guidelines for specific categories of industries, which are
transformed into specific discharge limits by permit writers. Where effluent guidelines for specific
categories of industry or industrial category do not exist, e.g., CERCLA sites, BCT/BAT
technology-based treatment requirements are determined on a case-by-case basis using best
professional judgement (BPJ). Once BPJ determination is made, the numerical effluent discharge
limits are derived by applying the levels of performance of a treatment technology to the
wastewater discharge.
NOR/K IWP\04400\07 t\FSODN001.DOC 3-21
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This document was prepared by Roy F. Weston, lnc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
For treatment of groundwater contaminated with VOCs, air stripping is typically accepted as BAT
based on BPJ. Performance expectations vary state-to-state. However, conservatively low effluent
limitation of 5 µg/L is generally accepted for VOCs, since it is the analytical detection limit for the
most widely used analytical methods.
3.3.3 Safe Drinking Water Act
The Safe Drinking Water Act (SOW A, 42 USC 300f et seq.) mandated EPA to establish
regulations to protect public health from contaminants in drinking water. As such, it can be
applied as an ARAR source based on identification of the current limited local use and the
potential future use of groundwater in the area surrounding the site as a potable water supply.
SOW A chemical-specific and action-specific ARARs have been identified and are discussed in this
section. No location-specific requirements were identified.
3.3.3.1 Chemical-Specific Requirements
The SOW A mandated that EPA establish regulations and standards to protect human health from
contaminants in drinking water. EPA has promulgated primary and secondary drinking water
regulations and standards applicable to public water systems. National Primary Drinking Water
Standards (NPDWS) are established in 40 CFR 141 and are expressed as Maximum Contaminant
Levels (MCLs) that are not to be exceeded in public water supplies. The MCLs are enforceable
human-health based standards that consider available treatment technologies and cost of
treatment. A complete listing of current SOW A MC Ls is given in Table 3-4 for reference.
National Secondary Drinking Water Standards (NSDWS) are established in 40 CFR 143 and are
expressed as Secondary Maximum Contaminant Levels (SMCLs) that should not be exceeded in
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written permission of EPA.
Table 3-4
Summary of National Maximum Concentration Levels {MCLs) for Drinking Water
Davis Park Road TCE Site
Contaminant
VOCs and Semivolatile Organic Compounds
Benzene
Chloroform
Carbon tetrachloride
para-Dichlorobenzene
1,2-Dichloroethane
I, 1-Dichloroethylene
I, I, I-Trichloroethane
Trichloroethylene
Vinyl chloride
Trihalomcthanes
(sum of chloroform, bromoform, bromodi-
chloromethane, dibromochloromethane)
Dichlorobenzene o-, m-
cis-1,2-Dichloroethylene
trans-1-2-Dichloroethylene
1,2-Dichloropropane
Ethylbenzene
Monochlorobenzene
Styrene
Tetrachloroethylene
Toluene
Xylene (total)
Benzo(a)anthracene (P AH)
Benzo(a)pyrene (PAH)
Benzo(a)fluoranthene (P AH)
Benzo(k)fluoranthene (P AH)
Dibenzo(a,h)anthracene (PAH)
Pesticides and PCBs
2,4-D
Endrin
Lindane
Methoxychlor
Toxaphene
2,4,5-TP (Silvex)
NOR/K:IWP\04400\071 IFS-TBLS.DOC
May 1998
3-23
MCL (µg/L)
0.005
0.01
0.005
0.075
0.005
0.007
0.2
0.005
0.002
0.1
0.6
0.07
0.1
0.005
0.7
0.1
0.1
0.005
I
10
0.000 I
0.0002
0.0002
0.0002
0.0003
0.07
0.002 (P)
0.0002
0.04
0.003
0.05
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 3-4 (Continued)
Summary of National Maximum Concentration Levels (MCLs) for Drinking Water
Davis Park Road TCE Site
Contaminant
Pesticides and PCBs (continued)
Alachlor
Atrazine
Carbofuran
Chlordane
DibromocWoropropane
Ethylene dibromide
Heptachlor
Heptachlor epoxide
Polychlorinated biphenyls (PCBs)
Inorganics
Asbestos
Arsenic
Barium
Cadmium
Chromium (total)
Fluoride
Lead
Mercury
Nitrate (as N)
Nitrite (as N)
Total nitrate & nitrite
Selenium
Sodium and corrosion
Radionuclidcs
Beta particle and photon radioactive
Gross alpha particle activity
Radium-226 plus radium-228
Microbials
Colifonns
Turbidity
(P): Proposed
NOR/K. IWP\044001071 IFS-TBLS. DOC
May 1998
3-24
MCL {µg/L)
0.002
0.003
0.04
0.002
0.0002
0.00005
0.0004
0.0002
0.0005
7xl06 fibers/L (longer than IO microns)
0.05
2
0.005
0.01
4
0.015 (action level)
0.002
IO
IO (as nitrogen)
0.05
No MCL; monitoring and
reporting only
4 mrem (annual dose equivalent)
15 pCi/L
20 pCi/L (P)
<1/100 mL
I ntu (up to 5 ntu)
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
public water supplies. The SMCLs are unenforceable (on the federal level), aesthetic-based
guidelines that consider available treatment technologies and cost of treatment.
In addition to the primary and secondary standards, EPA has established Maximum Contaminant
Level Goals (MCLGs), 40 CFR 141. The MCLGs are unenforceable guidelines based strictly on
human-health considerations without regard for available treatment technologies and/or the cost
of treatment. For a particular parameter, MCLGs are established by EPA at the time an MCL is
established.
Table 3-5 summarizes the current and proposed SOWA MCLs, MCLGs, and SMCLs for the
primary contaminants of concern at the site.
3.3.3.2 Action-Specific Requirements
Also included under the SOW A is the Underground Injection Control (UIC) program ( 40 CFR
144-147). The UIC program was established under Part C of the SOWA to protect underground
sources of drinking water from endangerment by subsurface emplacement of fluids through wells.
There are five classes of injection wells defined by the regulation:
•
•
Class I wells are wells that inject municipal or industrial wastewater (including hazardous
waste) below the lowermost underground source of drinking water. Underground sources
of drinking water are those currently serving as a public drinking water supply. or those
that have the potential to serve as a public drinking water supply, and have less than
I 0,000 mg/L Total Dissolved Solids.
Class II wells are wells that inject fluids related to oil and gas production .
NOR/K IWP\04400\071\FSDON001.DOC 3-25
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 3-5
Current and Proposed Federal Safe Drinking Water Act Standards
for Identified Compounds of Concern
Davis Park Road TCE Site
May 1998
Compound MCL MCLG SMCL Regulatory Status
(ug/L) (ug/L)
Volatile Organic Compounds (VOCs)
Chlorofonn 100 0 --Current MCL; Final MCLG
I, 1-Dichloroethene 7 7 --Final MCL/MCLG; no proposed SMCL
MTBE ------No regulation at present
Tetrachloroethylene 5 0 --Final MCL/MCLG; no proposed SMCL
Trichloroethylene 5 0 --Final MCL/MCLG; no proposed SMCL
NOR/K:\WP'\04400\071 \FS-TBLS. DOC 3-26
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written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Class III wells are wells that inject fluids for the extraction of minerals.
• Class IV wells are wells that inject hazardous or radioactive waste into or above an
underground source of drinking water. Class IV wells are banned by regulation.
• Class V wells are wells used for other practices not included in the first four classes. Class
V is subdivided into types ranging from industrial dry wells to aquifer remediation wells.
The EPA has not yet developed specific regulations for Class V wells.
Class II and III wells are not applicable to hazardous waste sites. Class I or IV wells are not
proposed as any part of a remedial action for the site. Class V wells may be part of a remedial
action involving groundwater remediation at the site if disposal of treated groundwater is to be
performed via reinjection into site aquifer using injection wells. As noted above, specific
regulations for Class V wells have not yet been developed by EPA.
3.3.4 Clean Air Act
The Clean Air Act (CAA), 42 USC 7401 et seq .. mandated EPA to establish regulations to
protect ambient air quality. It can be applied as an ARAR to the site for remedial actions that
potentially result in air emissions.
The following regulations have been established by CAA:
• National Ambient Air Quality Standards (NAAQS)
• Maximum emission standards as expressed under the National Emission Standards for
Hazardous Air Pollutants (NESHAP)
NOR/K. IWP\04400\071 \FSDDN001 .DOC 3-27
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
3.3.4.1 National Ambient Air Quality Standards (NAAQS)
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
NAAQS ( 40 CFR 50) have been developed by EPA for seven classes of pollutants: particulate,
sulfur oxides, nitrogen oxides, hydrocarbons, oxidants (ozone), carbon monoxide, and lead. The
NAAQS focuses on two levels of control: primary and secondary. The primary standards apply
exclusively to the protection of human health, while the secondary standards apply to the
prevention of property damage. Table 3-6 provides a listing of NAAQS. It should be noted that
these standards are not emission (i.e., discharge) standards. Further, these are standards to be met
for the ambient air after allowing for mixing of the particular discharge with the ambient air. State
Implementation Plans (SIP) are developed by individual states and contain the actual abatement
requirements necessary to achieve compliance with the NAAQS.
NAAQS attainment requirements are applicable only to maJor sources which are defined as
emitting over I 00 to 250 tons per year of regulated pollutants. NAAQS standards are not
applicable to the Davis Park Road site because emissions of this magnitude will not be generated
during the remedial actions.
3.3.4.2 National Emission Standards for Hazardous Air Pollutants (NESHAP) Standards
NESHAP Regulations, 40 CFR 61, currently cover seven separate contaminants, including
benzene. Subpart FF of 40 CFR 61 provides the national emission standard for benzene waste
operations. Application of this subpart is limited, however, to owners and operators of chemical
manufacturing plants, coke byproduct recovery plants, and petroleum refineries, therefore,
regulations do not specifically apply as potential ARARs to this site.
NOR/K \WP\04400\071 \FSODN001.00C 3-28
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Pollul:lnt
Sulfur Oxides
Particulate
Carbon Monoxide
Ozone
Nitrogen Oxides
Lead
Table 3-6
National Ambient Air Quality Standards (NAAQS)
Davis Park Road TCE Site
May 1998
Standard Averaging Period
Primary 12-month arithmetic mean
Primary 24-hour average (b)
Secondary 3-hour average (b)
Primary & Secondary Annual arithmetic mean
Primary & Secondary 24-hour average
Primary & Secondary 8-hour average
Primary & Secondary I-hour average
Primary Maximum daily I -hour
average
Secondary I-hour average
Primary & Secondary 12-rnonth arithmetic
mean
Primary & Secondary Quarterly mean
Rcb'lllatory Standard (a)
80 ug/cu. rn (0.03 ppm)
365 ug/cu. rn (0.1~ ppm)
1,300 ug/cu. m (0.5 ppm)
50 ug/cu. m
150 ug/cu. m
(10 mg/cu. m) 9 ppm (c)
(40 mg/cu. m) 35 ppm(c)
(235 ug/cu. m) 0.12 ppm (d)
(235 ug/cu. m) 0.12 ppm (d)
100 ug/cu. m (0.053 ppm)
1.5 ug/cu. m
NOTES:
(a)
(b)
National short-term standards are not to be exceeded more than once in a calendar year.
National standards are block averages rather than moving averages.
(c)
(d)
National secondary standards for carbon monoxide have been dropped.
Maximum daily I-hour average, averaged over a 2-year period; the expected number of days above the standard must be less than or equal to one.
NOR/K:\WP\044001071\FS.TBLS.OOC 3-29
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or In part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: i
Date: July 1998
3.3.5 Occupational Safety and Health Act
The Occupational Safety and Health Act (OSHA), 29 USCA 651, resulted in the creation of the
Occupational Safety and Health Agency to protect worker safety and to administer regulatory
control for worker safety.
Under OSHA, general industry standards have been promulgated under 29 CFR 1910. The
action-specific requirements given under 29 CFR 19 l 0.120, Hazardous Waste Operations and
Emergency Response, specifically apply to the site. Those requirements include provisions for:
• A written safety and health program that employers must develop and implement for
employees involved in hazardous waste operations. The program shall be designed to
identify, evaluate, and control safety and health hazards and provide for emergency
response for hazardous waste operations (29 CFR 1910.120 (b)).
• Characterization and analysis of the hazardous waste site for the identification of specific
site hazards and the determination of appropriate safety and health control procedures to
protect employees from hazards (29 CFR 1910.120 (c)).
• Appropriate site control procedures to control employee exposure to hazardous
substances before cleanup work begins (29 CFR 1910.120 (d)).
• Training of all employees and their supervisors working on-site who may be exposed to
hazardous substances, health hazards, or safety hazards. Employees cannot participate in
or supervise field activities until they have been trained to a level required by their job
function and responsibility. Refresher training must be performed annually (29 CFR
1910.120 (e)).
NOR/K:\WP\04400\071 IF SOON001.00C 3-30
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Institution of medical surveillance program by employers for employees engaged in
hazardous waste operations and emergency response. Annual medical examinations must
be administered to employees who are or may be exposed to hazardous substances at or
above permissible exposure limits or published exposure levels (29 CFR 1910.120 (f)).
• Implementation of engineering controls, work practices, and personal protection
equipment to protect employees from exposure to hazardous substances (29 CFR
1910.120 (g)).
• Monitoring of hazardous substance exposures where there may be a question of employee
exposure to hazardous concentrations of the substance. Monitoring aids in the proper
selection of engineering controls, work practices, and personal protective equipment so
that employees are not exposed to levels that exceed permissible exposure limits or
published exposure levels. Monitoring must be conducted upon initial entry at a site,
periodically while work is being performed on-site, and on high-risk employees following
site work (29 CFR 1910.120 (h)).
• An information program that advises employees, contractors, and subcontractors engaged
in hazardous waste operations of the nature, level, and degree of exposure likely as a
result of participation in the operations (29 CFR 1910.120 (i)).
• Handling, transportation, labeling, and disposal of hazardous substances and contaminated
soils, liquids, and other residues. Requirements for the opening and sampling of drums and
containers and the handling of radioactive and shock sensitive wastes are also covered
under this provision (29 CFR 1910.120 G)).
• Decontamination of personnel, clothing, and equipment. Decontamination procedures
must be developed, implemented, and communicated to employees before any employee
NOR/K:\WP\04400\071 \FSDDN001 . DOC 3-3 I
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
or equipment enter areas on-site where potential exposure to hazardous substances exists
(29 CFR 1910.120 (k)).
• Implementation of an emergency response plan to handle emergencies pnor to the
commencement of hazardous waste operations. The plan must be in writing and available
for inspection by employees, OSHA personnel, and other government agencies (29 CFR
1910.120 (I)).
• Illumination of areas accessible to employees while work is in progress. Actual minimum
illumination intensities are shown in Table H-120.1 of the provisions (29 CFR 1910.120
(m)).
• Provision of sanitary facilities at temporary workplaces. Standards for potable water
supplies, non-potable water supplies (such as for fire-fighting purposes), toilet facilities,
sleeping quarters, food handling services, washing facilities, and showers and change
rooms are contained in subsection 29 CFR 19 l O. l 20(n).
• Development and implementation of procedures for the introduction of effective new
technologies and equipment designed for the improved protection of employees working
with hazardous waste cleanup operations. New technologies, equipment, or control
measures must be evaluated by employers to determine the effectiveness of the new
methods before implementing their use on a large scale (29 CFR 1910.120 (o)).
• Operations conducted at TSD facilities. Employers at TSD facilities must provide and
implement the same programs as required by other contractors and subcontractors
including written safety and health programs, medical surveillance programs,
decontamination programs, emergency response plans, and others (29 CFR 1910.120 (p)).
NOR/K:\WP\04400\071 \FSDDN001, DOC 3-32
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. !I shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Employers whose employees are engaged in emergency response to hazardous substance
releases. Employers meeting this criteria must develop and implement certain safety and
health requirements listed in subsection (29 CFR I 910.120 ( q)).
3.3.6 Hazardous Materials Transportation Act
Through the Hazardous Materials Transportation Act, 49 USC 1801-1813, regulations regarding
the transportation of hazardous materials were promulgated by the Department of Transportation
(DOT) under 49 CFR Parts I 07 and 171-177. Transportation of DOT-defined hazardous
materials off-site is a potential remedial action for the site. The following action-specific
regulatory requirements represent potential ARARs.
• Hazardous materials table ( 49 CFR 172.101) listing DOT-designated hazardous materials
and waste, along with a summary of basic shipping requirements.
• Required manifest information (49 CFR 172.101, 172.203, and 173) including proper
shipping name, hazard classification, and identification number.
• Transportation mode requirements (49 CFR 172.101 and 174-177).
• Packaging. labeling, and marking requirements ( 49 CFR 172, 178, and 179).
• Transportation placarding requirements ( 49 CFR 172, Subpart F).
3.3. 7 Protection of Wetlands
Through Executive Order No. I 1990, regulations regarding protection of wetlands were
promulgated by EPA under 40 CFR 6.302(a). The following action-specific regulatory
requirements represent potential ARARs:
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written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Avoid, to the extent possible, adverse impacts associated with the destruction or loss of
wetlands.
• Avoid new construction on wetlands unless no other practical alternative exists.
• Prepare a wetlands assessment if wetlands will be affected.
• Avoid adverse effects or minimize them ifno practicable alternative to the action exists.
3.3.8 Floodplain Management
Through Executive Order No. 11,988, regulations regarding protection of wetlands were
promulgated by EPA under 40 CFR 6.302(b). The following action-specific regulatory
requirements represent potential ARARs:
• Avoid, to the extent possible, adverse impacts associated with the direct or indirect
development of a floodplain.
• Prepare a flood plains assessment if an action will be located in or will affect a floodplain.
• Avoid adverse effects or minimize them if no practicable alternative to the action exists.
3.3.9 Regulations Protecting of Landmarks, Historical, and Archeological Sites
The regulations associated with protection of landmarks, historical, and archeological sites are
specified under 40 CFR 6.301. The following location/action-specific regulatory requirements
represent potential ARARs:
• National Natural Landmarks -Under the Historic Sites Act of I 935, 16 USC 461 et seq ..
the Secretary of Interior is authorized to designate areas as national natural landmarks for
listing on the National Registry of Natural Landmarks. In conducting an environmental
NOR/K:IWP\044001071 \FSDDN001 .DOC 3-34
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Dale: July 1998
review of a proposed action, the existence and location of natural landmarks shall be
considered to avoid undesirable impacts upon such landmarks.
• Historic, Architectural, Archeological, and Cultural sites -Under Section 106 of the
National Historic Preservation Act of 1966, as amended, 16 USC 470 et seq., and
Executive Order 11593, if an action affects any property with historic, archeological, or
cultural value that is listed on or eligible for listing on the National Register of Historic
Places, the responsible official shall comply with the procedures for consultation and
comment promulgated by the Advisory Council on Historic Preservation in 36 CFR 800.
• Historic, Prehistoric, and Archeological Data -Under the Archeological Preservation Act
of 1974, I 6 USC 469 et seq., and Executive Order I I 593, if an action may cause
irreparable loss or destruction of significant scientific, prehistoric, historic, or
archeological data, data recovery and preservation activities shall be conducted m
accordance with implementing procedures promulgated by the Secretary oflnterior.
There are no historic sites located in the remedial action area, therefore, the regulations protecting
landmarks, historical, and archeological sites are not potentially applicable to the site.
3.3. l O Endangered Species Act
The Endangered Species Act, 16 USC 1531 et seq .. of 1973 is applicable if endangered species or
threatened species are present in the area. This Act requires that action be performed to conserve
endangered or threatened species. Any proposed activities must not destroy or adversely modify
the critical habitat upon which the species depend. No endangered and threatened species have been
identified at the Davis Park Road ICE site.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without tile express
written permission of EPA.
3.3.11 Fish and Wildlife Conservation Act
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
The purpDse Df the Fish and Wildlife CDnservatiDn Act, I 6 USC 666 et seq., is tD cDnserve and
prnmDte CDnservatiDn Df fish and their habitats. The Act pertains tD activities that mDdify a stream
Dr river and affect fish Dr wildlife. ActiDns must be taken tD prntect the fish and wildlife resDurces
affected by site activities.
3.4 ST A TE ARARS
State ARAR SDurces found tD be pDtentially applicable tD the site are discussed in this sectiDn and
cDnsist Dfthe follDwing:
• NDrth Carnlina Water and Air ResDurces Act
• NDrth Carnlina Drinking Water Act (State level equivalent tD Federal SOWA)
• NDrth Carnlina Water PDllutiDn CDntrnl RegulatiDns
• NDrth Carnlina Drinking Water and Grnundwater Standards
• NDrth Carnlina Surface Water Quality Standards
• NDrth Carnlina Well CDnstructiDn Standards
• NDrth Carnlina Air PDllutiDn CDntrnl RegulatiDns
• NDrth Carnlina HazardDus Waste Management Rules
• NDrth Carnlina SDlid Waste Management Rules
3.4.1 North Carolina Water and Air Resources Act
The NDrth Carnlina (NC) Water and Air ResDurces Act (General Statutes Df NC, Chapter 143,
Articles 21, 21B) represents the state equivalent Dfthe Federal CWA and CAA. The purpDse Df
this act is tD achieve and tD maintain a !Dial envirnnment Df superiDr quality. Standards Df water
and air purity are designed tD prntect human health, tD prevent injury tD plant and animal life, tD
prevent damage tD public and private prnperty, tD insure the cDntinued employment of the natural
NOR/K:IWP\04400\071 \FSDON001. DOC 3-36
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written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Sile
Section: 3
Revision: 1
Date: July 1998
attractions of the State, to encourage the expansion of employment opportunities, and to provide
a permanent foundation for healthy industrial development. NC Water and Air Resources Act is
potentially applicable to the Davis Park Road site as an action-specific ARAR.
3.4.2 North Carolina Drinking Water Act
The North Carolina Drinking Water Act (General Statutes of NC, Chapter 130 A, Article I 0)
represents the state-level equivalent of the Federal SOW A. Through this act, the North Carolina
Department of Environmental Health and National Resources (NCDEHNR) Water Quality
Section has established standards to regulate water systems within the State which supply
drinking water that may affect the public health.
Based on these acts/laws, the state agencies have drafted action-specific appropriate regulations
and standards which are discussed further in this section.
3.4.3 North Carolina Water Pollution Control Regulations
The North Carolina Water Pollution Control Regulations are specified in North Carolina
Administrative Code (NCAC), Title I 5, Chapter 2. Subchapter 2H discusses the procedures for
permits and approvals. Section 2H.0I00 discusses the regulations regarding wastewater
discharges to surface waters. These rules apply for waste discharge to surface waters or to a
pretreatment facility. The information about the forms to be completed and supporting documents
to be submitted for permit application is given in these rules. The time required for processing an
application and issuing a permit is about 90 to 120 days.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
3.4.4 North Carolina Drinking Water and Groundwater Standards
3.4.4.1 Groundwater Classification
The State of North Carolina has promulgated classifications and water quality standards
applicable to groundwater under Title 15, Subchapter 2L, Sections .0200 and .0201, respectively.
Groundwater Classification
The groundwater has been classified based on the usage and occurrence as follows:
• Class GA Waters:
Best Usage -Existing or potential source of drinking water supply for humans.
Conditions Related to Best Usage -This class is intended for those groundwaters in which
chloride concentrations are equal to or less than 250 mg/L, and are considered suitable for
drinking in their natural state, but may require treatment to improve quality related to
natural conditions.
Occurrence -In the saturated zone.
• Class GSA Waters:
Best Usage -Existing or potential source of water supply for potable mineral water and
conversion to fresh waters.
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written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
Conditions Related to Best Usage -This class is intended for those groundwaters in which
the chloride concentrations due to natural conditions are in excess of 250 mg/L, but which
otherwise may be considered suitable for use as potable water after treatment to reduce
concentrations of naturally occurring substances.
Occurrence -In the saturated zone.
• Class GC Waters
Best Usage -Source of water supply for purposes other than drinking.
Conditions Related to Best Usage. -This class includes those groundwaters that do not
meet the quality criteria of waters having a higher classification and for which efforts to
restore in-situ to a higher classification would not be technologically feasible or in the best
interest of the public.
Occurrence -In the saturated zone, as determined by the commission on a case by case
basis.
The groundwater quality standards for the most stringent Class (GA) are presented in Table 3-7.
NOR/K:\WP\04400\071 \FSDDN001.DOC 3-39
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 3-7
North Carolina Groundwater Quality Standards for Class GA
Da,·is Park Road TCE Site
May 1998
Compound
Acetone
Acrylamide (propenamide)
Arsenic
Barium
Benzene
Boron
Bromoform (tribromomethane)
Butylbenzyl phthalate
Cadmium
Carbofuran
Carbon Tetrachloride
Chlordane
Chloride
Chlorobenzene
Chloroform (trichloromethane)
2-chlorophenol
Chromium
Cis-1.2-dichloroethene
Coliform organisms (total)
Color
Copper
Cyanide
2,4-D (2,4-dichlorophenox-y acetic acid)
J ,2-dibromo-3-chloropropane
Dichlorodifluoromethane (Freon-12; Halon)
I, J-Dichloroetliane
l,2-dichloroetl1ane (ethylene dichloride)
1,1-dichloroethylene (vinylidene chloride)
1,2-dichloropropane
Di-n-butyl (or dibutyl) phthalate (DBP)
Diethylphthalate (DEP)
Di(2-ethylhex·yl) phthalate (DEHP)
Di-n-octyl phthalate
p-Dioxane (1,4-diethylene dioxide)
Dioxin
Dissolved solids (total)
Diundecyl phthalate (Santicizer 7 J I)
Endrin
Epichlorohydrin ( I -cltloro-2,3-epox,-propane)
Ethyl benzene
Ethylene dibromide (EDB; 1,2-dibromoetliane)
NOR/K:\WP\04400\071\FS-TBLS.DOC 3-40
Class GA Groundwater Qualit~·
Standard (mg/L)
0.7
0.00001
0.05
2.0
0.001
0.32
0.00019
0.10
0.005
0.036
0.0003
2.7 X 10·l
250.0
0.05
0.00019
0.000]
0.05
0.07
I per JOO milliliters
15 color units
1.0
0.154
0.07
2.5 X 10·'
1.4
0.7
0.00038
0.007
0.00056
0.7
5.0
0.003
0.14
0.007
2.2 X 10-JO
500
0.14
0.002
0.00354
0.029
4.0 X 10·7
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 3-7 (Continued)
North Carolina Groundwater Quality Standards for Class GA
Davis Park Road TCE Site
Compound
Ethylene glycol
Fluorene
Fluoride
Foaming agents
May 1998
Gross alpha (adjusted) particle activity (excluding
radium-226 and uranium)
Heptachlor
Heptachlor expoxide
Heptane
Hexachlorobenzene (perchlorobenzene)
N-hexane
Iron
Lead
Lindane
Manganese
Mercury
Metadichlorobenzene ( 1,3-dichlorobenzene)
Methox-ychlor
Methylene chloride (dichloromethane)
Methyl ethyl ketone (MEK; 2-butanone)
Methyl tert-butyl ether (MTBE)
Naphthalene
Nickel
Nitrate (as N)
Nitrite (as N)
Orthodichlorobenzene ( 1,2-dichlorobenzene)
Oxarnyl
Paradichlorobenzene ( 1,4-dichlorobenzene)
Pentachlorophenol
pH
Phenanthrene
Phenol
Radium-226 and radium-228 (combined)
Selenium
Silver
Styrene (et11enylbcnzcne)
Sulfate
Tetrachlorocthylcne (perchloroethylene; PCE)
Toluene (methylbenzene)
Toxaphene
2,4,5-TP (Silvex)
NOR/K·\WP\04400\071\FS-TBLS.DOC 3-41
Class GA Groundwater Quality
Standard (mg/L)
7.0
0.28
2.0
0.5
15 pCi/L
8.0 X 10"6
4.0 X 10.6
2.1
0.00002
0.42
0.3
0.015
2.0 X 10-4
0.05
0.0011
0.62
0.035
0.005
0.17
0.2
0.021
0.1
10.0
1.0
0.62
0.175
0.075
0.0003
6.5 -8.5
0.21
0.30
5 pCi/L
0.05
0.018
0.1
250.0
0.0007
1.0
3.lxl0-5
0.05
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Table 3-7 (Continued)
North Carolina Groundwater Quality Standards for Class GA
Davis Park Road TCE Site
May 1998
Compound
trans-1,2-Dichloroethene
1,1,l-trichloroethane (metl1yl chloroform)
Trichloroethylene (TCE)
TrichloroOuorometliane
Vinyl chloride (chloroethylene)
Xylenes (o-, m-, and p-)
Zinc
NOR/K:\WP\04400\071\FS-TBLS.DOC 3-42
Class GA Groundwater Quality
Standard (mg/L)
0.07
0.2
0.0028
2.1
1.5 X JO·l
0.53
2.1
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
3.4.5 North Carolina Surface Water Quality Standards
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
3.4.5.1 Surface Water Standards Based on the Receiving Water Body
The surface water classifications and surface water quality standards have been promulgated by
the State of North Carolina under the Title ISA NCAC 2B .0100 and ISA NCAC 2B 0200,
respectively.
Surface Water Classification
The following surface water classifications have been promulgated by the State of North Carolina:
(A) Freshwater Classification
• Class C: Waters protected for secondary recreation, fishing, wildlife, fish, and aquatic life
propagation and survival, agriculture and other uses suitable for Class C. Secondary
recreation includes wading, boating, and other uses involving human body contact with
water where such activities take place in an infrequent, unorganized, or incidental manner.
There are no restrictions on watershed development activities. Wastewater discharge and
stormwater management requirements are applicable.
• Class B: Waters used for primary recreation and other uses suitable for Class C. Primary
rec.reational activities include swimming, skin diving, water skiing, and similar uses
involving human body contact with water where such activities take place in an organized
manner or on an frequent basis. There are no restrictions on watershed development
activities. Discharges must meet treatment reliability requirements such as backup power
supplies and dual train design.
NOR/K:IWP\04400\071 \FSDDN001. DOC 3-43
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written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Class WS-1, Water Supply I Watersheds: Waters used as sources of water supply for
drinking, culinary, or food processing purposes for those users desiring maximum
protection for their water supplies. WS-1 water are those within essentially natural and
undeveloped watersheds with no permitted point source (wastewater) discharges.
WS-1 watersheds are entirely composed of publicly owned land and comprise just 0.2% of
the total state land area.
Dischargers: None
Allowable Development: None
• Class WS-11, Water Supply II Watersheds: Waters used as sources of water supply for
drinking, culinary, or food processing purposes for those users desiring maximum
protection for their water supplies where a WS-1 classification is not feasible. WS-Il
waters are generally located within predominantly undeveloped watersheds.
CRITICAL AREA
Dischargers: General Permits
Allowable Development:
• Low Density Option: I development unit (du) per 2 acres (ac) or 6% built-
upon area
■ High Density Option*: 6-24% built-upon area
(* Required to control the I" storm)
I 0/70 Provision: Not Allowed
Residuals Application: No new sites allowed
Landfills: No new landfills
Agriculture Best Management Plans (BMPs): Required
NOR/K: \WP\044001071 \FSDON001. DOC 3-44
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written permission of EPA.
BALANCE OF WATERSHED
Dischargers: General Permits
Allowable Development:
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Low Density Option: 1 du/ac or 12% built-upon area
• High Density Option*: 12-30% built-upon area
(* Required to control the l" storm)
10/70 Provision: Allowed
Residuals Application: Allowed
Landfills: No new discharging
Agriculture BMPs: Not required
• Class WS-III, Water Supply III Watersheds: Waters used as sources of water supply for
drinking, culinary, or food processing purposes for those users where a more protective
WS-1 or WS-II classification is not feasible. WS-III waters are generally located within
low to moderately developed watersheds.
CRITICAL AREA
Dischargers: General Permits
Allowable Development:
• Low Density Option: 1 du/ac or 12% built-upon area
• High Density Option*: 12-30% built-upon area
(* Required to control the 1" storm)
10/70 Provision: Not Allowed
Residuals Application: No new sites
Landfills: No new landfills
Agriculture BMPs: Required
BALANCE OF WATERSHED
Dischargers: General Permits
Allowable Development:
NQR/K\WP\04400\071 \FSDDN001.DOC 3-45
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Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Low Density Option: 2 du/ac or 24% built-upon area • High Density Option*: 24-50% built-upon area
(* Required to control the I" storm)
I 0/70 Provision: Allowed
Residuals Application: Allowed
Landfills: No new discharging landfills
Agriculture BMPs: Not required
• Class WS-IV, Water Supply IV Watersheds: Waters used as sources of water supply for drinking, culinary, or food processing purposes for those users where a WS-1, WS-II, or WS-III classification is not feasible. WS-IV waters are generally located within
moderately to highly developed watersheds.
CRITICAL AREA
Dischargers: Domestic and Industrial
Allowable Development:
• Low Density Option: 2 du/ac or 24% built-upon area • High Density Option*: 24-50% built-upon area
(* Required to control the I" storm)
I 0/70 Provision: Not Allowed
Residuals Application: No new sites
Landfills: No new landfills
Agriculture BMPs: Required
PROTECTED AREA
Dischargers: Domestic and Industrial
Allowable Development:
•
•
Low Density Option: 2 du/ac or 24% built-upon area High Density Option*: 24-70% built-upon area
(* Required to control the I" storm)
NORIK:IWP\04400\071\FSODN001.DOC 3-46
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written permission of EPA.
I 0/70 Provision: Allowed
Residuals Application: Allowed
Landfills: Allowed
Agriculture BMPs: Not required
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Class WS-V, Water Supply V Watersheds: Waters protected as water supplies which are
generally upstream and draining to WS-IV waters or waters used by industry. WS-V has
no categorical restrictions on watershed development or wastewater dischargers like other
WS classifications, and local governments are not required to adopt watershed protection
ordinances.
Dischargers: Domestic and Industrial
No categorical restrictions other than in-stream water quality standards applicable
to all surface water supply waters.
(B) Tidal Salt Water Classification
• Class SC: Salt waters protected for secondary recreation, fishing, and aquatic life
including propagation and survival; all salt waters are classified to protect these uses at a
minimum.
• Class SB: Salt waters protected for primary recreation which includes sw1mmmg on a
frequent and/or organized basis and all Class SC uses.
• Class SA: Suitable for commercial shellfishing and all other tidal salt water uses.
NOR/K:IWP\04400\071 \FSDDN001. DOC 3-47
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(C) Supplemental Classification
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
• Future Water Supply (FWS): Supplemental classification for waters intended as a future
drinking water source. FWS would be applied to one of the primary water supply
classifications (WS-1, WS-11, WS-III, or WS-IV). State permitting requirements applicable
to the primary water supply classification become effective upon reclassification.
However, local government water supply protection ordinances are not required until after
the FWS supplemental classification is removed.
• High Quality Waters (HQW): Supplemental classification intended to protect waters with
quality higher than state water quality standards. In general, there are two means by which
a water body may be classified as HQW. They may be by definition or they may qualify for
HQW and then be supplementally classified as HQW through the rule-making process.
The following are HQW by definition: WS-1, WS-11, SA (shellfishing), ORW, and waters
for which DWQ has received a petition for reclassification to either WS-1 or WS-11. The
following waters can qualify for the supplemental HQW classification: water rated as
Excellent by DWQ, Primary Nursery Areas, Native trout waters and Critical Habitat
Waters. There are associated wastewater treatment and stormwater runoff controls
enforced by DWQ.
• Nutrient Sensitive Waters (NSW): Supplemental classification intended for waters needing
additional nutrient management due to their being subject to excessive growth of
microscopic or macroscopic vegetation. In general, management strategies for point and
non-point-source pollution control require no increase in nutrients over background levels.
• Outstanding Resource Waters (ORW): Supplemental classification intended to protect
unique and special waters having excellent water quality and being of exceptional state or
NOR/K:\WP\04400\071 \FSODN001. DOC 3-48
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written permission of EPA.
•
•
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
national ecological or recreational significance. To qualify, waters must be rated Excellent
by DWQ and have one of the following outstanding resource values:
2.
3.
4.
Outstanding fish habitat or fisheries,
Unusually high level of water based recreation,
Some special designation such as NC or National Wild and Scenic Rivers, National
Wildlife Refuge, etc.,
Important component of state or national park or forest,
5. Special ecological or scientific significance (rare or endangered species habitat,
research or educational areas).
No new or expanded wastewater discharges are allowed and there are associated
watershed stormwater controls enforced by DWQ.
Swamp Waters (Sw): Supplemental classification intended to recognize those waters that
generally have naturally occurring very low velocities, low pH and low dissolved oxygen.
Trout Waters (Tr): Supplemental classification intended to protect freshwaters for natural
trout propagation and survival of stocked trout. Affects wastewater discharges but there
are no watershed development restrictions except stream buffer zone requirements of NC
Division of Land Resources. DWQ's classification is not the same as the NC Wildlife
Resources Commission's Designated Public Mountain Trout Waters classification.
Water Quality Standards Applicable to Surface Waters of North Carolina
The Environmental Management Commission has established an Antidegradation Policy to
maintain, protect, and enhance water quality within the State of North Carolina. Pursuant to this
NOR/K:\WP\04400\071 \FSDON001. DOC 3-49
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written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
policy, the requirements of 40 CFR 131.12 are adopted by reference in accordance with General
Statute 150B-14(b). These requirements are based on the type of usage of the surface water:
(A) Existing uses and water quality to protect such uses by properly classifying surface waters
and having standards sufficient to protect these uses.
(B)
(C)
Present and anticipated usage of waters with quality higher than the standards, including
any uses not specified by the assigned classification (such as outstanding national resource
waters or waters with exceptional quality) and will not allow degradation of the quality of
waters with quality higher than the standards necessary to maintain existing and
anticipated usage of those waters. The procedure to be followed to meet these
requirements is presented in 15A NCAC 2B.0201(c).
Present and anticipated usage of High Quality Waters (HQW), including any uses not
specified by the assigned classification (such as outstanding national resource waters or
waters with exceptional quality) and will not allow degradation of the quality of HQW
below the quality necessary to maintain existing and anticipated usage of those waters.
The procedure to be followed to meet these requirements is presented in I SA NCAC
2B.0201(d).
Surface Water Quality Standards Applicable to Davis Park Road Site
The surface water body located nearest to the Davis Park Road site is Blackwood Creek, a
tributary of Crowders Creek. Any treated water generated as a result of the remedial actions will
be potentially discharged to Blackwood Creek.
NOR/K:IWP\04400\071 \FSDDN001 . DOC 3-50
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
Under North Carolina surface water regulations, Blackwood Creek is classified under fresh water
with the identification Class C, as defined in Subsection 3.4.5. l. In addition, Toxic Substances
and Temperature Standards are applicable to all surface waters in North Carolina.
Standards for Toxic Substances and Temperature
The concentrations of toxic substances in surface waters either alone or in combination with other
wastes, will not render waters injurious to aquatic life or wildlife, recreational activities, public
health, or impair the waters for any designated uses.
(a) Aquatic Life Standards: The concentration of toxic substances will not result in chronic
toxicity.
(b) Human Health Standards: The concentrations of toxic substances must not exceed the
level necessary to protect human health through exposure routes of fish (or shellfish)
tissue consumption, water consumption, or other route identified as appropriate for the
water body. For non-carcinogens, these concentrations will be determined using a
Reference Dose (RID) as developed by the EPA. Standards to protect human health from
carcinogens through the consumption of fish (and shellfish) applicable to all waters are
listed in Table 3-8. Specific standards for the contaminants of concern at the site are:
Chloroform
I, 1-Dichloroethene
MTBE
Tetrachloroethene (PCE)
Trichloroethene (TCE)
None
None
None
None
92.4 µg/L
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 3-8
North Carolina Surface Water (Freshwater) Qualit)' Standards
Davis Park Road TCE Site
May 1998
Parameter Fresh Waters Hnman Health
Standards
Aquatic WS
Life Classes
Arsenic (ug/L) so
Barium (mg/L) 1.0
Benzene (ug/L) 1.19 71.4
Beryllium (ng/L) 6.8 117
Cadmium (ug/L) 2.0
Carbon tetrachloride (ug/L) 0.254 4.42
Chloride (mg/L) 230 (AL) 250
Chlorinated benzenes (ug/L) 488
Chlorine, total residual (ug/L) 17 (AL)
Chlorophyll a, corrected (ug/L) 40 (N)
Chromium, total (ug/L) so
Colifonn, total (MFTCC/I00mL) 50 (N)(2)
Coliform, fecal (MFTCC/I00mL) 200 (N)
Copper (ug/L) 7 (AL)
Cyanide (ug/L) 5.0
Dioxin (ng/L) 0.000013 0.000014
Dissolved gases (N)
Dissolved oxygen (mg/L) 5.0 (Sw) (I)
Fluoride (mg/L) 1.8
Hardness, total ( mg/L) l00
Hexachlorobutadiene (ug/L) 0.445 49.7
Iron (mg/L) 1.0 (AL)
Lead (ug/L) 25 (N)
Manganese (ug/L) 200
MBAS (ug/L) -(Methylene-Blue-500
Active Substances)
Mercury (ug/L) 0.012
Nickel (ug/L) 88 25
NOR/K:IWP\04400\071\FS-TBLS.DOC 3-52
Supplemental
Waters (To
Protect Trout)
0.4
17
IS(N)
6.0
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express written permission of EPA.
Table 3-8 (Continued)
North Carolina Surface Water (Freshwater) Quality Standards
Davis Park Road TCE Site
May 1998
Parameter Fresh Waters Human Health
Standards
Aquatic ws
Life Classes
Nitrate nitrogen {mg/L) IO
NH,-N
Pesticides
Aldrin {ng/L) 2.0 0.127 0.136
Chlordane (ug/L) 4.0 0.575 0.588
DDT (ng/L) 1.0 0.588 0.591
Demeton (ng/L) 100
Dieldrin (ng/L) 2.0 0.135 0.144
Endosulfan (ng/L) 50
Endrin (ng/L) 2.0
Guthion (ng/L) 10
Heptachlor (ng/L) 4.0 0.208 0.214
Lindane (ng/L) 10
Methox-ychlor (ng/L) 30
Mirex (ng/L) 1.0
Parathion (ng/L) 13
Toxaphene (ng/L) 0.2
2,4-D (ug/L) 100
2,4,5-TP (Silvex) (ug/L) 10
pH (units) 6.0-9.0
(Sw)
Phenolic compounds (ug/L) l.O (N) (N)
Polychlorinated biphenyls (ng/L) 1.0 0.079
Polynuclear aromatic hydrocarbons 2.8 31.l
(ng/L)
Radioactive substances (N)
Selenium (ug/L) 5
Silver (ug/L) 0.06 (AL)
NOR/K:\WP\04400\071\FS-TBLS.DOC 3-53
Supplemental
Waters (To
Protect Trout)
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Table 3-8 (Continued)
North Carolina Surface Water (Freshwater) Quality Standards
Davis Park Road TCE Site
May 1998
Parameter Fresh Waters Human Health
Standards
Aquatic ws
Life Classes
Solids, total dissolved (mg/L) 500
Solids, suspended (N)
Sulfates (mg/L) 250
Temperature (N)
Tetrachloroetliane (1,1.2,2) (ug/L) 0.172 10.8
Tetrachloroethylene (ug/L) 0.8
Toluene (ug/L) II
Toxic Substances (N)
Trialkyltin (ug/L) 0.008
Trichloroethylene (ug/L) 3.08 92.4
Turbidity (NTU) 50; 25 (N)
Vinyl chloride (ug/L) 2 525
Zinc (ug/L) 50 (AL)
Supplemental
Waters (To
Protect Trout)
0.36
lO(N)
Notes: (N)
(AL)
See 15A NCAC. 2B .0211 (b), (c), (d). or (e) for narrative description of limits.
Values represent action levels as specified in 15A NCAC.0211 (b)(4).
(Sw)
(I)
(2)
ws
=
Designated swamp waters under natural conditions may have a pH as low as 4.3 and
dissolved o~-ygen less than 5.0 mg/L.
An instantaneous reading may be as low as 4.0 ug/L, but the daily average must be 5.0
ug/L or more.
Applies only to unfiltered water supplies.
Water Supply (as additional use).
Only High Quality Water Standards and Human Health Standards Through Fish Consumption
are applicable surface waters at ABC. Other surface water standards are listed for comparison
only.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
3.4.5.2 Technology-Based Effiuent Limitations and Standards
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
Section I SA NCAC 2B.0400 requires all direct discharges to meet technology-based
requirements. These requirement include, for unconventional pollutants (as found in the
groundwater at the Davis Park Road site), application of the best available technology (BAT)
economically achievable. Where effluent guidelines for specific categories of industry or industrial
category do not exist, treatment requirements are determined on a case-by-case basis. Effluent
limitations designated by BAT will control the discharge pollutants determined to be toxic in
nature.
For treatment of groundwater contaminated with VOCs, air stripping is typically accepted as the
BAT. A conservatively low effluent limitation of 5 µg/L is generally accepted for VOCs, since it
is the analytical detection limit for the most widely used analytical methods.
3.4.6 North Carolina Well Construction Standards
These regulations are given m NCAC Title I SA, Subchapter 2C. These regulations establish
classes of injection wells and set forth requirements and procedures for permitting, construction,
operation, monitoring, reporting, and abandoning of approved injection wells. The discharge of
any wastes to the subsurface or groundwater of the states by means of wells is prohibited. The
well construction standards are potentially applicable to the site if groundwater monitoring or
extraction wells are installed at the site.
3.4. 7 North Carolina Air Pollution Control Regulations
The North Carolina Air Pollution Control Laws are given in General Statutes of North Carolina,
Chapter 143. The air pollution control regulations are given in !SA NCAC.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 3
Revision: 1
Date: July 1998
If emissions of volatile organic compounds (VOCs) from an air stripping system exceed 40
lbs/day, an air permit is required under regulations in I SA NCAC 2D.05 I 8. A permit must be
issued prior to operations. If emissions are less than 40 lbs/day (VOCs), information detailing
emissions and operations must be submitted to NCDEH.NR, but no air permit is required. Further,
if emissions increase over time, NCDEHNR must be informed.
NCDEHNR is in process of promulgating regulations dealing with air stripping operations. These
regulations, when promulgated, may subject air stripping operations to toxic regulations in I SA
NCAC 2D.l 104 and 2H.0610.
3.5 SUMMARY OF GROUNDWATER AND SURFACE WATER STANDARDS
APPLICABLE TO THE DAVIS PARK ROAD TCE SITE
A summary of surface water and groundwater standards for the contaminants of concern
applicable to groundwater objectives at the Davis Park Road TCE site are presented in Table 3-9.
Maximum observed groundwater concentrations are also tabulated for comparison. The table
indicates that TCE and PCE are the contaminants that substantially exceed the regulatory limits.
During the groundwater remediation at the Davis Park Road site, a conservatively low effluent
limitation of 5 µg/L will be used based on BAT as described in Subsections 3.3.2.2 and 3.4.5.2.
This limit is much lower than the North Carolina surface water standards for the contaminants of
concern (TCE-92.4 µg/L). There are no State surface water standards for PCE.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA. ·
Table 3-9
Summary of Groundwater and Surface Water Standards Applicable to Groundwater Objectives
Davis Park Road TCE Site
Compound Maximum Obsen-·ed
Groundwater
Concentration
voe,
Acetone 83
Chloroform 40A
1, 1-Dichloroethene 3.8
MTBE 790
Tetrachloroethylene 14
Trichloroethylene 34
I, I, I-Trichloroethane 7.8
Concentrations are in ug/L
A = Average value
May 1998
Federal Regulations North Carolina State
Regulations
Drinking Water Standards Groundwater Surface Water
(Safe Drinking Water Act)
Primary Secondary Class GA To Protect
Human Health
MCL MCLG SMCL
700
100 0.19
7 7 7
---
5 0 0.7 10.8
5 0 2.8 92.4
200 200 0 200
Note: Based on BAT, an effluent limitation of 5 ug/L will be used in the groundwater
remediation.
NOR/K:\WP\04400\071\FS-TBLS.DOC 3-57
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
SECTION 4
Feasibility Study Report
Davis Park Road TCE Site
Section: 4
Revision: 1
Date: July 1998
SITE-SPECIFIC REMEDIAL OBJECTIVES/GOALS
The purpose of this FS is to address the remediation of the groundwater contaminant plume due
to activities at the Davis Park Road TCE site. The contaminated groundwater presents potential
risks to the current and future residents in the area should they use the groundwater as a water
supply source. Migration of the contaminant plume would increase the potential for human
exposure by spreading the contamination into a larger area. The pnmary remedial action
objectives for the contaminated groundwater at the Davis Park Road site are:
• To implement institutional controls to protect humans from using contaminated
groundwater.
• To achieve groundwater cleanup goals for the contaminants of concern, TCE and PCE;
• To achieve appropriate treatment standards prior to discharge of treated water;
The ultimate goal of this Feasibility Study (FS) is to evaluate remedial action alternatives that may
be implemented at the Davis Park Road site to attain the remedial action objectives. The remedial
action objectives are fonnulated to protect human health, public welfare, and the environment
from potential impacts due to contaminants of concern.
4.1 CONTAMINANTS OF CONCERN
As discussed in Section 2, the only contaminants present in the groundwater above regulatory
limits are MTBE, TCE, and PCE. However, MTBE has only been detected at one location in an
area where water supply wells_ are not active, whereas TCE and PCE are present in active
NOR/K:IWP\044001071 IFSDON001. DOC 4-1
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park· Road TCE Site
Section: 4
Revision: 1
Date: July 1998
drinking water supply wells. Accordingly, this study of groundwater remediation alternatives for
the Davis Park Road site is focused on TCE and PCE.
4.2 REGULA TORY REQUIREMENTS
In groundwater remediation, there are two basic types of regulatoiy performance requirements
that have to be met.
(I) Groundwater Remediation Goals -Groundwater remediation goals (criteria) are typically
based on Federal or State groundwater/drinking water standards, and/or the results of a
baseline risk assessment. Groundwater remediation typically continues until groundwater
cleanup goals are met.
(2) Groundwater Treatment Standards -Groundwater treatment standards are applicable to
the treated effluent. Usually, the standards are issued by the State, based on the
classification of the receiving surface water body and the BAT capabilities.
4.3 GROUNDWATER REMEDIATION GOALS
The following groundwater remediation standards/criteria are applicable to the site:
• Federally enforced Safe Drinking Water Act (SDWA) maximum concentration levels
(MCLs)
• North Carolina Groundwater Quality Standards (NCGWQS)
• Risk Assessment results
• Analytical Method Detection Limits
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This document was prepared by Roy F. Weston, Inc.; expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA. ,,
RECl'=IVED
JUL 2 41998
SUPERFUND SECTION
Feasibility Study Report
Davis Park Road TCE Site
Section: 4
Revision: 1
Date: July 1998
State groundwater standards are equal to or more stringent than the Federal MCLs. The State
standards (NCGWQSs) are in some cases extremely difficult to achieve because they are below
reliable quantification limits. For example, the groundwater standard for PCE is 0. 7 µg/L, which
is less than the minimum analytical detection limit of I µg/L. Since the method detection limit is
less than the Federal MCL, the detection limits may also be considered as remedial goals.
The human health Baseline Risk Assessment was developed from the exposure to contaminated
groundwater in co1~unction with future residential development. According to the Risk
Assessment, the contaminants posing most of the estimated total carcinogenic risk are PCE, TCE,
chloroform, I, 1-dichloroethene, and bromodichloromethane. The contaminant posing most of the
estimated total non-carcinogenic risk is MTBE.
Based on the above discussion, analytical method detection limits (MDL) will be considered for ' the groundwater remediation goals for chloroform and PCE. Federal MCLs will be considered for
all other compounds that are equal to or more stringent than State of North Carolina guidelines,
or where NC guidelines exist. Specific standards for the contaminants of concern are as follows:
Tetrachloroethene (PCE)
Trichloroethene (TCE)
Chlorofonn
I, 1-Dichloroethene
MTBE
NOR/K: IWP\044001071 \FSDON001 . DOC 4-3
I µg/L(MDL)
2.8 µg/L (NC)
1.0 µg/L (NC)
7 µg/L (US and NC)
200 µg/L (NC)
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
4.4 GROUNDWATER TREATMENT STANDARDS
4.4.l Receptor-Based Treatment Standards
Feasibility Study Report
Davis Park Road TCE Site
Section: 4
Revision: 1
Date: July 1998
The receptor-based groundwater treatment standards applicable to the site are based on the
classification of the prospective receptor of treated water, Blackwood Creek. A complete
discussion on the classification of Blackwood Creek and the applicable standards are presented in
S~bsection 3.4.5. The treatment standards applicable to discharge of treated water to Blackwood
Creek for the contaminants of concern are summarized as follows:
Tetrachloroethene (PCE)
Trichloroethene (TCE)
1,2-Dichloroethene (1,2-DCE)
MTBE
Chloroform
10.8 µg/L
92.4 µg/L
None
None
None
However, treatment standards for discharge to surface water are actually determined through the
National Pollutant Discharge Elimination System (NPDES) permit process. This pennit must be
negotiated with NCDEHNR to establish discharge levels.
4.4.2 Technology-Based Effluent Limitations
Based on the Best Available Technology (BAT) described in Subsections 3.3.2.2 and 3.4.5.2, an
effluent criterion of 1 µg/L for each of the contaminants of concern is suggested for the
groundwater remediation at Davis Park Road. This is conservatively lower than the receptor-
based treatment standards for all the contaminants.
NOR/K'\WP\04400\071 \FSOON001. DOC 4-4
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 4
Revision: 1
Date: July 1998
4.5 SUMMARY OF GROUNDWATER REMEDIATION GOALSffREATMENT
STANDARDS
A summary of groundwater remediation goals and treatment standards for Davis Park Road are
presented in Table 4-1.
NORIKIWPUl4400\071\FSDDN001.DOC 4-5
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 4-1
Summary of Groundwater Remediation Goals and Treatment Standards
Davis Park Road TCE Site
May 1998
Remediation Goals Treatment
Contaminant (ug/L) Standards* (ug/L)
Tetrachloroethene (PCE) 1.0 5
Trichloroethene (TCE) 2.8 5
I, 1-Dichloroethene ( l, 1-DCE) 7.0 5
MTBE 200 200
Chloroform 1.0 5
* Treatment standards are suggested effluent criteria based upon BAT.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
SECTION 5
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
IDENTIFICATION AND SCREENING OF REMEDIAL TECHNOLOGIES
The objective of this section is to identify and screen remedial technologies and process options
that address the remedial action objectives and cleanup goals available for groundwater at the
Davis Park Road site. Technologies that do not adequately satisfy the criteria established during
the screening process will be eliminated from further consideration at this point. SARA guidelines
emphasize the use of treatment technologies that permanently and significantly reduce the toxicity,
mobility, or volume of waste. The screening process used to identify technologies includes:
identifying general response actions, specifying remedial technologies for each general response
action, identifying process options for each applicable remedial technology, and evaluation of the
process options against effectiveness, implementability, and cost. Actions one through three are
performed as part of the initial screening of technologies and· process options. The last action is
performed as the final screening of process options.
5,1 IDENTIFICATION OF GENERAL RESPONSE ACTIONS
A general response action is classified as a broad action or remedy that meets the remedial action
objectives for the site. The following eight general response actions have been identified for the
site:
• No Action -No active remedial options are implemented under this option.
• Institutional Control -Restrictions are established and implemented to control public and
environmental contact with site contaminants.
• Collection/Removal -Extraction of contaminated media and removal from the immediate
area.
NOR/K:IWP\04400\071 \FSDDN001.DOC 5-1
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
• Containment -Direct physical and/or chemical isolation of the contaminants.
• Treatment (In-Situ) -Contaminated media are treated in place by application of
biological, chemical, physical, or thermal processes that reduce the toxicity, mobility, or
volume of the contaminated material.
• Treatment (Ex-Situ) -Contaminated media are removed for application of biological,
chemical, physical, or thermal processes that reduce the toxicity, mobility, or volume of
the contaminated material.
• Disposal/Discharge -Contaminated and/or treated media are disposed of or discharged
either on-site or off-site.
• Residuals Management -Management of by-products from treatment of contaminated
materials.
5.2 REMEDIAL ACTION TECHNOLOGY IDENTIFICATION
The general response actions identified in the preceeding section were subdivided into potentially
applicable remedial technologies. These technologies are presented in Table 5-1. In subsequent
sections, each remedial technology is further subdivided into specific process options.
Remedial action alternatives are formed by combining screened technologies and process options
for groundwater. To develop the remedial action alternatives applicable to the site, the remedial
technologies and process options underwent an initial and a final screening. The two screenings
eliminated technologies and process options that will not be considered in developing remedial
action alternatives.
During the Remedial Design (RD), a site-specific design is developed for the selected alternative.
In many cases, various design parameters must be developed at the bench-, pilot-, or field-scale.
These parameters facilitate proper sizing of units and general measures of effectiveness to ensure
NOR/K:IWP\04400\071 I.FSDDN001. DOC 5-2
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 5-1
Groundwater Response Actions and Remedial Technologies
Feasibility Study
Davis Park Road TCE Site
May 1998
Response Action Groundwater Remedial Technology
No Action Not applicable
Institutional Action Access Restrictions
Alternate Water Supply
Monitoring
Natural Attenuation
Containment Cap
Vertical Barrier
Horizontal Barrier
Gradient Control
Collection/Removal Extraction
Interception
Physical
Chemical
Biological
Disposal/Discharge Off-Site
On-Site
Residual Management Off gas Treatment
Spent Granular Activated Carbon
NOR/K:IWP\044001071\FS.TBLS.DOC 5-3
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
that the design is appropriate and cost effective. The retention of any particular technology does
not ensure that it will be applicable to the Davis Park Road site. The screening process eliminates
technologies that have a low probability of being successfully applied to the affected media at the
site.
5.3 INITIAL SCREENING PHASE
During the initial screening activity, remedial action technologies identified in the previous section
and process options identified in this section are reviewed for a variety of criteria. In this section,
after the criteria are applied, the remedial technology and/or process option(s) can be accepted for
further evaluation or eliminated. The criteria are based on published information, experience with
the technology or process operation, knowledge of the site characteristics, and best engineering
judgement. Specific criteria used to reject technologies or process options during the initial
screening include one or more of the following:
• Technology/process option would not be a practical method for the volume or area of
contaminated media that is to be remediated.
• Technology/process would not be an effective method for the remediation of all the
contaminants as a sole technology or in combination with other technologies because of
the characteristics or concentrations of contaminants present at the site.
• Technology/process would not be feasible because of site conditions such as size, location,
weather, geology, hydrology, or surrounding land use.
• Technology/process option could not be effectively administered.
• Technology/process could result in the creation of a new site at a different location.
• Technology/process option has not been successfully demonstrated on site contaminants
or media.
NOR/K:IWP\04400\071 \FSOON001. DOC 5-4
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or ln part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
• Technology/process option is excessively expensive relative to other effective technologies
or process options.
The results of the initial screening of remedial technologies and process options applicable to
groundwater remediation at the Davis Park Road site are presented in Table 5-2. The table
includes a wide range of potentially applicable technologies and process options, brief descriptions
of each, and screening comments. The screening comments indicate whether the technology or
process option was retained or rejected, along with any screening rationale. A summary of the
technologies and process options that passed the initial screening for groundwater at the site is
provided in Table 5-3.
5.4 SCREENING OF REMEDIAL TECHNOLOGY PROCESS OPTIONS
The evaluation of technologies and process options 1s a continuation of the initial screening
procedure at a more detailed level. The goal of this evaluation is to select one representative
process, if possible, for each technology type to simplify the subsequent development of
alternatives without limiting flexibility during the remedial design. In some cases, more than one
process option may be selected for a technology type because the options are sufficiently different
in performance and impact that one would not adequately be represented by the other. In the
evaluation, effectiveness, implementability, and relative capital and operation and maintenance
costs are the criteria used to evaluate the technologies and process options. Comments regarding
effectiveness, implementability, and cost refer to relative differences between process options
under a remedial technology and for the basis of carrying an option forward for development into
a remedial alternative.
NOR/K:IWP\04400\071 \FSD0N001. DOC 5-5
--- ------ - -- -----
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General Remedial
Response Actions Technology
No action None
Institutional Alternate water supply
controls
Containment
technologies
Access restrictions
Groundwater monitoring
Point-of-use treatment
Natural attenuation
0IJ==•••~J"f"H Technologies and options screened out.
NOR/K.\WP\04-400\071\FS-TBLS.DOC
Table 5-2
Initial Screening of Technologies and Process Options
Davis Park Road TCE Site
Process
Options
Not applicable
City water connections
Deed rccordations
Monitoring of all
groundwater wells
Groundwater treatment at
potable water well head
Natural attenuation of
ground\vater contaminant
plume
May 1998
No action
Description of
Options
Extension of existing municipal well
system to serve residents in the area of
influence.
Removes groundwater as a potable
water source.
Screening
Comments
Required alternative
Potentially applicable.
Potentially applicable.
Periodic monitoring of wells. Potentially applicable.
Treatment of groundwater at wellhead Potentially applicable.
prior to immediate use.
Monitoring of groundwater contaminant Potentially applicable.
plume to define possible natural
degradation processes.
5-6
-
- - --- -- --- ------ -
This document was prepared by Roy F. Weston, Inc., expressly for EPA It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General
Response Actions
Containment
technologies
(continued)
Collection/
RcmO\·al
Remedial
Extraction
Collection and Discharge
l+r tnnn Technologies and options screened out.
NOR/K:\WP,04400\071 \FS-TBLS. DOC
Table 5-2 (Continued)
Initial Screening of Technologies and Process Options
Davis Park Road TCE Site
May 1998
Vertical extraction wells Pumping of groundwater and discharge Potentially applicable.
to a central point for treatment.
Horizontal extraction wells Pumping of groundwater and discharge Potentially applicable.
to a central point for treatment.
Dual phase extraction A high vacuum system is applied Potentially applicable.
simultaneously to remove liquid and gas
Discharge after collection
from low permeability or heterogeneous
formations.
After extraction of groundwater to
surface, discharge of water to local
POTW for treatment.
5-7
Potentially applicable if Gaston County or
City of Gastonia agrees.
-
--- -- - - - - - - ----- --
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General Remedial
Response Actions Technology
Collection/ Physical treatment
Removal
(continued)
~li~J~{==tj Technologies and options screened out.
NOR/K\WP\04400\071 \FS-TBLS. DOC
Table 5-2 (Continued)
Initial Screening of Technologies and Process Options
Davis Park Road TCE Site
Filtration
Process
Options
May 1998
Description of
Options
Physical means of separating solids
from liquids.
Screening
Comments
Potentially applicable for metals or silt
composition in groundwater.
1111111111111;1111111111 ••••••• llll~lll~l\lilillllllllllllllllill
Air stripping (ground
surface unit)
In-well vapor stripping
Bonding of organic molecules to carbon Potentially applicable.
surfaces.
!ul(iit~~l@m~!l!il!!itL .................. . M&tlw/ll!~i!;ijjlj~fi&m/ijffilwll~HH
llllllliilL1l;■1111
~ll1IJl~1ili1fl~1f
Air stripping is a mass transfer process
where air and water flow counter
currently through packing media that
strips contaminants.
Air stripping of volatile contaminants
within the well and reinjection of
treated water around well.
5-8
Potentially applicable.
Potentially applicable.
-
- ------ ---------
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General
Response Actions
Collection/
Removal
(continued)
Remedial
Technology
Pliysical treatment
(continued)
Chemical treatment
j ~~f=~'~K~K! Technologies and options screened out
NOR/K:\WPI04400\071 \FS-TBLS. DOC
Table 5-2 (Continued)
Initial Screening of Technologies and Process Options
Da,,is Park Road TCE Site
Process
Options
Hydraulic and pneumatic
fracturing
process
May 1998
Description of
Options
Techniques to create enhanced fracture
networks to increase soil pem1eability to
liquids and vapors and accelerate
contaminant removal.
--
Use of the chemical oxidation process
through injection and dispersion of
specific chemical compounds to the
subsurface environment.
5-9
Screening
Comments
Technology is applicable lo both saprolite
and bedrock aquifers,
-
----------------= -tiiil
This document was prepared by Roy F. Weston, Inc., expressly for EPA. Jt shall not be disclosed, in whole or in part, without the express written permission of EPA.
General Remedial
Response Actions Technology
Collection/ Chemical treatment
Removal (continued)
(continued)
Biological treatment
,, lHH@I Technologies and options screened out.
NOR/K.:\WP\04400\071 \FS-TBLS. DOC
Table 5-2 (Continued)
Initial Screening of Technologies and Process Options
Davis Park Road TCE Site
UV /Oxidation treatment
May 1998
Description of
Options
1111111
Addition of surfactants or cosolvents to
groundwater system to aid in mobilizing
or solubilizing NAPL or contaminants
sorbed to soil matrix.
Extraction of groundwater followed by
treatment process of combination of
ultraviolet light and chemical oxidants
to destroy organic contaminants.
This option is generally considered an
enhancement of the pump-and-treat
method. Only applicable if pump-and-treat
selected.
Potentially applicable.
In-situ biodegradation Treatment of contaminated groundwater Potentially applicable.
in place by microbial degradation.
5-10
----- ---- ------
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General Remedial
Response Actions Technology
Collection/ Biological treatment
RemoYal (continued)
(continued)
Disposal/ On site
Discharge (treated
water only)
Off site
I'""••• •+/I Technologies and options screened out.
NOR/K:\WP\04400\071\FS..TBLS.DOC
Table 5-2 (Continued}
Initial Screening of Technologies and Process Options
Da,·is Park Road TCE Site
May 1998
Process Description of
Options Options
Fluidized bed aerobic The FBBR system destroys organic
treatment (FBBR) compounds by combining the aerobic
biological process and granular
activated carbon.
Conventional aerobic Use of microorganisms to detoxify or
biological treatment decompose biodegradable organics in
aqueous waste streams.
Anaerobic biological Reduction of organic concentrations by
treatment aerobic processes.
Ph)1oremediation The general use of plants to reme-diate
environmental media in-situ.
Local stream Discharge of treated water to existing
surface water body.
Recharge/infiltration All treated groundwater would be
gallery disposed through an on-site infiltration
gallery.
Recharge wells Disposal of treated groundwater through
network of recharge wells.
POTW Treated water discharge to a nearby
sanitary sewer line.
5-11
Screening
Comments
Potentially applicable.
Potentially applicable.
Potentially applicable.
Potentially applicable; however, due to
depth to groundwater, extraction of
groundwater before treatment by plants
would be necessary.
Potentially applicable.
Potentially applicable.
Potentially applicable.
Potentially applicable.
------ - --- -
This document was prepared by Roy F. Weston, Inc., expressly for EPA It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General Remedial
Response Actions Technology
Residuals Off gas Treatment
Management
Spent Granular Activate
Carbon (GAC)
IH ,:9:;;, {I Technologies and options screened out.
NOR/K:\WP\04400\071\FS-TBLS DOC
Table 5-2 (Continued)
Initial Screening of Technologies and Process Options
Davis Park Road TCE Site
Process
Options
Carbon adsorption
Off-site regeneration
Off-site disposal.
May 1998
Description of
Options
Oflgas contaminants are adsorbed onto
activated carbon.
lltl1liJll':1111fJIIIIIII
Spent GAC is transported off-site for
regeneration at a pennitted facility.
Spent GAC is transported off-site for
disposal at a permitted facility.
5-12
Screening
Comments
Potentially applicable.
Potentially applicable.
Potentially applicable.
- -
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission or EPA.
Table 5-3
Technologies and Process Options Passing Initial Screening
Davis Park Road TCE Site
May 1998
General Response Action Remedial Technology Process Options
No Action None Not Applicable
Institutional Controls Access Restrictions Deed Recordations
Alternate Water Supply City Water Connections
Groundwater Monitoring Groundwater Sampling
Point-of-Use Treatment Groundwater Treatment at Wellhead
Natural Attenuation Natural Attenuation of Groundwater
Contaminant Plume
Collection/Removal Extraction Vertical Ex1:raction Wells
Horizontal Extraction Wells
Dual Phase Extraction
Collection and Discharge Discharge After Collection
Physical Treatment In-Well Vapor Stripping
Hydraulic & Pneumatic Fracturing
Filtration
Air Stripping
Carbon Adsorption
Chemical In-Situ Chemical Oxidation
UV/Oxidation
Surfactants/Cosolvents
Biological In-Situ Biodegradation
Fluidized Bed Aerobic Treatment
Conventional Aerobic Biological Treatment
Anaerobic Biological Treatment
Phytoremediation
Disposal/Discharge On-Site Local Stream
Infiltration Gallery
Recharge Wells
Off-Site POTW
Residuals Management Off gas Treatment Carbon Adsorption
Spent Granular Activated Carbon Off-Site Regeneration
Off-Site Disposal
NOR/K:\WP\04400\071\FS-TBLS.DOC 5-13
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
The effectiveness evaluation focuses on: (I) the potential effectiveness of process options m
handling the estimated areas or volumes of media and meeting the remediation goals identified in
the remedial action objectives; (2) the potential impacts to human health and the environment
during the construction and implementation phase; and (3) how proven and reliable the process is
with respect to the contaminants and conditions at the site.
Implementability encompasses both the technical and administrative feasibility of implementing a
technology. Technical implementability is used as an initial screen of technology types and process
options to eliminate those that are clearly unworkable at the site. Administrative aspects include
the ability to obtain necessary permits; the availability of treatment, storage, and disposal services;
and the availability of necessary equipment and skilled workers to implement the technology.
Cost plays a limited role in the screening of process options. Relative capital and O&M costs are
used rather than detailed estimates. At this stage in the process, the cost analysis is made on the
basis of engineering judgment, and each process is evaluated as to whether costs are high,
medium, or low relative to other process options in the same technology type with comparable
effectiveness.
Table 5-4 presents the technologies and process options retained from the initial screening and
provides comments based on the evaluation criteria.
5.5 FINAL EVALUATION SCREENING
The groundwater remediation technologies that have been retained from the initial screening are
discussed in this section are divided into the following categories:
NORI!(: IWP\04400\071 \FSDDN001 . DOC 5-14
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General Response Remedial Process
Actions Technoloev Options
No action None Not applicable
Institutional Alternate ,vatcr City water
controls supply connections
Access restrictions Deed recordations
Groundwater Groundwater
monitoring sampling
Point-of-use treat-Treatment of water
ment at wellhead
Natural attenuation Natural attenuation
of groundwater study
plume
Collection/ Extraction Vertical extraction
Removal wells
Horizontal
extraction wells
NOR/K:IWP\04400\071\FS-TBLS.DOC
Table 5--1
Evaluation of Process Options
Davis Park Road TCE Site
May 1998
Effectiveness
Does not achieve remedial action
objectives.
Effectively prevents use of
contaminated groundwater, but
does not reduce contaminant
concentration.
Possibly difficult to implement and
maintain control. Does not reduce
contamination.
Would not protect human health
and the environment. Effective for
evaluating other remedial actions.
Effective removal of contaminants
from potable water. Slight reduc-
tion of contamination. Does not
monitor contaminant plume.
Does not actively remediate plume
or eliminate immediate risk.
Effective removal of majority of
contamination. Suspect as to
removal of all contamination.
Highly useful in areas of ground
surface obstructions. More effective
than vertical extraction wells.
5-15
Implementability
Not acceptable to local, stale, or
federal government.
Conventional construction,
requires permitting and landowner
approval.
Legal requirements and authority.
Easily implemented. Monitor wells
already exist. Equipment readily
available.
Easily implemented with land-
owner authority.
Easily implemented
Implementation easy but well
connection difficult. Requires a
treatment unit connection.
Easily implemented. Requires ·a
treatment unit connection.
--
Cost
None
High capital
Low cost
Low capital,
moderate
operation and
maintenance
(O&M)
Low cost, low
O&M
Moderate capital,
highO&M
Moderate capital,
moderate O&M
Moderate capital,
moderate
maintenance
----... -,_
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General Response Remedial Process
Actions Technolo2v Ontions
Collection/ Dual phase extrac-
Removal (Cont) tion
Collection and Discharge after
discharge collection
Physical treatment Filtration
Carbon adsorption
Air stripping
(ground surface)
In-well vapor
stripping
Hydraulic and
pneumatic frac-
luring
Chemical In-situ chemical
treatment oxidation process
Surfactants/
consolvents
UV/Oxidation
treatment
NOR/K:\WP\04400\071 \FS-TELS.DOC
Table 5-4 (Continued)
Evaluation of Process Options
Davis Park Road TCE Site
May 1998
Effectiveness
When combined with
bioremediation or bioventing, this
process can soeed up VOC removal
Removal of contaminants from
groundwater. Suspect as to
removal of all contamination.
Effective for removal of metals and
silt in groundwater.
Effective for removal of organic
compounds. Effective treatment
method.
Effective and reliable treatment
method.
Effective removal of contaminants
from groundwater captured.
Increases effectiveness of other
removal technologies
Reduces contamination. Requires
test piloting.
Very similar to in-situ soil washing
process. Methods of introduction to
aquifer may vary.
Effective removal of organic
contaminants from groundwater.
Requires pumping methods.
5-16
Implementability
Readily implementable.
Implementation easy but well
connection difficult.
Readily implementable
Easily implemented into various
treatment systems.
Readily implemented. Pennitting
required.
Readily implemented. Permitting
required.
Readily implemented.
Readily implementable. Permit
required. May be difficult to
implement in fractured bedrock.
Readily implementable.
Readily implementable.
-
Cost
Moderate capital,
lowO&M
Moderate capital,
moderate O&M
Moderate capital,
lowO&M
Moderate capital,
lowO&M
High capital,
moderate O&M
High capital,
moderate O&M
High capital,
moderate O&M
High capital, low
O&M
Moderate capital,
lowO&M
High capital,
moderate O&M
--------
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General R~sponse Remedial Process
Actions Technoloev Ontions
Collection/ Biological In-situ
Removal (Cont) trc~1tment biodegradation
Biological Fluidized bed
treatment (Cont) aerobic treatment
ConYentional
aerobic biological
treatment
Anaerobic
biological
treatment
Phy1oremediation
Discharge/ On site Local stream
Disposal
Recharge/infiltra-
lion gallery
Recharge wells
Off site POTW
NOR/K:\WP\04400\071 \FS-TBLS. DOC
Table 5-4 (Continued)
Evaluation of Process O11tions
Davis Park Road TCE Site
May 1998
Effectiveness
Effective and reliable for moderate
to high concentrations of
contaminants.
Effective and rcliablc for moderate
to high concentrations of
contaminants.
Effective and reliable for moderate
to high concentrations of
contaminants.
Effective and reliable for moderate
to high concentrations of
contaminants.
Ex-situ type treatment effectively
removes organics; however,
organic contaminant level cannot
initially be high. Must be used in
concert with pump-and-treat
method.
Effective and reliable
Effective and reliable. Requires
pilot-study.
Effective, if placed in bedrock.
Effective and reliable. Requires
ore-testine.
5-17
Im11Iementability
Readily implementable. Requires
groundwater pumping.
Readily implcmentable. Requires
groundwater pumping.
Readily implementable. Requires
groundwater pumping.
Readily implementable. Requires
groundwater pumping.
Easily implemented.
Requires pretreatment of water and
permitting. Easily implemented.
Requires pre-treatment of water
and permits.
Pennit required.
Readily implemented. Permitting
reauired.
-
Cost
Moderate capital,
moderate O&M
Moderate capital,
lowO&M
Moderate capital,
moderate O&M
Moderate capital,
moderate O&M
Moderate capital,
lowO&M
Low capital, very
lowO&M
High capital, low
O&M
High capital, low
O&M
Moderate capital,
lowO&M
---,_ .. <all --
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
General Response Remedial
Actions Tcchnolo<•Y
Residuals Off gas treatment
Management
Spent Granular
ActiYate Carbon
NOR/K:\WP\04400\071\FS.TBLS.DOC
Process
o,,tions
Carbon adsorption
Off-site
regeneration
Off-site disposal
Table 5-4 (Continued)
Evaluation of Process Options
Davis Park Road TCE Site
May 1998
Effectiveness
Effective method for removing
off gas contaminants
Effective technology
Effective technology
5-18
Implementability
Easily implemented.
Readily implemented
Readily implemented
-....... -
Cost
Moderate capital,
moderate O&M
Moderate capital,
moderate O&M
Moderate capital,
lowO&M
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
• No Action
• Institutional Controls
• Collection/Removal Technologies
• Discharge/Disposal Options
• Residuals Management
5.5. l No Action
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Description -Under the no action alternative, no remedial measures would be implemented at the
Davis Park Road site. Contaminated groundwater would remain uncontrolled allowing for the
potential migration farther downgradient and deeper into bedrock.
Effectiveness -This alternative is not effective as it does not achieve remedial action objectives.
The alternative does not reduce or eliminate the potential hazards to human health or the
environment.
Implementability -This option is readily implementable technically, but does not meet institutional
requirements.
Cost -No costs would be incurred in implementing this alternative.
5.5.2 Institutional Controls
The institutional actions being considered are alternate water supply, access restrictions,
groundwater monitoring, and point-of-use treatment.
NOR/K. \WP\04A00\071\FSDON001.00C 5-19
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
5.5.2.1 Alternate Water Supply
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Description -Under this alternative, all homes, churches, and businesses not currently connected
to the City of Gastonia or Gaston County, public water supply within the affected groundwater
plume area would be connected. Groundwater underneath the Davis Park Road TCE site would
no longer be used as a potable water source. Private water supply wells would be disconnected
from further use.
Effectiveness -This alternative would effectively eliminate use of groundwater as a potable water
source for humans, but does not reduce environmental impacts or prevent the groundwater plume
from migrating to other areas.
Costs -Costs for this technology are expected to be moderate, involving land clearing, right-of-
way access agreements, and construction.
5.5.2.2 Access Restrictions
Description -Deed recordations; deeds in the area would record the fact that groundwater
contamination exists under the property and that if a potable well is located on the property, there
is a strong possibility that it may be contaminated with VOCs. These recordations would remain
in place unless or until the groundwater quality was returned to contaminant concentrations that
would allow unrestricted use.
Implementability -Deed recordations can be implemented only with the assistance of state and
local government authorities, and landowners downgradient of the site. Resistance may be
encountered from local landowners.
NOR/K: IWP\044001071 IFSDDN001. DOC 5-20
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
CDs! -Legal fees for deed nDtatiDn and groundwater use restrictiDn are expected ID be lDw.
5.5.2.3 Point-of-Use-Treatment
DescriptiDn -This technology involves providing groundwater treatment at the point of use for
wells currently installed in or in the event that wells are installed within the contaminant plume to
supply water ID either existing downgradient residents or potential future site residents. An
example of point-of-use treatment would be the use of carbon filter units for individual residences
who use private residential water supply wells.
Effectiveness -This technology is effective at providing safe drinking water at the point of use.
However, the technology does not remove or monitor contaminant plume migration. The
treatment units would be expected ID be in place for an extended period of time.
Implementability -Implementing this option requires the cooperation of the individual users. With
cooperation, it is readily implementable.
Costs -Costs for implementing this technology are low and depend primarily on the number and
type of individual treatment units required. Operation and maintenance of treatment units are also ·
low.
5.5.2.4 Groundwater Monitoring
Description -Groundwater monitoring would involve sampling both monitoring wells and potable
drinking water wells. Groundwater samples wDuld be collected and analyzed periodically to
evaluate the concentrations of contaminants in the groundwater and determine whether the
NOR/K:IWP\04400\071 \FSDDN001. DOC 5-2 I
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This document was prepared by Roy F. Weston, Jnc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
contaminants are continuing to migrate. Private wells will be analyzed to determine if
concentrations continue to increase.
Effectiveness -Groundwater monitoring is a proven, reliable method for assessing the migration
of contaminants and the effectiveness of groundwater remedial actions. It would not protect
human health or the environment.
Implementability -This option can be readily implemented.
Cost -The cost of implementing a monitoring program would include low construction costs of a
few additional wells and moderate maintenance costs.
5.5.2.5 Natural Attenuation
Description -Natural subsurface process such as dilution, volatilization, biodegradation,
adsorption, and chemical reactions with subsurface materials are allowed to reduce contaminant
concentrations to acceptable levels. Natural attenuation is not a "technology" per se, and there is
significant debate among technical experts about its use at hazardous waste sites. Consideration of
this option requires modeling and evaluation of contaminant degradation rates and pathways. The
primary objective of site modeling is to demonstrate that natural processes of contaminant
degradation will reduce contaminant concentrations below regulatory standards before potential
exposure pathways are completed. In addition, sampling and sample analysis must be conducted
throughout the process to confirm that degradation is proceeding at rates consistent with meeting
cleanup objectives.
Natural attenuation 1s not the same as "no action," although it often is perceived as such.
CERCLA requires evaluation of a "no action" alternative but does not require evaluation of
NOR/K:\WP\04400\071 \FSODN001 , DOC 5-22
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
natural attenuation. Natural attenuation is considered in the Superfund program on a case-by-case
basis, and guidance on its use is still evolving. It has been selected at Superfund sites where, for
example, removal of DNAPLs has been determined to be technically impracticable (Superfund is
developing technical impracticability (TI) guidance); and where it has been determined that active
remedial measures would be unable to significantly speed remediation time frames. Where
contaminants are expected to remain in place over long periods of time, TI waivers must be
obtained. In all cases, extensive site characterization is required.
The attitude toward natural attenuation vanes among agencies. USAF carefully evaluates the
potential for use of natural attenuation at its sites; however, EPA accepts its use only in certain
special cases.
Effectiveness -Target contaminants for natural attenuation are non-halogenated VOCs and
SVOCs and fuel hydrocarbons. Halogenated VOCs and SVOCs and pesticides also can be
allowed to naturally attenuate, but the natural process may be less effective and may be applicable
to only some compounds within these contaminant groups.
Various factors may limit applicability and effectiveness of natural attenuation:
• Site-specific data must be collected to determine model input parameters.
•
•
Intermediate degradation products may be more mobile and more toxic than the original
contaminant.
Natural attenuation should be used only in low-risk situations .
• Contaminants may migrate to an exposure point before they are degraded.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. 1t shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Implementability -Natural attenuation can be implemented through a detailed evaluation of data
elements collected through modeling, sampling, and sample analysis which are required for
justifying and monitoring natural attenuation. The extent of contaminant degradation depends on
a variety of parameters, such as contaminant types and concentrations, temperature, moisture, and
availability of nutrients/electron acceptors (e.g., oxygen, nitrate).
When available, information to be obtained during data review includes:
• Soil and groundwater quality data:
•
Three-dimensional distribution of residual-, free-, and dissolved-phase contaminants.
The distribution of residual-and free-phase contaminants will be used to define the
dissolved-phase plume source area.
Groundwater and soil geotechnical data.
Historical water quality data showing variations in contaminant concentrations through
time.
Chemical and physical characteristics of the contaminants.
Potential for biodegradation of the contaminants.
Geologic and hydrogeologic data:
Lithology and stratigraphic relationships.
Grain-size distribution (sand versus silt versus clay).
Aquifer hydraulic conductivity.
Flow gradient.
Preferential flow paths.
Interaction between groundwater and surface water.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
• Location of potential receptors:
Groundwater wells.
Surface water discharge points.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Cost -There are costs for modeling contamination degradation rates, to determine whether
natural attenuation is a feasible remedial alternative, for subsurface sampling and sample analysis
(potentially extensive) to determine the extent of contamination and confirm contaminant
degradation rates and cleanup status, and for migration and degradation monitoring.
5.5.3 Collection/Removal Technologies
The technologies considered for groundwater contamination collection/removal at the site are
extraction processes, collection and discharge, and physical, chemical, and biological treatment.
5.5.3.1 Vertical Extraction Wells
Description -Extraction ( or recovery) wells are often used to recover contaminated groundwater
from an aquifer system. These wells are designed to either capture affected groundwater or inhibit
further migration of contaminants by reversing the hydraulic gradient. Extraction wells are
typically located near or within contaminant source areas. A network of extraction wells may be
installed so that their cones of influence overlap, thereby intercepting lateral groundwater flow.
Recovered groundwater is then pumped to a treatment facility (if required) and subsequently
discharged.
A collector well system as described in Driscoll ( 1986) may consist of a large vertical caisson with
a horizontal screen. Collector well systems are typically designed for collection of large quantities
of water (millions of gallons per day).
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section:5
Revision: 1
Date: July 1998
Effectiveness -In the saprolite, groundwater flows through the intergranular pore spaces. The
rate of flow is controlled by the porosity of the soil, permeability, and existing hydraulic gradient.
Due to potentially low hydraulic conductivity of the soil, groundwater yield rates are expected to
be less than one gallon per minute per well, so recovery of contamination would be slow.
Groundwater recovery from properly designed and located extraction wells will capture
contaminants of concern from the aquifer system beneath the Davis Park Road site.
In the bedrock, groundwater flows through fractures or bedding planes between rock layers. Rate
of flow into a well will vary depending upon the intersection of the screen with these two open
areas. Aquifer testing will be required to determine potential zones of maximum groundwater
flow in the bedrock.
Implementability -This technology is easily implemented as it uses conventional well installation
practices. There are no apparent institutional obstacles to groundwater collection by this method.
Cost -Cost for this technology is expected to be moderate.
5.5.3.2 Horizontal Extraction Wells
Description -Drilling techniques are used to position wells horizontally, or at an angle, to reach
contaminants not accessible by direct vertical drilling. Directional well technology is used
exclusively as an enhancement technology for other in-situ treatment technologies. Technologies
used with directional wells include biodegradation, bioventing, SVE, soil flushing, air sparging,
and pump-and-treat.
Hardware used for directional boring includes wire line conng ngs, hydraulic thrust systems,
electric cone penetrometers, steering tracking hardware, sonic drilling, and push coring systems.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in ·whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Hydraulically activated thrust equipment capable of exerting more than 40 tons of thrust is used to
push the directional boring heads into the earth. Directional control is obtained by proper
positioning of the face of the asymmetric boring head. Slow rotation of the boring head will cut
and compact the geologic material into the borehole wall. Thrusting a boring head that is not
rotating will cause a directional change. The machinery is capable of initiating a borehole, steering
down to a desired horizontal depth, continuing at that depth, and then steering back to the surface
at a down range location.
Effectiveness -Horizontal wells have been shown to increase effective removal of contaminants
from soil layers by 30 percent while using SVE technology, air sparging, and pump-and-treat
groundwater extraction methods.
The following factors may limit the applicability and effectiveness of this technology:
• Well failures are possible during system installation;
• Specialized equipment is required;
• Wells are difficult to position precisely;
• Installation of horizontal wells is typically costly.
Implementability -Horizontal wells are readily implemented as it uses conventional and
specialized equipment. Drilling techniques of this type are used in areas where development of the
land surface is moderate to heavy.
Cost -Cost for this technology is moderate to high, depending upon well depths and number of
wells installed.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA
5.5.3.3 Dual Phase Extraction
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Description - A high vacuum system is applied simultaneously with other technologies to remove
liquid and gas from low permeability or heterogeneous formations. The vacuum extraction well
includes a screened section in the zone of contaminated soils and groundwater. As the vacuum is
applied to the well, soil vapor is extracted, and groundwater is entrained by the extracted vapors.
Once above grade, the extracted vapors and groundwater are separated and treated. Dual phase
extraction is a full-scale technology.
Dual phase extraction is generally combined with bioremediation, air sparging, or bioventing when
the target contaminants include long-chained hydrocarbons. Use of dual phase extraction with
these technologies can shorten the cleanup time at a site. It also can be used with pump-and-treat
technologies to recover groundwater from high yielding aquifers. Dual phase provides a better
control of the groundwater. When containment of vapors/liquids is necessary, the results are far
better than those obtained through air sparging.
Effectiveness -Dual phase vacuum extraction is used to remediate soil and groundwater. This
technology is more effective than SVE for heterogeneous clays and fine sands. This extraction
method may also quickly reduce contaminants within shallow aquifers.
The following factors may limit the applicability and effectiveness of the process:
• Site geology and contaminant characteristics/distribution may limit effectiveness;
• Combination with complementary technologies (e.g., pump-and-treat) may be required to
recover groundwater from high yielding aquifers;
• Dual phase extraction requires both water treatment and vapor treatment.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Dale: July 1998
Implementability -This technology is readily implementable with other technologies to improve.
overall remediation performance.
Cost -The cost for implementation of technology is moderate.
5.5.4 Discharge after Collection
Description -This process option involves the collection of groundwater via extraction wells
followed by direct discharge to the local POTW. This would eliminate installation of a treatment
system at the site; however, permitting by the County of Gaston or City of Gastonia would be
required.
Effectiveness -This system would ensure withdrawal of contaminated groundwater from the
aquifers underlying the site, but would not necessarily reduce the risk to local citizens using
groundwater as a potable water source.
Implementation -Equipment for the installation of this system is available and 1s readily
implemented. Permitting and agreement to accept the contaminated groundwater would be
required by local authorities.
Cost -The cost associated with this system would include moderate capital and operation and
maintenance.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
5.5.5 Physical Treatment Technologies
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
The process options being considered for physical treatment of contaminants in groundwater are
filtration, carbon adsorption, air stripping, in-well vapor stripping, and hydraulic and pneumatic
fracturing.
5.5.5.1 Filtration
Description -Filtration is a physical means of separating solids from liquids (and vice versa) by
forcing the fluid through a porous medium. For groundwater treatment, filtration can serve two
separate objectives:
• Remove suspended solids from a liquid stream for the purpose of producing a purified
liquid.
• Reduce volume of waste sludges by increasing the solids concentration by removing the
liquid (sludge dewatering).
Waste particulates greater than about 25 microns in diameter are trapped at the surface or within
the porous filter medium as the fluids flow through. Smaller particles must be agglomerated. In all
filtration systems, pressure or suction is required to force the fluid through the filters to remove
the trapped solids.
Effectiveness -Filtration is often effective for metals removal following the addition of chemicals
that render the metals insoluble and thus removable by filtration. Filtration is often used on
sludges or liquids generated during other waste treatment processes. There are three major types
of filtration systems:
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
• Granular media filter (e.g., sand)
• Rotary drum vacuum filter
• Filter press
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Solids characteristics in some applications may cause some clogging and reduce the overall
operating efficiency. The liquid effluent from sludge dewatering may contain hazardous materials
that will require appropriate disposal.
Implementation -Pilot studies are recommended for system design and determination of
operating parameters.
Cost -The capital cost components consist of filters and pumps. The filter medium cost is
dependent on the surface area. The operations and maintenance cost is for electricity and
replacement of filter medium. Overall process cost is expected to be moderate for metals removal.
5.5.5.2 Carbon Adsorption
Description -Activated carbon adsorption is a frequently applied technology for the removal of
trace organic compounds from an aqueous solution. Adsorption is a surface phenomenon in which
soluble molecules from a solution are bonded onto the surface of a solid substrate. Activated
carbon, which has a high surface area to mass ratio ranging from 500 to 1,400 m2/gm, is a good
adsorbent for the removal of many organic compounds as well as some inorganic chemicals. The
majority of carbon adsorption systems use cylindrical pressure vessels that contain activated
carbon. Typically, two carbon beds will be operated in series to provide maximum carbon
utilization while protecting against breakthrough. Additional equipment that may be required
includes pumps and piping, backwash equipment, carbon transfer equipment, and a carbon
regeneration system (ifit is cost-effective to regenerate on-site).
NOR/K:\WP<04400\071 \FSDDN001.00C 5-3 I
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Effectiveness -Carbon adsorption processes have been used extensively to treat industrial
wastewaters containing dissolved organic materials and certain inorganic constituents. It is
effective in removing many chlorinated organics and pesticides. There are practical limitations to
this process that restrict treatment of waste _streams that contain greater than 50 ppm of
suspended solids (without pretreatment) and I 0,000 ppm of organic concentrations; therefore,
prior filtration or settling of suspended solids extends the life of the carbon. The exhausted carbon
will contain the constituents removed from the feed streams and will probably be classified as a
hazardous waste. The carbon must be either regenerated (on-site or off-site) or disposed ofin an
approved landfill. Thermal regeneration of the spent carbon is the most common method currently
used by off-site regeneration vendors.
Implementability -Packaged carbon adsorption units can be purchased or leased and can be
implemented rather easily. Spent units are typically shipped off site for regeneration.
Cost -Total operating costs are heavily dependent on the carbon usage rate, as carbon
replacement is the largest cost factor; therefore, while capital cost are relatively low, operating
cost are relatively high.
5.5.5.3 Air Stripping
Description -The air stripping process is one of the most frequently applied technologies for the I removal of VOCs from water. Air stripping has been designated by EPA as the best available
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technology (BAT) for removal of regulated VOCs. Air stripping is a mass transfer process that
typically uses a cylindrical vessel containing high surface-area packing. Air and water flow
counter currently through the packing media. This enhances air/liquid contact by exposing a
greater amount of liquid surface area to the air. The more surface area exposed the greater the
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, wtthout the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
efficiency, because mass-transfer occurs at the gas-liquid interface. The air cames the
contaminants out of the stripper. When emitted into the atmosphere, the contaminants dissipate
and are broken down by natural ultraviolet (UV) degradation. Air strippers are now also available
as rectangular units containing a series of perforated trays carrying untreated water through which
air is bubbled to strip the contaminants. Tray aeration systems are typically appropriate for low
flow applications.
Effectiveness -Air stripping processes have been commonly used for VOC-contaminated
groundwater treatment. It is extremely reliable and effective for low levels of contaminants with
high Henry's Law constants. In many cases, pretreatment is needed to remove iron or other
chemicals that precipitate when oxidized. Air stripping would not be effective for the removal of
most pesticides or metals.
Implementability -Air stripping is an established technology which uses widely available air
stripping packed towers. Above the packing is a water distribution device. Air is supplied by a
blower, using either forced or induced draft. Tray aeration systems are also implemented rather
easily.
As per the current state guidelines (specified in I SA NCAC 20.0518), a permit is required for air
emissions of more than 40 lbs. per day of VOCs. For emissions less than 40 lbs. per day, no
permit is required but registration of the stripper with the NCDEHNR is required. Emissions at
the Davis Park Road site may be well below 40 lbs. per day.
Cost -Air stripping can generally be implemented at a relatively low cost. Operating costs are
also relatively low.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
5.5.5.4 In-Well Vapor Stripping (NoVOes®)
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Description. -This method of voe removal is an alternative to common "pump-and-treat"
methods. In-well vapor stripping operates through a "two level" process. By creating air pressure
at the lower level, water outside of the well is forced to enter, allowing the water/air bubble
mixture to rise, acting as an underground voe vapor stripper. The vapors rise to the top of the
well where they are drawn off by vacuum to an off-gas treatment unit.
The treated water is returned to the aquifer via a second well opening located above the water
table. Reinfiltrating water creates a toroidal circulation pattern around the well so that water can
be treated through multiple cycles to achieve the desired contaminant level. In addition, injecting
air/oxygen into the well stimulates the natural, biological breakdown of contaminants in the soil or
bedrock.
Effectiveness -Remediation of groundwater usmg in-well vapor stripping occurs without
extracting groundwater, lowering the groundwater table, or generating wastewater typical of
pump-and-treat systems. This technology has advantages over other technologies including lower
capital and operation and maintenance costs and quick reduction of highly concentrated
contaminant plumes.
Potential limitation include:
• If wells are not properly located, it is possible to spread the partially remediated plume by
recirculating partially treated water beyond the radius of influence of the well.
• Discharges to the vadose zone may also mobilize pockets of contaminant in the vadose
zone.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Implementability -This technology is readily implementable and has been tested on several
Department of Energy and Department of Defense sites. The technology would require permitting
under State of North Carolina guidelines.
Additional geologic and hydrogeologic data from the Davis Park Road site would have to be
collected prior to installation of the wells.
Cost -Capital and maintenance and operation costs are claimed to be significantly less than
traditional pump and treat systems.
5.5.5.5 Hydraulic and Pneumatic Fracturing
Description -Hydrofracturing is a technology in which pressurized water is injected to increase
the permeability of consolidated material or relatively impermeable unconsolidated material.
Fissures created in the process are filled with a porous medium that can facilitate bioremediation
and/or improve extraction efficiency. Fractures promote more uniform delivery of treatment fluids
and accelerated extraction of mobilized contaminants. Typical applications are linked with soil
vapor extraction, in-situ bioremediation, and pump-and-treat systems.
The fracturing process begins with the injection of water into a sealed borehole until the pressure
of the water exceeds the overburden pressure and a fracture is created. A slurry composed of a
coarse-grained sand and guar gum gel is then injected as the fracture grows away from the well.
After pumping, the sand grains hold the fracture open while an enzyme additive breaks down the
viscous fluid. The thinned fluid is pumped from the fracture, forming a permeable subsurface
channel suitable for delivery or recovery of a vapor or liquid.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
The hydraulic fracturing process can be used in conjunction with soil vapor extraction technology
to enhance recovery. Hydraulically-induced fractures are used to deliver fluids and nutrients for
in-situ bioremediation applications.
Effectiveness -Hydrofracturing is applicable to a wide range of contaminant groups with no
particular target group. The technology has had widespread use in the petroleum and water-well
construction industries but is an innovative method for remediating hazardous waste sites.
There are several factors that may limit the applicability and effectiveness of the process. The
technology should not be used in bedrock susceptible to seismic activity. Investigation of possible
underground utilities, structures, or trapped free product is required. The potential exists to open
new pathways leading to the unwanted spread of contaminants (e.g., DNAPLS). Pockets of low
permeability may still remain after using this technology.
Implementability -This technology would be suitable for the saprolite aquifer at the Davis Park
site; however, there may be difficulty with the application of this technology to the bedrock
aquifer.
Cost -The cost per fracture is estimated to be $1,000 to $1,500, based on creating four to six
fractures per day. This cost (including equipment rental, operation, and monitoring) is small
compared to the benefits of enhanced remediation and the reduced number of wells needed to
complete the remediation. A number of factors affect the estimated costs of creating hydraulic
fractures at a site. These factors include physical site conditions such as site accessibility and
degree of soil consolidation; degree of soil saturation; and geographical location, which affects
availability of services and supplies. The first two factors also affect the effectiveness of hydraulic
fracturing.
NOR/K:\WP\04400\071 \FSOON001.00C 5-36
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written perm·1ssion of EPA.
5.5.6 Chemical Treatment Technologies
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Dale: July 1998
The process options being considered in this category are in-situ chemical oxidation, surfactants/
solvents, and UV/oxidation treatment.
5.5.6.1 In-Situ Chemical Oxidation
Description -This process involves injection and dispersion of specific non-hazardous chemical
compounds and amendments to the subsurface environment for the purpose of increasing the
permeability of the soil and destroying organic contaminants. The reagents employed in the
process will degrade rapidly into water and oxygen upon completion of the treatment process.
This will reduce the toxicity of the contaminant, reduce the concentration of the contaminant, or
completely eliminate the contaminant from the subsurface soil and groundwater.
This technology utilizes strong oxidizing agents and other amendments which convert various
organic contaminants into harmless, naturally occurring compounds presenting no harm to the
environment. This process has been proven effective in remediation of both "loose" and "tight"
soils (i.e., silts and clays) contaminated with organic contaminants.
Remediation of soil contaminated with discharges of organic contaminants is accomplished by
injecting a mixture of strong oxidizers, trace metallic salts, stabilizers, and surfactants in an
aqueous-based solution. Prior to injection, the hydrogeological parameters of the soils and
groundwater are defined and a pilot program is conducted to determine the quantity and
formulation of the injection mix. These results, in addition to the horizontal and vertical extent of
the contaminants with their respective characteristics and concentration gradients, are defined and
determined. This is necessary to determine the quantity of reagent needed for injection and the
proper spacing of the injectors to permit remediation over the entire affected area. Once the
NOR/K. \WP\04400\071 lFSDON001. DOC 5-37
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
contaminant region has been defined and delineated, reagent volumes and concentrations are
determined.
Effectiveness -This technology is relatively new but has been used on several sites. There may be
some difficulty associated with the injection of the treatment fluids into the fractured bedrock
underlying the site.
Implementability -Permitting by the State of North Carolina would be required. Also, a pilot
program would be required to assure that the technology and the injection fluids are capable of
treating the contaminants. In addition, all local citizens using groundwater as a potable water
source would have to be notified of this treatment method.
Cost -This technology uses conventional equipment and generally involves low to moderate
capital costs.
5.5.6.2 Surfactants/Cosolvents
Description -Addition of cosolvents, mixtures of surfactants, or surfactant/cosurfactant/cosolvent
mixtures to the groundwater system to aid in mobilizing and solubilizing non-aqueous phase liquid
(NAPL) or contaminants sorbed to the soil matrix. Generally considered an enhancement to
conventional pump-and-treat by increasing contaminant mass removal per pore volume of
groundwater flushing through contaminated zone. May be used for variety of organic
contaminants and NAPL; may have application to some inorganic contaminants.
Effectiveness -This technology is most efficient in moderate to high permeability geologic
material. May also be effective in the fractured bedrock aquifer system. This process option has
been used successfully in enhanced oil recovery options of the petroleum business. The
NOR/K:\WP\04400\071 \FSDDNOO 1. DOC 5-38
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
application of surfactants or cosolvents does not ensure the complete removal of contaminants
from the aquifer.
Implementability -Excellent understanding of hydrogeologic conditions is essential. Equipment
and materials for application of this procedure are readily available.
Cost -Moderate capital costs are required to begin application of the surfactant/cosolvent
process. Operation and maintenance of this system is low to very low, as most maintenance will
be toward the extraction system operating in concert with this process.
5.5.6.3 UV/Oxidation Treatment
Description -UV oxidation is a destruction process that oxidizes organic and explosive
constituents in wastewaters by the addition of strong oxidizers and irradiation with UV light. The
oxidation reactions are achieved through the synergistic action of UV light, in combination with
ozone (03) and/or hydrogen peroxide (H20 2). If complete mineralization is achieved, the final
products of oxidation are carbon dioxide, water, and salts. The main advantage of UV oxidation is
that it is a destruction process, as opposed to air stripping or carbon adsorption, for which
contaminants are extracted and concentrated in a separate phase. UV oxidation processes can be
configured in batch or continuous flow modes, depending on the throughput under consideration.
Effectiveness -This ex-situ innovative groundwater treatment technology has been used in full-
scale groundwater treatment applications for more than ten years. A majority of the applications
are for groundwater contaminated with petroleum products or with a variety of solvent-related
organics. A wide range of UV/oxidation systems are commercially available and can handle
outputs of I ,000 to 1,000,000 gallons per day.
NOR/K:\WP\04400\071 \FSOON001. DOC 5-39
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This document was prepared by Roy F. Weston, Inc., expressly ror EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Limitations of this technology include:
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
• The aqueous stream being treated must provide for good transmission of UV light (high
turbidity causes interference). This factor can be critical for UV/H2O2 and UV/O3.
• Free radical scavengers can inhibit contaminant destruction efficiency. Excessive dosages
of chemical additives may act as a scavenger.
• The aqueous stream to be treated by UV/oxidation should be relatively free of heavy metal
ions (less than IO mg/L) and insoluble oil or grease to minimize the potential for fouling of
the quartz sleeves.
• When UV/O3 is used on volatile organics such as TCA, the contaminants may be
volatilized (e.g., "stripped") rather than destroyed. They would then have to be removed
from the offcgas by activated carbon adsorption or catalytic oxidation.
• Costs may be higher than competing technologies because of energy requirements.
• Pretreatment of the aqueous stream may be required to minimize ongoing cleaning and
maintenance of UV reactor and quartz sleeves.
• Handling and storage of oxidizers require special safety precautions.
Implementability -Practically any organic contaminant that is reactive with the hydroxyl radical
can potentially be treated. A wide variety of organic and explosive contaminants are susceptible to
destruction by UV/oxidation, including petroleum hydrocarbons; chlorinated hydrocarbons used
as industrial solvents and cleaners; and ordnance compounds such as TNT, RDX, and HMX. In
many cases, chlorinated hydrocarbons that are resistant to biodegradation may be effectively
treated by UV /oxidation. Equipment is readily available to implement this process.
Cost -Costs are moderate for the operation and maintenance of the UV/oxidation system but
may have moderate to high capital costs. Factors that influence the cost to implementing
UV /oxidation include:
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
• Types and concentration of contaminants (as they affect oxidizer selection, oxidizer
dosage, UV light intensity, and treatment time);
• Degree of contaminant destruction required;
• Desired water flow rates;
• Requirements for pretreatment and/or post-treatment.
5.5. 7 Biological Treatment Technologies
The biological treatment options being considered for organics in the groundwater are in-situ
biodegradation, fluidized bed aerobic, conventional aerobic, and anaerobic treatment.
5.5.7.l In-Situ Biodegradation
Description -In-situ biological treatment is a technique for treating contaminated soils and
groundwater in place by microbial degradation. The addition of oxygen and nutrients to the
groundwater enhances the natural biodegradation of organic compounds by microorganisms,
resulting in the breakdown and detoxification of the organic contaminants. These microorganisms
can either be naturally occurring, specially adapted, or genetically engineered. In most cases,
oxygen and nutrients are delivered to the groundwater through injection wells. A system of
collection wells is used so that treatment can occur for groundwater circulating through the
contaminant plume area.
Effectiveness -To date, in-situ biodegradation has been applied to sites contaminated with readily
biodegradable, non-halogenated organics, including gasoline and fuel oils, hydrocarbon solvents
(e.g., benzene, toluene), non-halogenated aromatics and alcohols, ketones, ethers, and glycol.
Heavy metals concentrations will not be significantly affected and in fact may impede
NOR/K:\WP\044001071 \FSDDN001, DOC 5-41
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
biodegradation. In-situ biodegradation is generally inhibited by halogenated organics and elevated
levels of metals, acids, or caustics. It is generally not effective for treating groundwater containing
low concentrations of halogenated organics. The long-term effects of nutrient introduction on
groundwater must be evaluated, and final contaminant reduction is generally not readily
predictable. Relatively high initial organic concentrations are needed to grow large enough
microbial populations and to keep them growing. Organic concentrations in groundwater at the
Davis Park Road site may be too low to support high microbial activity.
Implementability -For in-situ biodegradation, injection wells would be installed using
conventional construction techniques. Following positive evaluation of site environmental factors
and waste characteristics, systems for introduction of nutrients and oxygen (through wells) into
the groundwater would be developed. These may include pumping and recirculation or infiltration
galleries for replacement of groundwater.
Water quality characteristics must be monitored at regular intervals, and nutrient and oxygen
supplies must be adjusted accordingly. Biodegradation may occur slowly. Contaminant levels in
water may not drop below designated action levels.
A major factor in implementing this and other in-situ groundwater processes is the control of flow
through the treatment zone to ensure treatment of all contaminated areas and prevent unwanted
migration of either contamination or added reagents. Transport of oxygen through a low
permeability aquifer is difficult.
Cost -In-situ biodegradation, where applicable, may produce acceptable results at costs below
conventional treatment systems. While costs are difficult to generalize, examples cited by vendors
suggest that costs are lower than pump and treat costs, but the period of treatment is longer.
NOR/K. \WP\04400\071 \FSDON001.00C 5-42
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
5.5.7.2 Fluidized Bed Aerobic Treatment
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Description -This system combines the aerobic biological process and granular activated carbon
(GAC) in one fluidized bed biological reactor (FBBR). The FBBR system destroys the organic
compounds rather than transferring them into another phase. Pure oxygen is supplied to the
reactor by dissolving it in a recycle stream. As a result there is no off-gas or stripping action to
transfer contaminants to the atmosphere. GAC provides an excellent support medium for
microbial attachment and growth. The high surface area and the existence of many large
macropores provide excellent attachment sites and shield the microbes from the fluid shear in the
reactor. The adsorption capacity of the GAC has the potential to control large changes in the
substrate concentration to the reactor. During shock loads, adsorption can maintain the effluent
quality until the microbial population can increase to accommodate higher substrate loadings.
Adsorption may substitute as the sole removal mechanism in the latter stages of the remediation
process when substrate concentrations may fall to levels too low to support a viable biological
population.
The carbon is biologically regenerated within the bed. Any carbon loss is solely due to natural
attrition and the adsorption of refractory materials. This process may eventually exhaust the
carbon but in much lower quantities than in conventional systems since biodegradable organics are
destroyed biologically.
Effectiveness -FBBR can treat aqueous waste streams contaminated with biodegradable organics
at low concentrations (part per million levels) as well as higher concentrations. Effluent levels in
the low part per billion range can be achieved.
NOR/K: IWP\04400\071 \FSDDN001. DOC 5-43
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This document was prepared by Roy~. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Implementability -FBBR is a relatively small, simple, and reliable system. FBBRs are readily
transportable and well suited for treatment of aqueous waste streams contaminated with organics.
Careful monitoring of the biodegradation process and water quality parameters is necessary. An
on-site laboratory may be required for this purpose. Laboratory or pilot-scale testing may be
required if significant levels of other non-specific (non-BTEX) organics are present in the I groundwater.
I Cost -Costs for FBBR treatment can be relatively small to that of comparable physical/chemical
systems; however, for volatile organics treatment, FBBR is not competitive with air stripping if
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emission controls on the stripping unit are not required.
5.5. 7.3 Conventional Aerobic Biological Treatment
Description -Aerobic biological treatment methods use microorganisms to detoxify or
decompose biodegradable organics in aqueous waste streams. This technology consists of
conventional activated sludge processes as well as alternative processes, including sequencing
batch reactors, rotating biological contractors, trickling filters, and fixed film reactors.
Effectiveness -Aerobic biological reactors can treat aqueous waste streams contaminated with I relatively high concentrations of organics. The addition of powdered activated carbon may permit
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treatment of aqueous waste streams contaminated at low to moderate levels with pesticides,
herbicides, and hydrocarbons. Heavy metals are often removed to a certain extent through
adsorption by, and concentrated in, the biomass. Biological reactors can be used effectively for
groundwater treatment because of the relative stability of groundwater characteristics. Often this
treatment must be followed by additional treatment technologies to meet low cleanup goals.
NOR/K \WP\04400\071 \FSDDN001. DOC 5-44
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Settled sludge or excess biomass residues may contain elevated levels of non-biodegradable
organics or heavy metals. Sludge will require dewatering and disposal, possibly as a hazardous
waste.
Implementability -Biological reactors are relatively simple and generally reliable. Several
companies have developed mobile biological reactors that are readily transportable and well-
suited for treatment of aqueous waste streams contaminated with organics. Careful monitoring of
the biodegradation process and water quality parameters is necessary. An on-site laboratory may
be required for this purpose. Laboratory or pilot-scale testing is suggested.
Cost -Costs for aerobic biological treatment will probably be slightly lower than comparable
physical/chemical systems.
5.5. 7.4 Anaerobic Biological Treatment
Description -In anaerobic biological treatment systems, organic concentrations are reduced by
anaerobic microbial metabolism. When applied to most conventional pollutants, end products
include a mixture of methane and carbon dioxide gas, soluble organics, and a small quantity of
excess biomass. One typical process uses a column filled with solid media as an anaerobic filter.
This process is capable of handling high-strength aqueous wastes that are not efficiently treated by
aerobic treatment processes or many physical treatment processes.
Effectiveness -Anaerobic biological treatment processes are able to handle more concentrated I waste streams than aerobic treatment processes but are sensitive and more susceptible to changes
in stream characteristics, which can cause shock loading and termination of the biological process. I
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For this reason, anaerobic treatment has not been applied to process waste streams on a frequent
basis. A by-product of this process is methane gas, which requires monitoring to protect the local
NOR/K:\WP\04400\071 \FSDDNOO 1. DOC 5-45
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Thls document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
environment. Most heavy metals would likely be captured in the sludge fraction as insoluble metal
sulfides. Anaerobic treatment systems are generally not capable of treating a low concentration
water.
Implementability -Laboratory or pilot-scale tests would be required to confirm the feasibility of
this process option and to determine the optimum process for the site. Mobile anaerobic biological
systems are available from several vendors. Careful monitoring of digester operating parameters
would require an on-site or nearby off-site laboratory.
Cost -Costs for implementing this process option are similar to those described for aerobic
biological treatment.
5.5. 7.5 Phytoremediation
Description -Phytoremediation uses plants to clean up contaminated soil and groundwater,
taking advantage of plants' natural abilities to take up, accumulate, and/or degrade constituents of
their soil and water environments. There are five basic types of phytoremediation techniques: I)
rhizofiltration, a water remediation technique involving the uptake of contaminants by plant roots;
2) phytoextraction, a soil technique involving uptake from soil; 3) phytotransformation, applicable
to both soil and water involving the degradation of contaminants through plant metabolism; 4)
phyto-stimulation or plant-assisted bioremediation, also used for both soil and water, which
involves the stimulation of microbial biodegradation through the activities of plants in the root
zone; and 5) phytostabilization, using plants to reduce the mobility and migration potential of
contaminants in soil.
Effectiveness -Results of research and development into phytoremediation processes and
techniques report it to be applicable to a broad range of contaminants, including numerous metals
NOR/K.\WP\Q.1400\071\FSDON001.DOC 5-46
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
and radionuclides, vanous organic compounds (such as chlorinated solvents, BTEX, PCBs,
PAHs, pesticides/insecticides, explosives, nutrients, and surfactants). According to information
reviewed, general site conditions best suited for potential use of phytoremediation include large
areas of low to moderate surface soil (0 to 3 feet) contamination or large volumes of water with
low-level contamination subject to low (stringent) treatment standards. Depth to groundwater for
in-situ treatment is limited to about IO feet, but ex-situ treatment in constructed troughs or
wetlands has also been investigated.
Implementability -Major advantages reported for phytoremediation as compared to traditional I remediation technologies include the possibility of generating less secondary wastes, minimal
associated environmental disturbance, and the ability to leave soils in place and in a usable
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condition following treatment. It may or may not involve periodic harvesting of plants, depending
upon method utilized. Cited disadvantages include the long lengths of time required (usually
several growing seasons), depth limitations (3 feet for soil and IO feet for groundwater), and the
possibility of contaminant entrance into the food chain through animal consumption of plant
material.
Cost -Installation of a system involving the use of phytoremediation would include moderate
capital and operation and maintenance costs.
5.5.8 Discharge Options
The options being evaluated for treated water disposition are on-site and off-site options. On-site
options include local stream/surface discharge, recharge/infiltration gallery, and recharge wells.
The off-site option includes discharge to a publicly-owned treatment works (POTW).
NOR/K:\WP\04400\071 \FSODNOO 1. DOC 5-47
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
5.5.8.1 On-Site Options
Local Stream Surface Discharge
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Description -Treated water discharge to existing surface water bodies is widely used. Treated
groundwater can be discharged to Blackwood Creek on the eastern edge of the Davis Park Road
site.
Effectiveness -This option effectively achieves the objective of effluent discharge.
Implementability -The unnamed stream located on site approximately 0. 5 miles from the source
contamination. A header system with discharge line and holding pool could be installed for
collection and conveyance to the creek. State and local approvals would be required, and
discharge limits would need to be negotiated.
Cost -Costs for surface discharge primarily consist of costs for the sampling and monitoring
requirements as designated in the surface discharge (NPDES) permit. The cost is typically low.
While a permit is not specifically required at an NPL site, the substantive requirements of a permit
must be satisfied.
Recharge/Infiltration Galleries
Description -For this alternative, the treated groundwater would be disposed through an on-site
infiltration gallery. The effluent would be discharged to the shallow and/or deep aquifer systems.
NOR/K:\WP\04400\071 \FSDDN001. DOC 5-48
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Effectiveness -The effectiveness of this process option depends upon the inherent soil conditions,
particularly the penneability of the aquifer materials. The potential low-penneability soils at the
Davis Park Road site may not be suitable for this method of treated water discharge.
Implementability -Due to the soil conditions on the site, the ponding of the water table should be
considered at the site. Clay soils would restrict infiltration rates, increasing the land required for
the galleries. Infiltration galleries are generally used for low flow rates.
Cost -Costs for construction, operation, and maintenance of an infiltration gallery system would
be moderate as compared to other disposal options.
Recharge Wells
Description -Under this alternative, the treated groundwater would be disposed through a
network of recharge wells. These wells would most likely be installed in the deep aquifer system.
Effectiveness -The effectiveness of this process option depends upon the inherent soil conditions.
The hydrogeologic conditions associated with fractured bedrock at the Davis Park Road site may
be suitable for this method of groundwater discharge.
Implementability -The size and number of the recharge wells depends on the flow rate, hydraulic
conductivity of the deep aquifer, and porosity of the aquifer materials.
Cost -Costs for construction, operation, and maintenance of a recharge well system would be
moderate as compared to other disposition options.
NOR/K:\WP\04400\071 \FSOON001. DOC 5-49
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
5.5.8.2 Off-Site Options
Sanitary Sewer Discharge
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Description -Treated water discharge to a nearby sanitary sewer line would carry the water to
the local POTW.
Effectiveness -This option, if possible, achieves the objective of effluent discharge.
Implementability -City of Gastonia sewer lines are present on the site. The on-site treatment
system could therefore be tied into the POTW. Permission from the local sewer authority would
be required. EPA would be expected to contact the sewer authority for discharge approval.
Costs -Costs for this option consist of costs associated with sampling and monitoring
requirements as designated by the POTW. The cost is typically low.
5.5.9 Residuals Management
5.5.9. l Offgas Treatment
Carbon Adsorption
Description -Contaminated offgases would be pumped into a vessel packed with granular
activated carbon. As the gas diffuses through the carbon pack, contaminants are adsorbed onto
the surface of the carbon. Eventually, the surface of the carbon becomes saturated. The
contaminants are no longer removed from the air and "break through" the carbon pack. The
carbon is then removed and either reactivated or disposed. To eliminate the need to continuously
NOR/K:\WP\04400\071 \FSDDN001. DOC 5-50
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Dale: July 1998
monitor the effluent from a carbon unit for breakthrough, a similar sized carbon unit is often
placed in series with the original. Thus, when contaminants break through the lead unit, they are
adsorbed by the second unit. The carbon units in the treatment system are arranged so that either
unit can be the lead vessel. When breakthrough occurs, the carbon in the lead vessel is removed
and sent to be reactivated. The backup unit is changed over to the lead position, the empty vessel
is refilled with virgin or reactivated carbon, and the refilled unit is used as the backup.
Effectiveness -Carbon adsorption 1s an effective treatment option for removing a variety of
organic contaminants from air.
Implementability -Carbon adsorption units can be rented or purchased in a variety of sizes and
capacities. Equipment for this process is readily available from many vendors.
Cost -Capital and maintenance costs are expected to be moderate.
5.5.9.2 Spent Granular Activated Carbon
Off-Site Regeneration/Off-Site Disposal
Description -Granulated carbon can be regenerated by oxidizing the adsorbed organics by
heating them in a furnace. When exhausted, the carbon may have to be disposed/landfilled in a
permitted facility.
Effectiveness -Off-site regeneration or disposal are both effective means of dealing with spent
carbon.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or In part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
Implementability -Many vendors provide this service including supplying the fresh/regenerated
GAC, removing the spent GAC, and either regenerating or disposing ofit.
Cost -Capital and maintenance costs would be moderate.
5.6 SUMMARY
Based on the preceding evaluation of effectiveness, implementability and costs, the following process
options have been retained for further consideration for remediation of groundwater:
No Action (Retained as required by NCP)
Institutional Controls
• Access Restrictions
• Alternate Water Supply
• Groundwater Monitoring
• Point-of-Use Treatment
• Natural Attenuation
Containment Technologies -No technologies retained
• None
Removal/Collection Technologies
• Extraction (Vertical, Horizontal, and Dual-Phase) Wells
• Discharge After Collection
• Filtration (metals removal)
• Activated Carbon Adsorption ( organics removal)
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It st',a!I not be disclosed, in whole or in part, without the express
written permission of EPA.
• Air Stripping (VOC removal)
• In-Well Vapor Stripping
• Chemical Reduction/Oxidation ( organics removal)
• In-Situ Biodegradation
• Aerobic Biological Treatment
• Anaerobic Biological Treatment
Feasibility Study Report
Davis Park Road TCE Site
Section: 5
Revision: 1
Date: July 1998
• Fluidized Bed Aerobic Treatment ( organics removal)
Disposal/Discharge Options
• Surface Discharge
• POTW Discharge
• Recharge Wells (bedrock)
Residuals Management
• Offgas Treatment -Carbon Adsorption
• Spent Granular Activated Carbon -Off-Site Regeneration/Disposal·
NOR/K: \WP\04400\071 \FSODN001 . DOC 5-53
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
SECTION Ii
Feasibility Study Report
Davis Park Road TCE Site
Section: 6
Revision: 1
Date: July 1998
DEVELOPMENT OF REMEDIAL ACTION ALTERNATIVES
6.1 INTRODUCTION
Remedial action alternatives were formulated to address the environmental issues associated with
the Davis Park Road site. Section 5, "Screening of Remedial Technologies," provided a
preliminary evaluation of each potentially applicable remedial technology identified, considering
the effectiveness of the technology in obtaining the remedial action objectives, implementability,
and cost. Based on this preliminary screening, several technologies were retained for a detailed
evaluation either alone or in combination with other technologies.
The purpose of the alternative development process is to produce remedial action alternatives that
provide a range of approaches and effectiveness; therefore, the alternatives vary in the degree of
remediation they provide. Various remediation categories have been identified by the NCP and
modified according to the SARA guidelines to specify a range of remediation levels. These categories
are as follows:
• No action alternatives (may include minimal actions such as monitoring activities).
• Alternatives that meet CERCLA goals (preventing or limiting present or future migration
of hazardous substances and protecting public health and the environment) and attain
ARARs for Federal public health and environmental standards, guidance, and advisories.
• Alternatives that exceed all applicable or relevant and appropriate Federal public health
and environmental standards, guidance, and advisories.
NORJK: IWP\04400\071 \F SODN001. DOC 6-1
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
•
•
6.2
Feasibility Study Report
Davis Park Road TCE Site
Section: 6
Revision: 1
Date: July 1998
Alternatives specifying off-site destruction, treatment, or secure disposal of hazardous
substances at a facility approved under RCRA. Such a facility must also be in compliance
with all other applicable EPA standards.
Alternatives utilizing a containment option involving little or no treatment of site source
contamination.
SUMMARY OF REMEDIAL GOALS
The overall objective of the remediation process at the site is to protect public health and the
environment.
The groundwater remediation goals at the Davis Park Road site are:
• To implement institutional controls to protect humans from further use of contaminated
groundwater.
• To achieve groundwater cleanup goals for the contaminants of concern, TCE and PCE.
6.2.l Groundwater Cleanup Goals
The evaluation of alternatives is based upon remediation of TCE and PCE in groundwater at the
Davis Park Road TCE site to NCDEHNR Groundwater Quality Standards, analytical method
detection limits, and Federal Drinking Water Standards (MCLs). Cleanup goals· for the
contaminants of concern at the site are as follows:
Tetrachloroethylene (PCE)
Trichloroethylene (TCE)
1, 1-Dichloroethene
NOR/K:\WP\044001071 IFSDDN001.DOC 6-2
Cleanup Goals
LO µg/L
2.8 µg/L
7.0 µg/L
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
6.3
MTBE
Chloroform
Feasibility Study Report
Davis Park Road TCE Site
Section: 6
Revision: 1
Date: July 1998
200 µg/L
1.0 µg/L
DEVELOPMENT OF REMEDIAL ALTERNATIVES
Based on the requirements of SARA and the remedial objectives discussed· in this study, four
remedial alternatives have been formulated for detailed evaluation. The four alternatives are as
follows:
•
•
•
•
•
Alternative I -No Action -This alternative consists of no active remedial actions. Only five-year reviews are conducted.
Alternatii,e 2 -Institutional Controls -This alternative consists of deed recordations,
periodic groundwater monitoring, and performance of five-year reviews.
I Alternative 3 -Monitored Natural Attenuation with Exposure Abatement -This alternative consists of providing an alternate water supply to affected residents, treatment
of groundwater at the wellhead, natural attenuation of the groundwater contaminant
plume, periodic groundwater monitoring, and performance of five-year reviews.
Alternative 4 -Reduction of Groundwater Exposure and Groundwater Treatment -
This alternative consists of providing an alternative_ water supply to affected residents,
treatment of contaminated groundwater, treatment of groundwater at the wellhead, periodic groundwater monitoring, and performance of five-year reviews.
Alternative 5 -Reduction of Groundwater Exposure and Groundwater Pump and Treat -This alternative consists of providing an alternative water supply to affected residents, treatment of contaminated groundwater via pump and treat, treatment of groundwater at the wellhead, periodic groundwater monitoring, and performance of five-year reviews.
NOR/K:\WP\044001071 \FSOON001.DOC 6-3
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
6.3.1 Alternative I -No Action
Feasibility Study Report
Davis Park Road TCE Site
Section: 6
Revision: 1
Date: July 1998
Under the no action alternative, the site receives no active remedial processes for control of the
groundwater contaminant plume. Contaminated groundwater would remain uncontrolled,
allowing for potential migration further downgradient and possibly deeper into the bedrock
aquifer. The NCP requires consideration of this alternative as a baseline for comparing other
remedial actions and the level of improvement achieved. However, five-year reviews of the site
remediation decision consisting of one round of sampling of selected monitoring and potable
wells, would be conducted over an estimated 30-year period.
6,3.2 Alternative 2 -Institutional Controls
In this alternative, deeds in the area would be required to record the fact that groundwater
contamination exists beneath the property, and if a potable well is constructed, a strong possibility
exists that the water will be contaminated with unacceptable levels of volatile organic
contaminants. These recordations would remain in place until the groundwater quality returned to
contaminant concentrations that would allow unrestricted use.
Periodic groundwater monitoring (the frequency will be determined by EPA) would be conducted
on both monitor wells and potable drinking water wells. Wells would be sampled for volatile
organic compounds. The five-year reviews would be required since concentrations of chemicals at
the site are at levels above those that would otherwise allow unrestricted use of the groundwater.
6.3.3 Alternative 3 -Monitored Natural Attenuation with Exposure Abatement
Under this alternative, all homes, churches, and businesses in the Davis Park Road site area not
currently connected to the City of Gastonia or Gaston County public water supply would be
NOR/K:IWP1044001071\FSDDN001.DOC 6-4
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 6
Revision: 1
Date: July 1998
connected. In addition, residents will also be given the option to obtain wellhead treatment of
their private well; i.e., groundwater treatment such as a carbon filter unit would be connected to
the private water supply well.
This alternative includes natural attenuation as a remedy for the groundwater contaminant plume.
The natural attenuation processes that are at work in such a remediation approach include a
variety of physical, chemical, or biological processes that, under favorable conditions, act without
human intervention to reduce the mass, toxicity, mobility, volume, or concentration of
contaminants in soil or groundwater (OSWER Directive 9200.4-17). A study of natural
attenuation would be conducted in conjunction with the performance of periodic groundwater
monitoring and would be considered as part of the Remedial Design. Periodic groundwater
monitoring (the frequency will be determined by EPA) would be conducted on both monitoring
wells and potable drinking water wells. Wells would be sampled for volatile organic compounds.
The five-year reviews would be required since concentrations of chemicals at the site are at levels
above those that would otherwise allow unrestricted use of the groundwater.
6.3.4 Alternative 4 -Reduction of Groundwater Exposure and Groundwater Treatment
This alternative would include all of the prov1s1ons for reduction of groundwater exposure
contained in Alternative 3, in addition to active treatment of the contaminated groundwater
plume.
Although the final remedial method will be determined by EPA, the most feasible treatment
process will consist of in-well vapor stripping.
NOR/K:\WP\04400\071 \FSDDN001. DOC 6-5
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 6
Revision: 1
Date: July 1998
The in-well vapor stripping technology would be used at points throughout the plume. A
treatability study would be performed to determine the applicability of this treatment process, and
the best conditions for use.
Additional study and monitoring would be needed to determine the effectiveness of this treatment.
The study would also focus on determining the optimum treatment technology based on the
unique aspects of the plume; i.e., the bedrock aquifer plume will be complex due to overall depth
and the presence of fractures in the bedrock. In addition, another factor that should be taken into
consideration is the location of this site; the majority of the plume is located in residential,
privately-owned areas and the remedy would have to be designed so that its impact to local
residences would be minimal.
6.3.5 Alternative 5 -Reduction of Groundwater Exposure and Pump and Treat
This alternative would include all provisions of Alternative 4 except that the final remedial method
will be groundwater pump and treat instead of in-well vapor stripping. The groundwater pump
and treat technology would consist of extraction wells at points throughout the plume.
Additional study and monitoring may be required to determine the effectiveness of this treatment.
The study would be focused on the complexity of the bedrock aquifer and determining the
optimum well locations for groundwater extraction. Other important factors are that the plume is
located in a residential area, private land would have to be accessed for well and system
installation, and the system must be designed to have minimal impact to residences.
NOR/K.\WP\04400\071 \FSDONOO 1. DOC 6-6
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
6.4 LIMITATIONS
Feasibility Study Report
Davis Park Road TCE Site
Section: 6
Revision: 1
Date: July 1998
The number of alternatives retained for the detailed analysis is limited to five. Based on
reasonableness, certain CERCLA guidelines were omitted when developing remedial alternatives.
The requirements and the reasons for omission are presented below:
•
•
•
Alternatives that exceed all applicable or relevant and appropriate Federal public health
and environmental standards, guidance, and advisories -The alternatives that do not meet
the ARARs were not considered as this is a final FS for alternate water source supply and
potential groundwater remediation; however, no action and institutional controls
alternatives were included for comparison with other active alternatives, as required by the
NCP.
Alternatives specifying off-site destruction, treatment, or secure disposal of hazardous
substances at a facility approved under RCRA. Such a facility must also be in compliance
with all other applicable EPA standards -Off-site transport and treatment of groundwater
is not practicable and is usually omitted.
Alternatives utilizing a containment option involving little or no treatment of site source
contamination -Due to the substantial depth of the contamination, containment options
are not suitable to the site.
NOR/K:IWP\04400\071 \FSDDN001. DOC 6-7
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. II shall not be disclosed, in whole or in part, without the express
written permission of EPA.
7.1
SECTION 7
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
DETAILED EVALUATION OF REMEDIAL ALTERNATIVES
INTRODUCTION AND EVALUATION CRITERIA
Based on the initial screening and further evaluation of remedial technologies, five alternatives
were developed for detailed evaluation. A brief description of each of the alternatives was
presented in Subsection 6.3. The detailed evaluation of the alternatives provides the relevant
information needed to allow decision makers to select a site remedy. During the detailed analysis,
each alternative is evaluated against the seven evaluation criteria described in this subsection. The
results of this assessment are then used to make comparisons among alternatives, and the key
tradeoffs among alternatives can be identified. This approach to analyzing alternatives is designed
to provide decision makers with sufficient information to compare the alternatives adequately,
select an appropriate remedy for a site, and demonstrate satisfaction of the statutory requirements
in the ROD.
A detailed analysis of alternatives consists of the following components.
•
•
•
Further definition of each alternative, if appropriate, with respect to the specific measures
to be taken, the volumes or areas of contaminated media to be addressed, the technologies
to be used, and any performance requirements associated with those technologies.
An assessment and a summary of each alternative against the seven evaluation criteria .
A comparative analysis among the alternatives to assess the relative performance of each
alternative with respect to each evaluation criterion (comparative analysis is presented in
Section 8).
NORJK:\WP\04400\071 \FSOON001.00C 7-1
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA. ·
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
The analysis process described above is based on the statutory requirements of CERCLA; the
initiatives promulgated in the November 20, 1985 National Contingency Plan, and EPA's
"Guidance for Conducting Remedial Investigations and Fea_sibility Studies under CERCLA,"
Interim Final, October 1988. The seven evaluation criteria listed below encompass technical, cost
and institutional considerations; and compliance with specific statutory requirements. These
evaluation criteria are as follows:
• Short-term Effectiveness -The assessment against this criterion examines the effectiveness
of alternatives in protecting human health and the environment during the construction and
implementation phase, until response actions are complete and objectives have been met.
• Long-term Effectiveness -The assessment of alternatives against this criterion evaluates
the long-term effectiveness of alternatives in protecting human health and the environment
after response objectives have been met.
• Reduction of Toxicity, Mobility, and Volume -The assessment against this criterion
evaluates the anticipated performance of the specific treatment technologies that make up
the alternatives.
• Implementability -This assessment evaluates the technical and administrative feasibility of
alternatives and the availability of required resources.
• Compliance with ARARs -The assessment against this criterion describes how the
alternative complies with ARARs, or whether a waiver may be required. The assessment
includes non-ARAR advisories, criteria, and guidance that the lead and support agencies
have agreed to consider.
• Overall Protection -The assessment against this criterion describes how the alternative, as
a whole, protects and maintains protection of human health and the environment.
• Cost -This assessment evaluates the capital, operation and maintenance (O&M), and total
project present-worth costs of each alternative. Capital costs include direct ( construction)
and indirect (non-construction and overhead) costs. O&M costs include post-construction
costs incurred to ensure effective implementation of the alternative.
NOR/K:\WP\04400\071 \FSDDN001. DOC 7-2
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
The capital and O&M costs for each alternative are prepared to provide an accuracy of -50 to
+30%. The present-worth value method is utilized to evaluate the total cost of implementing a
remedial alternative (! 998 dollars). The present worth was calculated based upon the project life
of the alternative and a 3.5% discount rate.
Two other evaluation criteria, state and community acceptance, are not evaluated here and will be
addressed in the ROD. These criteria are as follows:
• State Acceptance -This assessment reflects the State's preference among or concerns
about alternatives.
• Community Acceptance -This assessment reflects the community's preferences among or
concerns about alternatives.
7.2 ALTERNATIVE 1-NO ACTION
7 .2.1 Description
Under the No Action alternative, no remedial actions would be implemented. Contaminated
groundwater would be left in place without treatment allowing continued migration of the
contaminants of concern. Any reduction in VOC concentrations in the groundwater would be only
due to natural migration, dispersion, attenuation, and degradation processes. The only funding
required for this alternative would be for the five-year reviews.
NOR/K:\WP\04400\071 \FSODN001.DOC 7-3
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
7 .2.2 Detailed Evaluation
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
7.2.2. l Overall Protection of Human Health and the Environment
Risks posed by the continued presence of contaminants in the groundwater will not be addressed.
These unacceptable risks to human health and the environment are not mitigated and are expected
to exist for an extended period of time. Residents in the vicinity of the site would continue to
drink water from private wells that contain contaminants above the remediation goals. Therefore,
this alternative does not achieve the desired remediation goals, and is not protective of human
health. However, since soil samples collected at the site did not reveal any contamination, the
concentration of contaminants in the groundwater may potentially decrease with time due to
natural attenuation and degradation. Under this action, monitoring or verification of natural
attenuation would be conducted only at the five-year review stage.
7.2.2.2 Compliance with ARARs
ARARs will not be met under the No Action alternative. Contaminants of concern in groundwater
will remain in groundwater above the chemical_-spec:ific ARARs for an indefinite period of tirne;
however, concentrations may decrease with time due to natural attenuation and degradation.
Location-and action-specific ARARs are not applicable as there are no remedial actions
associated with this alternative.
7.2.2.3 Short-Term Effectiveness
The No Action alternative will not mitigate on-site contamination on a short-term basis. This
alternative will achieve on-site remedial objectives only after an indefinite period of time and
exclusively through natural processes Given the low rates of degradation and dispersion for the
NOR/KIWP\04400\071 \FSDON001. DOC 7-4
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
detected contaminants, little reduction in contaminant concentrations can be expected in the short-
term.
7.2.2.4 Long-Term Effectiveness and Permanenc,e
This criteria addresses the results of a remedial action in terms of the risk remaining at the site
after remedial action objectives have been met. Any reduction in concentrations in the long-term
will be due to natural migration, dispersion, attenuation, and degradation processes. The
magnitude of the risks remaining at the site after many years may still exceed acceptable levels.
7.2.2.5 Reduction of Toxicity, Mobility, or Volume of Contaminants
The No Action alternative provides no active treatment process for groundwater. As a result,
contaminants will only be destroyed by passive, natural processes. Toxicity and mobility of the
contaminated material may remain at their present levels for extended periods of time. Further, the
overall volume of affected groundwater may increase as the contaminants migrate. This migration
typically occurs more rapidly than natural degradation processes for these compounds.
7.2.2.6 Implementability
The No Action alternative can be easily implemented as it does not require any present or future
efforts.
7.2.2. 7 Cost
The only costs associated with the No Action alternative are from five-year review activities. The
total present worth cost for this alternative is approximately $140,055, as presented in Table 7-1.
NOR/K\WP\04400\071\FSODN001.00C 7-5
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written
permission of EPA.
Item
1
2
3
4
Table 7-1
Costs for Alternative I -No Action
Davis Park Road TCE Site
Gastonia, North Carolina
Description Quantity
Five-Year Review with
sampling of monitor and
ootable wells I
Subtotal
Administration ( 15%)
Subtotal
Contin~encv (25%)
Total
Present Worth Cost
K:IWP\04400\071\Fs-tbls Table 7-1 7-6
Unit Cost($) Total Cost ($)
27,500 27,500
27,500
4,125
31,675
7920
39,595
($116,861.63)
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. Jt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
7.3 ALTERNATIVE 2 -INSTITUTIONAL CONTROLS
7.3.1 Description
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
As with the no action alternative, no active remediation would be conducted under this
alternative. Instead, institutional measures will be enacted to prevent exposure to contaminated
groundwater. The institutional controls include ei:tablishing deed recordations and groundwater
monitoring. Five-year reviews will also be conducted (as required by the NCP) to determine if
contaminants that remain on-site are causing additional risk to human health or the environment.
As a result of this review, EPA will determine if additional site remediation is required. Five-year
reviews are assumed to.be conducted for a 30-year period.
Deed recordations would be established for all affected properties downgradient of the suspected
source area, or properties within the extent of the groundwater plume. These recordations would
remain in place until the groundwater quality improved enough to allow for unrestricted use.
Under this alternative, groundwater monitoring will take place. Although the frequency of
monitoring episodes will be determined by EPA, for cost purposes the assumption is made that
groundwater will be monitored semi-annually for five years and annually for the next twenty-five
years at the existing eight overburden aquifer monitor wells, the six bedrock aquifer monitor
wells, and four on-site residential wells to be chosen by EPA. Figure 7-1 presents the locations of
the existing monitor wells.
After an initial 5-year period has ended, it is assumed that the plume will have migrated beyond
the furthest downgradient monitor well. Three more downgradient wells will be installed after 5
years to track the migration pattern of the plume and the concentration of the contaminants.
Thereafter, the existing and new monitor wells will be monitored semi-annually for five years and
NORJK:\WP\04400\071\FSDONOOt.OOC 7-7
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wW JO$
MW JS$
// II II II II
MW-1/0,IW-2 $
DA\1S PARK
AUTO REPAIR
,._
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N -5,46,704.186'
E -t,J37,878.1M' ElLV. -no.1♦•
GlENRAVEN A\£NUE
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\
PROJECT TITLE,
DAVIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
MONITOR WELL LOCATION MAP
FIGURE 7-1
LEGEND
MW-1 " MONITOR WELL LOCATIONS
SW-1 • SURF ACE WATER SAMPLE LOCATIONS
PW " PRIVATE W£Ll LOCAllONS
cw " CONVERTED WELL LOCATIONS
EMW " EXISTING MONITOR WELL LOCATIONS
COMBINED FACTOR :c 0.9998411 (NAO 83)
POINT NORTHING EASTING ELEVATION ELEVATION ELEVATION
TOP PIPE TOP PLATE GROUND
100 545544.652 1338740.388 6B8.27 MW-1S 688.85 688.85
101 545495.204 1338846.893 687.50 MW-10 687.80 687.81
102 545674.010 1338358.610 707.21 CW-5 706.61
103 544827.129 1338881.1 08 684.60 MW-20 684.89 684.88
104 544846.945 1338868.067 684.60 MW-2S 685.04 684.99
105 544510.539 1 338455. 456 677.26 MW-5S 677.52 677.52
106 544881.886 1338621.461 687.57 PW-1 686.15
107 545319.342 1337914.911 716.12 MW-4S 716.65 716.68
108 546610.771 1337145.070 743.74 MW-3S 744.42 744.37
109 546676.623 1337132.994 746.29 MW-3D 746.75 746.75
110 546139.528 1338513.369 705.76 CW-6 705.21
111 545175.589 1337035.677 739.97 MW-40 740.44 740.45
112 546474.476 1337682.514 764.35 PW-2 764.09
113 546568.657 1337641.640 768. 75 CW-4 766.78 141 546888.586 1337295. 709 761.18 CW-3 761.41 761.41 128 546827.8B5 1336850.31B 757. 79 CW-2 758.62 758.59 129 547139.622 1336707.806 761.69 CW-1 760.88 136 546654.891 1337483.389 771.21 EMW-1 771.19 769.78 137 546857.745 1337485.094 771.86 EMW-2 773.00 770.22
BENCH MARK USED WAS THE CITY OF GASTONIA BENCH MARK, QUADRANT 3, BENCH MARK
No. 41, LOCATED AT THE INTERSECTION OF DA\1S PARK ROAD AND STAGE COACH ROAD.
ELEVATION = 731.05'
DRA\JN1 DATE• DES.
M. SNEED 5 18 98
CHECKED1 DATE• APPROVED,
\J.O. N□.,
04400-071-095
CAD FILE NAME•
MWLOCMAP.DWG
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
then annually for 25 additional years. The locations of the new wells will be based upon the results
of monitoring the existing monitor wells over the first five-year period. All groundwater samples
will be analyzed for VOCs.
7.3.2 Overall Protection of Human Health and the Environment
The Institutional Controls alternative does not achieve remedial action objectives. Risks to the
community and the environment are mitigated but only by deed recordations that alert residents to
potential hazards associated with contaminated groundwater. Long-term groundwater monitoring
will serve as a tracking system to monitor changes in groundwater contamination that gives prior
warning to reduce risks if unacceptable concentrations in the groundwater or unusual migration of
contaminants is detected. Risks posed by the continued transport of contamination through the
groundwater to future groundwater users would have to be addressed as migration is tracked.
7.3.3 Compliance with ARARs
As with the no action alternative, contaminant concentrations will remain above the chemical-
specific ARARs for an indefinite period of time. Location-specific and action-specific ARARs will
be met during the installation of additional monitoring wells. Results from the proposed
monitoring activities will be compiled and evaluated for comparison with groundwater MCLs and
surface water quality standards.
7.3.4 Short-Term Effectiveness
The Institutional Controls alternative will not mitigate on-site contamination on a short-term
basis. Implementing this alternative will require approximately one year of activity. Groundwater
NOR/K·\WP\04400\071 \FSOON001. DOC 7-9
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shalt not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
monitoring could begin immediately; however, the deed recordation process will require a longer
period of time.
7 .3.5 Long-Term Effectiveness and Permanence
Properly implemented deed recordations would make residents aware of the contamination and
thus potentially prevent ingestion and direct contact with contaminated groundwater, thereby
reducing risk to potential users. The long-term monitoring results and the actual effectiveness of
the deed recordations would require periodic reassessment to determine the continued
effectiveness of this alternative. This alternative does not involve a remedial action.
7.3.6 Reduction of Toxicity, Mobility, or Volume
Institutional controls provide no active treatment process for groundwater. As a result,
contaminants may only be destroyed by natural processes or ingestion. Toxicity and mobility of
the contaminated materials may remain at unacceptable levels for extended periods of time. The
overall volume of affected groundwater may increase as the contaminants migrate.
7.3. 7 Implementability
Implementation of deed recordations and enforcement of these would require the cooperation of
the State and local governments. Voluntary acceptance by the affected property owners is
questionable. Consequently, present or future property owners could choose to ignore or be
unaware of the deed recordations. The recordation is subject to loss during future property
transfers. In addition, the deed recordations may be subject to change in legal and political
interpretations over time. For these reasons, the reliability of groundwater use deed recordations
is considered uncertain.
NOR/K:IWP\04400\071 \FSDDNOO 1. DOC 7-10
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
The monitor wells, converted monitor wells, and residential wells to be sampled during the first
five years are already in place. Additional wells that are proposed after five years can easily be
installed with standard engineering and construction practices, with permission of the property
owners. Well installation permits may be required from the State prior to the installation of the
wells.
7.3.8 Cost
The total estimated present worth cost for this alternative is $990,225. The capital costs
associated with this alternative include the installation of three monitor wells after 5 years. The
O&M costs include long-term monitoring activities. An itemized breakdown of capital and O&M
costs for this alternative is presented in Table 7-2.
7.4 ALTERNATIVE 3 -MONITORED NATURAL ATTENUATION WITH EXPOSURE
ABATEMENT
7.4.1 Description
Under this alternative, all homes, churches, and businesses in the Davis Park Road TCE site area
not currently connected to the City of Gastonia public water supply system would be connected.
Users may also be given the choice of obtaining wellhead treatment of their private well. If
requested, aqueous phase activated carbon units for removal of organics from groundwater would
be installed at the wellhead of each well. Filtration will also be used as a precursor to the carbon
treatment units.
NOR/K\WP\04400\071 \FSOON001. DOC 7-11
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This document was prepared by Roy F. Weston, Inc., expressly for EPA, it shall not be disclosed, in whole or in part, without the
express written permission of EPA
Table 7-2
Estimated Costs for Alkrnativc 2 -Institutional Controls
Davis Pnrk Road TCE Site
Gastonia, North Carolina
ltrm Description Annual Quantity
Canital Cost
I Deed Recordations I
2 Samnlino Enuinmcnt I
3 Monitor Well Installation I
Total
Estimate O& M Costs
Five-Year Reviews (includes
4 groundwater sampling) I
Present Worth (5-Year review)
Subtotal
5 Maintenance*
Groundwater monitoring (VOC
analysis)-wells, I field blank. 2
duplicate, l MS) Semiannual for
years I thru 5 and Annual for
6 years 6 thru 30.
· VOC Analysis 48
· Labor (samnlino) 2
· Labor f reno rt nrenaration) 2
· Other exncnses
Subtotal
Administrative costs( 153/~
Subtotal
7 Continu.,encv (25%)
Subtotal
8 Present Worth O&M ( I thru 5)
Present Worth O&M (6 thru 30)
Total PW O&M
O&M and Capital Cost Subtotal
Present Worth Total
Notes: *Includes replacement of equipment every IO years and site access pennitting.
Assumes a 3.5% discount rate
Unit Cost (S)
lumo sum
lump sum
lumn sum
27.500
lumo sum
125/samnle
4,800/samolinu. event
2.500/samoling event
lumn sum
lumo sum
lumn sum
Total Cost/yr($)
5.000
7.500
14.250
26,750
27.500
97,430
97,430
27.000
6.000
9,600
5.000
5.000
52.600
7.890
60,490
15.123
75.613
341,397
524.648
866,04;
892.79;
990,225
Semi-annual groundwater monitoring for the first 5 years and annual for the remaining 25 years. Itemized costs sho\vn arc
for semiannual monitoring. Total Present Worth takes into account the reduction to S37 ,806 for annual monitoring
years 6 thru 30.
K:IWP\04400\071\TabJes Table 7-2 7-12
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
This alternative also includes monitoring of groundwater from approximately 18 monitor,
converted monitor, and residential wells for 5 years on a semi-annual basis. As in Alternative 2,
because of expected migration of the bedrock aquifer plume, three additional monitor wells will
need to be installed. The monitoring schedule for this alternative is quarterly for the first three
years and, after well installation, all existing and newly installed monitor wells will continue to be
sampled on an annual basis for a period of27 years.
Natural attenuation is the selected remedy for this alternative. A review of historical data from the
site indicates natural attenuation processes are currently active at the site. This review is found in
Subsection 7.4.1.1. Natural attenuation processes may be more effective if the residential wells
are disconnected and are no longer drawing water from the bedrock aquifer. Much of the data
required for the examination of natural attenuation processes has been collected during the RI;
however, additional consistent data will need to be collected. This data includes groundwater
geochemical data, hydrogeologic parameters, as well as other information described in the EPA
Region IV Draft Region 4 Approach to Natural Attenuation of Chlorinated Solvents. Natural
attenuation for this site is discussed further in Subsection 7.4.1.2.
All connections to the city water system would require assistance from state and local authorities,
especially in the areas of public notification, system design, and system construction. During initial
procedures, an accurate count of the number of residences that are, or may be potentially affected
by the groundwater contaminant plume would have to be determined. Once determined, EPA,
state and local authorities would have to notify each resident and present the positive and negative
aspects of a public water connection. After notification of the public, system design will begin.
System design will require agreement between local authorities and EPA as to the total number of
connections and total extent of pipeline. Following completion of the system design, system
NORJK:\WP\04400\071 \FSDON001.00C 7-13
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
construction will commence. The system will most likely be installed by the local authority or
qualified contractor.
Groundwater treatment at the wellhead will consist of the installation of a filtration unit and
granular activated carbon (GAC) unit. Both of the filter systems will be installed in-line on present
residential water systems. The systems will be designed to remove particulates from the influent
groundwater as well as any organics present.
The first filtering unit of the in-line treatment system will consist of a particulate filter for removal
of sediment and other matter from the influent water line. Following the particulate filter, the feed
water will flow into a GAC system. The GAC system will consist of two units operated in a
down-flow fixed-bed mode, as it has been found to be cost effective and produces the lowest
effluent concentrations for low solids feed streams. Due to space constraints, each unit will
contain a maximum of 50 pounds of carbon and will need to be replaced on a semi-annual to
annual basis. Spent carbon will be taken off site for regeneration or disposal.
To assess the effectiveness of the treatment system, the water effluent will be routinely (semi-
annually) monitored. Monitoring will be more frequent during startup and early operation.
7.4.1.1 Historical Data Review for Natural Attenuation Processes
A historical review of TCE and PCE concentrations m groundwater samples collected from
residences north and south of the Davis Park Road Auto Repair Shop generally indicates a decline
in contaminant levels, with the exception being the residence sampled farthest to the south (2816
Davis Park Road). Appendix A contains a map of residential well locations and graphs of the
historical groundwater sample data.
NOR/K:\WP\04400\071 IFSDDN001.00C 7-14
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
The two residences sampled north of the Auto Repair Shop (2231 and 230 I Davis Park Road)
had historical maximum concentrations of less than I µg/1 TCE and PCE occurring during 1990
sampling events. PCE and TCE concentrations in groundwater since that time were below
laboratory detection limits (see graphs included in Appendix A). Groundwater from the monitor
well sampled at the Auto Repair Shop (2307 Davis Park Road) contained maximum
concentrations of TCE (30 µg/1) and PCE (trace) in August I 991. Concentrations of TCE were
less than I µg/1 and below detection in April and June, 1993. PCE was not detected above
laboratory detection limits in groundwater sampled from this well in April and June I 993 sampling
events. Neither TCE nor PCE were detected during the 1997/1998 RI groundwater sampling
event of the two monitor wells at the Davis Park Auto Repair facility.
Fluctuating levels of PCE and TCE with a predominant decreasing trend (see graphs in Appendix
A) were recorded in groundwater sampled from the private wells located south of the Auto
Repair Shop (2403, 2419, and 2425 Davis Park Road). In groundwater sampled from the
residential well located south and closest to the Auto Repair Shop, TCE decreased from a
maximum concentration of 44.5 µg/1 in May 1990 to below laboratory detection limits from June
I 994 through January I 998. Trace levels of PCE were detected in groundwater sampled from the
same well in 1990 and 1991 but PCE concentrations remained below detection limits from July
1992 through January 1998. TCE concentrations decreased from a maximum of 134.4 µg/1 in
June 1990 to 8 µg/1 in February 1998 in groundwater sampled from the residence farther south at
2419 Davis Park Road. PCE concentrations in groundwater sampled from the same well
decreased from less than I µg/1 in 1990 sampling events to below detection limit from June 1993
through February 1998. TCE concentrations in groundwater sampled from the residence farther
south at 2425 Davis Park Road decreased from a maximum concentration of 30 µg/1 in February
1993 to 3 µg/1 in groundwater sampled in May 1996. PCE concentrations decreased from less
than I to below laboratory detection limits from June 1993 through May 1995.
NOR/K:IWP\04400\071\FSDDN001.DOC 7-15
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This document was prepared by Roy~. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
Groundwater sampled from the Community Well located southeast of the Auto Repair shop and
across Davis Park Road in the Cedar Oaks subdivision had a maximum TCE concentration of 56
µg/1 in August 1990. In May 1996 and January 1998, the TCE concentration in groundwater
sampled from this well was 32 µg/1. A maximum concentration of20.9 µg/1 PCE was reported for
groundwater sampled from the community well in August 1990. In January I 998, the PCE
concentration had decreased to 14 µg/1.
Increasing trends in TCE and PCE were recorded in groundwater sampled from the residential
well sampled farthest southeast of the Davis Park Auto Repair Shop (2816 Davis Park Road). I TCE concentrations increased from 1.2 µg/1 in May 1990 to I 8 µg/1 in February 1998. PCE
concentrations increased from less than I µg/1 in June 1990 to 10 µg/1 in February 1998.
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PCE and TCE concentrations appear to have increased in private wells to the south and east of
the suspected source of these contaminants (the Auto Repair facility) while contaminant
concentrations in groundwater sampled closer to the shop continue to decrease or have been
nonexistent over an extended period of time. Data collected during the RI investigation revealed
that the suspected source area is on top of a local groundwater high and groundwater flows semi-
radially from that point. Also, the RI revealed that the groundwater plume appears to be located
within the bedrock aquifer only. Based on this information, the groundwater contaminant plume
appears to have been flushed from the suspected source area and the saprolite aquifer (assuming
that the contamination was present in this aquifer at some time), and is now migrating south to
southeast through the bedrock aquifer towards the Blackwood Creek area.
NOR/K IWP\04400\071 \FSODN001. DOC 7-16
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
7.4.1.2 Natural Attenuation Evaluation
Background
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
Based on a revtew of NCDHENR regulations concerning corrective action usmg natural
attenuation, performance of fate and transport modeling was performed to estimate the length of
time expected for natural attenuation to occur. The objectives of this modeling effort were:
• To evaluate the distance groundwater contamination originating from the Davis Park TCE
Site has the potential to migrate at concentrations exceeding MCLs, and;
• To evaluate the time required for groundwater to degrade to levels below MCLs.
Modeling of the TCE plume was performed usmg the groundwater model BIOSCREEN.
BIOSCREEN is a screening model that simulates remediation through natural attenuation. The
model was designed to simulate biodegradation by both aerobic and anaerobic reactions. It was
developed for the Air Force Center for Environmental Excellence (AFCEE) Technology Transfer
Division at Brooks AFB (Newell et al, 1996; 1997). The software, programmed on a Microsoft®
Excel spreadsheet and based on the Domenico analytical solute transport model, simulates
advection, dispersion, and adsorption, in addition to the aerobic and anaerobic reactions.
BIOSCREEN is a very flexible model in that it allows the use of separate decay coefficients for
the solute (groundwater) phase and the source. It can also estimate dispersion parameters from
the plume length. The model can predict the maximum extent of plume migration, which then can
be compared to the distance to potential points of exposure. Analytical groundwater transport
models have been widely applied and experience has shown that such models can produce reliable
results when site conditions in the plume area are adequately understood and relatively uniform
(Newell et al, 1996). BIOSCREEN includes three different model types:
NOR/K:IWP\04400\071 \FSODN001. DOC 7-17
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
l)
2)
3)
Solute transport without decay,
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
Solute transport with biodegradation modeled as a first-order decay process,
Solute transport with biodegradation modeled as an "instantaneous"
biodegradation reaction (used for modeling degradation of fuel compounds).
BIOSCREEN can be used to model chlorinated solvent plumes; however the instantaneous
reaction output cannot be used and decay is modeled using only the first-order decay process.
Methodology
The site-specific data were compiled and used as input to BIOSCREEN. The model-input data
required include:
• Hydrogeology
• Dispersion
• Adsorption
• Biodegradation
• Source data
Average groundwater velocity was calculated according to the following equation:
V I . hydraulic gradient• hydraulic conductivity e oc1ty = -"------'=--------=------------=--
effective porosity
Using a hydraulic gradient of 0.0 I 8 ft/ft, a hydraulic conductivity of 1.51 ft/day (5.33E-04
cm/sec) and an effective porosity of0.05, a groundwater velocity of 197 ft/year was calculated for
the bedrock aquifer.
NOR/K:\WP\04400\071 \FSDDN001. DOC 7-18
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
The retardation factor was calculated using the following equation:
Rd = (( P.. Ko,. f o) I 11,) + I
Where: Ri = Retardation Factor
Pb = Bulk Density
n, = Effective Porosity
K,, = Organic Carbon Distribution Coefficient
fo, = Organic Carbon Content of Soil
Using a bulk density of 2.6 g/cm3, an effective porosity of 0.05, an organic carbon distribution
coefficient of I 00 L/kg (Montgomery, I 99 I), and an organic carbon content in the bedrock of
0.00 I%, the resulting retardation factor for TCE is 1.05. This retardation factor was used to in
conjunction with the average groundwater velocity to calculate an average contaminant velocity
using the following relationship:
Where: Ri
V
=
=
=
Retardation Factor
Average Groundwater Velocity
Contaminant Velocity
Using the retardation factor of 1.05 and the average groundwater velocity of 407 ft/year, the
resulting contaminant velocity for TCE is estimated as 188 ft/year.
NOR/K: IWP\04400\071 \FSDON001. DOC 7-19
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Dale: July 1998
Dispersion was calculated by BIOSCREEN based on the current plume length of approximately
250 ft. The first-order decay coefficient was taken from the Handbook of Environmental
Degradation Rates (Howard, 1991 ). The source thickness in the saturated zone was estimated
from drilling logs from the site. Source zone widths were based on the current plume
configuration in the source area and source concentrations were determined based on values that
were higher than the current measured concentrations. Table 7-3 presents the model inputs and
the sources of the data.
The basic assumption in this model is that the plume is at least 13 years old (beginning in mid
1980s) and originated at the Davis Park Auto Repair location. The model was calibrated to
concentrations measured during May 1996 (11th year configuration) and January 1998 (13th year
configuration). Predicted concentrations for 1996 were compared to the groundwater
concentrations measured in wells 121, 239, and well 285 (currently known as PW-2, CW-5, and
PW-I), located approximately 400, 1,400 and 2,400 ft, respectively, downgradient of the source.
Predicted concentrations for 1998 were compared to the groundwater concentrations measured in
wells PW-2, CW-5, and MW-2D, located approximately at approximately the same distances as
the 1996 wells, respectively, downgradient of the source.
Using available data (groundwater velocity and retardation), the source zone concentration and
source zone half lives were adjusted until the BIOSCREEN output matched the I 996 and 1998
plume and source geometry. The model was then run for an additional 7 years (beyond 1996) to
determine the likely plume shape and dissolved concentrations after those times.
NOR/K:\WP\04400\071 \FSDDN001. DOC 7-20
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 7-3
Parameters Used for BIOSCREEN Model
Davis Park Road TCE Site
May 1998
Hydraulic Conductivity Remedial
(K) Investigation Report -
Slug Tests
Hydraulic Gradient (i) Remedial Investigation
Report
Effective Porosity (n.,) Walton, 1988
Seepage velocity (V) Calculated from above
Dis Jersion
Longitudinal Model Calculation
Dispersivity
Transverse Dispersivity Model Calculation
Estimated Plume Length Existing Plume Data
Adsor lion
Rock Bulk Density (Ps) Walton, 1988
Organic Carbon Montgomery, 1991
Distribution Coefficient
<Koo)
Fraction Organic Estimated-Bedrock
Carbon (f;,.,)
Retardation Factor (Rd) Calculated from above
data
Biodc radation
Solute half-life (years) Howard ct al, 199 I
Original Source Present plume
concentration (mg/L) concentrations 2
Source half-life (years) Model
Calibration/Calculation
NOR/K:IWP\04400\071\FS. TBLS.OOC 7-21
5.3 x 10-• cm/sec
( 1.51 ft/day)
0.018 ft/ft
0.05
197 ft/year
12.5 ft
1.3 ft
250 ft
2.6 g/cm'
100 L/kg
0.001 %
1.05
2.5
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Results
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
Figure 7-2 presents the input screen for the first order decay model. Figures 7-3 through 7-6
present the I Ith year, 13th year, 15th year, and 20th-year centerline outputs. Table 7-4 presents a
comparison of the results between the BIOSCREEN first order decay and the concentration
measured in the monitoring wells. The correlation between the predicted concentrations and the
measured concentrations appears to be fairly good.
In the first-order decay function in BIOSCREEN, separate decay functions are used for the
source and solute phases. In most first-order decay models, the source half-life rate is generally
much higher than the groundwater (solute) phase, and as a consequence produces a concave or
log-linear decay. Also, in most first-order decay models the source does not migrate. However,
for this model the source apparently has migrated approximately I 400 feet, based on maximum
concentrations. To model this, the source half-live was set lower than the solute half-life. The
solute first order decay function for the groundwater and source terms were determined by varying
them and comparing to the groundwater data. A source half-life of I to 2 years and a solute half-life
of 2.5 years were found to fit the data best. The groundwater half-live calculated (2.5 years) is within
the values listed in Howard (Howard et al, 199 I) for anaerobic degradation. The model predicted that
the plume will reach a maximum length (above MCL levels of0.005 mg/L) ofless than 3,400 feet in I 7
years from the estimated date of release or four years from present time (year 2002), and will be below
MCLs 20 years from the estimated date of release or 7 years from the present time (year 2005).
NOR/K\WP\04400\071 \FSOON001. DOC 7-22
11111 - ---
DAVISPK11a.XLS
- -.. - -FIGURE 7-2 - - --
Restore Formulas for Vs,
Dispersivities, R, lambda, other
-------------------FIGURE 7-3
0.023 0.020 0.023 0.029 0.039 0.039 0.004 0.000 0.000 0.000 0.000
DAVISPK11 a.XLS
---·----- - - -11111 -- - - - - -
FIGURE 7-4
0.009 0.008 0.009
DAVISPK11a.XLS
----------· ·-------- -
FIGURE 7-5
DAVISPK11 a.XLS
--- ------ - ----111111 - - --
FIGURE 7-6
0.000 0.000 0.000 0.000 0.001 0.001 0.001 0.002 0.002 0.003 0.001
DAVISPK11 a.XLS
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 7-4
Comparison of Measured Well Concentrations with First Order Decay Models for TCE Davis Park Road TCE Site
May 1998
0
23 9 3 400 15 8 20 8 3 800
23 9 4 1200 32 32 29 II 4 1600
39 15 6 2000
39 21 8 2400 14 17 4 20 II 2800
ND 2 11 3200
ND ND 3600
ND ND ND 4000
ND ND ND
1 Years after leak. equates to 1996 ND -Not Detected
NOR/K;\Wp.()4400\071 \FS-TBLS .DOC 7-28
l! -
ND
ND
ND
ND
2
2
2
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This document was prepared by Roy F. Weston, Inc .. expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
Assumptions
Certain assumptions were made in the above calculations and apply to the results described:
I.
2.
3.
4.
5.
6.
Concentrations in the wells were assumed to be indicative of the center of plume at the
appropriate distance from the source and that the source is Davis Park Auto Repair.
The release(s) occurred in approximately l 985.
The measured groundwater concentrations measured in 1994 and l 996 accurately reflect
the concentrations at these locations and changes in concentration between these years is
primarily due to degradation and migration.
The direction of groundwater flow 1s horizontal and uniform, and vertical flow ts
negligible.
The unit is homogeneous, isotropic, and of uniform thickness.
Recharge rates are insignificant relative to regional flow.
7. Groundwater flow directions and velocities are constant over time.
Sensitivity Analysis
An abbreviated sensitivity analysis was performed to determine the impact of a higher seepage
velocity on predicted plume degradation and extent ( a substantially lower seepage velocity is not
possible because it would not allow the contaminants to have migrated 2,400 feet within the
NOR/K:\WP..04400\071 IFSDDN001. DOC 7-29
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
stated time frame). The porosity was decreased to 0.04, resulting in a seepage velocity of 247
ft/yr (a 25 % increase). The model was then recalibrated by varying the source and solute half-
lives. Table 7-5 presents these results.
The groundwater and source half-lives are very similar to those calculated in the original model.
This model predicted that the plume (above MCL levels of 0.005 mg/L) will reach a maximum
length of less than 4,000 feet in 16 years from the estimated date of release or three years from
present time (year 200 I), and will be below MCL levels in a total of I 8 years from the estimated
date of release or five years from present time (year 2003). Therefore, the impact increasing the
seepage velocity 25 percent would be that the plume could travel an additional 400 feet, but
would decay below MCLs more rapidly.
Conclusions
The following conclusions are drawn based upon the available data and the modeling results:
• Based on the first order decay model, the maximum distance TCE above RBSLs should
migrate is less than 3,600 feet.
• The first order model predicts that the TCE plume will be degraded below RBSLs m
approximately 7 years from the present.
• An increase in seepage velocity would result in a longer plume, but would cause the plume
to decay more rapidly than predicted
NOR/K:\WP\04400\071 \FSDONOO 1. DOC 7-30
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 7-5
Comparison of Measured Well Concentrations with First Order Decay Models
for TCE with an Increased Seepage Velocity
Davis Park Road TCE Site
May 1998
l3 years II years 1 13 years 15 years 20 years
0 23 9 3 ND
400 15 8 18 7 3 ND
800 19 8 3 ND
1200 32 32 22 9 3 ND
1600 27 II 4 ND
2000 34 13 5 ND
2400 14 17 35 17 7
2800 8 19 9
3200 ND 7 10
3600 ND ND 5
4000 ND ND 2
1 Years after leak, equates to 1996
ND -Not Detected
NOR/K:\WP\04400\071\FS-TBLS.OOC 7-3 I
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This document was prepared by Roy F. Weston, lnc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
References
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
Howard, P.H. et al, 1991, Handbook of Environmental Degradation Rates, Lewis Publishers, 725 pp.
Montgomery, J.H., 1991, Groundwater Chemicals Field Guide, Lewis Publishers, 271 pp.
Newell, C.J., et al, I 996, BIOSCREEN, Natural Attenuation Decision Support System, User's
Manual Version 1.3, National Risk Management Research Laboratory, 63 p.
Newell, C.J., et al, 1997, BIOSCREEN, Natural Attenuation Decision Support System, Version 1.4
Revisions, National Risk Management Research Laboratory, 9 p.
7.4.2 Overall Protection of Human Health and the Environment
This alternative provides protection to residents from contaminated groundwater during an
extended period of time, especially for those connected to City of Gastonia public water supply
system; therefore, risks to current and potential groundwater users are expected to decrease.
However, this alternative does not preclude potential impacts to the environment from migration
of the current groundwater plume or migration of the plume to other areas.
7.4.3 Compliance with ARARs
• Under this alternative, groundwater recovered from the wellhead treatment will be treated such
that contaminant concentrations in the effluent will be belo·w the remediation goals. However, this
alternative will do little to control the migration of the overall groundwater plume. Natural
attenuation processes are expected to decrease the contaminant concentration. The natural
NOR/K:IWP\04400\071 \FSOON001. DOC 7-32
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
attenuation study during the Remedial Design will provide the data necessary to determine if
contaminant concentrations are actually decreasing and the potential rate of decrease.
7.4.4 Short-Term Effectiveness
Appropriate levels of protection will be used during installation of the treatment system and
connection of residents to the city water supply to avoid direct contact with contaminated
groundwater. Disposal of any wastes generated during construction and operation will follpw
proper handling practices and should not have adverse environmental impact.
7.4.5 Long-Term Effectiveness and Permanence
Connecting affected residents to city water supply will provide a permanent remedy for protection
of human health. The wellhead treatment would require regular maintenance and continued
monitoring. Groundwater monitoring will continue to occur regularly during implementation of
this alternative. There will be a remaining risk associated with groundwater use for an extended
period of time with this alternative.
7.4.6 Reduction of Toxicity, Mobility, and Volume
Pumping at a water supply well would capture the plume on a limited basis and thus reduce the
mobility. Treating the groundwater by aqueous phase GAC will reduce the concentrations of
organics in the groundwater to the remediation goals and therefore, the toxicity and volume.
Natural attenuation processes may also act to reduce the overall concentration of the contaminant
plume.
NORJK. IWP\04400\071 \FSDDN001.DOC 7-33
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This document was prepared by Roy F. Weston, lnc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
7.4.7 Implementability
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Dale: July 1998
This alternative involves installation of in-line groundwater treatment units, including filtration
units and activated carbon units. These components are widely available and the system can be
assembled using standard engineering and construction techniques. All of the units of the
treatment system are easily transportable and installed. For the organic contaminants detected at
the Site, carbon adsorption is a proven technology and is often used as a means for treatment.
Permission will be required from the respective property owners for the installation of carbon
units.
Water lines currently used by the city are adjacent to many of the residences at the site and would
only require extensions of the lines to connect new residences. Permits and designs would have to
be obtained by the local authority or qualified contractor.
7.4.8 Cost
Costs associated with the connection of residences to the public water supply include public
notification, system design, and system construction. For estimating purposes, it was assumed 75
additional users would be connected to city water. Capital costs associated with the groundwater
treatment unit portion of the alternative includes treatability study costs, installation of the filter
and carbon adsorption units, and other associated instrumentation and equipment. For estimating
purposes, it was assumed that 75 residents would receive wellhead treatment maintenance for a
period of I year. Capital costs for a natural attenuation study have been estimated. The estimated
total present worth cost for this alternative is $3,873,299. Tables 7-6 and 7-7 present itemized
breakdowns of capital and O&M costs, respectively.
NOR/K\WP\04400\071 \FSDDN001. DOC 7-34
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without tho express written permission of
EPA.
Item
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Table 7-6
Estimated Capital Costs for Alternative 3 -Reduction of Groundwater Exposure
Davis Park Road TCE Site
Gastonia, North Carolina
Description Quantity Unit Cost (S)
Treatability Studv I Lurno Swn
Installation· Per residence (includes
carbon, UV light and Fe filter) 75 7,550
On-site activated carbon filter·
Replacement & disposal (required once a
vear) 75 530
Installation of public water supply to
approximately 75 residences {A) 5,500 feet 85/foot
Designs, specifications, regulatory,
approval, and permits (20% ofltem 3))
Examination of natural attenuation
processes
I Lumo Sum
Subtotal
Five-Year Review (includes groW1dwater
sampling) I 27,500
Present Worth (5-Year Reviews)
Subtotal
Administration / 15%)
Subtotal
Contirni:encv (25%)
Total capital cost (rounded)
Note: Assumes a 3.5% discount rate and six 5 Year Reviews over a 30 year period.
K:\WP\04400\071\Tables Table 7-6 7.35
Total Cost (S)
17,500
566,250
39,750
467,500
93,500
50,000
1,234,500
27,500
97,430
1,331,930
I 99,790
1,531,720
382,930
1,914,650
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of
EPA.
Table 7-7
Estimated Operating Co.~ts for Alternative 3 -Reduction of Groundwater Exposure
Davis Park Road TCE Site
Gastonia, North Carolina
[tern Description
Annual Quantity Unit Cost($)
l Labor ((a) 6% of capital cost) Lumn Sum
2 Maintenance(@ 2% of capital cost) Lumn Sum
Monitoring of eilluent (analysis) (A)· Treated
3 water from on-site GAC colwnn 75 X 4 = 300 300
Groundwater Monitoring -Quarterly for years
l thru 3 and Annual for years 4 thru 30. See
4 Alternative 2 (Item 6) for Cost Breakdown. 1 120,980
5 Groundwater Modeling l 5,000
Subtotal
6 Administrative ( l 5% 1
Subtotal
7 Contineencv 125%)
Estimated Annual OneratinP Total
Present Worth Total (Years 1-3)
Present Worth Total /Years 4-301
Total Present Worth Total /O&Ml
Notes: Assumes 3.5% discount rate. The duration of the remedial program is asswncd to be 30 years.
A = Asswnes one.year period of quarterly sampling at the effiuent end of each well.
Quarterly monitoring for the first 3 years and annual for the remaining 27 years. See Item 6 of Altemative 2
for itemized costs.
Assumes discontinuation of wellhead treatment at the end of year I.
K:IWP\04400\071\Tablos Table 7.7 7-36
Total Cost Per
Year($)
114,879
38,293
90,000
120,980
5,000
369,152
55,373
424.543
106,131
530,674
1,486,073
472,576
1.958.649
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
7.5 ALTERNATIVE 4-REDUCTION OF GROUNDWATER EXPOSURE AND
GROUNDWATER TREATMENT
This alternative includes all the provisions of Alternative 3 ( except for natural attenuation as a
remedy of the groundwater contaminant plume) and adds remediation of the groundwater that
contains contaminant concentrations above the remediation goals. The major component of the
groundwater treatment option includes in-well vapor stripping.
The in-well VOC removal system volatilizes VOCs contained in groundwater and removes them
as a vapor. The vapor is retrieved using vacuum extraction and is treated above ground by
adsorption onto granular activated carbon (GAe). The voe-enriched vapor is extracted and the
partially cleaned water is returned to the aquifer. The system recirculates the groundwater
through air-lift pumping. The system converts groundwater contamination into a vapor that is
vacuum-extracted and treated. At the same time, air-lift pumping circulates the groundwater,
which becomes cleaner with each pass through the in-well air stripper. The only input to the
system is gas, which is injected into the well. The injected gas is typically air and can be recycled
during the process. For cost estimating purposes, three vapor stripping wells were assumed to be
required.
The only output of the system is gas that is removed from the well; this gas contains the voes
removed from the groundwater. After removal, this voe vapor is adsorbed onto GAC. The GAe
is regenerated and reused. No major facilities are needed for this technology. Power is needed to
operate the pumps and compressors. The method itself involves no moving parts beneath the
ground surface; however, careful packer and well designs would be required to successfully divert
the groundwater from the well back into the saturated zone and to the water table. The system is
expected to operate approximately IO years.
NORIK. IWP\04400\071 \FSDDNOO 1. DOC 7-37
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
The groundwater treatment is expected to last approximately l O years. Therefore, with the
addition of groundwater treatment, wellhead treatment is expected to only be required for
approximately l O years. Groundwater monitoring will be conducted semi-annually for the first
five years and annually for the next twenty-five years.
7.5.1 Overall Protection of Human Health and the Environment
This alternative would provide significant protection of human health and the environment
through groundwater remediation and connection of residents to the city water supply.
7.5.2 Compliance with ARARs
Under this alternative, groundwater will be treated such that the contaminant concentrations in the
effluent will be below remediation goals. This treatment option will comply with chemical-,
location-, and action-specific ARARs.
7.5.3 Short-Term Effectiveness
During installation of the treatment system, the usual precautions necessary for construction
activities will be taken. The installation of wells and the treatment system will not involve a
significant release of volatiles to the environment. Disposal of any wastes generated during
construction and operation would follow established handling practices.
NOR/K:\WP\04400\071 \FSDDNOO 1. DOC 7-38
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
7.5.4 Long-Term Effectiveness and Permanence
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
The use of treatment processes provides a permanent method for treating the voe contaminants
in the groundwater. Spent carbon will be disposed in an approved facility or regenerated off-site.
There will be essentially no risk at the site upon completion of the remedial actions.
7.5.5 Reduction of Toxicity, Mobility and Volume
Pumping at the wells would capture the plume and thus reduce plume mobility. Treating the
groundwater would remove voes present in the groundwater to the remediation goals, thus
reducing the toxicity and volume of groundwater contamination. This process would not release
voes to the atmosphere.
7.5.6 Implementability
This alternative involves installation of groundwater extraction wells, small pumps, compressor,
and GAe canisters, in addition to electrical connections. These components are widely available
and the system can be assembled using common construction techniques. All the units of the
treatment system are easily transportable and installed.
7.5. 7 Cost
The total present worth cost for this alternative is approximately $7,014,434. Total capital costs
are estimated to be $2,879,874. Detailed cost estimates are presented in Tables 7-8 and 7-9.
NOR/K:IWP\04400\071 \FSDON001. DOC 7-39
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
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Notes:
Table 7-8
Estimate of Capital Costs for Alternative 4
Reduction of Groundwater Exposure and Groundwater Treatment
Davis Park Road TCE Site
Gastonia, North Carolina
Description Quantity Unit Cost ($)
Installation in-well air stripping wells 3 50,000
Air Injection and Piping -
Supply air into wells I 30,000
GAC columns (vapor phase, @ 3.25 ft-100 lbs. 2 7,200
carbon) with ancillaries
Alternative Water Supply (includes connection
of City water supply and/or installation of
carbon filters on wells). Items 2 through 5 of
Alternative 3 Capital Costs.
Subtotal
Mobilizationldemobilization, construction
management (20%)
Designs, specifications, regulatory approval, and
permits (20%)
Five-Y car Review (includes groundwater I 27,500
sampling)
Present Worth (5-Year Reviews)
Subtotal
Administration (15%)
Subtotal
Contingency (25%)
Subtotal capital cost for in-well air stripping
Estimated Total Capital Cost
I. Assumes a 3.5% discount rate.
2. Includes capital costs for Altenmtive 3, excluding the natural attenuation study.
NOR/K:\WP\04400\071 \FS. TBLS. DOC 7-40
Total Cost (S)
150,000
30,000
14,400
1,167,000
1,361,400
272,280
272,280
27,500
97,430
2,003,390
300,509
2,303,899
575,975
2,879,874
2,879,874
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This document was prepared by Roy F. Weston, lnc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Table 7-9
Estimate of Annual Operating and Maintenance Costs for Alternative 4
Reduction of Groundwater Exposure and Groundwater Treatment
Davis Park Road TCE Site
Gastonia, North Carolina
Annual Total Cost
Item Description Quantity Unit Cost ($) Per Year($)
I Labor(@ 6 % of capital cost) Lump sum 172,792
2 Maintenance(@ 2 % of capital cost) Lump sum 57,598
3 On-site activated carbon (vapor phase)
to Replacement & disposal I 6,000/changeout 6,000
4 Utilities Lump Sum 3,000
5 Annual Operating Cost for Alternative 3 308,662
(Items I through 5 of Table 7-7) (Years 1-5)
Subtotal 548,052
6 Administrative (15%) 82,208
Subtotal 630,260
7 Contingency (25 % ) 157,565
Total 787,825
Present Worth Cost (Years 1-10) 6,567,812
Present Worth Cost (Years 10-30) 446,622
Total Estimated Present Worth 7,014,434
Note: The duration of the remedial program is assumed to be 10 years. After 10 years, the O&M costs
associated with this al_temative will be groundwater monitoring only. Semi-annual monitoring will be conducted
for year I through 5 and annually for years 6 through 30. Assumes 3.5% discount rate.
NORIK:IWP\0<1400\071 \FS. TBLS. DOC 7-41
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
7.6 ALTERNATIVE 5-REDUCTION OF GROUNDWATER EXPOSURE AND
GROUNDWATER PUMP AND TREAT
This alternative includes all the provisions of Alternative 4, except that the active remedial method
is groundwater pump and treat instead of in-situ or in-well vapor stripping.
The groundwater pump and treat system involves the use of extraction wells to remove
contaminated groundwater from the bedrock aquifer via pumping and discharge to an air stripping
system that volatilizes the VOCs. The vapor is retrieved using vapor vacuum extraction and is
treated by adsorption onto GAC or is released without treatment to the atmosphere. The treated
water exits the air stripping system and is discharged to a local surface water body, which in this
case is Blackwood Creek. An NPDES permit will be required prior to any discharge and the
permit will define levels of constituents that may be present in the treated water.
System requirements include power for operation of the pumps and air stripping system. The air
stripping system is built to be able to operate in the open environment; however, costs have been
included for the system to be housed within a building for protection against the elements and
human interference. The system is expected to operate approximately IO years.
Groundwater treatment is expected to last approximately IO years. Wellhead treatment at the site
will only be maintained for a one-year period. Groundwater monitoring will be conducted semi-
annually for the first five years and annually for the next twenty-five years.
7.6.1 Overall Protection of Human Health and the Environment
This alternative would provide significant protection of human health and the environment
through groundwater remediation and connection of residents to the city water supply.
NOR/K:\WP\04400\071\FSDDN001.DOC 7-42
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, ln whole or in part, without the express
written permission of EPA.
7.6.2 Compliance with ARARs
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision; 1
Date: July 1998
Under this alternative, groundwater will be treated such that the contaminant concentrations in the
effluent will be below remediation goals. This treatment option will comply with chemical-,
location-, and action-specific ARARs.
7.6.3 Short-Term Effectiveness
During installation of the treatment system, the usual precautions necessary for construction
activities will be taken. The installation of wells and the treatment system will not involve a
significant release of volatiles to the environment. Disposal of any wastes generated during
construction and operation would follow established handling practices.
7.6.4 Long-Term Effectiveness and Permanence
The use of treatment processes provides a permanent method for treating the voe contaminants
in the groundwater. If GAe is used in the treatment system, spent carbon will be disposed in an
approved facility or regenerated off-site. Otherwise, air stripping trays can be cleared and
rejuvenated on site. There will be essentially no risk at the site upon completion of the remedial
actions.
7.6.5 Reduction of Toxicity, Mobility and Volume
Pumping at the wells would capture the plume and thus reduce plume mobility. Treating the
groundwater would remove voes present in the groundwater to the remediation goals, thus
reducing the toxicity and volume of groundwater contamination.
NOR/K:IWP\044001071\FSD□N001.DOC 7-43
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. lt shall not be disclosed, in whole or in part, without the express
written permission of EPA.
7.6.6 Implementability
Feasibility Study Report
Davis Park Road TCE Site
Section: 7
Revision: 1
Date: July 1998
This alternative involves installation of groundwater extraction wells, small pumps, air stripping
system, and possibly GAC canisters, in addition to electrical connections. These components are
widely available and the system can be assembled using common construction techniques. All the
units of the treatment system are easily transportable and installed.
7.6.7 Cost
The total present worth cost for this alternative is approximately $4,543,480. Total capital costs
are estimated to be $2,018,869. Detailed cost estimates are presented in Tables 7-10 and 7-11.
NOR/K:\WP\04400\071 IFSDDN001 . DOC 7-44
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of
EPA.
Item
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Table 7-10
Estimated Capital Costs for Alternative 5 -Reduction of Groundwater Exposure
and Groundwater Pump and Treat
Davis Park Road TCE Site
Gastonia, North Carolina
Description Quantity Unit Cost($)
Treatment system installation (includes I 35,000 svstem building, etc.)
Extraction well installation 3 5,000
Extraction well oumos and oioin.e. 3 5,000
Piping between wells and connection to I 75,000 the treatment svstem
Engineering design, specifications,
regulatory approval, and pennits (20% of I Lwnp Swn
Items I through 4)
Ntemative Water Supply (includes
connection of city water supply and/or
installation of carbon filters on wells).
Items 2 through 5 of Alternative 3 -
Canital Costs
Subtotal
Five-Year Review (includes groundwater
I 27,500 sarnolint1)
Present Worth (5-Ycar Reviews)
Subtotal
Administration ( 15%)
Subtotal
Contim!:encv (25%)
Total capital cost (rounded)
Note: Assumes a 3.5% discount rate and six 5 Year Reviews over a 30 year period.
K:\WP\04400\071\Tables Table 7-10 7-45
Total Cost ($)
35,000
15,000
15,000
75,000
28,000
1,167,000
I 307 000
27,500
97,430
1.404430
2 I0,665
1,615.095
403,774
2,018,869
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of
EPA.
Table 7-11
Estimated Operating Costs for Alternative 5 -Reduction of Groundwater Exposure
and Groundwater Pump and Treat
Davis Park Road TCE Site
Gastonia, North Carolina
Description Total Cost Per
Item Annual Quantity Unit Cost ($)
I Labor ((a) 6% ofcaoital costs) Lwnn Swn
2 Maintenance Lwno Sum
GroW1dwater Monitoring -Semiannual for
years I thru 5 and Annual for years 6 thru 30.
See Alternative 2 (Item 6) for Cost
3 Breakdown. I 60,490
Monitoring of effiuent (analysisXA). Treated
4 water from on-site GAC column. 75 x4 = 300 300
Subtotal
5 Administrative 1)5% \
Subtotal
6 Continoencv f25%)
Estimated Annual Oneratinu Total
Present Worth Total rYear 1)
Present Worth Total Nears 2-5\
Present Worth Total Nears 6-30\
Total Present Worth Total
Notes: Assumes 3.5% discow1t rate. The duration of the remedial program is asswned to be 30 years.
A = Asswnes one-year period of quarterly sampling at the effiuent end of each well.
Semi-annual monitoring for the first 5 years and annual for the remaining 25 years. See Item 6 of Alternative 2
for itemized costs.
K:\WP\044001/J71 \Tables Table 7-11 7-46
Year($)
121,132
5,000
60,490
90,000
276,622
41,493
318.115
79,529
397,644
397,644
1,072,624
3,073,212
4 543 480
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
SECTION 8
Feasibility Study Report
Davis Park Road TCE Site
Section: 8
Revision: 1
Date: July 1998
SUMMARY AND COMPARISON OI<' ALTERNATIVES
This section summarizes the detailed analysis of remedial alternatives performed in Section 7 and
compares the features and merits of all alternatives. In Subsection 8.1, a comparative analysis
based on non-cost criteria 1s presented to distinguish the effectiveness and
advantages/disadvantages among the alternatives. A cost comparative analysis is presented in
Subsection 8.2.
The following five remedial alternatives were included in the detailed analysis.
• Alternative I: No Action
• Alternative 2: Institutional Controls
• Alternative 3: Monitored Natural Attenuation with Exposure Abatement
• Alternative 4: Reduction of Groundwater Exposure and Groundwater Treatment
• Alternative 5: Reduction of Groundwater Exposure and Groundwater Pump and Treat
8.1 NON-COST COMPARATIVE ANALYSIS
A summary of non-cost comparison of the remedial alternatives is presented in Table 8-1.
Alternative 1 does not meet the groundwater remedial objectives. It was included as a baseline
alternative to compare with other remedial alternatives. Alternative I does not provide protection
of human health or the environment, nor does it comply with chemical-, location-, or action-
specific ARARs. Alternative 2 is designed to prevent exposure to contaminated groundwater but
NOR/K\WP\04400\071 IFSODN001. DOC 8-1
- ----- ------_ ... -
This document was prepared by Roy F. Weston, Inc., expressly ror EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Evaluation Alternative 1:
Criteria No Action
()yerall Protection Does not protect
of Human Health human health or the
and the environment. Potential
Environment risks are expected to
continue for an
extended period of
time.
Compliance with Does not comply with
ARARs ARARs. Potential
risks are expected to
continue for an
extended period of
time.
NOR/K:\WPul4400\071\FS-TBLS.OOC
Table 8-1
Summary of Non-Cost Comparison of Remedial Alternatives
Davis Park Road TCE Site
May 1998
Alternath·e 2: Alternative 3: Alternative 4:
Institutional Controls Reduction of Reduction of Groundwater
Groundwater Exposure Exposure in Addition to
Groundwater Treatment
Potential risks to the Protection of human health Adequate protection of human
human health and the and the environment will health and the em·ironment
environment are reduced be provided to those will be provided during the
by deed recordations. connected to the public remediation period. No
Groundwater monitoring water supply. Risk will significant risk will remain
will provide prior warning remain to the environment upon completion of remedial
if unacceptable conditions from migration. actions.
arise.
Does not comply with· Groundwater treatment This alternative will comply
chemical-specific ARARs. will occur at the wellhead. with all chemical-, location-,
Inslaliaiion of additional Plume migration will not and action-specific ARARs.
wells will comply \\1th be controlled.
location-and action-
specific ARARs.
8-2
Alternative 5:
Reduction of Groundwater
Exposure and Groundwater
Pump and Treat
Adequate protection of human
health and the enYironment
will be provided during the
remediation period. No
significant risk will remain
upon completion of remedial
actions.
This alternative will comply
with all chemical-, iocation-,
and action-specific ARARs.
----.. ------
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Evaluation Alternative 1:
Criteria No Action
Short-Term A significant reduction
Effectiveness of contaminant
concentration is not
expected in the short-
term.
NOR/K:\WP\04400\071 \FS-TBLS. DOC
Table 8-1 (Continued)
Summary of Non-Cost Comparison of Remedial Alternatives
Da,·is Park Road TCE Site
May 1998
Alternative 2: Alternative 3: Alternative 4:
Institutional Controls Reduction of Reduction of Groundwater
Groundwater Exposure Exposure in Addition to
Groundwater Treatment
A significant reduction of Appropriate levels of Adequate protection will be
contaminant concentration protection will be used provided to the workers and to
is not expected in the during installation of the the community during the
short-tenn. treatment system and remedial actions (by taking
connection of residents to standard precautions during
Adequate protection will the city water supply to construction, restricting well
be provided to the workers avoid direct contact with installations, by properly
during the installation of contaminated dispersing air emissions from
monitoring wells and groundwater. the presumptive air stripper,
institutional measures will etc.).
be used lo prevent
exposure from
contaminated
groundwater.
8-3
Alternative 5:
Reduction of Groundwater
Exposure and Groundwater
Pump and Treat
Adequate protection will be
provided to the workers and to
the community during the
remedial actions (by taking
standard precautions during
construction, restricting well
installations).
------·-_,_ ---
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Evaluation Alternative I:
Criteria No Action
Long-Tenn It is not expected to
EffectiYcness meet the remedial
action objectives in the
foreseeable future. A
significant residual risk
will remain at the site
for an extended period
of time.
Reduction of No reduction in
Toxicity, Mobility, toxicity or mobility is
or Volume of expected in the
Contaminants foreseeable future.
O\•erall volume of the
contaminants may
increase with the
downgradient
migration of the plume.
NOR/K:\WP\04400\071\FS-TBLS.DOC
Table 8-1 (Continued)
Summary of Non-Cost Comparison of Remedial Alternatives
Davis Park Road TCE Site
Ma)· 1998
Alternative 2: Alternative 3: Alternative 4:
Institutional Controls Reduction of Reduction of Groundwater
Groundwater Exposure Exposure in Addition to
Groundwater Treatment
It is not expected to meet Permanent protection will Remedial objectives will be
the remedial action be provided to residents met upon completion of the
objectives in the connected to public water remedial actions.
foreseeable future. A supply.
significant residual risk Treatment and discharge will remain at the site for Wellhead treatment will
an extended period of require regular methods used in this
time. Risk will only be maintenance and altemati,·e are pennanent.
mitigated by continued continued monitoring.
diligent application of There will be a remaining There will be no significant
institution-11 measures. risk associated wilh remaining risk at the site upon
groundwater use for an completion of the remedial
extended period of time. actions.
No reduction in toxicity or Pumping at a water supply The mobility of the
mobility is expected in the well would capture the contaminants will be reduced
foreseeable future. Overall plume on a limited basis. by the proposed groundwater
volume of the Natural attenuation well system. The toxicity and
contaminated ground\1,ater processes may also act to volume of the contaminated
may increase with the reduce the overall groundwater will be reduced
downgradicnt migration of concentration of the through treatment.
the plume. contaminant plume.
8-4
Alternative 5:
Reduction of Grouridwater
Exposure and Groundwater
Pump and Treat
Remedial objectives will be
met upon completion of the
remedial actions.
Treatment and discharge
methods used in this
alternative are permanent.
There will be no signifirnnt
remaining risk at the site upon
completion of the remedial
actions.
The mobility of the
contaminants will be reduced
by the proposed groundwater
well system. The toxicity and
volume of the contaminated
groundwater will be reduced
through treatment.
----... ---
This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express written permission of EPA.
Evaluation Alternative I:
Criteria No Action
hnplementability Can be easily
implemented as it does
not require present or
future efforts.
NOR/K.:\WP\04400\071 \FS-TBLS. DOC
Table 8-1 (Continued)
Summary of Non-Cost Comparison of Remedial Alternati\'es
Davis Park Road TCE Site
May 1998
Alternative 2: Alternati\'e 3: Alternative 4:
Institutional Controls Reduction of Reduction of G roundn·ater
Groundwater Exposure Exposure in Addition to
Groundwater Treatment
Can be easily Can be implemented using Can be implemented using
implemented. Installation standard engineering and standard engineering and
of additional groundwater construction practices. construction practices.
monitoring wells can be Permission will be Permission ,vill be required
performed using standard required from the property from the property owners for
engineering and owners for the installation the installation of
construction practices. of carbon units. Permits groundwater monitoring and
Pennits will be required will be required from the extraction wells, and
from the appropriate appropriate authorities for associated piping. Pennils
authorities, for the the installation of water will be required from U1e
installation of groundwater connections. approptiaie authorities, for the
moniforing wells. installation of groundwater
Natural attenuation study wells.
Deed recordation can be readily
implementation would implemented with
require cooperation of additional data.
State and local
governments. Reliability of
groundwater use
recordations is considered
uncertain.
8-5
Alternative 5:
Reduction of Grouridwater
Exposure and Groundwater
Pump and Treat
Can be implemented using
standard engineering and
construction practices.
Permission will be required
from the property owners for
U1e installation of
groundwater monitoring and
extraction wells, and
associated piping. Pennits
will be required from the
appropriate authorities, for the
installation of groundwater
wells.
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or In part, without the express
written permission of EPA.
Feasibility Study Report
Davis Park Road TCE Site
Section: 8
Revision: 1
Date: July 1998
dDes not include measures to actively remediate the groundwater. Alternative 2 provides limited
protection of human health and the environment by implementing deed recordations. Alternative 2
does not comply with chemical-specific ARARs. However, it does comply with location-and
action-specific ARARs applicable to the monitoring well installation. No reduction in toxicity or
mobility is expected in Alternatives I or 2. Overall volume of the contaminated groundwater will
increase with the downgradient migration of the plume. Any reduction in contaminant
concentration will be due to natural processes only. Contaminant concentrations will remain
above acceptable regulatory levels for an extended period of time. Alternative I can be
implemented easily as there are no present or future efforts associated with this alternative. In
Alternative 2, deed recordations can be implemented with the assistance of local authorities.
Alternative 3 will provide permanent protection to those residents that are connected to the City
of Gastonia public water supply. With respect to the alternate water supply and installation of
carbon units at the wellhead, this alternative will comply with location-and action-specific
ARARs. The alternative does not comply with chemical-specific ARARs because the plume will
not be completely controlled. Limited control or reduction of the plume will be through pumping
of water into the carbon treatment units at the wellhead and as a result of natural attenuation.
Alternatives 4 and 5 meet all groundwater remedial objectives at the Davis Park Road site.
Adequate protection of human health and the environment will be provided to the community and
the environment during the remedial actions. Alternatives 4 and 5 comply with chemical-,
location-, and action-specific ARARs. The treatment and discharge technologies used in this
alternative are permanent. The toxicity, mobility, and the volume of contaminants will be reduced
through treatment. There will be no significant risk remaining at the site due to groundwater upon
completion of the remedial actions.
NOR/K:IWP\04400\071 \FSDDN001.00C 8-6
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
8.2 COST COMPARATIVE ANALYSIS
Feasibility Study Report
Davis Park Road TCE Site
Section: 8
Revision: 1
Date: July 1998
A summary of capital, O&M and present worth costs associated with the remedial alternatives are
presented in Table 8-2. There are no capital or O&M costs associated with Alternative I, only
costs associated with the five-year review. The capital costs associated with Alternative 2 include
the installation of groundwater monitoring wells. The O&M costs associated with this alternative
are the groundwater monitoring activities, which are expected to continue for an indefinite period
of time. The total present worth cost for Alternative 2 is $990,225. This cost appears to be
significant, particularly for an alternative that does not actively address groundwater
contamination at. the site, when compared to the two active remedial alternatives which are
expected to meet all remedial objectives. The present worth cost of Alternative 2 is approximately
26% of the present worth cost of Alternative 3 ($3,873,299) and 14% of the present worth of
Alternative 4 ($7,014,434). The total present worth cost of Alternative 5 is $4,543,480.
When comparing costs of Alternatives 4 and 5, it is clear that Alternative 5 is less expensive than
Alternative 4 while both alternatives address the groundwater contamination problem at the site.
Alternatives 4 and 5 are similar in capital cost, which is a result of comparable methods of
remediation in the alternatives. The primary difference is a result of the higher cost of design,
materials required for the system, maintenance, and construction of the active groundwater
treatment system in Alternative 4.
NOR/K:IWP\04400\071 \FSDON001. DOC 8-7
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This document was prepared by Roy F. Weston, Inc., expressly ror EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
I.
2.
3.
4.
5.
Table 8-2
Summary of Cost Comparison of Remedial Alternatives •
Davis Park Road TCE Site
Gastonia, North Carolina
Alternative Capital Cost Annual O&M
($) Cost ($/yr)
No action (5-year reviews only) 0 0
Institutional Controls 26,750 75,613
Groundwater Exposure Abatement and 1,914,650 424,543
Monitored Natural Attenuation
Reduction of Groundwater Ex'J)osure in 2,879,874 787,825
Addition to Groundwater Treatment
Reduction of Groundwater Ex'J)osure 2,018,869 397,644
and Groundwater Pump and Treat
Total Present
Worth Cost ($)
140,055
990,225
3,873,299
9,894,308
6,562,349
Note: The present worth costs have been calculated based on the project life of the alternative and a 3.5%
discount rate.
• Alternatives I and 2 will last approximately 30 years, Alternative 3 for 7 years, and Alternatives 4 and 5 for JO
years.
NOR/K;\WP,04400\071\FS.TBLS.DOC 8-8
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This document was prepared by Roy F. Weston, Inc., expressly for EPA. It shall not be disclosed, in whole or in part, without the express
written permission of EPA.
APPENDIX A
Feasibility Study Report
Davis Park Road TCE Site
Section: Appendix A
Revision: 1
Date: July 1998
HISTORICAL SAMPLING ANALYSIS GRAPHS
NOR/K.\WP\04400\071\FSODN001.00C
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2231 O,IMS PARI< ROAD
2J01 OAVIS PARK ROAO
// // II II II
CW-J $
WW-1/EMW-2 $
DAVIS PARK AUTO REPAIR
2301 o,1,VIS PAAK ROAO
,._
z z w
N -5-4e.704.186'
E • 1.JJ7,171S.188' DLV. -no.1•·
GLENRAVEN AVENUE
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28115 0.-MS P..WO: RQl,O
PROJECT TITLE1
DAVIS PARK ROAD TCE SITE
GASTONIA, GASTON COUNTY, NORTH CAROLINA
RESIDENTIAL WELL LOCATION MAP
HISTORICAL DATA REVIEW
LEGEND
t.lW-1 .. MONITOR WELL LOCATIONS
SW-1 • SURFACE WATER SAMPLE LOCATIONS
PW .. PRIVATE '!\£LL LOCATIONS
cw .. CONVERTED WELL LOCATIONS
EMW .. EXISTING MONITOR \YELL LOCATIONS
COMBINED FACTOR = 0.9998411 (NAO 83)
POINT NORTHING EASTING ELEVATION ELEVATION ELEVATION
TOP PIPE TOP PLATE GROUND
100 545544.652 1338740.388 688.27 MW-1S 688.85 688.85
101 545495.204 1338846.893 687.50 MW-10 687.60 687.81
102 545674.010 1338358.610 707.21 CW-5 706.61
103 544827.129 1338881.108 684.60 MW-20 684.89 684.88
104 544846.945 1338868.067 684.60 MW-2S 685.04 684.99
105 544510.539 1338455.456 677.26 MW-5S 677.52 677.52
106 544881.886 1338621.461 687.57 PW-1 686.15
107 545319.342 1337914.911 716.12 MW-4S 716.65 716.68
108 546610.771 1337145.070 743.74 MW-3S 744.42 744.37
109 546676.623 1337132.994 746.29 MW-3D 746.75 746.75
110 546139.528 1338513.369 705.76 CW-6 705.21
111 545175.589 1337035.677 739.97 MW-40 740.44 740.45
112 546474.476 1337682.514 764.35 PW-2 764.09 113 546568.657 1337641.640 768. 75 CW-4 766.78 141 546888.586 1337295. 709 761.18 CW-3 761.41 761.41 128 546827.885 1336850.318 757. 79 CW-2 758.62 758.59 129 547139.622 1336707.806 761.69 CW-1 760.88 136 546854.891 1337483.389 771.21 EMW-1 771.19 769.78 137 546857.745 1337485.094 771.86 EMW-2 773.00 770.22
BENCH MARK USED WAS 1HE OTY OF GASTONIA BENCH MARK, QUADRANT 3, BENCH MARK
No. 41, LOCATED AT 1HE INTERSECTION OF DAVIS PARK ROAD ANO STAGE COACH ROAD.
ELEVATION c 731.05'
DRA\i/N1 DATE• DES. ENG.1
M. SNEED 5 18 98
DESIGNERS/CONSULTANTS
DATE1 \ol.O. NO.•
04400-071 -095
CHECKED1 DATE1 APPR□VEDt ATE1 CAD FILE NAME1 ...... _________________________________ ._ _______ ...._ ________ r_1G_u_R_E_A_-_1 _________ ._ ____ _. ..... __ _.._ _____ _.._ ___ "-'R'-'W'-'L;;..;Oa.;:C""M""A"'P __ .D __ W_G___,
- -- - -- - --- - -- - -- - --Historical TCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2231 Davis Park Road
0.005
0.0045
0.004
0.0035
'§,
2, 0.003 ·
C:
0 :;:: 0.0025 ·-"' ~ -C: .,
(J
C: 0.002 --0 ()
0.0015
0.001 -
0.0005 --
0-
5/7/90 11/23/90 6/11/91 12/28/91 7/15/92 1/31/93 8/19/93 3/7/94
Date
K:\04400\077\DATA\Wc\lsum\2231 TCE
-------------------Historical PCE Concentrations in Groundwater
0.9:
0.8
0.7 ·
! 06
C: 0
-~ 0.5 ~ -C: .,
(.)
§ 0.4 u
0.3
0.2
0.1 ·
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2231 Davis Park Road
0 . -•~----+------+-----+-----+-----1---------+---~-,
5/7/90 11/23/90 6/11/91 12/28/91 7/15/92 1/31/93 8/19/93 3/7/94
Date
K:\04400\077\DAT A\Wellsum\2231 PCE
-------------------Historical TCE Concentrations in Groundwater
0.9
0.8
0.7
-10.6
C: .2 e a.s -C: Cl> 0
§ 0.4 u
0.3
0.2 -
0.1
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2301 Davis Park Road (CW-3)
0-t------+-------f-----~----+------+------4-------'>----'
5/7/90 9/19/91 1/31/93
K:\04400\077\DATA\Wc!lsum\2301 TCE
6/15/94
Date
10/28/95 3/11/97 7/24/98
-------------------Historical PCE Concentrations in Groundwater
0.25 •
0.2
-'g, 0.15
C 0 .:: "' ~ i: .,
u 5 0.1 ·-u
. 0.05 --
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2301 Davis Park Road (CW-3)
0+------+------t-----'---+--f------l--+-----+----+-------j
5f7/90 9/19/91 1/31/93 6/15/94 10/28/95 3/11/97 7/24/98
Date
K:\04400\077\DATA\Wellsuin\2:l0I PCE
-------------------Historical TCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Monitor Well, 2307 Davis Park Road
30
25
20 -
'a,
2-
C: .2 iii 15 --~ -C: .,
0
C:
0 u
10
5
0+----+----+-----t-~---t-----t-----1------=~>--------j
6/11/91 9/19/91 12/28/91 4/6/92
K:\04400\077\DAT A\Wellsum\2307 TCE
7/15/92
Date
10/23/92 1/31/93 5/11/93 B/19/93
- - ------.. ----------Historical PCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Monitor Well, 2307 Davis Park Road
0.005
0.0045
0.004
0.0035
-'a, 0.003 .2,
C 0 .= 0.0025 "' ~ -C
Q) u
C 0.002 .. 0 u
0.0015
0.001
0.0005 ·
0
6111191 9119191 12128191 416192 7/15192 10123192 1131193 5111 /93 8119193
Date
K:\04400\077\DATA\Wcl\sum\2:107 PCE
-------------------
'a,
2-
C: .!2 "' ~ -C: .,
()
C: 0 u
45 --
40
35 -
30
25
20
15
10 -
5 -
Historical TCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2403 Davis Park Road (CW-4)
0-t-------+------t-~>------+-+-------4~--t-------+---------1
5/7/90 9/19/91 1/31/93 6/15/94 10/28/95 3/11/97 7/24/98
Date
K:\04400\077\DATA\Wellsum\2403 TCE
--- - - -------- ---- --Historical PCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2403 Davis Park Road {CW-4)
0.005
0.0045
0.004
0.0035
-'a,
2. 0.003 ..
C
0 ·.;; 0.0025 · "' ~
i: .,
u
C 0.002 0 u
0.0015
0.001
0.0005
0 --I
5/7/90 9/19/91 1/31/93 6/15/94 10/28/95 3/11/97 7/24/98
Date
K:\04400\077\DATA\Wcllsum\2403 PCE
-------------------Historical TCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2419 Davis Park Road (PW-2)
140.0
120.0 ..
100.0
'a,
2, 80.0
C: 0 .:: .. ~ -C: .,
60.0 u C: 0 u
40.0
20.0
0.0 +-------+-----+-------t-~---•---=-----+-------+-------'
12/23/88 5/7/90 9/19/91 1/31/93 6/15/94 10/28/95 3/11/97 7/24/98
Date
K:\04400\077\DATA\Wcllsurn\2419 TCE
-------------------Historical PCE Concentrations in Groundwater
1.00
0.90
0.80
0.70
10.60
C: 0 :,:: ~ 0.50
C: Cl> 0 5 0.40. u
0.30 -
0.20 --
0.10 -
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2419 Davis Park Road (PW-2)
0.00 -1-------t-+---+----t-----+---+-+-_-+ ______ ...._ _____ ----I
12/23/88 5/7/90 9/19/91 1/31/93 6/15/94 10/28/95 3/11/97 7/24/98
Date
K:\04400\077\DATA\Wcllsum\2419 PCE
-------------------Historical TCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2425 Davis Park Road
30
25 -
20 -'a,
2-
C 0 .,
15 "' ~ -C
Cl> 0
C
0 u
10 -
5
0+--------t---------+---'-_._------t------+-----------j
5/7/90 9/19/91 1/31/93 6/15/94 10/28/95 3/11 /97
Date
K :\04400\077\IJAT A\Wcllsum\2425 TCE
-------------------Historical PCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2425 Davis Park Road
0.35
0.3 ..
0.25 ..
-'a,
2-0.2 ..
C: 0 :;:;
lU ~ -C: Cl) 0.15 · · u
C:
0 u
0.1
0.05
O-t~>---===;========1~~-----+-<-------1-----------'
5/7/90 9/19/91 1/31/93 6/15/94 10/28/95 3/11/97
Date
K:\04400\077\DATA\Wcllsum\2425 PCE
-------------------
'§,
2-
C:
0 ·.;::
"' ~ -C: .,
()
C: 0 u
18 -
16 -
14
12
10 -
8
6
4-
2
Historical TCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2816 Davis Park Road (PW-1)
0t-------f------t--~---+------+------+-----------l
5(7/90 9/19/91 1/31/93
K:\04400\077\DAT A\Wellsum\2816 TCE
6/15/94
Date
10/28/95 3/11/97 7/24/98
-------------------Historical PCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Private Well, 2816 Davis Park Road (PW-1)
10
9·
8 ..
7
-'a, 6 2-
C:
0 :;::; 5· "" ~ -C: Q)
0 C: 4 .. 0 u
3.
2
0-t-------t-------+---~---+-------+-------+-------,
5f7l90 9/19/91 1/31/93 6/15/94 10/28/95 3/11/97 7/24/98
Date
K:\04400\077\DA T A\Wcllsurn\2816 PCE
-------------------Historical TCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Cedar Oaks Subdivision Community Well (CW-5)
60.0
50.0
40.0
~
'§,
2.
C:
0 .: 30.0 "' ~ -C: <I)
0 C: 0
(.)
20.0 -
10.0
0.0 +------+---..__---+----------,f------------t------+--------1
5/7/90 9/19/91 1/31/93
K:\04400\077\DAT A\Wdlsum\Ccdar Oaks TCE
6/15/94
Date
10/28/95 3/11/97 7/24/98
-------------------Historical PCE Concentrations in Groundwater
Davis Park Road TCE Site
Gastonia, North Carolina
Cedar Oaks Subdivision Community Well (CW-5)
25.0
20.0
'§,
2. 15.0
C:
0 . .,
" ~ -C: .,
()
C: 10.0 0 u
5.0
0.0 -j-------t---------+-'------t---------------+-------------j
5f7/90 9/19/91 1/31/93 6/15/94 10/28/95 3/11/97 7/24/98
Date
K:\04400\077\DAT A\Wcllsum\Ccdar Oaks PCE