RA-2507_15985_CA_MRP_20120110_CES GW_Report_Final

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TABLE OF CONTENTS

SIGNATURE/CERTIFICATION PAGE ................................................................................................. ii
EXECUTIVE SUMMARY ....................................................................................................................... iii
1.0 INTRODUCTION ......................................................................................................................... 1
2.0 SITE ASSESSMENT ..................................................................................................................... 1
2.1 Site Description ................................................................................................................... 1
2.2 Site History ......................................................................................................................... 4
2.3 Topography ......................................................................................................................... 4
2.4 Local Geology ..................................................................................................................... 4
2.5 Receptor Survey .................................................................................................................. 5
2.6 Hydrogeology ..................................................................................................................... 7
3.0 RISK ASSESSMENT .................................................................................................................... 8
3.1 Identification of Receptors .................................................................................................. 8
3.1.1 On-Site Receptors .................................................................................................. 8
3.1.2 Off-Site Receptors ................................................................................................. 8
3.1.3 Identification of Exposure Pathways ..................................................................... 8
3.1.3.1 Inhalation ................................................................................................. 9
3.1.3.2 Ingestion ................................................................................................... 9
3.1.3.3 Dermal Contact ......................................................................................... 9
4.0 GROUNDWATER MONITORING REPORT SUMMARY .................................................... 9

Tables
Table 1. Potential Receptor Information ............................................................................ 5
Table 2. Summary of Groundwater Elevation Data ........................................................... 7
Table 3. Summary of Calculated Purge Volumes ............................................................... 8

Figures

Figure 1. Site Location Map ................................................................................................ 2
Figure 2. Site Plan ............................................................................................................... 3
Figure 3. Potential Receptor Map ........................................................................................ 6

Appendices

Appendix A. Physical Properties of Observed Petroleum Compounds
Appendix B. Photo-documentation
Appendix C. Groundwater Quality Data
Appendix D. Laboratory Certificates of Analysis and Chain-of-Custody Documentation

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EXECUTIVE SUMMARY

Drinking wells affected

Drinking wells potentially threatened

Surface water affected

___ Surface water potentially threatened

___ Free-phase product in groundwater

Dissolved-phase concentrations present which exceed
current water quality standards

X Sump, basement, utility potentially threatened

Sump or basement affected

Utility affected

X Residual-phase contaminants present that may impact
groundwater

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1.0 INTRODUCTION

Crawford Environmental Services, Inc. (CES) has completed a Groundwater Monitoring Report
(GMR) associated with a confirmed petroleum release from the former underground storage tank (UST)
system serving the Harold’s Food Mart in Chapel Hill, North Carolina. This report, prepared in
accordance with North Carolina Department of Environment and Natural Resources (NCDENR) directive
dated November 23, 2011, as part of the State Lead Contract, is being delivered to the NCDENR Raleigh,
North Carolina office prior to January 23, 2012, the regulatory deadline for the submittal.

2.0 SITE ASSESSMENT

2.1 Site Description

The subject property is located at 117 Old Durham Road in a mixed-use area within the
jurisdictional limits of Chapel Hill, North Carolina (Figure 1). The site is improved with a one-
story masonry block building formerly serving as Harold’s Food Mart. The store currently is
operational as the R&H MiniMart convenience store. The site formerly maintained three
gasoline USTs and one kerosene UST of unknown size. The USTs were removed from the
ground in 1988. The site further is improved with asphalt parking and access areas. Old Durham
Road borders the site to the north with residences and commercial parcels, including a Hardee’s
restaurant, to the east and west. The site obtains potable water from Orange County Water
Authority located at 400 Jones Ferry Road in Carrboro, NC. A site plan depicting pertinent
features of the subject property is provided as Figure 2. A summary of the physical properties of
gasoline and kerosene, the petroleum fuels of concern at the site, are presented as Appendix A.
Photographic documentation of the subject site is included as Appendix B.

FIGURE 1

Site Location Map
Harold’s Food Mart
117 Old Durham Road
Chapel Hill, NC 27517
600 Towne Centre Blvd. Suite 305 Pineville, North Carolina 28134
704-889-0178 (office) 704-889-0179 (fax)
CHAPEL HILL, NORTH
CAROLINA

Source: Delorme Topo USA ver. 7
Scale: 1:12,000 Contour Interval: 250 Feet
Vertical Datum: National Geodetic Vertical Datum
1929
Horizontal Datum: North American Datum 1927
Project: December 2011 GMR
Latitude:
35o 56’ 38.16” N Longitude: 79o 00’ 42.26” W
Client: NCDENR
CES Job #: 16.022
Date: January 2, 2012

SITE
SITE
REVSite PlanHarold's Food Mart117 Old Durham RoadChapel Hill, North Carolina 27517Figure TitleDRAWING NUMBERBYDATEREVGroundwaterMonitoring Report600 Towne Centre Blvd. Suite 305Pineville, North Carolina 28134704-889-0178704-889-0179 (fax)Figure 2WNSELEGENDUtility PoleIN 15985Old Durham RoadS c a r le t t D r iv eResidenceFormer Harold's FoodmartAbandoned Building121Former Gasoline UST BasinFormer Kerosene UST Basin2Water LineOverhead Electric ServiceMonitoring WellMW-1Former Dispenser Area

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2.2 Site History

1988
Tank closure activities associated with the three gasoline USTs and one kerosene UST
were conducted in 1988. No soil or groundwater samples were collected during UST closure
activities.

1993:
During roadway expansion activities conducted by the North Carolina Department of
Transportation (NCDOT), approximately three feet of free-phase petroleum were observed in a
potable water supply well located northeast across Old Durham Road near the Hardee’s
Restaurant. Reportedly, there was a service station located approximately 35 feet from the
impacted water supply well. NCDOT abandoned the potable water supply well. Specific details
related to locations of the service station and water supply well are not known.

July to August 2011:
Due to the presence of residual-phase impacts observed during NCDOT road expansion
activities, NCDENR requested further investigation to evaluate the extent of petroleum impacts
and the associated potential risk to human health and the environment. Terraine, Inc. (Terraine)
installed one monitoring well (MW-1) proximal to the right-of-way of Old Durham Road to
confirm the presence or absence of dissolved- and free-phase petroleum as part of Phase I
Limited Site Assessment (LSA) activities. Subsequent soil and groundwater analyses revealed
dissolved-phase benzene, toluene, ethylbenzene, and xylenes (BTEX) concentrations in excess of
the respective soil and groundwater standards.

Terraine also completed a receptor survey to identify potential receptors located within
1,000-feet of the site. Potable water supply well WSW-1 was located approximately 450 feet
west of the site and is used only for water in the restrooms. Water supply well WSW-2 is not
active and is located approximately 370 feet south of the site. Both parcels utilize municipally-
supplied water for consumption. At the time of the receptor survey, municipal water provided by
the Orange County Water Authority was available to and utilized by parcels located within the
search radius.

2.3 Topography

The subject site is located within the jurisdictional limits of Chapel Hill, North Carolina
and is situated in Carlina Slate Belt of the Piedmont Physiographic Province. According to the
U.S. Geological Survey 7 ½ Minute Series Topographic Map of the Chapel Hill Quadrangle,
North Carolina, the site elevation is approximately 1,734 feet above mean sea level. The nearest
identified surface water body, an unnamed pond, is located approximately 1,760 feet northwest of
the site.

2.4 Local Geology

CES reviewed the Geologic Map of North Carolina prepared by the Department of
Natural Resources and Community Development, dated 1985. Published geologic information
indicates that local geologic structures primarily comprise the boundary area of Metamorphosed
Granitic Rock.

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Megacrystal, well-foliated, locally contains hornblende; Vance County suite and
Buckhorn granite.

The above descriptions were extracted from the Geologic Map of North Carolina
prepared by the Department of Natural Resources and Community Development, dated 1985.

2.5 Receptor Survey

On November 30, 2011, CES performed an updated site reconnaissance to confirm the
presence or absence of potential receptors located within a 1,000-foot radius of the subject
property. CES confirmed the identity of two potential receptors located within the 1,000-foot
search radius. Visual inspections were performed at the properties for evidence indicating the
presence of supply wells/springs. The approximate locations of the potential receptors are
presented on Figure 3. Table 1 is a summary of the potential receptors including property
owner/occupant, address, water usage, and the estimated distance/direction from the source area
corresponding to the locations presented on Figure 3.

Table 1.

Potential Receptor Information
Harold’s Food Mart
Incident Number: 15985
1Full mailing address is: (address given), Chapel Hill, North Carolina 28717, unless noted otherwise.

Well
Identification
Parcel
Identification
Property
Owner(s) Property Address Owner Address
Estimated
Distance &
Direction from
Source
Usage
WSW-1 9799680313 Michael L.
Wilson
1720 Old
Durham Road
1720 Old
Durham Road 450 feet West Potable Water;
Sinks and toilets
WSW-2 9799685507 Bates C.
Buckner
107 Scarlett
Drive
107 Scarlett
Drive 370 feet South Inactive

FIGURE 3

Potential Receptor Map
Harold’s Food Mart
117 Old Durham Road
Chapel Hill, North Carolina 27517
600 Towne Centre Blvd. Suite 305
Pineville, North Carolina 28134

704-889-0178 (office) 704-889-0179 (fax)

CHAPEL HILL, NORTH
CAROLINA

Source: Google, Inc.
Imagery Date: 07/10/2010
Latitude: 35o 56’ 38.16” N
Longitude: 79o 00’ 42.26” W
Project: December 2011
GMR

Client: NCDENR
CES Job #: 16.022
Date: January 11, 2012
SITE WSW-1
WSW-2

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2.6 Hydrogeology

In accordance with NCDENR directives, CES performed a groundwater monitoring event
on November 30, 2011 to assess current dissolved-phase contaminant levels and free-product
thicknesses. CES collected a groundwater sample from monitoring well MW-1 and from the
water supply well WSW-1. Prior to purging and sampling the monitoring well, a Heron
InstrumentsTM H.01L interface probe was used to record the static water level and to investigate
for the presence of free-phase petroleum in the monitoring points. CES recorded the static water
level using the interface probe from a reference mark scribed at the top of the well casing. CES
also collected a groundwater sample from potable supply well WSW-1 from an interior faucet
located in the restroom. Groundwater elevation data is presented in Table 2. Groundwater flow
direction could not be determined due to the limited amount of data collection associated with
this investigation. Based on a review of locally mapped contours, shallow groundwater flow at
the site likely is a function of the topographic gradient flowing towards the south.

Table 2.

Groundwater Elevation Data
Harold’s Food Mart
Incident Number: 15985
Elevations measured by CES on November 30, 2011, relative to the site elevation of 1,734.00 feet.

Prior to sampling, CES purged the well to remove suspended solid material from the water
column and to collect a sample representative of aquifer conditions. Monitoring well MW-1 was purged
until a minimum of three well volumes had been displaced. The interior faucet located in the restroom of
the subject facility was purged for approximately 10 minutes prior to collection of supply well sample
WSW-1. The groundwater sample from monitoring well MW-1 was collected using a dedicated,
disposable, HDPE bailer and was transferred directly into the appropriate sample containers immediately
upon collection. Disposable, nitrile gloves were used during all phases of sample collection. The
groundwater samples were labeled and maintained on ice pending delivery to an independent laboratory.
The supply well and monitoring well samples were submitted to Prism Laboratories, Inc. (Prism) in
Charlotte, North Carolina for volatile organic compounds (VOCs), methyl tert butyl ether (MTBE), and
diisopropyl ether via Standard Method (SM) 6200B and 1,2-dibromoethane (EDB) via SM 504.1. Strict
sample security and chain-of-custody documentation were maintained during all phases of transport. A
summary of the calculated purge volumes is presented in Table 3. A summary of current and historic
groundwater quality data is presented in Appendix C. Chain-of-custody documentation and the
laboratory Certificates of Analyses are included as Appendix D.

Well
Identification
Top of Casing
(feet)
Total Depth
(feet)
Date
Measured
Depth to
Water (feet)
Depth to Free
Product (feet)
Free-Product
Thickness
(feet)
Relative
Groundwater
Elevation
(feet)
MW-1 1,734.00 55.0 8/3/2011 48.68 NA1 1685.32
11/30/2011 28.13 NA 1705.87

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Table 3.

Summary of Calculated Purge Volumes
Harold’s Food Mart
Incident Number: 15985
NA – Not applicable

3.0 RISK ASSESSMENT

CES performed a risk assessment to evaluate the potential risk to human health and the
environment associated with the petroleum compounds detected at the site. The findings of the risk
assessment are presented in the following sections.

3.1 Identification of Receptors

The following sections present the potential on- and off-site receptors of petroleum
contaminants existing on-site, and the possible pathways of exposure.

3.1.1 On-Site Receptors

The subject property is served potable water by a municipal water line located
north of Old Durham Road. CES identified multiple underground utilities on-site and
within the surrounding area. The confirmed absence of dissolved-phase impacts likely
mitigates concern associated with subgrade utilities serving as preferential migration
conduits.

3.1.2 Off-Site Receptors

The receptor survey performed during GMR and site reconnaissance activities
confirmed the presence of two water supply wells located within the 1,000-foot search
radius. Groundwater analysis performed on the sample collected from water supply
WSW-1 yielded petroleum compounds in excess of the respective laboratory method
detection limits.

Based on topographic information, the nearest potential surface water receptor to
the migration of dissolved-phase contaminants is an unnamed pond located
approximately 1,760 feet northwest of the subject site.

3.1.3 Identification of Exposure Pathways

The identification of potential exposure pathways is necessary to evaluate the
risk posed by the extent of the release. An exposure pathway requires that there be some
mechanism for any person or population to come into contact with one or more of the
media which contain the contaminant of concern. No risk is assumed in the absence of
contamination or in the absence of an exposure pathway.
Well
Identification Date
Depth to
Product
(feet)
Depth
to
Water
(feet)
Amount
of
Product
(feet)
Total
Well
Depth
(feet)
Water
Column
(feet)
Well
Diameter
(inches)
Conversion
Factor
(gallons/feet)
Volume
Purged
(gallons)
MW-1 11/30/2011 NA1 28.13 NA 55.0 26.87 2.0 0.163 13.14

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3.1.3.1 Inhalation

The presence of asphalt and compacted gravel surface coverings in the
immediate vicinity of the UST basins and product lines mitigate concern
associated with potential exposure to VOC vapors emanating from the
subsurface. The surrounding area consists of residential and business parcels.

3.1.3.2 Ingestion

The presence of on- and off-site water supply wells could serve as
potential exposure pathways to petroleum-impacted groundwater.

3.1.3.3 Dermal Contact

The UST basins and product lines are covered with asphalt mitigating
concern associated with inadvertent contact with adsorbed-phase contaminants.

4.0 GROUNDWATER MONITORING REPORT SUMMARY

Laboratory analyses performed on the groundwater samples collected during this investigation
yielded measurable levels of dissolved-phase MTBE and IPE above the laboratory method detection
limits in potable water supply well WSW-1. The NCDENR Incident Manager was informed of the
compound detections from water supply well WSW-1 on December 15, 2011. Dissolved-phase
petroleum constituents were not measured above the respective laboratory method detection limits in the
groundwater sample collected from monitoring well MW-1 CES’ review of historical data does not
suggest increasing concentrations of dissolved petroleum compounds in monitoring well MW-1. CES
concludes that current observed site conditions indicate the continued dissolution of petroleum in local
groundwater; however, CES was unable to discern whether the impacts in water supply well WSW-1 are
associated with petroleum activities from the subject property. As such, CES recommends a historical
investigation be conducted to determine the presence/absence of potential release incidents in the vicinity
of the site. Water supply well WSW-1 also should be slated for sampling in the next quarter. This
report, prepared in accordance with NCDENR correspondence dated November 23, 2011, is being
delivered to Mr. Mark Petermann of the Raleigh, North Carolina NCDENR office.

APPENDIX A

Physical Properties
of
Observed Petroleum Compounds

Summary of Physical Properties of Gasoline

Composition: Complex combination of hydrocarbons (C-4
through C-12). Benzene content typically from 0.5% to 2.5%.
May contain up to 10% of various oxygenated hydrocarbons,
such as aliphatic alcohols and ethers.

Specific Gravity (H2O = 1): 0.72 - 0.76
Percent Volatile by Volume: 100%
Evaporation Rate: 10-11
Vapor Density: (air = 1) Approximately 3.5 Toxicity Data: A poison by inhalation. Repeated or
prolonged dermal contact causes dermatitis, can cause
blistering. Inhalation causes respiratory depression.
Aspiration can cause severe pneumonitis. Can cause
hyperemia of the conjunctiva and other disturbances of
the eyes.

Vapor Pressure: 7.0 to 14.5 psi (RVP)
Flashpoint: -40o F

Viscosity: 0.37 - 0.44 centipoise @ 60o F
Solubility in Water: Negligible Appearance and Odor: Clear liquid, aromatic
hydrocarbon odor.
Boiling Point: 100 to 425 oF (approx)
Source: Material Safety Data Sheet for Gasoline.

Summary of Physical Properties of Kerosene

Composition: Kerosene is a complex mixture of hydrocarbons
from a variety of chemical processes blended to meet
standardized product specifications. Composition varies
greatly and includes C-9 through C-16 hydrocarbons with a
boiling range of about 160-300 degrees Celsius.
Specific Gravity (H2O = 1): 0.82 - 0.85
Percent Volatile by Volume: Not Analyzed
Evaporation Rate: Not Analyzed
Vapor Density: (air = 1) Approximately 4.5 Toxicity Data: The major effect of exposure to this
product is headache, drowsiness, irritation of the eyes
and nose, and lungs. Target organs include the
respiratory system, nervous system, and mucous
membranes.
Vapor Pressure: > 8 mm Hg @ 38oC
Flashpoint: >100o F
Viscosity: 1.0-1.9 cSt @ 40o C
Solubility in Water: Insoluble Appearance and Odor: Colorless to pale straw, or red
oily liquid with characteristic odor. Boiling Point: 280 to 574 oF (approx)
Source: Material Safety Data Sheet for Kerosene.

APPENDIX B

Photo-Documentation

Groundwater Monitoring Report – December 2011
Harold’s Food Mart
117 Old Durham Road
Chapel Hill, North Carolina 27517
Incident Number: 15985
Page 1

Harold’s Food Mart # 1 Harold’s Food Mart # 2

Facing south toward site building. Facing southwest toward site building and solid waste
receptacles.

Harold’s Food Mart # 3

Property served potable water from WSW-1.

APPENDIX C

Groundwater Quality Data

Table 4Groundwater Quality DataHarold's Food MartIncident Number 15985Well IdentificationSample DateBenzene1TolueneEthylbenzeneXylenes (Total)MTBEIPEEDB2NaphthaleneBis(2-Ethylhexl)phtTetrachloroethylenC5-C8 AliphaticsC9-C18 AliphaticsC19-C36 AliphaticsC9-C22 AromaticsLead8/3/2011ND3ND ND ND ND ND ND ND110.65 8.7 J ND ND ND5211/30/2011 ND ND ND ND ND ND ND NDNA4ND NA NA NA NA NAWSW-1 11/30/2011 ND ND ND ND 2.1 0.87 ND ND NA ND NA NA NA NA NA1 600 600 500 20 70 0.02 6 3 0.7 40070010000 200 155,000 260,000 84,500 85,500 20,000 70,000 50 6,000 170 700 NENENE NE 15,0005 Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit.3 Non-detect4 Not AnalyzedGross Contamination Level (GCL)15A NCAC 2L .0202 (2L) StandardMW-11 VOCs, MTBE, & IPE analysis via Standard Me2 EDB analysis via Standard Method 504.1; repo

APPENDIX D

Laboratory Certificates of Analysis
and
Chain-of-Custody Documentation

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