HomeMy WebLinkAboutWA-1034_12709_CA_RPTS_20140722
July 22, 2014
Ms. Rose Ballance
NCDENR Washington Regional Office
Division of Waste Management, UST Section
943 Washington Square Mall
Washington, North Carolina 27889
Subject: GROUNDWATER MONITORING REPORT
ETHERIDGE OIL & GAS COMPANY
34970 US HIGHWAY 264
ENGELHARD, HYDE COUNTY, NORTH CAROLINA
INCIDENT NO. 12709
MID-ATLANTIC JOB NO.: 000R2394.02
Dear Ms. Ballance:
On behalf of Etheridge Oil & Gas Company, Mid-Atlantic Associates, Inc. submits the
enclosed Groundwater Monitoring Report for the above-referenced site. If you have any
questions, please contact me at (919) 250-9918.
Sincerely,
MID-ATLANTIC ASSOCIATES, INC.
Charles B. Hoffman, P.G.
Project Geologist
pc: Mr. T.J. Etheridge, Jr. – Etheridge Oil & Gas Company
July 22, 2014
Mr. T.J. Etheridge, Jr.
Etheridge Oil & Gas Company, Inc.
Post Office Box 65
Engelhard, North Carolina 27824
Subject: GROUNDWATER MONITORING REPORT
ETHERIDGE OIL & GAS COMPANY
34970 US HIGHWAY 264
ENGELHARD, HYDE COUNTY, NORTH CAROLINA
INCIDENT NO. 12709
MID-ATLANTIC JOB NO.: 000R2394.02
Dear Mr. Etheridge:
Mid-Atlantic Associates, Inc. (Mid-Atlantic) is pleased to present this report of
environmental services performed at the above-referenced site. The purpose of our
services, as described in the attached report, was to perform groundwater monitoring at
the above-referenced site, as requested in NCDENR’s Notice of Regulatory
Requirements (NORR) dated November 8, 2013.
As requested, a copy of this report has been sent to the North Carolina Department of
Environment and Natural Resources, Washington Regional Office, UST Section. We
appreciate the opportunity to provide environmental services to Etheridge Oil & Gas
Company and look forward to assisting you through project completion. Please contact us
at 800-486-7568 if any questions arise or if we may be of further service.
Sincerely,
MID-ATLANTIC ASSOCIATES, INC.
Charles B. Hoffman, P.G.
Project Geologist
GROUNDWATER MONITORING REPORT
ETHERIDGE OIL AND GAS COMPANY
34970 US HIGHWAY 264
ENGELHARD, HYDE COUNTY, NORTH CAROLINA
INCIDENT NO. 12709
Risk Classification: Intermediate
Ranking: I-140-D
Prepared For:
Mr. T.J. Etheridge, Jr.
Etheridge Oil & Gas Company
Post Office Box 65
Engelhard, North Carolina 27824
(252) 925-4301
Prepared By:
Mid-Atlantic Associates, Inc.
409 Rogers View Court
Raleigh, North Carolina 27610
(919) 250-9918
July 22, 2014
TABLE OF CONTENTS
1.0 INTRODUCTION ..................................................................................................... 1
2.0 BACKGROUND ...................................................................................................... 1
3.0 POTENTIAL RECEPTORS ..................................................................................... 2
4.0 FIELD ACTIVITIES ................................................................................................. 3
4.1 Liqujid Level Measurements .......................................................................... 3
4.2 Monitoring Well Sample Collection ................................................................ 3
5.0 DISCUSSION OF SAMPLING RESULTS .............................................................. 3
5.1 Free Product Thickness ................................................................................. 3
5.2 Summary of Analytical Results ...................................................................... 3
5.3 Description of Current Plume Size and Location ........................................... 4
5.4 Additional Monitoring Information .................................................................. 4
6.0 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS ................................... 5
DRAWINGS
Drawing 1.1 Topographic Site Map
Drawing 2.1 Site and Monitoring Well Location Map
Drawing 5.1 Estimated Benzene in Groundwater Isoconcentration Map –
May 20, 2014
Drawing 5.2 Estimated MTBE in Groundwater Isoconcentration Map –
May 20, 2014
Drawing 5.3 Estimated Water Table Contour Map – May 20, 2014
TABLES
Table 4.1 Monitoring Well Construction Data
Table 4.2 Groundwater Elevation Data
Table 5.1 Summary of Historical Groundwater Quality Data for Selected
Compounds
TABLE OF CONTENTS (CONTINUED)
APPENDICES
Appendix A Notice of Regulatory Requirements
Appendix B Mid-Atlantic Field Procedures
Appendix C Laboratory Analytical Report and Chain-of-Custody Record for
Groundwater Samples
Appendix D Hydraulic Gradient Determination
1.0 INTRODUCTION
Mid-Atlantic Associates, Inc. (Mid-Atlantic) has performed groundwater monitoring
activities at the Etheridge Oil and Gas Company facility located at 34970 US Highway 264
in Engelhard, North Carolina (Drawing 1.1). This work was completed under Trust Fund
Pre-Approval Task Authorization Number 12709-13.
2.0 BACKGROUND
The subject site is the Etheridge Oil and Gas Company facility (also referred to as the
Ethco Service Station) located at 34970 US Highway 264 in Engelhard, North Carolina.
The site is currently in use as a convenience store and retail petroleum dispensing facility,
which operates one 8,000-gallon gasoline underground storage tank (UST) and one
4,000-gallon gasoline UST. According to information provided in previous reports and
regulatory databases, the site historically operated one 1,000-gallon diesel fuel UST, one
1,000-gallon gasoline UST and two 2,000-gallon gasoline USTs, which were reportedly
removed from the site in June 1994. The layout of the subject site, along with the
approximate locations of the current and former UST basins, are shown on Drawing 2.1.
Based on available information, a petroleum release was reported to the North Carolina
Department of Environment and Natural Resources (NCDENR) following removal of the
former UST system from the site in 1994. As a result, a Limited Site Assessment (LSA)
and Comprehensive Site Assessment (CSA) were conducted for the release in 1998 and
1999, respectively. During these activities, a total of 12 monitoring wells (MW-1 through
MW-5, MWD-6, MW-7 through MW-9 and MW-11 through MW-13) were installed at the
site (Note: no information was available for monitoring well MW-10). Based on the results
of the LSA, the site was assigned an intermediate risk classification (I-140-D) due to the
presence of surface water within 500 feet of the release area. Therefore, the cleanup
standards for groundwater at the site will be ten times the North Carolina Surface Water
Quality Standards (NCSWS) and/or EPA National Water Quality Criteria, as identified in
NCDENR’s NC and EPA Criteria Table updated on May 15, 2013.
According to the NCDENR, a Corrective Action Plan was approved for the site in April
2001 and implemented in March 2003. The approved CAP reportedly included monitored
natural attenuation combined with extraction events for the site. An Aggressive Fluid-
Vapor Recovery event was conducted at the site in August 2013, and the site monitoring
wells were last sampled in September 2013. The results of the September 2013 sampling
event indicated that four of the wells (MW-1, MW-2, MW-7 and RW-1) exhibited target
compounds at concentrations exceeding ten times the NCSWS and/or EPA National
Water Quality Criteria (cleanup goals for the site). Based on these results, NCDENR
issued a Notice of Regulatory Requirements (NORR) dated November 8, 2012
(Appendix A), which requested the performance of a groundwater sampling event at
the site in May 2014.
Groundwater Monitoring Report July 22, 2014
Etheridge Oil & Gas Company Page 2
Engelhard, North Carolina
This report documents groundwater monitoring activities performed at the site in
accordance with the November 8, 2013 NORR and Trust Fund Pre-Approval Task
Authorization 12709-13. The opinions included herein are based on our experience and
the information obtained during the study. This report is based on limited observations
made on the dates noted using the procedures described herein. If additional information
becomes available, we request the opportunity to review the information, reassess the
potential environmental concerns and modify our conclusions, if appropriate.
3.0 POTENTIAL RECEPTORS
Receptor information pertaining to this site is summarized in the Ground Water Monitoring
Report, Update Receptor Survey and Free Product Recovery Report prepared by
Geological Resources, Inc. (GRI) and dated April 28, 2010. The site is currently
classified as “intermediate” risk due to the presence of nearby surface waters. A brief
summary of potential receptors, as identified in the GRI report, is summarized below.
Water-Supply Wells
GRI personnel conducted an updated receptor survey on April 28, 2010. Based on the
results, GRI reported no active, potable water-supply wells within a 1,000-foot radius of
the subject site.
Public Water Supplies
The GRI report indicated that municipal water is available to the site and surrounding
properties.
Surface Water
According to the GRI report, the closest surface water body to the site is Far Creek,
located approximately 75 feet to the north, west and northeast of the site. In addition, an
on-site ditch (the depth of which appears to be beneath the water table) also runs along
the north and east property boundaries of the subject site.
According to Classifications and Water Quality Standards Assigned to the Waters of the
Tar-Pamlico River Basin, the portion of Far Creek from its source to US Highway 264 is
classified as Class C, Swamp Waters. A Class C Water is defined as waters protected
for uses such as secondary recreation, fishing, wildlife, fish consumption, aquatic life
including propagation, survival and maintenance of biological integrity, and agriculture.
Groundwater Monitoring Report July 22, 2014
Etheridge Oil & Gas Company Page 3
Engelhard, North Carolina
4.0 FIELD ACTIVITIES
4.1 Liquid Level Measurements
On May 20, 2014, Mid-Atlantic measured the depth to water in site monitoring wells with
an electronic water level indicator and/or oil/water interface probe using the methods
outlined in Appendix B. Monitoring well construction data is summarized in Table 4.1 and
a summary of liquid level measurements from the May 2014 sampling event is provided in
Table 4.2.
4.2 Monitoring Well Sample Collection
On May 20, 2014, Mid-Atlantic personnel collected groundwater samples from recovery
well RW-1 and monitoring wells MW-1 through MW-5, MWD-6, MW-7 through MW-9 and
MW-11 through MW-13. Groundwater samples were collected using the procedures
described in Appendix B. The samples were decanted into pre-labeled, laboratory-
supplied glassware, packed into an ice-filled cooler and shipped under chain-of-custody
to Con-Test Analytical Laboratories, Inc. in East Longmeadow, Massachusetts.
Samples were analyzed by methods shown on the chain-of-custody record provided in
Appendix C.
5.0 DISCUSSION OF SAMPLING RESULTS
5.1 Free Product Thickness
Free product was not detected in site monitoring wells during the May 2014 groundwater
sampling event. Please note that based on the shallow water table, the static water level
elevations of the site monitoring wells appear to be above the screened intervals of these
wells. Therefore, although there is no direct evidence to suggest that free product is
present at the site, there is a potential that free product remains on the water table above
the screened interval for the site wells. Monitoring well construction information and
depth-to-groundwater measurements are summarized in Table 4.1.
5.2 Summary of Analytical Results
The laboratory analytical report and chain-of-custody record for groundwater samples
collected in May 2014 are provided in Appendix C and summarized in Table 5.1, which
also includes historical groundwater sampling results. As summarized, samples collected
from several on-site monitoring wells exhibited target compounds exceeding their
respective North Carolina Groundwater Quality Standards (NCGQS). The samples
collected from monitoring wells MW-1, MW-2, MW-7 and recovery well RW-1 also
Groundwater Monitoring Report July 22, 2014
Etheridge Oil & Gas Company Page 4
Engelhard, North Carolina
exhibited target compounds at concentrations exceeding ten times the NCSWS and/or
EPA National Water Quality Criteria, as identified in NCDENR’s NC and EPA Criteria
Table updated on May 15, 2013. When compared with results from the most recent
groundwater sampling event (September 2013), contaminant concentrations appear to
have generally exhibited an overall decrease. Historical sampling results indicate that
groundwater contaminant concentrations appear to have fluctuated at the site over time.
5.3 Description of Current Plume Size and Location
Isoconcentration maps for benzene and MTBE in shallow groundwater are provided as
Drawings 5.1 and 5.2, respectively. The extent of the dissolved-phase groundwater
contaminant plume appears to be defined to ten times the NCSWS and/or EPA National
Water Quality Criteria within the existing monitoring well network; however, based on the
apparent depth of the northern adjacent ditch and depth-to-groundwater measurements
within the site monitoring wells, groundwater appears to be discharging to this adjacent
surface water body. Therefore, the extent of potential surface water contamination to the
north of the release area appears to remain undetermined at this time.
5.4 Additional Monitoring Information
• Proximity of Plume to Nearest Receptor
During the receptor survey update conducted by GRI in 2010, several water-supply
wells were identified within 1,500 feet of the source area of the release; however,
based on the information provided in the GRI report, the wells appear to no longer
be in use. As previously stated, groundwater at the site appears to be discharging
into the northern adjacent ditch/surface water body.
• Estimated Groundwater Flow Direction
Based on data from the May 2014 monitoring event, groundwater flow at the site
appears to be generally toward the west with a hydraulic gradient (measured
from MW-9 towards MW-3) of approximately 0.0023 ft/ft. This groundwater flow
direction appears to be consistent with historical determinations.
An Estimated Water Table Contour Map is provided as Drawing 5.3. Water level
measurements and groundwater elevations are provided in Table 4.2. Hydraulic
gradient was calculated using the procedure discussed in Appendix D.
Groundwater Monitoring Report July 22, 2014
Etheridge Oil & Gas Company Page 5
Engelhard, North Carolina
6.0 SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS
Based on the monitoring event activities and laboratory analytical results, Mid-Atlantic has
determined the following:
• Free product was not detected at the site. Please note that based on the shallow
water table, the static water level elevations of the site monitoring wells are above
the screened intervals of these wells;
• Samples collected from several of the site monitoring wells exhibited petroleum
fuel-related compounds exceeding the NCGQS;
• Samples collected from monitoring wells MW-1, MW-2, MW-7 and recovery well
RW-1 exhibited petroleum fuel-related compounds exceeding ten times the
NCSWS and/or EPA National Water Quality Criteria (site cleanup goals); and
• The extent of the dissolved-phase groundwater contaminant plume appears to be
defined to ten times the NCSWS and/or EPA National Water Quality Criteria;
however, based on the apparent depth of the northern adjacent ditch and depth-to-
water measurements within the site monitoring wells, groundwater appears to be
discharging to the adjacent ditch. The potential surface water impacts associated
with the release have not been assessed at this time.
Based on these results, Mid-Atlantic recommends the following:
• Sampling of the adjacent surface water body to help determine the extent of
contamination and potential surface water impacts associated with the release;
and
• Submittal of this report to the NCDENR UST Section.
DRAWINGS
TABLES
MW-1 2 10/25/1994 13.0 3.0 - 13.0 2.31MW-2 2 10/25/1994 13.0 3.0 - 13.0 1.82MW-3 2 10/25/1994 13.0 3.0 - 13.0 1.96MW-4 2 6/17/1998 9.0 4.0 - 9.0 1.76MW-5 2 6/17/1998 15.0 5.0 - 15.0 1.38MWD-6 4 / 2 6/18/1998 35.0 30.0 - 35.0 2.24MW-7 2 10/19/1998 15.0 5.0 - 15.0 1.28MW-8 2 10/19/1998 15.0 5.0 - 15.0 1.51MW-9 2 10/19/1998 15.0 5.0 - 15.0 1.66MW-11 2 8/23/1999 7.5 2.5 - 7.5 0.12MW-12 2 8/23/1999 15.0 5.0 - 15.0 1.83MW-13 2 8/23/1999 15.0 5.0 - 15.0 2.02Notes:.BTOC - Below Top of CasingShaded values indicate depth-to-water elevation above screened interval of wellSCREENED INTERVAL (FEET)DEPTH-TO-GROUNDWATER - MAY 2014 (FEET BTOC)TABLE 4.1MONITORING WELL CONSTRUCTION DATAETHERIDGE OIL & GAS COMPANYENGELHARD, NORTH CAROLINAMID-ATLANTIC JOB NO. 000R2394.02WELL I.D.WELL DIAMETER (INCHES)INSTALLATION DATETOTAL WELL DEPTH (FEET)
WELL NUMBER DATE TOC (ft) DTP (ft)
FP THICKNESS
(ft)
DTW (ft),
BTOC SWLE (ft)
RW-1 05/20/14 NS -- 0.00 2.95 NS
MW-1 05/20/14 100.57 -- 0.00 2.31 98.26
MW-2 05/20/14 100.00 -- 0.00 1.82 98.18
MW-3 05/20/14 99.85 -- 0.00 1.96 97.89
MW-4 05/20/14 99.82 -- 0.00 1.76 98.06
MW-5 05/20/14 99.36 -- 0.00 1.38 97.98
MWD-6 05/20/14 100.20 -- 0.00 2.24 97.96
MW-7 05/20/14 99.39 -- 0.00 1.28 98.11
MW-8 05/20/14 99.71 -- 0.00 1.51 98.20
MW-9 05/20/14 99.91 -- 0.00 1.66 98.25
MW-11 05/20/14 NS -- 0.00 0.12 NS
MW-12 05/20/14 NS -- 0.00 1.83 NS
MW-13 05/20/14 NS -- 0.00 2.02 NS
Notes and Abbreviations:
2. Measuring point is top of well (TOC) casing unless otherwise noted.
NS - Well Not Surveyed
DTP - Depth-to-Free Product in feet
DTW - Depth-to-Water in feet
SWLE - Static Water Elevation in feet
1. All elevations shown relative to site benchmark (well casing rim for MW-2) - Assumed
datum 100.00 feet.
BTOC - Below Top of Casing (TOC)
TABLE 4.2
GROUNDWATER ELEVATION DATA
ETHERIDGE OIL & GAS COMPANY
ENGLEHARD, NORTH CAROLINA
MID-ATLANTIC JOB NO. 000R2394.02
5,00084,500260,00085,50070,00020,0006,000NLNLNL15,0005109701104,500NL15,00012014,000NLNL2501600600500702064007002001504/28/10 NS NS NS NS NS NS NS NS NS NS NS09/06/12 NS NS NS NS NS NS NS NS NS NS NS09/03/132,3006.5 J 22 J 93 2987ND / NA NA NA NA NA05/20/142,50012 22 84 J 2173ND / NA NA NA NA NA04/28/101,420 5,440 2,390 16,800NA ND1,580 / 798 9,760ND9,940NA09/06/121,600 2,600 760 4,300ND20 650 / 190NA NA NA NA09/03/132,200 1,6004504,280ND65 430 / 380NA NA NA NA05/20/14740 1,3002102,830ND 9.5 J420 / NA NA NA NA NA04/28/101,5204.08 3.83 6.72 NA84.0ND / 0.907 J842ND ND NA09/06/123,60011 10 43 23270.81 J / ND NA NA NA NA09/03/132,0007.0 J 6.5 J 18 J 17 J570ND / ND NA NA NA NA05/20/141,4003.8 J 5.2 21 J 5.330ND / NA NA NA NA NA04/28/10 ND ND ND ND NA 2.03 ND / ND ND ND ND NA09/06/12 ND ND ND ND ND 3.6 ND / ND NA NA NA NA09/03/13 ND ND ND ND 0.22 J 2.9 ND / NA NA NA NA NA05/20/14 ND ND ND ND ND 2.0 ND / NA NA NA NA NA04/28/10 ND ND ND ND NA22.9ND / ND ND ND ND NA09/06/12 ND ND ND ND ND 18 ND / ND NA NA NA NA09/03/13 ND ND ND ND ND 15 ND / NA NA NA NA NA05/20/14 ND ND ND ND ND 6.1 ND / NA NA NA NA NAMW-4MW-3MW-2MW-1Well NumberSample DateTotal XylenesDiisopropyl ether (DIPE)NCGQS10X SWSGCLRW-1Benzene TABLE 5.1SUMMARY OF HISTORICAL GROUNDWATER QUALITY DATA FOR SELECTED COMPOUNDSETHERIDGE OIL AND GAS COMPANYENGLEHARD, NORTH CAROLINAMID-ATLANTIC PROJECT NO. 000R2394.02Ethyl-benzene TolueneMTBE NaphthaleneC5-C8 AliphaticsLead C9-C18 AliphaticsC9-C22 AromaticsPage 1 of 3
5,00084,500260,00085,50070,00020,0006,000NLNLNL15,0005109701104,500NL15,00012014,000NLNL25016006005007020640070020015Well NumberSample DateTotal XylenesDiisopropyl ether (DIPE)NCGQS10X SWSGCLBenzene TABLE 5.1SUMMARY OF HISTORICAL GROUNDWATER QUALITY DATA FOR SELECTED COMPOUNDSETHERIDGE OIL AND GAS COMPANYENGLEHARD, NORTH CAROLINAMID-ATLANTIC PROJECT NO. 000R2394.02Ethyl-benzene TolueneMTBE NaphthaleneC5-C8 AliphaticsLead C9-C18 AliphaticsC9-C22 Aromatics04/28/10 ND ND ND ND NA 22.4 ND / ND ND ND ND NA09/06/12 ND ND ND ND 2.7 5.2 ND / ND NA NA NA NA09/03/13 ND ND ND ND 3.9 15 ND / NA NA NA NA NA05/20/14 ND ND ND ND 4.323ND / NA NA NA NA NA04/28/10 ND ND ND ND NA 6.48 ND / ND ND ND ND NA09/06/12 ND ND ND ND ND83ND / ND NA NA NA NA09/03/13 ND ND ND ND ND36ND / NA NA NA NA NA05/20/14 ND ND ND ND ND71ND / NA NA NA NA NA04/28/103,550 77947.2 173 NA2,220 63.8 / 36.2 2,690196 199 NA09/06/121,80063 12 91100 9,900 23 / 14NA NA NA NA09/03/133,100 1,200 5,200 5,90068 J4,800ND / 100NA NA NA NA05/20/141,900 660 930 2,280463,100ND / NA NA NA NA NA04/28/10 ND ND ND ND NA 19.6 ND / ND ND ND ND NA09/06/12 ND ND ND ND ND 12 ND / ND NA NA NA NA09/03/13 ND ND ND ND ND140ND / NA NA NA NA NA05/20/14 ND ND ND ND ND58ND / NA04/28/10262.92 1.57 16.2 NA 8.46156 / 55.3276 ND410NA09/06/12212.5 1.7 12 1.3 8.3160 / 70NA NA NA NA09/03/13132.0 1.4 9.3 0.90 J 7.078 / NA NA NA NA NA05/20/147.81.6 J 1.2 J 7.0 J ND 5.762 / NA NA NA NA NAMWD-6MW-5MW-9MW-8MW-7Page 2 of 3
5,00084,500260,00085,50070,00020,0006,000NLNLNL15,0005109701104,500NL15,00012014,000NLNL25016006005007020640070020015Well NumberSample DateTotal XylenesDiisopropyl ether (DIPE)NCGQS10X SWSGCLBenzene TABLE 5.1SUMMARY OF HISTORICAL GROUNDWATER QUALITY DATA FOR SELECTED COMPOUNDSETHERIDGE OIL AND GAS COMPANYENGLEHARD, NORTH CAROLINAMID-ATLANTIC PROJECT NO. 000R2394.02Ethyl-benzene TolueneMTBE NaphthaleneC5-C8 AliphaticsLead C9-C18 AliphaticsC9-C22 Aromatics04/28/10 ND ND ND ND NA37.2ND / ND ND ND ND NA09/06/12 ND ND ND ND ND432.0 / ND NA NA NA NA09/03/13 ND ND ND ND ND32ND / NA NA NA NA NA05/20/14 ND ND ND ND ND 18 ND / NA NA NA NA NA04/28/10 ND ND ND ND NA ND ND / ND ND ND ND NA09/06/12 NS NS NS NS NS NS NS NS NS NS NS09/03/13 ND ND ND ND ND ND ND / NA NA NA NA NA05/20/14 ND ND ND ND ND ND ND / NA NA NA NA NA04/28/10 ND ND ND ND NA ND ND / ND ND ND ND NA09/06/12 ND ND ND ND ND ND ND / ND NA NA NA NA09/03/13 ND ND ND ND ND ND ND / NA NA NA NA NA05/20/14 ND ND ND ND ND ND ND / NA NA N N NANotes: All concentrations reported in ug/L - micrograms per literBold values exceed NCGQSMTBE - Methyl tertiary-butyl etherShaded cells exceed 10X SWSNCGQS - North Carolina Groundwater Quality Standards430 / 380 Naphthalene results from EPA 6200B / 625 Methods10X SWS - Ten times 2B NC Surface Water Quality Standards and/or EPA National Qater Quality Criteria NA - Not analyzed for this compoundND - Not detected at or above laboratory's practical quantitation limitJ - Estimated concentrationMW-13MW-12MW-11Page 3 of 3
APPENDIX A
NOTICE OF REGULATORY REQUIREMENTS
APPENDIX B
MID-ATLANTIC FIELD PROCEDURES
APPENDIX C
LABORATORY ANALYTICAL REPORT
AND CHAIN-OF-CUSTODY RECORD
FOR GROUNDWATER SAMPLES
APPENDIX D
HYDRAULIC GRADIENT DETERMINATION