23022_Chapel Hill Police Property_HHERA_20210506

Terra Science &Engineering Consultants
syn511 Keisler Dr # 102, Cary, NC 27518 1919.858.9898
HUMAN HEALTH AND ECOLOGICAL RISK
ASSESSMENT REPORT
828 MARTIN LUTHER KING, JR. BOULEVARD PROPERTY
CHAPEL HILL, NORTH CAROLINA
MAY 6, 2021
PREPARED FOR:
TOWN OF CHAPEL HILL
CHAPEL HILL, NORTH CAROLINA
PREPARED BY:
SYNTERRA CORPORATION
CARY, NORTH CAROLINA
Kevin P. Kelt, G.I.T.
Project Geologist
David L. Duncklee, P.G.
Senior Hydrogeologist
Kenneth Rudo, Ph. D
Toxicologist

Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
EXECUTIVE SUMMARY
As requested by the Town of Chapel Hill (the Town), Duncklee & Dunham, P.C.
(Duncklee & Dunham), now part of SynTerra Corporation (SynTerra), prepared this
Human Health and Ecological Risk Assessment (HHERA) report regarding the
property located at 828 Martin Luther King Jr. Boulevard in Chapel Hill, North Carolina
(the Site). The HHERA was conducted in conjunction with Dr. Kenneth Rudo of Rudo
Toxicological Consultants, LLC. The HHERA was prepared in order to evaluate
potential human health and ecological risk at the 10.24 acre Site and was conducted in
accordance with the United States Environmental Protection Agency (USEPA) and
North Carolina risk assessment guidance. The site generally slopes along an
embankment to the south to a lower area along Bolin Creek and the Bolin Creek
Greenway Trail.
Two primary assessments were performed for the site (pre- and post- remedial
measures). A preliminary risk evaluation was performed in 2019 and concluded that
interim remedial measures (IRM), including the removal of surficial coal ash in selected
locations in the lower portion of the Site, would be protective of trail users. The interim
remedial measures were to be performed in conjunction with the completion of
modifications to the Bolin Creek Greenway Trail (Greenway). Human health risk
calculations were updated in September 2019 by Dr. Kenneth Rudo in order to reflect
results of additional data collected in August 2019, including the results of a trail use
survey to better establish the duration and frequency of exposure to trail users of
different ages.
The second assessment performed included a post-IRM risk assessment update. The
Town performed IRM from January through 2020 in conjunction with the completion of
modifications to the Bolin Creek Greenway Trail (Greenway). The IRM included
removal and off -Site disposal of exposed CCPs along the Greenway, implementation of
cover and migration control measures to minimize the potential for exposed CCPs in
the embankment to mobilize to the Greenway in the future, and implementation of
stormwater control measures. The results of the post IRM risk assessment in
conjunction with the implementation of additional protective measures indicate the
levels of risks to construction workers, recreational trail users, and trespassers posed by
coal combustion products (CCPs) are currently acceptable based on North Carolina
Department of Environmental Quality (NCDEQ) and United States Ecological
Protection Agency (USEPA) criteria.
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
A Screening Level Ecological Risk Assessment (SLERA) was performed for the Site as
part of the post IRM assessment. The SLERA concludes that no significant ecological
risk exists; however, additional ecological study is recommended as part of the design
and selection of the final remedy.
The SLERA included a comparison of constituents in the source area surface water,
sediment and soil to published ecological screening levels. Constituents detected at
concentrations greater than ecological screening levels are recommended for further
evaluation. The COPCs after consideration of background concentrations are
summarized below:
Media/Location
COPC
Surface Water- source area
None
Sediment- source area
Barium
Chromium
Soil- source area
Arsenic
Lead
Mercury
Strontium
Thallium
Vanadium
Zinc
The following conclusions and recommendations were made:
• IRM have been effective in reducing risk to Greenway users to within acceptable
USEPA ranges.
• Ecological risk is believed to be minimal. However, the final remedy design
process should include the performance of an ecological risk assessment that
includes evaluation of the ecological COPCs.
• The Town should continue to monitor Site conditions so that effects from events
are noted and can be evaluated.
• If Site conditions change such that new areas of exposure to CCP are evident,
additional data collection efforts should be implemented and the human health
risk calculations should be updated.
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
• If additional construction activities are needed in areas of concern, the current
site worker training plan, which includes the use of PPE, should be continued.
Depending on the nature of construction activities, additional sampling and
update of the human health risk assessment may also be warranted.
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
TABLE OF CONTENTS
SECTION
PAGE
EXECUTIVE SUMMARY.................................................................................................... ES-1
1.0 INTRODUCTION...........................................................................................................1
1.1 Background................................................................................................................. 1
1.2 Summary of Primary Work Scope Items................................................................ 2
2.0 PRELIMINARY RISK EVALUATION FINDINGS FOR INTERIM REMEDIAL
MEASURESDESIGN.................................................................................................... 3
3.0 HUMAN HEALTH RISK ASSESSMENT.................................................................. 6
3.1 Recreational Receptors for the Bolin Creek Greenway —
Pre -Interim Measures September 2019................................................................... 6
3.2 Recreational and Trespasser Receptors for the Bolin Creek Greenway —
Post Interim Measures............................................................................................. 10
3.3 Construction Worker Receptor for the Bolin Creek Greenway —
Post Interim Measures............................................................................................. 10
3.4 Risk Characterization Results - Post Interim Measures ..................................... 10
4.0 SCREENING LEVEL ECOLOGICAL RISK ASSESSMENT................................13
5.0 CONCLUSIONS AND RECOMMENDATIONS...................................................15
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
LIST OF FIGURES
Figure 1
Site Location and Topographic Map
Figure 2
Site Boundary and Exposure Unit Map
Figure 3
Post -Interim Remedial Measures Site Map
LIST OF TABLES
Table 1 Soil and Sediment Data Input to Risk Calculator Tool
Table 2 Surface Water Data Input to Risk Calculator Tool
Table 3 Risk Calculator Tool Risk Summary with Polling Data Adjustments- Recreator
Table 4 Risk Calculator Tool Risk Summary with Polling Data Adjustments- Trespasser
Table 5 Ecological Screening Results
LIST OF APPENDICES
Appendix A September 2019 Risk Calculator Tool Output
Appendix B Analytical Data Summary Tables for Human Health Risk Assessment
Appendix C Analytical Data Summary Tables for Screening Level Ecological Risk Assessment
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
1.0 INTRODUCTION
1.1 Background
As requested by the Town of Chapel Hill (the Town), Duncklee & Dunham, P.C.
(Duncklee & Dunham), now part of SynTerra Corporation (SynTerra), prepared this
Human Health and Ecological Risk Assessment (HHERA) report regarding the property
located at 828 Martin Luther King Jr. Boulevard in Chapel Hill, North Carolina (the Site).
The HHERA was conducted in conjunction with Dr. Kenneth Rudo of Rudo Toxicological
Consultants, LLC.
The HHERA was prepared in order to evaluate potential human health and ecological
risk at the Site and was conducted in accordance with the United States Environmental
Protection Agency (USEPA) and North Carolina risk assessment guidance. The Site
consists of one parcel approximately 10.24 acres in size and features a two-story police
station building of approximately 35,000-square feet (Figure 1). Previous reports indicate
the Site was used as a borrow pit from the late 1950s to the early 1960s, with structural
fill placed on the property from the mid-1960s to the mid-1970s. Available information
indicates the fill consist of a mix of construction debris and coal combustion products
(CCPs). Site topography is elevated in the area of the building and associated parking lots
and slopes along an embankment to the south to a lower area along Bolin Creek and the
Bolin Creek Greenway Trail (Figure 2).
The requested work scope included an evaluation of what extent the use of interim
remedial measures would better control the risk profile of the site. The use of interim
measures was designed to enable the Town to ensure protectiveness of the nearby
community, including users of the adjacent Bolin Creek Greenway Trail, while the
development, feasibility, and selection of a final remedial plan is completed. The Town
determined the performance of the interim measures risk evaluation should be supported
by the collection of additional environmental samples for analytical testing.
Duncklee & Dunham prepared a Sampling and Analysis Plan (SAP), dated March 29,
2019, that recommended the collection of samples for soil, groundwater, sediment, and
surface water. The SAP also recommended the collection of additional samples from the
coal combustion products (CCP) exposed along the southern -facing bluff located south
on the Chapel Hill Police Department property. Hart & Hickman documented these
additional sampling activities in A Results of Data Gap Sampling Report dated May 23,
2019.
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
1.2 Summary of Primary Work Scope Items
This report describes the following primary work scope items:
• Preliminary Risk Evaluation findings. The initial risk evaluation findings were
described in a draft memorandum dated May 2019 prepared by Duncklee &
Dunham. This initial analysis, which was based upon data collected from the Site
from 2013 to 2016, concluded that interim remedial measures (IRM), including
the removal of surficial coal ash in selected locations in the lower portion of the
Site, would be protective of trail users. The initial risk evaluation findings have
been updated and finalized and are presented in Section 2 of this report.
• Update HHRA calculations. These calculations, updated in September 2019 by
Dr. Kenneth Rudo, are in included in Section 3.1. These updates were conducted
to reflect results of additional data collected in August 2019 to fill in data gaps,
including the results of a trail use survey to better establish the duration and
frequency of exposure to trail users of different ages.
• Post-IRM risk assessment update. The Town performed IRM from January
through 2020 in conjunction with the completion of modifications to the Bolin
Creek Greenway Trail (Greenway). The IRM included removal and off -Site
disposal of exposed CCPs along the Greenway, implementation of cover and
migration control measures to minimize the potential for exposed CCPs in the
embankment to mobilize to the Greenway in the future, and implementation of
stormwater control measures. Section 3.2 describes the results of updating the
risk assessment after the recent completion of the IRM based upon the results of
analysis of additional soil sampling completed in the southern exposure unit
after the removal of surficial CCPs (Figure 3). The results of the post IRM risk
assessment (as well as other protective measures implemented such as posting of
informative signs along the Greenway) indicate the levels of risks to construction
workers (with training and protective clothing), trail users, and trespassers posed
by CCPs are currently acceptable based on North Carolina Department of
Environmental Quality (NCDEQ) and United States Ecological Protection
Agency (USEPA) criteria.
• Screening Level Ecological Risk Assessment findings. Section 4.0 presents the
findings of a Screening Level Ecological Risk Assessment. These findings did not
find evidence of significant ecological risks. However, additional ecological
study is recommended as part of the design and selection of the final remedy.
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
2.0 PRELIMINARY RISK EVALUATION FINDINGS FOR INTERIM
REMEDIAL MEASURES DESIGN
Assessment of the Site soil, groundwater, surface water, and sediment was conducted in
phases from 2013 to 2016 which culminated in the preparation of a Phase II Remedial
Investigation Report Revision 2 dated August 25, 2017. To fill assessment data gaps for the
risk assessment process, additional soil, sediment, surface water, and groundwater
testing was performed at the Site in April 2019. Using this and the previously collected
Site data, Dr. Rudo used the 2018 NCDEQ Risk Calculator to perform preliminary
human health risk assessments pertaining to the Site. The most recent version of the
NCDEQ Risk Calculator can be found at (httl2s:Hdeg.nc.gov/permits-rules/risk-based-
remediation/risk-evaluation-resources). The results of this work were presented in the
memorandum Draft Preliminary Risk Evaluation -Findings for Interim Measures Along Bolin
Creek Greenway dated May 24, 2019.
The purpose of this HHERA is to evaluate potential risks associated with COIs that
might remain in environmental media on -Site and in the vicinity. The HHERA includes
four steps defined by the National Academy of Sciences (1983) in their report, 'Risk
Assessment in the Federal Government: Managing the Process." These steps include:
1. Hazard Identification
2. Exposure Assessment
3. Toxicity Assessment
4. Risk Characterization
The hazard identification process: 1) evaluates the nature and extent of constituents
reported at the Site and 2) selects a subset of constituents of interest (COIs). The
exposure assessment evaluates the likelihood, magnitude, and frequency of exposure to
the COIs, and identifies exposure pathways and routes by which receptors may be
exposed to these constituents. For this Site, completed exposure pathways were
evaluated as part of the exposure assessment. The assessment identified completed two
complete exposure receptors: human recreators and construction workers. Exposure
pathways for these receptors are further described in the NCDEQ Risk Calculator User
Guide
(httl2s:Hfiles.nc. gov/ncdeq/W aste%20Management/DWM/SF/RiskBasedRemediation/FI
NAL-RiskCalculatorUserGuide-Feb-2021.pdf). The toxicity assessment incorporates
toxicity indices literature sources for each COI. Toxicity factors for each COI are
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
included in the NCDEQ Risk Calculator. Exposure Point concentrations (EPCs) are
calculated for each COI and used in the risk characterization step of the process.
Exposure doses are defined differently for potential carcinogenic and non -carcinogenic
effects in humans. Target Risk, or the level of risk that above which is unacceptable is
calculated for human health. For known or suspected carcinogens, the sum of
individual excess lifetime cancer risk values for all constituents and for all exposure
pathways may not exceed 1 in 10,000. For systemic toxicants (non -carcinogenic), the
Hazard Index (HI) for all contaminants for all complete exposure pathways may not
exceed 1.0.
The most conservative data were input to these calculations. The maximum
concentrations of COIs detected in samples from each media were used as the EPC.
Human health risk estimates were evaluated using soil toxicity values and exposure
parameters as specified by USEPA and NCDEQ. Next, the data sets collected from 2014
and 2016 were used to establish a baseline condition for the Site. The April 2019 data set
was used, along with conservative scenarios and default values, to help identify the
exposure scenarios that would most benefit from risk minimization steps, and to help
lead to the most effective and protective interim measures.
The findings of this work indicated:
• An increase in the potential for risk was suggested by the 2019 data set when
compared with the 2014/2016 data set.
• Potential unacceptable risk pertaining to two exposure scenarios at the Site
existed:
o Future construction worker — Arsenic and manganese non -cancer risks
from soil
o Recreational user — Arsenic non -cancer risks from soil exposure
• Cancer risks were not greater than NCDEQ or USEPA criteria.
• Exposure risks estimated for the recreational pathway along or in Bolin Creek
using the 2019 data did not increase as compared to risk estimates using the 2014
to 2016 data.
Other receptors and pathways are present, by default, in the risk calculator tool output
(e.g., resident and non-residential worker). Neither of those pathways are applicable to
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
Site conditions due to the different exposure frequencies and durations of those
scenarios.
The risk calculation results for a construction worker were within a range such that
proper training and the use of personal protective equipment (PPE) could minimize
actual risk. Also, the results of the preliminary risk evaluation indicated that potential
risks under the recreational user scenario could be reduced through implementation of
interim measures. Those measures included the following components:
• Removal of exposed CCPs that had migrated from the embankment to locations
adjacent to and near the Greenway
• Installation of clean backfill in excavated areas
• Placement of additional signage along the paved trail segment adjacent to the
embankment where CCPs are present to inform users of the presence of CCPs
and to encourage them to stay on the Greenway
• Polling of Greenway users to collect data regarding frequency and duration of
trail use to better reflect actual use conditions rather than use of default exposure
parameters used in the preliminary calculation
• Repair of existing standard silt fence and installation of new standard and
"super" silt fencing in the wooded area along the embankment where exposed
CCPs are present
• Hydroseeding on the embankment where exposed CCPs are present for
stabilization purposes
• Periodic inspections to identify newly migrated CCPs if present
• Sampling and analytical testing along the Greenway after removal of CCPs
• Updated risk assessment to confirm interim measures have accomplished
protectiveness goals
Following these findings, the Town proceeded to implement these IRMs in January
through November 2020 and keep the Greenway open. A report which describes the
IRMs has been prepared by Hart & Hickman, PC and is provided under separate cover.
The following section describes the results of HHRA calculations conducted in
September 2019 prior to the IRMs and the results of risk calculations conducted after
completion of the IRMs.
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
3.0 HUMAN HEALTH RISK ASSESSMENT
3.1 Recreational Receptors for the Bolin Creek Greenway —
Pre -Interim Measures September 2019
In September 2019 (pre -interim measures), an HHRA was performed by Dr. Rudo that
included risk estimates using data from soil, surface water, and sediment samples
collected on the Site in April 2019 and August 2019 (see Appendix A). The maximum
concentrations of constituents detected in samples collected near or adjacent to the
Greenway from each media (soil, surface water, and sediment) were used as the
exposure point concentrations.
Risk estimates for soil exposures were determined using the maximum COI
concentrations from the data set that included the April 2019 soil samples and the soil
and sediment samples collected in August 2019 from eight locations - SS-3A, and SED-
11 though SED-17. Constituent concentrations of beryllium, trivalent chromium, cobalt,
and manganese from the August 2019 samples included in the recreational user risk
assessment represented the maximum soil concentrations of the April 2019 and August
2019 data sets.
All risk estimates in this analysis were for recreational user exposures. USEPA and
NCDEQ Division of Waste Management (DWM) default exposure parameters
pertaining to recreational users were used, except as specified below and in Appendix
A, to identify potential Site -specific exposures. Survey data collected from actual trail
users was used to modify default input parameters for the number of Greenway visits
per week and the duration of those visits. These risk estimates were calculated using the
February 2018 NCDEQ Risk Calculator.
For the September 2019 Site -specific risk analyses, the following were modified for the
range of reported data provided in the Greenway user survey: 1) the exposure
frequency (EF), in days per week on the Greenway; and 2) the exposure duration (ED),
as minutes per day on the Greenway. Risk estimates were calculated for the reported
minimum frequency and duration responses, average frequency and duration
responses, and maximum frequency and duration responses for each age group.
Frequency values for Site -specific recreational user exposure pertaining to each age
group were set as one, three, and seven days per week. Duration values for Site -specific
recreational user exposure used for each age group were set as 1 hour, 2 hours, and 8
hours per visit. Average frequency and duration values were selected rather than
median reported values since the calculated average values were greater than the
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
median values and, thus, the average values reflected greater potential exposure risks.
Appendix A includes a summary of the default and Site -specific exposure assumptions.
Child and adult recreational receptors were evaluated as part of this assessment. Three
age groups were selected on the basis of responses provided in the user survey to reflect
common HHRA receptor age ranges and to reflect age and duration ranges known to
represent sensitive users. The child age groups are: birth to 1 year of age (0 to 1 year),
birth to 2 years of age (0 to 2 years), and birth to 6 years of age (0 to 6 years). Adult
recreational receptors were assumed to live in the area for a period of 26 years.
For the birth to 2 years of age child receptor, a body weight (BW) value of 9.60 kg was
used to reflect risks to this specific age range. This BW value was calculated using data
derived by the Agency for Toxic Substances and Disease Registry (ATSDR)1 and reflects
the time -weighted average BW for children in the birth to 1 year of age and from 1 to 2
years of age. The BW used for the 0 to 6 years of age child receptor was the default 15
kilogram (kg) BW value. Adult recreational receptors were assumed to live in the area
for a period of 26 years, reflective of default USEPA and NCDEQ DWM upper -bound
residential occupancy periods. The adult recreational receptors were assumed to use the
Greenway at the Site -specific exposure frequency and duration during this 26-year
period. Appendix A summarizes the exposure parameters for each receptor.
As specified in DWM protocols, constituents reported at sample reporting levels (SRLs)
equal to or greater than the 0.1 non -cancer toxicity endpoint hazard quotient (HQ) or
the 1 in 1,000,000 cancer endpoint toxicity value were included in the risk calculations at
the reported SRL concentration. Laboratory practical quantitation limit (PQL) must be
used for points where concentrations are at or below lab reporting limits. Sample data
should not be diluted or elevated unnecessarily above normal reporting limits.
Chromium (Cr) is a polyvalent element and can exist in several distinct oxidation
states, but only trivalent chromium [Cr (III)] and hexavalent chromium [Cr (VI)] occur
with any frequency in the natural environment. The mobility, bioavailability, and
toxicity of chromium largely depend on which of these two chemical species is
prevalent. Where chromium data was not speciated to trivalent [Cr(III)] and hexavalent
chromium [Cr(VI)], the reported total chromium (CrT) concentration was assumed to be
the more toxic Cr(VI) species. Speciated hexavalent and trivalent chromium were used
for risk estimates when available.
ATSDR is a federal public health agency within the Centers for Disease Control and Prevention (CDC) that conducts and establishes
protocols and methodology for public health assessments. ATSDR web page at: https://www.atsdr.cdc.gov/
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
Using the input data described above, output from the risk calculator tool shows: 1) the
NCDEQ DWM human health acceptable additive (cumulative) risk criteria is less than
or equal to 1.0 HI for a specific target organ or critical effect for non -cancer effects
(systemic effects), and 2) an additive lifetime increased cancer risk of less than or equal
to 1 in 100,000 for cancer endpoints. These maximum acceptable risk criteria apply to
COIs for the combined exposure routes (ingestion, inhalation, and dermal) and
exposure pathways for each receptor.
The maximum concentration of a constituent detected in each media was used for the
September 2019 risk estimates, without consideration of naturally occurring
background (or unaffected reference) concentrations. Background constituent levels will
be considered in the discussion of the results of the risk assessment. The need to refine
the risk estimates for naturally occurring background contributions may be considered
as the Site -specific HHRAs are further developed. It is important to recognize that
background COI concentrations contribute to the risk of persons exposed on the Site
and should be considered in the risk management and risk communication.
A summary of the calculated risk estimates, pertaining to each receptor classification
and the range of exposure frequency and exposure duration parameter values, was
used to perform the September 2019 Site -specific recreational receptor risk analysis.
The DWM risk calculator allows for determination of risks to specific receptors by
allowing for the adjustment of exposure parameters including for a specific selected age
range of concern for site -specific receptors. The risk estimates for each exposure
medium (soil, sediment, sediment) were calculated individually for each site -specific
recreational receptor age range (0-2 years old, 0-6 years old, and adults). Maximum
detected media concentrations were used as the exposure concentrations. Receptor -
specific exposure parameters including exposure duration, exposure frequency and
body weight were adjusted as appropriate based on USEPA values and site -specific
criteria and risk estimates calculated for each media
The Site -specific recreational receptor risk estimates, using the survey -determined
exposure parameters, indicate increased levels of risk (greater than 1.0 non -cancer HI
and greater than 1E-04 lifetime excess cancer risk) for children in the birth through 6
years of age group who may be exposed to Site soil and sediment near the Greenway.
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
Recreational Adult Risk Results
Site -specific increased risks were not identified for adult recreational receptors under
the defined exposure scenario for individuals or combined soil, surface water and
sediment media.
Recreational Child Risk Results
Increased risks to children were identified by media for the following exposures:
Children from birth (0) to 2 years of age -
1. Non -cancer risks for combined soil, surface water, and sediment exposures
of one or more visits per week for visit durations. The major proportion (90
percent) of the risk is attributed to the soil exposures.
2. Non -cancer risks for soil exposures of three or more visits per week for all
visit durations.
Children from birth (0) to 6 years of age -
1. Non -cancer risks for the combined soil, surface water, and sediment
exposures for three or more visits per week for visit durations. Ninety
percent (90 percent) of the risk is attributed to the soil exposures.
2. Non -cancer risks for soil exposures for three or more visits per week for
visit durations.
3. Cancer risks for soil exposures for seven or more visits per week for all visit
durations.
Summary of the September 2019 Risk Evaluation
The non -cancer risk driver for children in the September 2019 analysis was attributed to
arsenic and cobalt. The cancer risk driver for children in the 0-6 years age range was
attributed to arsenic. For adult recreators, elevated risks were not indicated for
individuals or combined soil, surface water and sediment media for each Site -specific
exposure parameter. Interim measures were implemented to address these risk
identified during the September 2019 assessment. A post-remediation risk evaluation
was performed after implementation of interim measures and is summarized in the
following section.
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
3.2 Recreational and Trespasser Receptors for the Bolin Creek
Greenway — Post Interim Measures
After the completion of IRMs conducted from January through November 2020,
SynTerra conducted additional Bolin Creek human health risk estimate calculations for
recreators and trespassers exposed to soil and surface water. The 2020 risk estimates
incorporate post interim measure soil and surface water constituent concentrations
(note that the CCP removal was conducted initially prior to the remainder of the IRMs).
Table 1 presents the soil data used to model the 2020 risk estimates, and Table 2
presents the surface -water data used to model the 2020 risk estimates.
To evaluate the greatest potential for risk, the maximum concentration of constituents
in samples collected adjacent to or near the Greenway for each media were used as the
EPCs. These data were included in the risk estimates with no modification for potential
background constituent concentrations. Hexavalent and trivalent chromium analytical
data was collected and used for risk estimates. Risk estimates were calculated using the
January 2021 version of the NCDEQ risk calculator.
The May 2020 site -specific recreator and trespasser receptor risk estimates for exposure
to the soil and surface water media were calculated using reasonable maximum values
(RM) and are summarized in Appendix B. The selected RM for exposure duration (ED)
is 0.5-hour, a more conservative (health protective) value relative to the median 8-
minute ED identified in the on -site user survey. The U.S.EPA and DWM default 195-
day per year Exposure Frequency was used for the recreator receptor to reflect a value
greater than the median value determined in the 2019 user survey. The final soil and
surface water analyte concentrations for samples collected following the interim
measures undertaken at the site were used for the exposure concentrations.
3.3 Construction Worker Receptor for the Bolin Creek Greenway —
Post Interim Measures
The construction worker scenario was evaluated for the Greenway using the maximum
concentrations of constituents in soil remaining at the site after implementation of
interim measures. The exposure parameters used for the construction worker risk
estimates reflect the default USEPA and NCDEQ DWM exposure parameters.
3.4 Risk Characterization Results - Post Interim Measures
Table 3 presents risk summary data from the risk calculator for recreational/trespasser
user and construction worker pathways. Table 4 summarizes the risk assessment
results for the recreational/trespasser and construction worker pathways. Appendix B
May 2021
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
contains the exposure factors, target risks, and direct contact risk calculator output for
of these exposure scenarios.
The NCDEQ DWM human health acceptable additive (cumulative) risk criteria is less
than or equal to 1.0 hazard index (HI) to a specific target organ or critical effect for non -
cancer effects (systemic effects), and an additive lifetime increased cancer risk of less
than or equal to 1 in 10,000 for cancer endpoints. The maximum acceptable risk criteria
apply to constituents for the combined exposure routes (ingestion, inhalation, and
dermal) and exposure pathways for each receptor.
The SRLs for constituents reported as not detected in analyses were evaluated relative
to cancer and non -cancer screening values. These were calculated using the Site -specific
exposure parameters to evaluate whether these constituents should be included in the
risk estimates. NCDEQ DWM criteria states that constituents reported as not -detected
(ND or U qualifier) with SRLs that exceed the cancer risk level (1 in 1,000,000) or the 0.1
non -cancer hazard quotient (HQ) level are to be included in the risk estimate.
In the surface water data set, thallium was not detected in concentrations at a maximum
SRL [10 micrograms per liter (µg/L)], which is greater than the 0.2 HQ level. Including
thallium at the 10 µg/L SRL value in the risk estimate for the recreator user results in a
2.3 HQ, indicating concentrations of thallium at greater than non -cancer risk levels. As
thallium was not detected in the surface water or soil data for the Site, it was
determined that including the thallium SRL value in the risk estimates was not
representative of Site conditions.
The 2020 additive non -cancer and cancer risk estimates for the recreator and trespasser
receptors, using the Site -specific exposure parameters identified above, are within
acceptable risk levels as established by the NCDEQ DWM. The additive cancer risk
estimates for the construction worker receptor calculated using the Site -specific
exposure parameters are less than cancer risk levels. As indicated by a hazard index
(HI) equal to 3.5, the non -cancer additive risk estimate for the construction worker,
using the Site -specific exposure parameters, was calculated to be greater than the non -
cancer risk levels. With an HQ equal to 2.7, manganese is the constituent with the
greatest contribution to the non -cancer risk estimate for the construction worker
scenario. Manganese concentrations detected at the Site are consistent with the range of
background concentrations for the site. Construction worker risk model inputs are
extremely conservative and do not account for implementation of personal protection
requirements and best management practices for construction activities.
Implementation of personal protection equipment and best management practices was
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
required at the Site for all construction activities, which would minimize and/or prevent
construction worker exposure. This pathway is not required by NCDEQ and is only
included as a conservative evaluation. A Site construction plan was developed and
implemented as part of the interim measure activities.
The 2020 Site -specific human health risk estimates for Bolin Creek Greenway
recreational users, trespassers, and construction worker receptors assume the data is
representative of the current and future soil and surface water at the Site. Persons
exposed to constituent concentrations that are greater than those reflected in the data
provided or exposed to other environmental constituents not represented in this data,
or persons who are exposed on the basis of the exposure parameters used for this risk
analysis, may be subject to greater levels of potential health risks.
May 2021
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
4.0 SCREENING LEVEL ECOLOGICAL RISK ASSESSMENT
To be protective of site ecology, and to help the Town plan for the future design of the
full remedy, SynTerra performed screening level ecological risk assessment calculations
utilizing USEPA guidance documents. Surface water, sediment, and soil data were
compared with ecological screening values (ESVs) that are designed to provide a
conservative estimate of the concentration to which an ecological receptor can be
exposed without experiencing adverse health effects. Due to the conservative methods
used to derive screening levels, it can be assumed that concentrations less than
screening levels will not result in any adverse effects to receptor survival, growth,
and/or reproduction; therefore, further evaluation is not necessary. Concentrations
greater than conservative risk -based screening levels do not necessarily indicate that a
potential ecological risk exists; however, further evaluation might be warranted.
These calculations were performed using data collected after interim measures were
conducted. Also, data from soil samples collected deeper than 4 feet and under
impervious surfaces (e.g., parking lots) were excluded from the screening level
assessment. Once remedial options for the full remedy are proposed, these calculations
and assumptions can be reset to show the effectiveness of the proposed final remedies
on Site ecological issues.
As shown in Appendix C, maximum concentrations in surface water, sediment, and soil
data were input into tables to identify the presence of constituents of potential concern
(COPCs). A set of tables for surface water, sediment, and soil are provided for
background areas and the source area. The downgradient area was evaluated for
surface water and sediment (no soil sample data are available in this area).
Table C1, Table C2, and Table C3 show background values compared to the
recommended USEPA ecological screening criteria (Table C4). The data show COPCs
were found in background sediment and soil locations exceeding the ESVs. Surface
water COPCs were not found above ESVs in the background area, the source area, nor
areas downgradient of the source area.
Sediment calculations pertaining to background samples are presented in Table C2,
calculations pertaining to the source area are presented in Table C6, and calculations
pertaining to areas downgradient of the source area are presented in Table C10. The
COPCs barium, chromium, and manganese were identified in background sediment. As
summarized below, sediment in the source area and areas downgradient of the source
area contained the COPCs barium and chromium. The maximum detected source area
May 2021 Page 13
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
concentration for barium and chromium is within the range detected in background.
Otherwise, the COPCs identified (using the USEPA ecological screening criteria shown
in Table C8 and Table C11) in source area samples or downgradient samples were
found in background samples.
Table C7 shows the findings for the ecological screening for soils in the source area.
Seven COPCs were identified after consideration of constituents that were found with
concentrations consistent with background soil concentrations, as shown in Table 5 and
summarized below. The result of this screening is a list of COPCs to be further
evaluated quantitatively in a baseline risk assessment.
Media/Location
COPC
Surface Water- source area
None
Sediment- source area
Barium
Chromium
Soil- source area
Arsenic
Lead
Mercury
Strontium
Thallium
Vanadium
Zinc
May 2021
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Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
5.0 CONCLUSIONS AND RECOMMENDATIONS
SynTerra concludes and recommends the following:
• Interim remedial measures have been effective in reducing risk to Greenway
users to within acceptable EPA ranges. Based on the current site use and data,
this risk assessment concludes the greenway trail is safe for use.
• Ecological risk is believed to be minimal. However, the final remedy design
process should include the performance of an ecological risk assessment that
includes evaluation of the seven constituents referenced in Section 4.0 above.
• The Town should continue to monitor Site conditions so that effects from storms
or potential flooding events are noted and can be evaluated.
• If Site conditions change due to newly identified migration or exposure of CCP,
we recommend the collection of additional samples to update the human health
risk calculations.
• If additional construction activities are needed in areas of concern, the current
site worker training plan, which includes the use of PPE, should be continued.
Depending on the nature of construction activities, additional sampling and
update of the human health risk assessment may also be warranted.
May 2021
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Project: 00.2312.00

Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
FIGURES
Lip
synTerra
Science & Engineering Consultants

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828 Martin Luther King, Jr. Boulevard Property
Cha el Hill, North Carolina
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4

Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
TABLES
Lip
synTerra
Science & Engineering Consultants

Table 1
Soil and Sediment Data Input to Risk Calculator Tool
Chapel Hill, North Carolina
Analyte
CAS
Number of
Samples
Frequency
of
Detection
Range of Detection
Location of
Maximum
Concentration
ConcentrationCurrent
Used for
Screening
(mg/kg)
Interim
Maximum Allowable
Concentration
Min.
Max.
0
Antimony
7440-36-0
2
0
NA
NA
NA
NA
NA
Arsenic
7440-38-2
26
26
0.792
14.5
SED-13
14.5
14.5
Barium
7440-39-3
26
26
20.0
958
SED-13
958
958
Beryllium
7440-41-7
26
16
0.118
J
1.56
SED-13
1.56
1.56
Boron
7440-42-8
1
0
NA
NA
NA
NA
NA
Cadmium
7440-43-9
26
6
0.122
J
0.284
J
SED-13
0.284
0.284
Chromium, Trivalent
16065-83-1
25
25
5.76
63.8
1 Excavation H-2
63.8
63.8
Chromium Hexavalent
18540-29-9
25
12
0.313
J
0.578
J
Excavation H-2
0.578
0.578
Chromium Total
7440-47-3
1
1
14
14
SS-7
NA
NA
Cobalt
7440-48-4
26
26
3.68
20.8
Excavation H-4
15*
15.0
Copper
7440-50-8
26
26
6.58
59.2
Excavation H-2
59.2
59.2
Lead
7439-92-1
2
1 2
13
18
HH-8
18
400**
Manganese
7439-96-5
26
26
193
1,480
H-4
591 *
591
Mercury
7439-97-6
26
23
0.0071
J
0.077
SED-12
0.077
0.077
Molybdenum
7439-98-7
1
0
NA
NA
NA
NA
NA
Nickel
7440-02-0
26
26
1 2.19
19.2
SED-13
19.2
19.2
Selenium
7782-49-2
26
14
0.237
J
3.07
SED-13
3.07
3.07
Strontium
7440-24-6
26
26
6.2
125.0
SED-13
125.0
125
Thallium
7440-28-0
2
0
NA
NA
NA
NA
NA
Vanadium
7440-62-2
2
2
37
52
HH-8
52
52
Zinc
7440-66-6
2
2
37
54
HH-8
54
54
Notes:
NA - Not Applicable
* - 95% UCL of site -specific backround range was used
**-Note that EPA has no consensus on reference does or cancer slop factor values for lead, therefore it is not possible to calculate cancer risk, or hazard
uotient. Lead concentrations are compared to the EPA screeiniz level of 400 nwJke for Residential soil

um
Analyte
Total reco`
Trivalent
Hexavalent
Nickel tot
Selenium
Strontium
Thallium
Vanadium
Zinc tot
Notes:
NA- Not Applicable
CAS
7429-90-5
7440-36-0
7440-38-2
7440-39-3
7440-41-7
7440-43-9
7440-47-3
16065-83-1
18540-29-9
7440-48-4
7440-50-8
7439-89-6
7439-92-1
7439-96-5
7439-97-6
7440-02-0
7782-49-2
7440-24-6
7440-28-0
7440-62-2
7440-66-6
Table 2
Surface -Water Data Input to Risk Calculator Tool
Chapel Hill, North Carolina
Number of
Samples
2
4
10
10
10
10
10
NA
4
10
10
4
4
10
10
6
10
10
4
4
4
Frequency of
Detection
0
0
6
10
0
0
2
NA
0
6
6
NA
NA
10
0
6
5
10
0
0
0
Range of Detection
Min.
Q
I Max.
NA
NA
NA
NA
0.15
0.45
16.9
32.1
NA
NA
NA
NA
0.62
0.73
NA
NA
NA
NA
0.094
0.36
0.88
3.2
NA
NA
NA
NA
9.3
37.4
NA
NA
0.21
J
0.62
0.088
J
0.120
43.5
89.1
NA
NA
NA
NA
NA
NA
Location of
Maximum Concentration
NA
NA
SW-3
SW-21
NA
NA
SW-21
NA
NA
SW-21
SW-21
NA
NA
SW-3
NA
S W-21
SW-5
SW-4
NA
NA
NA
Concentration Used
for Screening (ug/L)
NA
NA
0.45
32.1
NA
NA
0.73
NA
NA
0.36
3.2
NA
NA
37.4
NA
0.62
0.120
89.1
NA
NA
NA

Risk for Individual Pathways
1
Version Date: January 2021
Basis: November 2020 EPA RSL Table
Site ID: Human Health Risk Assessment - Recreator
Exposure Unit ID: Southern Exposure Unit
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Non -Residential Worker
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Construction Worker
Soil
1.4E-06
3.5E+00
YES
Recreator/Trespasser
Soil
1.3E-05
9.0E-01
NO
Surface Water*
3.3E-06
1.8E-02
NO
an VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carciinn kenic
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Exceeded?
Groundwater
Source Soil
Exceedence of 2L at Receptor?
NM
Source Groundwater
Exceedence of 2L at Receptor?
NC
Surface Water
Source Soil
Exceedence of 213 at Receptor?
NM
Source Groundwater
Exceedence of 213 at Receptor?
NC
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead
concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the
NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk -based
closure.
3. NM = Not Modeled
4. NC = Pathway not calculated
North Carolina DEQ Risk Calculator

Risk for Individual Pathways
1
Version Date: January 2021
Basis: November 2020 EPA RSL Table
Site ID: Human Health Risk Assessment - Trespasser
Exposure Unit ID: Southern Exposure Unit
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Non -Residential Worker
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Construction Worker
Soil
1.4E-06
3.5E+00
YES
Recreator/Trespasser
Soil
1.7E-06
7.7E-02
NO
Surface Water*
7.3E-07
4.4E-03
NO
an VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carciinn kenic
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target Receptor Concentrations Exceeded?
Groundwater
Source Soil
Exceedence of 2L at Receptor?
NM
Source Groundwater
Exceedence of 2L at Receptor?
NC
Surface Water
Source Soil
Exceedence of 213 at Receptor?
NM
Source Groundwater
Exceedence of 213 at Receptor?
NC
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead
concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the
NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk -based
closure.
3. NM = Not Modeled
4. NC = Pathway not calculated
North Carolina DEQ Risk Calculator

Table 5
Ecological Screening Results
Chapel Hill North Carolina
Area/Media
SW
SED
SOIL
Background
NONE
Barium
Chromium Total
Chromium Total
Chromium, Hexavalent
Chromium Trivalent
Cobalt
Copper
Manganese
Manganese
Selenium
Source
NONE
Arsenic
Barium
Barium
Chromium Total
Chromium Total
Chromium, Hexavalent
Chromium, Trivalent
Cobalt
Copper
Lead
Manganese
Me rcu r
Nickel
Selenium
Strontium
Thallium
Vanadium
Zinc
Downgradient
NONE
Barium
NO DATA
Chromium Total
Notes:
Compounds in bold are Contaminants of Potential Concern that exhibit elevated concentrations
in the source area.
Soil samples in the source area that are under impervious areas and are at depths greater than four

Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
APPENDIX A
SEPTEMBER 2019 RISK CALCULATOR TOOL
OUTPUT
,(rip
symTerra
Science & Engineering Consultants

Summary of Risk Assessment Output
o
Version Date: February 2018
Basis: November 2017 EPA RSL Table
Site ID: Resident, Occptl, Construction Wrkr, Recreational - default
Exposure Unit ID: sediment adjacent to Bolin Crk, April 2019 samples
PRIMARY CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil Combined Pathways
5.7E-06
4.2E-01
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil Combined Pathways
8.9E-07
2.9E-02
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Construction Worker
Soil Combined Pathways
5.3E-07
1.5E+00
YES
User Defined
Soil Combined Pathways
3.2E-06
2.4E-01
NO
Surface Water Combined Pathways*
0.0E+00
0.0E+00
NO
IL
VAPOR INTRUSION CALCULATORS qr
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target POE Concentrations Exceeded?
Protection of Groundwater Use
Source Soil
Exceedence of 2L at POE?
NM
Source Groundwater
Exceedence of 2L at POE?
NM
Protection of Surface Water
Source Soil
Exceedence of 213 at POE?
NM
Source Groundwater
I Exceedence of 213 at POE?
NM
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for
lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed
the NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a
risk -based closure.
North Carolina DEQ Risk Calculator

Summary of Risk Assessment Output
o
Version Date: February 2018
Basis: November 2017 EPA RSL Table
Site ID: 828 MLK, Chapel Hill
Exposure Unit ID: sediment adjacent to Bolin Crk, April 2019 samples
PRIMARY CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil Combined Pathways
5.7E-06
4.2E-01
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil Combined Pathways
8.9E-07
2.9E-02
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Construction Worker
Soil Combined Pathways
5.3E-07
1.5E+00
YES
User Defined
Soil Combined Pathways
5.9E-07
3.7E-02
NO
Surface Water Combined Pathways*
0.0E+00
0.0E+00
NO
IL
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target POE Concentrations Exceeded?
Protection of Groundwater Use
Source Soil
Exceedence of 2L at POE?
NM
Source Groundwater
Exceedence of 2L at POE?
NM
Protection of Surface Water
Source Soil
Exceedence of 213 at POE?
NM
Source Groundwater
I Exceedence of 213 at POE?
NM
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for
lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed
the NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a
risk -based closure.
North Carolina DEQ Risk Calculator

Summary of Risk Assessment Output
o
Version Date: February 2018
Basis: November 2017 EPA RSL Table
Site ID: 828 MLK April 2019 Sample data
Exposure Unit ID: April 019 sample data, with 6Cr
PRIMARY CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil Combined Pathways
1.4E-04
3.9E+00
YES
Groundwater Combined Pathways*
4.4E-04
6.7E+00
YES
Non -Residential Worker
Soil Combined Pathways
3.2E-05
2.9E-01
NO
Groundwater Combined Pathways*
8.9E-05
1.0E+00
YES
Construction Worker
Soil Combined Pathways
6.0E-06
5.8E+00
YES
User Defined
Soil Combined Pathways
8.0E-05
2.1E+00
YES
Surface Water Combined Pathways*
1.0E-05
3.0E-02
NO
IL
VAPOR INTRUSION CALCULATORS qr
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
2.3E-01
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
5.4E-02
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target POE Concentrations Exceeded?
Protection of Groundwater Use
Source Soil
Exceedence of 2L at POE?
NM
Source Groundwater
Exceedence of 2L at POE?
NM
Protection of Surface Water
Source Soil
Exceedence of 213 at POE?
NM
Source Groundwater
I Exceedence of 213 at POE?
NM
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for
lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed
the NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a
risk -based closure.
North Carolina DEQ Risk Calculator

Summary of Risk Assessment Output
o
Version Date: February 2018
Basis: November 2017 EPA RSL Table
Site ID: 828 MLK April 2019 Sample data
Exposure Unit ID: April 019 Sample data, Trespasser w/ 6Cr
PRIMARY CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil Combined Pathways
NC
NC
NC
Groundwater Combined Pathways*
NC
NC
NC
Non -Residential Worker
Soil Combined Pathways
NC
NC
NC
Groundwater Combined Pathways*
NC
NC
NC
Construction Worker
Soil Combined Pathways
NC
NC
NC
User Defined
Soil Combined Pathways
1.8E-05
3.6E-01
NO
Surface Water Combined Pathways*
2.4E-06
7.8E-03
NO
IL
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
NC
NC
NC
Indoor Air
NC
NC
NC
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target POE Concentrations Exceeded?
Protection of Groundwater Use
Source Soil
Exceedence of 2L at POE?
NM
Source Groundwater
Exceedence of 2L at POE?
NM
Protection of Surface Water
Source Soil
Exceedence of 213 at POE?
NM
Source Groundwater
I Exceedence of 213 at POE?
NM
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for
lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed
the NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a
risk -based closure.
North Carolina DEQ Risk Calculator

Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
APPENDIX B
ANALYTICAL DATA SUMMARY TABLES FOR
HUMAN HEALTH RISK ASSESSMENT
,(rip
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Science & Engineering Consultants

Exposure Factors and Target Risks
Version Date: January 2021
Basis: November 2020 EPA RSL Table
Site ID: Human Health Risk Assessment - Recreator
Exposure Unit ID: Southern Exposure Unit
Exposure Parameter Default Value I Site Specific Value Justification
General
Target Cancer Risk (individual)
1.0E-06
1.0E-06
Target Cancer Risk (cumulative)
1.0E-04
1.0E-04
Target Hazard Index (individual)
2.0E-01
2.0E-01
Target Hazard Index (cumulative)
1.0E+00
1.0E+00
Residential Child
Lifetime (LT) (years)
70
70
Body Weight(BW) (kg)
15
15
Exposure Duration (ED) (yr)
6
6
Exposure Frequency (EF) (d/yr)
350
350
Exposure Time (ET) (hr)
24
24
Skin Surface Area - Soil Exposure (SAg) (cm2)
2373
2373
Soil Adherence Factor (AF) (mg/cm)
0.2
0.2
Soil Ingestion Rate (IRS) (mg/day)
200
200
Skin Surface Area - Water Exposure (SA„) (cm2)
6365
6365
Water Ingestion Rate (IRW) (L/d)
0.78
0.78
Water Exposure Time (ET_) (hr/event)
0.54
0.54
Water Event Frequency (EV) (events/day)
1
1
Residential Adult
Lifetime (LT) (years)
70
70
Body Weight(BW) (kg)
80
80
Exposure Duration (ED) (yr)
20
20
Exposure Frequency (EF) (d/yr)
350
350
Exposure Time (ET) (hr)
24
24
Skin Surface Area - Soil Exposure (SAg) (cm2)
6032
6032
Soil Adherence Factor (AF) (mg/cm)
0.07
0.07
Soil Ingestion Rate (IRS) (mg/day)
100
100
Skin Surface Area - Water Exposure (SA„) (cm2)
19652
19652
Water Ingestion Rate (IRW) (L/d)
2.5
2.5
Water Exposure Time (ET_) (hr/event)
0.71
0.71
Water Event Frequency (EV) (events/day)
1
1
Non -Residential Worker
Lifetime (LT) (years)
70
70
Body Weight(BW) (kg)
80
80
Exposure Duration (ED) (yr)
25
25
Exposure Frequency (EF) (d/yr)
250
250
Exposure Time (ET) (hr)
8
8
Skin Surface Area - Soil Exposure (SAg) (cm2)
3527
3527
Soil Adherence Factor (AF) (mg/cm)
0.12
0.12
Soil Ingestion Rate (IR) (mg/day)
100
100
Skin Surface Area - Water Exposure (SA„) (cm2)
19652
19652
Water Ingestion Rate (IRW) (L/d)
0.83
0.83
Water Exposure Time (ET_) (hr/event)
0.67
0.67
Water Event Frequency (EV) (events/day)
1
1
Construction Worker
Lifetime (LT) (years)
70
70
Body Weight(BW) (kg)
80
80
Working Weeks (EW) (wk/yr)
50
50
Exposure Duration (ED) (yr)
1
1
Exposure Frequency (EF) (d/yr)
250
250
Exposure Time (ET) (hr)
8
8
Skin Surface Area - Soil Exposure (SAJ (cm2)
3527
3527
Soil Adherence Factor (AF) (mg/cm2)
0.3
0.3
Soil Ingestion Rate (IR) (mg/day)
330
330
North Carolina DEQ Risk Calculator

Exposure Factors and Target Risks
Version Date: January 2021
Basis: November 2020 EPA RSL Table
Site ID: Human Health Risk Assessment - Recreator
Exposure Unit ID: Southern Exposure Unit
Exposure Parameter Default Value Site Specific
Value Justification
North
User Defined Child
Recreator
Trespasser
Lifetime (LT) (years)
70
NA
70
Averaging Time (AT) (days/yr)
365
NA
365
Body Weight (BW) (kg)
15
NA
15
Exposure Duration 0-2 (ED) (yr)
2
NA
2
Exposure Duration 2-6 (ED) (yr)
4
NA
4
Exposure Frequency (EF) (d/yr)
195
NA
195
Exposure Time (ET) (hr)
2
NA
0.5
Polling data adjustment
Skin Surface Area -Soil Exposure (SAg) (cmZ)
2373
NA
2373
Soil Adherence Factor (AF) (mg/cm2)
0.2
NA
0.2
Soil Ingestion Rate (IRS) (mg/day)
200
NA
200
Skin Surface Area -Water Exposure (SA„) (Cm Z)
6365
NA
6365
Water Ingestion Rate (IRW) (L/lu)
0.124
NA
0.124
Water Exposure Time (ETA) (hr/event)
2
NA
0.5
Polling data adjustment
Water Event Frequency (EV) (events/day)
1
NA
1
User Defined Adult
Recreator
Trespasser
Lifetime (LT) (years)
70
70
70
Body Weight(BW) (kg)
80
45
80
Exposure Duration 6-16 (ED) (yr)
10
10
10
Exposure Duration 16-26 (ED) (yr)
10
0
10
Exposure Frequency (EF) (d/yr)
195
90
195
Exposure Time (ET) (hr)
2
2
0.5
Polling data adjustment
Skin Surface Area -Soil Exposure (SAs) (Cm Z)
6032
6032
6032
Soil Adherence Factor (AF) (mg/cm)
0.07
0.2
0.07
Soil Ingestion Rate (IRS) (mg/day)
100
200
100
Skin Surface Area -Water Exposure (SA,) (cm)
19652
19652
19652
Water Ingestion Rate (IRW) (L/hr)
0.0985
0.071
0.0985
Water Exposure Time (ETA (hr/event)
2
2
0.5
Polling data adjustment
Water Event Frequency (EV) (events/day)
1
1
1
Carolina DEQ Risk Calculator

North Carolina DEQ Risk Calmlaior

Divider
Page

Exposure Factors and Target Risks
Version Date: January 2021
Basis: November 2020 EPA RSL Table
Site ID: Human Health Risk Assessment - Trespasser
Exposure Unit ID: Southern Exposure Unit
Exposure Parameter Default Value I Site Specific Value Justification
General
Target Cancer Risk (individual)
1.0E-06
1.0E-06
Target Cancer Risk (cumulative)
1.0E-04
1.0E-04
Target Hazard Index (individual)
2.0E-01
2.0E-01
Target Hazard Index (cumulative)
1.0E+00
1.0E+00
Residential Child
Lifetime (LT) (years)
70
70
Body Weight(BW) (kg)
15
15
Exposure Duration (ED) (yr)
6
6
Exposure Frequency (EF) (d/yr)
350
350
Exposure Time (ET) (hr)
24
24
Skin Surface Area - Soil Exposure (SAg) (cm2)
2373
2373
Soil Adherence Factor (AF) (mg/cm)
0.2
0.2
Soil Ingestion Rate (IRS) (mg/day)
200
200
Skin Surface Area - Water Exposure (SA„) (cm2)
6365
6365
Water Ingestion Rate (IRW) (L/d)
0.78
0.78
Water Exposure Time (ET_) (hr/event)
0.54
0.54
Water Event Frequency (EV) (events/day)
1
1
Residential Adult
Lifetime (LT) (years)
70
70
Body Weight(BW) (kg)
80
80
Exposure Duration (ED) (yr)
20
20
Exposure Frequency (EF) (d/yr)
350
350
Exposure Time (ET) (hr)
24
24
Skin Surface Area - Soil Exposure (SAg) (cm2)
6032
6032
Soil Adherence Factor (AF) (mg/cm)
0.07
0.07
Soil Ingestion Rate (IRS) (mg/day)
100
100
Skin Surface Area - Water Exposure (SA„) (cm2)
19652
19652
Water Ingestion Rate (IRW) (L/d)
2.5
2.5
Water Exposure Time (ET_) (hr/event)
0.71
0.71
Water Event Frequency (EV) (events/day)
1
1
Non -Residential Worker
Lifetime (LT) (years)
70
70
Body Weight(BW) (kg)
80
80
Exposure Duration (ED) (yr)
25
25
Exposure Frequency (EF) (d/yr)
250
250
Exposure Time (ET) (hr)
8
8
Skin Surface Area - Soil Exposure (SAg) (cm2)
3527
3527
Soil Adherence Factor (AF) (mg/cm)
0.12
0.12
Soil Ingestion Rate (IR) (mg/day)
100
100
Skin Surface Area - Water Exposure (SA„) (cm2)
19652
19652
Water Ingestion Rate (IRW) (L/d)
0.83
0.83
Water Exposure Time (ET_) (hr/event)
0.67
0.67
Water Event Frequency (EV) (events/day)
1
1
Construction Worker
Lifetime (LT) (years)
70
70
Body Weight(BW) (kg)
80
80
Working Weeks (EW) (wk/yr)
50
50
Exposure Duration (ED) (yr)
1
1
Exposure Frequency (EF) (d/yr)
250
250
Exposure Time (ET) (hr)
8
8
Skin Surface Area - Soil Exposure (SAJ (cm2)
3527
3527
Soil Adherence Factor (AF) (mg/cm2)
0.3
0.3
Soil Ingestion Rate (IR) (mg/day)
330
330
North Carolina DEQ Risk Calculator

Exposure Factors and Target Risks
Version Date: January 2021
Basis: November 2020 EPA RSL Table
Site ID: Human Health Risk Assessment - Trespasser
Exposure Unit ID: Southern Exposure Unit
Exposure Parameter Default Value Site Specific
Value Justification
North
User Defined Child
Recreator
Trespasser
Lifetime (LT) (years)
70
NA
NA
trespasser
Averaging Time (AT) (days/yr)
365
NA
NA
trespasser
Body Weight (BW) (kg)
15
NA
NA
trespasser
Exposure Duration 0-2 (ED) (yr)
2
NA
NA
trespasser
Exposure Duration 2-6 (ED) (yr)
4
NA
NA
trespasser
Exposure Frequency (EF) (d/yr)
195
NA
NA
trespasser
Exposure Time (ET) (hr)
2
NA
NA
trespasser
Skin Surface Area -Soil Exposure (SAg) (cmZ)
2373
NA
NA
trespasser
Soil Adherence Factor (AF) (mg/cm2)
0.2
NA
NA
trespasser
Soil Ingestion Rate (IRS) (mg/day)
200
NA
NA
trespasser
Skin Surface Area -Water Exposure (SA,) (Cm Z)
6365
NA
NA
trespasser
Water Ingestion Rate (IRW) (L/lu)
0.124
NA
NA
trespasser
Water Exposure Time (ETA) (hr/event)
2
NA
NA
trespasser
Water Event Frequency (EV) (events/day)
1
NA
NA
trespasser
User Defined Adult
Recreator
Trespasser
Lifetime (LT) (years)
70
70
70
Body Weight (BW) (kg)
80
45
45
trespasser
Exposure Duration 6-16 (ED) (yr)
10
10
10
Exposure Duration 16-26 (ED) (yr)
10
0
0
trespasser
Exposure Frequency (EF) (d/yr)
195
90
90
trespasser
Exposure Time (ET) (hr)
2
2
0.5
Polling data adjustment
Skin Surface Area -Soil Exposure (SAs) (Cm Z)
6032
6032
6032
Soil Adherence Factor (AF) (mg/cm)
0.07
0.2
0.2
trespasser
Soil Ingestion Rate (IRS) (mg/day)
100
200
100
Skin Surface Area -Water Exposure (SA,) (cmZ)
19652
19652
19652
Water Ingestion Rate (IRW) (L/hr)
0.0985
0.071
0.071
trespasser
Water Exposure Time (ETA (hr/event)
2
2
0.5
Polling data adjustment
Water Event Frequency (EV) (events/day)
1
1
1
Carolina DEQ Risk Calculator

North Carolina DEQ Risk Calmlaior

Human Health and Ecological Risk Assessment Report
828 Martin Luther King, Jr. Boulevard Property
Chapel Hill, North Carolina
APPENDIX C
ANALYTICAL DATA SUMMARY TABLES FOR
SCREENING LEVEL ECOLOGICAL RISK
ASSESSMENT
,(rip
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Science & Engineering Consultants

Table C1
Ecological Screening - Surface Water (Background) - Bolin Creek
Chapel Hill, North Carolina
Analyte
CAS
Number of
Samples
Frequency of
Detection
Range of Detection
Location of
Maximum
Q Concentration
Range of
Detection Limits
Concentration Used
for Screening (ug/L)
15A NCAC 28
Freshwater A uatic Life Acute
15A NCAC 28
Freshwater Aquatic Life Chronic
USEPA Region 4
Freshwater
USEPA Region 4
Freshwater Chronic
USEPA AWQC (b)
CMC acute u L
USEPA AW QC (b)
CCC chronic u L
Screening
Value
Used u L
COPC?
Min.
0 Max.
Total
Dissolved
Total
Dissolved
Total
Dissolved
Total
I Dissolved
Total
Dissolved
Total
I Dissolved
Arsenic tot
7440-38-2
2
2
0.42
0.44
SW-1
NA
0.45
NA
NA
NA
NA
340 th, lit
NA
150 h
NA
340 h
NA
150 h
NA
150
N
Barium
7440-39-3
2
2
23.10
23.20
SW-2
NA
25.70
NA
NA
NA
NA
2000 cc
NA
220 cc
NA
NA
NA
NA
NA
220
N
Beryllium tot
7440-41-7
2
0
<0. 10
10.10
NA
0.10
0.10
NA
NA
NA
NA
31 r cc
NA
3.6 r cc
NA
NA
NA
NA
NA
3.6
N
Cadmium tot
7440-43-9
1 2
0
<0.080
`A080
NA
1 0.080
0.080
NA
NA
NA
NA
1.1 r
NA
0.16 r
NA
2.13 r
NA
0.27 r
0.16
N
Calcium
7440-70-2
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
116,000
NA
NA
NA
NA
NA
116000
NA
Chromium Total recov
7440-47-3
2
1
0.45
1 0.53
SW-1
NA
0.62
NA
NA
50
NA
1 022 n r
NA
48.8 n r
NA
1803 n r
NA
86.2 n r
NA
50
N
Cobalt
7440-48-4
2
2
0.16
0.16
SW-1/SW-2
NA
0.16
NA
NA
NA
NA
120 cc
NA
19 cc
NA
NA
NA
NA
NA
19
N
Copper tot
7440-50-8
2
2
1.1
1.2
SW-1
NA
1.2
NA
NA
NA
NA
7.3 r
NA
5.16 r
NA
14.0 r
NA
9.33 r
NA
5.16
NA
Iron
7439-89-6
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
1 000 b
NA
NA
NA
1,000
NA
1000
NA
Lead tot
7439-92-1
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
33.8 r
NA
1.32 r
NA
81.6 r
NA
3.18 r
NA
1.32
NA
Magnesium
7439-95-4
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
82000 dd
NA
NA
NA
NA
NA
82000
NA
Manganese
7439-96-5
2
2
21.2
22.2
SW-1
NA
22.2
NA
NA
NA
NA
1 1680 cc
NA
93 cc
NA
NA
NA
NA
NA
93
N
Mercury tot
7439-97-6
2
0
<0.20
<0.20
NA
0.20
0.20
NA
NA
0 .012
NA
1.4 s
NA
0.77 b s
NA
1.4
NA
0.77 s
NA
0.012
N
Nickel tot
7440-02-0
2
2
0.29
1 0.33 .I
SW-2
NA
0.33
NA
NA
NA
NA
261 r
NA
29.0 r
NA
469 r
NA
52.2 r
NA
29
N
Potassium
7440-09-7
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
53000 dd
NA
NA
NA
NA
NA
53000
NA
Selenium
7782-49-2
2
2
0.096
1 0.11
J SW-2
NA
0.11
NA
NA
5
NA
20 cc
NA
5 cc
NA
12.82 t
NA
5 t
NA
5
N
Sodium
7440-23-5
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
680000 dd
NA
NA
NA
NA
NA
680000
NA
Strontium
7440-24-6
2
2
85.3
85.5
SW-2
NA
85.5
NA
NA
NA
NA
48000 (cc)
NA
5300 cc
NA
NA
NA
NA
NA
5300
N
Thallium
7440-28-0
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
54 cc
NA
6 cc
NA
NA
NA
NA
NA
6
NA
Vanadium
7440-62-2
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
79 cc
NA
27 cc
NA
NA
NA
NA
NA
27
N
Zinc tot
7440-66-6
2
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
67(,)
NA
67(,)
NA
120 r
NA
120 r
NA
67
N
H
PH
2
2
7.13
7.22
1 SW-1
NA
7.22
NA
NA
6.0 - 9.0
NA
I NA
I NA
16.5 - 9.0
NA
I NA
I NA
1 6.5 - 9.0
1 NA
NA ii
NA
P:\Chapel Hill, Town ofl201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Background

Table C2
Ecological Screening - Sediment (Background) - Bolin Creek
Chapel Hill, North Carolina
Analyte
CAS
Number of
Samples
Frequency
of Detection
Range of Detection
g
Location of
Maximum
Concentration
Range of
Detection Li mits
Concentration
Used
for Screening
m /
USEPA Region 4 Sediment
�
Screening Values (g) (mg/kg)
Screening
Value Used
m
(/ g)
COPC.
Min.
Q
Max.
Q
ESV
RSV
Antimony
7440-36-0
2
NA
NA
NA
NA
NA
NA
2
25
2
NA
Arsenic
7440-38-2
2
2
1.95
2.74
SED-2
NA
2.74
9.8 z
33 z
9.8
N
Barium
7440-39-3
2
2
29.6
38.4
SED-1
NA
38.4
20 z
60 z
20
Y
Beryllium
744041-7
2
2
0.249
J
0.305
J
SED-2
NA
0.305
NA
NA
NA
NA
Cadmium
744043-9
2
0
0.619
<
0.636
<
NA
NA
0.636
1 z
5 z
1
NA
Chromium Total
744047-3
2
2
57.1
65.4
SED-1
NA
65.4
43.4 z
111 z
43.4
Y
Chromium Hexavalent
18540-29-9
2
2
0.428
J
0.796
J
SED-2
NA
0.796
NA
NA
NA
NA
Chromium Trivalent
16065-83-1
2
2
56.3
65.0
SED-1
NA
65.0
NA
NA
NA
NA
Cobalt
7440484
2
2
7.63
20.9
SED-2
NA
20.9
50 as
NA as
50
N
Colver
7440-50-8
2
2
8.42
13.8
SED-2
NA
13.8
31.6 z
149 z
31.6
N
Lead
7439-92-1
2
NA
NA
NA
NA
NA
NA
35.8 z
128 z
35.8
NA
Manganese
7439-96-5
2
2
449
811
SED-2
NA
811
460 b
1100 b
460
Y
Mercury
7439-97-6
2
2
0.0053
J
0.0078
SED-1
NA
0.0078
0.18 z
1.1 z
0.18
N
Nickel
7440-02-0
2
2
7.10
9.16
SED-2
NA
9.16
22.7 z
48.6 z
22.7
N
Selenium
778249-2
2
1
0.306
J
0.409
J
SED-4
NA
0.344
11 bb
20 b
11
N
Strontium
7440- 24-6
2
2
8.4
16.9
SED-4
NA
16.9
NA
NA
NA
NA
P:\Chapel Hill, Town of201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Background

Table C3
Ecological Screening - Soil (Background) - Bolin Creek
Chapel Hill, North Carolina
Analyte
CAS
Number Of
Samples
Frequency
�l y
Of Detection
Range Of Detection
Location of
Maximum
Concentration
Concentration Used
for Screening
(mg/kg}
USEPA Region 4 Soil
Screening Benchmark (g)
(mg/kg)
Eco-SSL (ee) Avian Soil
Screening Benchmark
(mg/kg)
Eco-SSL (ee) Invertebrate
Soil Screening Benchmark
(mg/kg)
Eco-SSL (ee) Mammalian
Soil Screening
Benchmark (mg/kg)
Eco-SSL (ee) Plants
Soil Screening
Benchmark (mg/kg)
ORNL (ff) Invertebrate
Soil Screening
Benchmark (mg/kg)
ORNL (gg) Plant
Screening
Benchmark
(mg/kg)
Screening
Value Used
(mg/kg)
COPC?
Min.
Max.
Arsenic
7440-38-2
3
1 3
1.8
2.05
1 BG-6
2.05
18
43
NA
46
18
60
10
10
N
Barium
7440-39-3
3
3
52.4
64.4
BG-6
64
330
NA
330
2,000
NA
NA
500
330
N
Beryllium
7440-41-7
3
3
0.370
J
0.625
BG-6
0.6
10
NA
40
21
NA
NA
10
10
N
Cadmium
7440-43-9
3
3
0.095
J
0.177
J
BG-6
0.177
0.36
0.77
140
0.36
32
20
4
0.36
N
Chromium Total
7440-47-3
3
3
24.5
1 70.2
BG-7
70.2
28
NA
NA
NA
NA
0.4
1
0.4
Y
Chromium Hexavalent
18540-29-9
3
1
1.14
<
5.34
BG-6
5.34
0.35
NA
NA
130
NA
0.4
1
0.35
1 Y
Chromium Trivalent
16065-83-1
3
3
24.5
J
70.2
BG-7
70.2
18
26
NA
34
NA
NA
NA
18
Y
Cobalt
7440-48-4
3
3
14.4
21.8
BG-8
21.8
13
120
NA
230
13
NA
20
13
Y
Copper
7440-50-8
3
3
26.40
62.8
BG-8
62.8
28
120
NA
230
13
50
100
13
Y
Manganese
7439-96-5
3
3
448.0
813
BG-7
813
220
4,300
450
4,000
220
NA
500
220
Y
Mercury
7439-97-6
3
3
0.007
1 0.025
BG-7
0.025
0.1
NA
0.1
NA
0.3
0.1
0.3
0.1
N
Nickel
7440-02-0
3
1 3
9.04
12.8
BG-6/BG-7
12.8
38
210
280
130
38
200
30
38
1 N
Selenium
7782-49-2
3
3
0.485
J
0.562
J
BG-6
0.562
0.52
1.2
4.1
0.63
0.52
70
1
0.52
Y
Strontium
7440-24-6
3
3
17.0
1 24.4
BG-8
24.4
96
NA
NA
NA
NA
NA
NA
96
N
P:\Chapel Hill, Town of\201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Background

Notes:
(a) - USEPA Regional Screening Levels (June 2015). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed November 2015. http:// www2 .epa.gov/risk/risk-based-screening-table-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed April 2015. http: / / water, epa.gov/scitech / swguidanee/standards/ criteria/current/index.cfm
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2012 Edition of the Drinking Water Standards and Health Advisories. Spring 2012. Accessed April 2015. http: // water.epa.gov/action /adviso ries/d rinking / upload/dwstandards20l2.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental Epidemiolog y Branch. http: //po rta l.ncdenr.org /c/doc ument _library /ge t_file?p_U d= 1169848&folderid=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Ground ware r Standards & IMACs. http: // porta l.ncdem.org /c/doc ument _library /ge t_file7uuid= 1 aa3fal3-2 cOf-45b7-ae96-5427fbld25b4 &groupi d= 38364 Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http: // report s.oah.state.nc.us / ncac/ title%2015a%20-%20environmental%20quality /chapter°/2002%20-%20en vironmental%20management /su bchapter%20b/subchapter%20b%20mles .pdf WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption offish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stringent of all applicable standards.
(g) - USEPA Region 4. 2015. Region 4 Ecological Risk Assessment Supplemental Guidance Interim Draft. August.
http :/ /www 2.epa.gov/ sites/production/ files/ 2015-09 /document s/ r4 _era _guidance _document _draft _final _8-25-2015.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
0) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(I) - Lead Treatment Technology Action Level is 0.015 mg/ L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium .
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site -specific total hardne ss of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(fl/CMCI) + (f2/CMC2)] where fl and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and CMCI and CMC2 are 185.9 ug/L and 12.82 ug/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site -specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 ug/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http: // www. lanl.gov/ commu nity-en vironment /environmen tal-ste wardship/pro tection /e co-risk-assessment.php
(y) - Long, Ed ward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program. NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bemacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for Florida Inland Waters . Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario. (bb) - Washington State Sediment Management Standards, Cleanup Objections. http: // www.ecy.wa.gov/ programs/ tcp/smu/sed _standards.htm
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http: // www.ep a.gov /g liclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/ TM-96 / R2. http: // www .esd.o ml.gov/ programs/eco risk/documents /t m96r2. pdf
(cc) - USEPA. 2015. Interim Ecological Soil Screening Level Documents. hup: // www2.epa.gov/chem ical-research/i nter im-ecological- soil -screening -level -documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter lI, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process: 1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/ TM-126 / R2. (Available at http: // www.esd.o ml.gov/ programs/ecorisk/doc uments /t ml26r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants: 1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ ER/TM-85 /R3. (Available at http:// www.esd.o ml.go v/ programs/ecorisk/doc uments / tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI= 0.2. September 2015. http://po rta l.ncdenr.org /c/ document _library/get _file7uuid= Of 60lffa-574d-4479-bbb4-253a f0665bf5&groupi d=38361
P:\Chapel Hill, Town of\201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Background

Source

Table C5
Ecological Screening - Surface Water (Source) - Bolin Creek
Chapel Hill, North Carolina
Analyte
CAS
Number of
Samples
Frequency of
Detection
Range of Detection
Location of
Maximum
Concentration
Concentration
Used
for Screening
(u /L)
15A NCAC 28
Freshwater Aquatic Life Acute
a /L
15A NCAC 28
Freshwater Aquatic LifeFreshwater
Chronic u /L
SEPA Region 4
jAcuteScreenin Values
USEPA Region 4
Freshwater Chronic
Screenin Values
USEPA AW C b
Q O
CMC acute u
(acute) ( �)
USEPA AW C b
Q O
CCC chronic u
( ) ( �)
Screening
g
Value
Used (ug/L)
COPC7
Min.
Q
Max.
Q
Total
Dissolved
Total
Dissolvedtal
Dissolved
Total
Dissolved
Total
Dissolved
Total
Dissolved
Arsenic tot
7440-38-2
2
2
0.41
0.45
SW-3
5
NA
NA
NA
NA
b h
NA
150 b h
NA
340 h
NA
150 h
NA
150
Barium
7440-39-3
2
2
23.70
25.70
1 SW-3
75.70
NA
NA
NA
NA
2000 cc
NA
220 cc
NA
NA
NA
NA
NA
Beryllium tot
7440-41-7
2
0
<0.10
<0.10
NA
0.10
NA
NA
NA
NA
31 r cc
NA
3.6 r cc
NA
NA
NA
NA
NA
Chromium Total recov
7440-47-3
2
1
0.62
0.62
SW-3
0.67
NA
NA
50
NA
1 022 n r
NA
48.8 n r
NA
1803 n r
NA
86.2 n r
NA
Cobalt
7440-48-4
2
2
0.14
0.26
SW-3
0,76
NA
NA
NA
NA
120 cc
NA
19 cc
NA
NA
NA
NA
NA
Copper tot
7440-50-8
2
2
0.98
2.8
SW-3
NA
NA
NA
NA
7.3 r
NA
5.16 r
NA
14.0 r
NA
9.33 r
NA
5.16
NA
Manganese
7439-96-5
2
2
24.80
37.40
NA
37.40
NA
NA
NA
NA
1680 cc
NA
93 cc
NA
NA
NA
NA
NA
Mercury tot
7439-97-6
2
0
<0.20
<0.20
NA
0,70
NA
NA
0.012
NA
1.4 b s
NA
0.77 b s
NA
1.4
NA
0.77 s
NA
Nickel tot
7440-02-0
2
2
0.26
J
0.50
SW-3
0.50
NA
NA
NA
NA
261 r
NA
29.0 r
NA
469 r
NA
52.2 r
NA
Selenium
7782-49-2
2
2
0.11
J
0.088
J
SW-4
0,088
NA
NA
5
NA
20 cc
NA
5 cc
NA
12.82 t
NA
5 W
NA
5
Strontium
7440-24-6
2
2
87.7
88.8
SW-3
88.8
NA
NA
NA
NA
48000 cc
NA
5300 ccL
NA
NA
NA
NA
NA
53
H
PH
2
2
7.39
7.46
SW-3
NA
NA
6.0 - 9 .0
NA
NA
NA
6.5 - 9.0 b
NA
NA
NA
6.5 - 9.0
NA
NA
NA
P:\Chapel Hill, Town ot\201959-Bolin CreekHHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Source v2 final

Table C6
Ecological Screening - Sediment (Source) - Bolin Creek
Chapel Hill, North Carolina
Analyte
CAS
Number of
Samples
Frequency of
Detection
Range of Detection
Location of
Maximum
Concentration
Concentration Used
for Screening (mg/kg)
USEPA Region 4 Sediment
ScreeningValues m /k
(g) ( g g)
Screening Value
Used (mg/kg)
COPC?
Min.
Q
Max.
Q
ESV
RSV
Arsenic
7440-38-2
2
2
1.36
2.35
SED-4
2.35
9.8 z
33 z
9.8
N
Barium
7440-39-3
2
2
16.4
20.3
SED-4
20.3
20 z
60 z
20
Y
Beryllium
744041-7
2
2
0.111
J
0.191
J
SED-4
0.191
NA
NA
NA
NA
Cadmium
744043-9
2
0
0.586
<
0.607
<
NA
0.607
1 z
5 z
1
NA
Chromium(Total)
744047-3
2
2
14.2
64.3
SED-4
64.3
43.4 z
ill z
43.4
Y
Chromium Hexavalent
18540-29-9
2
2
0.456
J
0.670
J
SED-3
0.670
NA
NA
NA
NA
Chromium Trivalent
16065-83-1
2
2
13.5
63.8
SED-4
63.8
NA
NA
NA
NA
Cobalt
7440484
2
2
5.18
7.26
SED-4
7.26
50 as
NA as
50
N
Copper
7440-50-8
2
2
8.39
20.2
SED-3
20.2
31.6 z
149 z
31.6
N
Mancianese
7439-96-5
2
2
225
293
SED-4
293
460 b
1100 b
460
N
Mercury
7439-97-6
2
2
0.0054
J
0.008
SED-4
0.008
0.18 z
1.1 z
0.18
N
Nickel
7440-02-0
2
2
4.81
10.5
SED-4
10.5
22.7 z
48.6 z
22.7
N
Selenium
778249-2
2
1
0.607
<
0.344
J
SED-4
0.344
11 b
20 b
11
N
Strontium
7440- 24-6
2
2
9.2
30.7
RED-4
30.7
NA
NA
NA
NA
P:\Chapel Hill, Town of201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Source v2 final

Table C7
Ecological Screening - Soil (Source) - Bolin Creel
Chanel RR North Carolina
Analyze
CAS
of
Samples
p
Frequency
of
Detection
Range of Detection
Location of
Maximum
Concentration
Concentration Used
for Screening
(mg/kg}
USEPA Region 4 Soil Screening
Benchmark (g)(mgAcg)
Eco-SSL (ee)Avian Soil
Screening Benchmark
(mg/kg)(1n9M9)
Eco-SSL (ee) Invertebrate Soil
Screening Benchmark(mgAcg)
Eco-SSL (ee)Mammalian
SoilScreeningBenchmark
Eco-SSL (ee)Planls Soil
Screening Benchmark
(m9M9)
ORNL(If)Invertebrate Soil
Screening Benchmark
(mg/kg)(mg/kg)
ORNL (gg) Plant
Screening
Benchmark
ScreeningNumber
Value Used
�mg1kg)
COPC?
Antimony
7440-36-0
8
0
NA
NA
NA
NA
0.27
NA
78
0.27
NA
NA
5
NA
NA
Arsenic
7440-38-2
39
39
0.792
60.3
HH-10
60.3
18
43
NA
46
18
60
10
10
Y
Barium
7440-39-3
39
39
13.5
3 260
HH-11
3260
330
NA
330
2,000
NA
NA
500
330
Y
Bery Ilium
7440-41-7
36
26
0.118
5.9
HH-11
5.9
10
NA
40
21
NA
NA
10
10
N
Boron
7440-42-8
1
0
NA
NA
NA
NA
7.5
NA
NA
NA
0.5
NA
0.5
NA
NA
Cadmium
7440-43-9
39
10
0.122
J 0.328
J
SED-15
0.33
0.36
0.77
140
0.36
32
20
4
0.36
N
Chromium Total
7440-47-3
39
39
5.76
B 45.0
HH-4
45.0
28
NA
NA
NA
NA
0.4
1
0.4
Y
Chromium Hexavalent
18540-29-9
38
22
0.21
J 2.7
S-6
2.7
0.35
NA
NA
130
NA
0.4
1
0.35
Y
Chromium Trivalent
16065-83-1
39
38
5.76
44.5
HH-4
44.5
18
26
NA
34
NA
NA
NA
18
Y
Cobalt
7440-48-4
36
36
3.9
20.8
Excavation H-4
20.8
13
120
NA
230
13
NA
20
13
Y
Copper
7440-50-8
36
36
3.90
180.0
MW-7
180.0
28
120
NA
230
13
50
100
13
Y
Lead
7439-92-1
11
11
2.3
30.0
HH-2
30.0
11
11
1700
56
120
500
50
11
Y
Manganese
7439-96-5
36
36
73.3
1480
Excavation H-4
1480
220
4,300
450
4,000
220
NA
500
220
Y
Mercury
7439-97-6
39
34
0.007
0.44
S-7
0.4
0.1
NA
0.1
NA
0.3
0.1
0.3
0.1
Y
Molybdenum
7439-98-7
1
0
NA
NA
NA
NA
2
NA
NA
NA
2
NA
2
2
NA
Nickel
7440-02-0
36
36
2.19
33.0
HH-4
33.0
38
210
280
130
38
200
30
30
Y
Selenium
7782-49-2
39
25
0.263
J 6.1
S-6
6.1
0.52
1.2
4.1
0.63
0.52
70
1
0.52
Y
Strontium
7440-24-6
36
36
6.7
269
HH-10
269
96
NA
NA
NA
NA
NA
NA
96
Y
Thallium
7440-28-0
8
2
0.60
0.81
MW-6
0.81
0.22
NA
NA
NA
NA
NA
NA
0.22
Y
Vanadium
7440-62-2
8
8
31.0
73.0
HH-4
73.0
7.8
7.8
NA
280
2
NA
2
2
Y
Zinc
7440-66-6
8
8
35.0
100
HH-3
100.0
46
46
120
79
160
100
50
46
1 Y
P:\Chapel Hill, Town ofl201959-Bolin CreekHHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Source v2 final adjustments

Notes:
(a) - USEPA Regional Screening Levels (June 2015). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed November 2015. http:// www2 .epa.gov/risk/risk-based-screening-table-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed April 2015. http: / / water, epa.gov/scitech / swguidanee/standards/ criteria/current/index.cfm
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2012 Edition of the Drinking Water Standards and Health Advisories. Spring 2012. Accessed April 2015. http: // water.epa.gov/action /adviso ries/d rinking / upload/dwstandards20l2.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental Epidemiolog y Branch. http: //po rta l.ncdenr.org /c/doc ument _library /ge t_file?p_U d= 1169848&folderid=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Ground ware r Standards & IMACs. http: // porta l.ncdem.org /c/doc ument _library /ge t_file7uuid= 1 aa3fal3-2 cOf-45b7-ae96-5427fbld25b4 &groupi d= 38364 Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http: // report s.oah.state.nc.us / ncac/ title%2015a%20-%20environmental%20quality /chapter°/2002%20-%20en vironmental%20management /su bchapter%20b/subchapter%20b%20mles .pdf WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption offish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stringent of all applicable standards.
(g) - USEPA Region 4. 2015. Region 4 Ecological Risk Assessment Supplemental Guidance Interim Draft. August.
http :/ /www 2.epa.gov/ sites/production/ files/ 2015-09 /document s/ r4 _era _guidance _document _draft _final _8-25-2015.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
0) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(I) - Lead Treatment Technology Action Level is 0.015 mg/ L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium .
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site -specific total hardne ss of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(fl/CMCI) + (f2/CMC2)] where fl and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and CMCI and CMC2 are 185.9 ug/L and 12.82 ug/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site -specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 ug/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http: // www. lanl.gov/ commu nity-en vironment /environmen tal-ste wardship/pro tection /e co-risk-assessment.php
(y) - Long, Ed ward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program. NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bemacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for Florida Inland Waters . Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario. (bb) - Washington State Sediment Management Standards, Cleanup Objections. http: // www.ecy.wa.gov/ programs/ tcp/smu/sed _standards.htm
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http: // www.ep a.gov /g liclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/ TM-96 / R2. http: // www .esd.o ml.gov/ programs/eco risk/documents /t m96r2. pdf
(cc) - USEPA. 2015. Interim Ecological Soil Screening Level Documents. hup: // www2.epa.gov/chem ical-research/i nter im-ecological- soil -screening -level -documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter lI, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process: 1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/ TM-126 / R2. (Available at http: // www.esd.o ml.gov/ programs/ecorisk/doc uments /t ml26r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants: 1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ ER/TM-85 /R3. (Available at http:// www.esd.o ml.go v/ programs/ecorisk/doc uments / tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI= 0.2. September 2015. http://po rta l.ncdenr.org /c/ document _library/get _file7uuid= Of 60lffa-574d-4479-bbb4-253a f0665bf5&groupi d=38361
P:\Chapel Hill, Town of\201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Background

Downgradient

Table C9
Ecological Screening - Surface Water (Downgradient) - Bolin Creek
Chapel Hill, North Carolina
Analyze
CAS
Number of
Samples
Frequency of
Detection
Range of Detection
Location of
Maximum Concentration
Range of
Detection Limits
Concentration
Used
for Screening
(ug/L)
15A NCAC 28
Freshwater Aquatic Life Acute (f)
(ug/L)
15A NCAC 28
Freshwater Aquatic Life Chronic
(f) (ug/L)
USEPA Region 4
Freshwater
Acute Screening Values
USEPA Region 4
Freshwater Chronic
Screening Values (g)
USEPA AWQC (b)
CMC (acute) (ug/L)
USEPA AWQC (b)
CCC (chronic) (ug/L)
Screening
Value
Used (ug/L)
COPC7
Min.
Q
Max.
Q
Total
Dissolved
Total
Dissolved
Total
Dissolved
Total
Dissolved
Total
Dissolved
Total
Dissolved
Aluminum
7429-90-5
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
750
NA
87 b
NA
750
NA
87
NA
87
NA
Antimony
7440-36-0
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
900 cc
NA
190 cc
NA
NA
NA
NA
NA
190
NA
Arsenic tot
7440-38-2
3
3
0.40
0.42
SW-7
NA
0.45
NA
NA
NA
NA
340 b h
NA
150 b h
NA
340 h
NA
150 h
NA
150
N
Barium
7440-39-3
3
3
16.9
18.4
SW-7
NA
25.70
NA
NA
NA
NA
2000 cc
NA
220 cc
NA
NA
NA
NA
NA
220
N
Beryllium tot
744041-7
3
0
m.10
m.10
NA
0.10
0.10
NA
NA
NA
NA
31 r cc
NA
3.6 r cc
NA
NA
NA
NA
NA
3.6
N
Cadmium tot
744043-9
3
0
m.080
m.080
NA
0.080
0.080
NA
NA
NA
NA
1.1 r
NA
0.16 r
NA
2.13 r
NA
0.27 r
NA
0.16
N
Calcium
7440-70-2
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
116,000
NA
NA
NA
NA
NA
116000
NA
Chromium Total recov
744047-3
3
0
<0.50
<0.50
NA
NA
0.50
NA
NA
50
NA
1 022 n r
NA
48.8 n r
NA
1803 n r
NA
86.2 n r
NA
50
N
Cobalt
7440-48-4
3
3
0.14
0.16
SW-7
NA
0.16
NA
NA
NA
NA
120 cc
NA
19 cc
NA
NA
NA
NA
NA
19
N
Copper tot
7440-50-8
3
3
0.84
1.1
SW-7
NA
1.1
NA
NA
NA
NA
7.3 r
NA
5.16 r
NA
14.0 r
NA
9.33 r
NA
5.16
NA
Iron
7439-89-6
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
1 000 b
NA
NA
NA
1,000
NA
1000
NA
Lead tot
7439-92-1
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
33.8 r
NA
1.32 r
NA
81.6 r
NA
3.18 r
NA
1.32
NA
Magnesium
7439-95-4
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
82000 dd
NA
NA
NA
NA
NA
82000
NA
Manganese
7439-96-5
3
3
18.7
23.1
SW-7
NA
23.1
NA
NA
NA
NA
1680 cc
NA
93 cc
NA
NA
NA
NA
NA
93
N
Mercury tot
7439-97-6
3
0
<0.20
<0.20
NA
0.20
0.20
NA
NA
0 .012
NA
1.4 b s
NA
0.77 b s
NA
1.4
NA
0.77 s
NA
0.012
N
Nickel tot
7440-02-0
3
3
0.21
J
0.23
J
SW-7
NA
0.23
NA
NA
NA
NA
261 r
NA
29.0 r
NA
469 r
NA
52.2 1 r
NA
1 29
N
Potassium
7440-09-7
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
53000 dd
NA
NA
NA
NA
NA
53000
NA
Selenium
7782-49-2
3
3
0.10
J
0.12
J
SW-5
NA
0.12
NA
NA
5
NA
20 cc
NA
5 cc
NA
12.82 t
NA
5 t
NA
5
N
Sodium
7440-23-5
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
680000 dd
NA
NA
NA
NA
NA
680000
NA
Strontium
7440-24-6
3
3
81.3
86.7
SW-7
NA
86.7
NA
NA
NA
NA
48000 cc
NA
5300 cc
NA
NA
NA
NA
NA
5300
N
Thallium
7440-28-0
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
54 cc
NA
6 cc
NA
NA
NA
NA
NA
6
NA
Vanadium
7440-62-2
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
79 cc
NA
27 cc
NA
NA
NA
NA
NA
27
N
Zinc tot
7440-66-6
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
67 r
NA
67 r
NA
120 r
NA
120 r
NA
67
N
H
PH
3
3
7.61
7.86
SW-5
NA
7.86
NA
NA
6.0 - 9.0
NA
NA
NA
6.5 - 9.0
NA
NA
I \'A
6.5 - 9.0
NA
NA (ii)NA
P:\Chapel I -Till, Town of\201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - DG

Table C10
Ecological Screening - Sediment (Downgradient) - Bolin Creek
Chapel Hill, North Carolina
Analytc
CAS
Number of
Samples
Frequency of
Detection
Range of Detection
Location of
Maximum
Concentration
Range of Detection
Limits
Concentration Used
for Screening (mg/kg)
USEPA Region 4 Sediment
Screening Values (g) (mg/kg)
Screening Value
Used (mg/kg)
COPC?
Min.
Q
Max.
Q
ESV
RSV
Aluminum
7429-90-5
NR
NR
NR
NR
NR
NR
NR
25000 x
58000 x
25000
NA
Antimony
7440-36-0
3
NA
NA
NA
NA
NA
NA
2
25
2
NA
Arsenic
7440-38-2
3
3
1.35
1.96
SED-6
NA
1.96
9.8 z
33 z
9.8
N
Barium
7440-39-3
3
3
16.4
24.3
SED-5
NA
24.3
20 z
60 z
20
Y
Beryllium
7440-41-7
3
3
0.179
J
0.247
J
SED-6
NA
0.247
NA
NA
NA
NA
Boron
7440-42-8
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Cadmium
7440-43-9
3
0
0.617
<
0.643
<
NA
NA
0.643
1 z
5 z
1
NA
Calcium
7440-70-2
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Chromium Total
7440-47-3
3
3
17.4
60.4
SED-7
NA
60.4
43.4 z
III z
43.4
Y
Chromium Hexavalent
18540-29-9
3
3
0.517
J
0.995
J
SED-7
NA
0.995
NA
NA
NA
NA
Chromium Trivalent
16065-83-1
3
3
16.8
59.4
SED-7
NA
59.4
NA
NA
NA
NA
Cobalt
7440-48-4
3
3
5.90
6.57
SED-6
NA
6.57
50 as
NA as
50
N
Colver
7440-50-8
3
3
8.39
20.2
SED-3
NA
20.2
31.6 z
149 z
31.6
N
Iron
7439-89-6
NR
NR
NR
NR
NR
NR
NR
20000 as
40000 as
20000
NA
Lead
7439-92-1
3
NA
NA
NA
NA
NA
NA
35.8 z
128 z
35.8
NA
Macinesium
7439-95-4
NR
NR
NR
_
NR
_
NR
NR
NR
NA
NA
NA
NA
Mancianese
7439-96-5
3
3
262
399
SED-5
NA
399
460 b
1100 b
460
N
Mercury
7439-97-6
3
2
0.0025
J
0.0058
SED-6
NA
0.0058
0.18 z
1.1 z
0.18
N
Molybdenum
7439-98-7
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Nickel
7440-02-0
3
3
4.86
9.04
SED-7
NA
9.04
22.7 z
48.6 z
22.7
N
Potassium
7440-09-7
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Selenium
7782-49-2
3
0
0.617
<
0.643
<
NA
NA
0.643
11 b
20 b
11
N
Sodium
7440 - 23- 5
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Strontium
7440- 24-6
3
3
6.2
8.4
SED-6
NA
8.4
NA
NA
NA
NA
Thallium
7440- 28-0
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Titanium
7440-32-6
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Vanadium
7440-62 -2
3
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Zinc
7440-66-6
3
NA
NA
NA
NA
NA
NA
121 z
459 z
121
NA
Alkalinity
ALK
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Bicarbonate Alkalinity
ALKBICARB
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Carbonate Alkalinity
ALKCARB
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Chloride
7647-14-5
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Methane
74- 82-8
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Nitrate
14797-55-8
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
loH
PH
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Sulfite
7757- 82-6
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Sulfide
18496- 25 -8
NR
NR
NR
NR
NR
NR
NR
39 b
61 b
39
NA
Total Dissolved Solids
TDS
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Total Orcianic Carbon
TOC
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
Total Suspended Solids
TSS
NR
NR
NR
NR
NR
NR
NR
NA
NA
NA
NA
P:\Chapel Hill, Town of201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - DG

Notes:
(a) - USEPA Regional Screening Levels (June 2015). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed November 2015. http:// www2 .epa.gov/risk/risk-based-screening-table-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed April 2015. http: / / water, epa.gov/scitech / swguidanee/standards/ criteria/current/index.cfm
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2012 Edition of the Drinking Water Standards and Health Advisories. Spring 2012. Accessed April 2015. http: // water.epa.gov/action /adviso ries/d rinking / upload/dwstandards20l2.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental Epidemiolog y Branch. http: //po rta l.ncdenr.org /c/doc ument _library /ge t_file?p_U d= 1169848&folderid=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Ground ware r Standards & IMACs. http: // porta l.ncdem.org /c/doc ument _library /ge t_file7uuid= 1 aa3fal3-2 cOf-45b7-ae96-5427fbld25b4 &groupi d= 38364 Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http: // report s.oah.state.nc.us / ncac/ title%2015a%20-%20environmental%20quality /chapter°/2002%20-%20en vironmental%20management /su bchapter%20b/subchapter%20b%20mles .pdf WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption offish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stringent of all applicable standards.
(g) - USEPA Region 4. 2015. Region 4 Ecological Risk Assessment Supplemental Guidance Interim Draft. August.
http :/ /www 2.epa.gov/ sites/production/ files/ 2015-09 /document s/ r4 _era _guidance _document _draft _final _8-25-2015.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
0) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(I) - Lead Treatment Technology Action Level is 0.015 mg/ L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium .
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site -specific total hardne ss of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(fl/CMCI) + (f2/CMC2)] where fl and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and CMCI and CMC2 are 185.9 ug/L and 12.82 ug/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site -specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 ug/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http: // www. lanl.gov/ commu nity-en vironment /environmen tal-ste wardship/pro tection /e co-risk-assessment.php
(y) - Long, Ed ward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program. NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bemacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for Florida Inland Waters . Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario. (bb) - Washington State Sediment Management Standards, Cleanup Objections. http: // www.ecy.wa.gov/ programs/ tcp/smu/sed _standards.htm
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http: // www.ep a.gov /g liclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/ TM-96 / R2. http: // www .esd.o ml.gov/ programs/eco risk/documents /t m96r2. pdf
(cc) - USEPA. 2015. Interim Ecological Soil Screening Level Documents. hup: // www2.epa.gov/chem ical-research/i nter im-ecological- soil -screening -level -documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter lI, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process: 1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/ TM-126 / R2. (Available at http: // www.esd.o ml.gov/ programs/ecorisk/doc uments /t ml26r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants: 1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ ER/TM-85 /R3. (Available at http:// www.esd.o ml.go v/ programs/ecorisk/doc uments / tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI= 0.2. September 2015. http://po rta l.ncdenr.org /c/ document _library/get _file7uuid= Of 60lffa-574d-4479-bbb4-253a f0665bf5&groupi d=38361
P:\Chapel Hill, Town of\201959-Bolin Creek HHECO RA\Reports\2020 June BRA Report\Appendicies\Ecological Screening Table - Background