2019.09.27_CCO.p12_PFASLoadingReductionPlanReviewFinal

Technical Review of Cape Fear River
PFAS Loading Reduction Plan for Cape
Fear Public Utility Authority (CFPUA)
September 27, 2019

PREPARED FOR PREPARED BY
Cape Fear Public Utility Authority
235 Government Center Drive
Wilmington, NC 28403
Tetra Tech
One Park Drive, Suite 200
PO Box 14409
Research Triangle Park, NC 27709
Tel [phone]
Fax [phone]
www.tetratech.com

(This page was intentionally left blank.)
Technical Review of Cape Fear River PFAS Loading Reduction Plan September 27, 2019
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1.0 BACKGROUND
Chemours Company issued the Cape Fear River PFAS Loading Reduction Plan (Geosyntec, 2019) to the
North Carolina Department of Environmental Quality (NCDEQ) and Cape Fear River Watch (CFRW) on
August 26, 2016 in response to the Consent Order (CO) entered by the Bladen County Superior Court
(paragraphs 12 and 11.1) on February 25, 2019. The CO was issued regarding emissions and
discharges of per- and polyfluoroalkyl substances (PFAS), including hexafluoropropylene oxide dimer
acid (HFPO-DA; 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid) and the ammonium salt of
HFPO-DA, which has the trade name of GenX®, from the Fayetteville Works facility. GenX is used to
manufacture high performance fluoropolymers. GenX replaces the ammonium salt of perfluorooctanoic
acid (PFOA), which was phased out of production in 2009 because PFOA is persistent in the
environment, bioaccumulates, and is toxic. At that time the Fayetteville Works facility was owned and
operated by E.I. du Pont de Nemours and Company (DuPont). The Chemours Company was founded in
July 2015 as a spin-off from DuPont.
In 2009 EPA authorized the manufacture of GenX; however, EPA also issued an order that required
DuPont to capture, at an overall efficiency of 99%, new chemical substances from wastewater effluent
and air emissions (premanufacture notice numbers P-08-508 and P-08-509). News broke regarding high
levels of GenX and PFAS in the Cape Fear River and downstream potable waters in 2017 – spurring
further environmental investigations and facility inspections. Shortly thereafter NCDEQ filed a Complaint
alleging violations of the premanufacture order due to evidence in downstream waters of PFAS
discharges by Chemours and DuPont, ultimately leading to the August 26, 2016 CO.
The Fayetteville Works facility is located in Bladen County, NC on the west side of the Cape Fear River
just upstream of the William O, Huske Lock and Dam (Lock and Dam #3). The facility includes two
Chemours manufacturing areas, the Monomers IXM area and the Polymer Processing Aid Area (PPA
area), as well as an onsite process Wastewater Treatment Plant (WWTP) and Power Area (Geosyntec,
2019). In addition, manufacturing areas on the facility grounds are leased to Kuraray America Inc. for
Butacite® and SentryGlas® production and to DuPont for polyvinyl fluoride (PVF) resin manufacturing.
The Chemours Fayetteville Works facility is located about 55 miles upstream of the Kings Bluff water
intake on the Cape Fear River where the Cape Fear Public Utility Authority (CFPUA) withdraws water for
treatment and potable use distribution. Elevated levels of PFAS have been observed in both the raw
source water from the Cape Fear River and finished water at the CFPUA’s Water Treatment Plants
(WTPs). Traditional water treatment processes do not successfully remove GenX and other PFAS
(Hopkins et al., 2018). The effectiveness of currently implemented and proposed PFAS pollution control
strategies adopted by Chemours directly affect the quality of CFPUA’s intake water and community
exposure to these substances.
In light of these concerns, CFPUA engaged Tetra Tech to conduct a technical review of the PFAS
Loading Reduction Plan and associated environmental assessments. Specifically, CFPUA requested
input on the technical soundness of the surface and groundwater modeling, reasonableness of the
assumptions applied in the analyses, reasonableness of the seven proposed strategies for reducing
PFAS loads, identification of critical gaps in the analyses, and recommendations for additional studies
related to reducing PFAS loads.
The Cape Fear River PFAS Loading Reduction Plan itself consists of 33 pages plus a cover letter, but is
supported by five technical appendices: 1) PFAS Mass Loading Model, 2) Seeps and Creeks
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Investigation Report, 3) Outfall 002 Assessment, 4) Terracotta Pipe Grouting Report, and 5) HFPO-DA
Loading Reduction Estimates, all of which were completed by Chemours’ consultant, Geosyntec
Consultants of NC, P.C. The PFAS Loading Reduction Plan includes seven proposed actions aimed to
reduce PFAS loading to the Cape Fear River. Findings from the review of the plan and supporting
technical reports are discussed in this memorandum.
To better understand the relationship between river flow rate at the Kings Bluff intake and PFAS
concentrations, CFPUA has developed a correlation analysis between the variables. CFPUA requested a
technical review of the correlation analysis, which is also discussed in this memorandum as are
implications related to the loading reduction plan.
2.0 TECHNICAL REVIEW
The PFAS loading reduction plan is informed by the PFAS Mass Loading Model (MLM), which evaluates
contributions of PFAS to the Cape Fear River from nine pathways (Figure 1):
• Upstream river water and groundwater
• Willis Creek (north of the facility)
• Direct atmospheric deposition on the river in the vicinity of the facility
• Outfall 002
• Onsite upwelling groundwater
• Four identified onsite channelized seeps
• Old Outfall 002
• Offsite groundwater
• Georgia Branch Creek (south of the facility)

Figure 1. PFAS Transport Pathways (Geosyntec, 2019; Figure 5)
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The MLM incorporates analyses and findings from the other appendices, such as the Seeps and Creeks
Investigation Report that is used for characterizing groundwater conditions and contributions. Comments
on the technical soundness, reasonableness of the assumptions applied, and critical gaps are discussed
in the sections below. Key comments are summarized in Table 1.
Table 1. Key Comments from the Technical Review
Brief Description of Comment Section (Comment
Number)
Lack of adequate groundwater monitoring data and application of post-
Hurricane Florence data.
2.1 (#1) and 2.2 (#1 and
#5)
The modeling applied insufficient extents for resurfacing groundwater,
resulting in potentially underestimated loads to the river. 2.2 (#2 and #3)
Limited scope of atmospheric deposition modeling (e.g., only HFPO-DA;
seemingly conservative application of October 2018 conditions; limited
spatial extent)
2.1 (#4)
Lack of information about the extent, magnitude, and impacts of offsite
PFAS groundwater and soil contamination that may continue to contribute
PFAS to the river.
2.2 (#4) and 2.3 (#7)
Lack of information to characterize PFAS contamination of sediment in the
Cape Fear River bed and riparian wetlands. 2.2 (#6) and 2.3 (#7)
Implementation timing and ongoing risks for untreated sources. 2.3 (#1 and #2)
Lack of information regarding the effectiveness of treatment technologies. 2.3 (#3)
Need for notification requirements regarding spills or other releases since
no production related changes have been required to date. 2.3 (#5)
Concerns regarding discharges of Kuraray process wastewater shown to
contain elevated PFAS concentrations. 2.3 (#6)

2.1 TECHNICAL SOUNDNESS
This section summarizes our concerns regarding the technical soundness of data that has been
assembled and cited to support conclusions in Cape Fear River PFAS Loading Reduction Plan and
supporting appendices.
1. Onsite groundwater sampling data used to estimate mass loading to the river is based on a single
round of samples collected primarily post Hurricane Florence – four of the five well samples in
Appendix A are from late October – early November 2018, while the hurricane occurred in
September 2018 with over 12 inches of rain recorded in nearby Fayetteville during the hurricane.
This rainfall (and associated infiltration) may have significantly impacted short-term groundwater
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sampling data, thus the representativeness of the data used is in question, especially since no
other sampling data for the wells were provided for comparison purposes.
2. Onsite and offsite groundwater (transport pathways 5 and 8) PFAS concentrations used for the
mass loading model are not provided in Table 3 of the MLM report. Is there a reason why these
were specifically excluded while all other transport pathways had concentrations provided? What
are the concentrations that were used?
3. It is unclear how groundwater south of the plant between Old Outfall 2 and Georgia Bank Creek
was handled. Was groundwater in this area included in the onsite or offsite groundwater mass
loading calculations? What parameters were used in the evaluation of contributions to the river
from this area?
4. Previously reported deposition contours for air emissions from the Fayetteville Works facility were
used to quantify the atmospheric deposition load in the MLM (ERM, 2018). Estimated deposition
rates were combined with the average Cape Fear River surface area and estimated residence
time to estimate a mass loading from aerial deposition to the river. The deposition load to the
river surface was only evaluated for a ~3.5 km segment of the river near the facility. Key
concerns regarding the modeling analysis follow, and critical gaps in the overall study related to
atmospheric deposition are discussed in the next subsection. Note that some information
discussed here is presented in the atmospheric deposition modeling report (ERM, 2018).
a. The atmospheric deposition modeling focuses solely on HFPO-DA (ERM, 2018). To
estimate the atmospheric deposition load of other PFAS compounds (non-HFPO-DA) for
the MLM, concentration ratios derived from well monitoring samples are applied. The
report, however, lacks proof that ratios from well measurements are directly applicable to
air concentrations. Indeed, the ratios are likely to be different as PFAS compounds
volatility, airborne transport, and subsurface soil sorption characteristics are not linearly
related (ITRC, 2018). Therefore, this is not a reasonable assumption given the lack of
evidence. The report also does not describe how the air transport and deposition of other
PFAS compounds (non-HFPO-DA) differs from that of HFPO-DA.
b. The MLM applies expected not actual emissions from the facility for October 2018. The
MLM does not thoroughly discuss how factors that influence variability in air transport and
deposition (e.g., fluctuations due to weather) are addressed. It is unclear if the results
applied represent a single month (i.e., October 2018) extrapolated to represent annual
deposition or if annual deposition is characterized by modeling emissions, transport, and
deposition over a multi-year period. If it is the former, the application of October 2018
seems to be conservative; simulations of PFAS deposition for May 2018 are more
widespread compared to October 2018. According to Table C-1 the same emission rates
are applied for both (May and October 2018) scenarios, which means the differences in
the extent of deposition are due to atmospheric conditions. Application of conditions for a
single month is not reasonable for evaluating the annual load and the MLM should
account for variability in conditions that impact the load. If in fact the atmospheric
deposition modeling used to inform the MLM simulated a multi-year period, the report
should clarify the methods. In addition, it is important that the impacts of intra- and inter-
annual variability are discussed, including fluctuating emissions from the facility (i.e., due
to operations cycling) and weather (e.g., wind direction and speed).
c. Dilution factors are applied to estimate resulting concentrations in groundwater wells
surrounding the property for various atmospheric deposition scenarios, however, the
approach assumes zero concentration in existing aquifer water. Thus, the resulting
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groundwater concentrations presented are biased low. [Note this information does not
seem to be applied in the MLM.]
5. It is noted in Section 2.1.5. of the “Seeps and Creeks” appendix that samples were collected to
avoid inclusion of suspended solids. In the final bullet of Section 3.4 of the Outfall 002
Assessment report it is stated that no relationship between TSS and total or dissolved PFAS was
found (although details of the analysis are not provided). However, this conflicts with the fact that
elevated PFAS concentrations at Location 22 are attributed to sediment clogging the autosampler
(Outfall 002 Assessment report). Sorption of PFAS compounds is complex because the
compounds have a lipophilic head and a hydrophobic tail. Thus, a clear relationship to TSS is not
expected. A relationship to organic carbon on a PFAS species-by-species basis is likely yet was
not examined.
6. The MLM approximates loading rates for each pathway based on PFAS concentration and flow
data. The validity of the results for certain pathways is impacted by sparse monitoring records.
For example, only a single sample was applied to characterize the upstream load (Section 4.1),
even though elevated PFAS levels have been observed in upstream waters such as the Haw
River (Barnes, 2019). Using a single sample to estimate the long-term load is not sufficient and
additional monitoring should be conducted to characterize the upstream load across various
seasons and flow regimes. It is stated in Section 4.5 that all EPA 537 PFAS compounds did not
originate from the site as these were present in intake water. Therefore, EPA 537 PFAS
compounds were assigned a zero concentration for the MLM. It can be deferred (although it is
not explicitly stated) that this finding is based on the single upstream sample. Additional sampling
is needed to evaluate the potential contribution of EPA 537 PFAS from the site.
7. No explanation is provided as to why some EPA 537 PFAS sampling method substances are
reported as “NS” – defined as compound was not analyzed for in collected sample(s) or sample
was not collected. Due to the lack of monitoring for these compounds, the total PFAS
concentrations and loads reported in the study may be an underestimate of actual total PFAS
concentrations and loads.
8. The DVM Narrative Reports show that many of the collected samples applied in the MLM did not
meet sampling protocols (e.g., due to exceeded hold time). In addition, there are several cases
where the dissolved concentration exceeds that of the total concentration for a PFAS substance
(Table 10 Analytical Results – Stormwater Sampling). These data quality concerns contribute
uncertainty to the monitoring and modeling results.
9. Results from TestAmerica were pending from the Outfall 002 monitoring at the time the report
was issued. Results presented are from the onsite Chemours lab. The report does not specify if
the Chemours lab is approved through the Resource Conservation and Recovery Act (RCRA).
The report and modeling should be updated to incorporate the TestAmerica records.
10. HFPO-DA reductions from 2017 and 2019 in the load to the Cape Fear River are presented in the
HFPO-DA Loading Reduction Estimates report. For both 2017 and 2019 monitoring from a single
day was applied to estimate a typical daily load, which was directly extrapolated to generate an
annual load (by multiplying by the number of days per year). The river flow applied to compute
the annual load estimate for 2019 was less than one-third of the river flow applied to compute the
annual load estimate for 2017, which falsely skews (overestimates) the reported percent
reductions in loading to the Cape Fear River. It is not reasonable to assume that monitoring from
a single day can be used to compute an accurate annual load. Recent load estimates computed
by CFPUA based on more frequent monitoring at Lock and Dam #1 are higher. The analysis
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should be redone and samples from multiple monitoring events spanning various seasons and
flows should be applied for characterizing baseline and current loads and associated reductions.
2.2 CRITICAL GAPS
1. Overall, there is a significant lack of site-specific data regarding groundwater conditions at the
facility. The report indicates that a total of five monitoring wells were available and used in the
mass loading evaluation, which is not nearly adequate for delineating site geologic/hydrogeologic
conditions and groundwater impacts considering the three groundwater flow systems involved.
The report also indicates that additional groundwater characterization work is planned/underway
for the site, which should provide data to more accurately portray onsite groundwater impacts to
the river and improve the representativeness of the loading model. Hydrogeologic characteristics
were in many cases estimated based on literature values and/or empirical evidence – generic
ranges for hydraulic conductivity were used from general hydrogeology references, and
groundwater flow gradients were estimated from water levels in riverside wells and a river
gauging level remote from the site. It is important to collect adequate site-specific data to use in
developing a technically sound detailed hydrogeologic conceptual site model that encompasses
all three groundwater flow zones identified at the site (perched zone, surficial aquifer, and Black
Creek aquifer) for quantifying groundwater flow rates and volumetric discharges/mass loading to
the river.
2. Using observed mass loading at Bladen Bluffs, the MLM was calibrated through the adjustment of
the following parameters: hydrologic conductivity for the Upper and Lower portions of the Black
Creek Aquifer, groundwater discharge length (i.e., area contributing resurfacing groundwater to
the river), and an offsite gradient adjustment factor. The rationale for modifying the discharge
area for groundwater during model calibration iterations (only 40% to 75% of the total area was
used) is unclear – all groundwater in the three flow zones identified (perched zone, surficial
aquifer, Black Creek aquifer) should eventually discharge to the Cape Fear River either via direct
discharge (Black Creek aquifer) or via seeps and surface water. Clearly the onsite groundwater
discharge area length is significantly under-represented as described in Table D-2 of the onsite
groundwater flow estimate (2,900 feet), which results in an under-estimation of onsite
groundwater discharge from the Chemours site to the river. The calibration process was used as
the rationale for this reduced length, however, the calibration process should be constrained to
accurately reflect site conditions. Assuming 100% discharge of the Black Creek aquifer to the
river would increase discharge/mass loading to the river significantly.
3. Similar to the previous comment, groundwater upwelling to the river is assumed to be less than
100%. Based on a USGS report regarding groundwater flow in the Coastal Plain Aquifer System
of North Carolina, some shallow groundwater in the area may resurface as baseflow to the Cape
Fear River while some may resurface further downstream (Giese et. al., 1991); however,
additional field information is needed to support this parameterization. The assumed aquifer
thickness for offsite groundwater discharge to the river is not provided – what was assumed and
what is the basis for the assumption? Finally, a hydraulic conductivity value of 2.55 x 10-4 m/s
was used for calculating offsite groundwater discharge to the river; however much lower K values
were assumed for onsite groundwater (Black Creek aquifer). It is reasonable to assume that
offsite shallow groundwater across the river is from the same formation; why the difference in K
values? This would underestimate the relative mass loading via onsite groundwater versus
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offsite groundwater. In addition, the Black Creek aquifer is likely to be slightly thicker on the other
side of the River as it is generally down-dip; was this taken into account?
4. The loading analysis excludes deposition to surrounding land (wet or dry) that is stored in offsite
soils, transported to streams via erosion, and leached into groundwater. These mechanisms and
associated loadings have yet to be properly quantified. An investigation for the DuPont
Washington Works plant near the Ohio-West Virginia border found contamination from
atmospheric deposition up to 20 miles from the plant (Zevitas and Zemba, 2018). It is plausible
that air emissions at the Fayetteville Works facility were/are transported further than assumed in
the loading analysis, deposited, stored in soils, and leached into groundwater that resurfaces as
baseflow to the river. Wells exhibiting high levels of PFAS contamination opposite of observed
groundwater pathways (e.g., wells on the east side of the river) support this concept (ERM,
2018). This also could explain why concentrations and loads of some PFAS compounds are
higher at the Kings Bluff intake compared to Bladen Bluffs, specifically during June 2019 (Table
7-A and Table 7-B), but the MLM was only calibrated at the Bladen Bluffs intake located about
five miles downstream of the facility. CFPUA analyzed the relationship between raw water total
PFAS and river flow rate using 2019 monitoring records (Figure 2). Elevated PFAS
concentrations occur during periods of low flow. Given the halting of the release of process
wastewater by Chemours, the elevated concentrations are likely attributable to onsite and offsite
groundwater, releases from sediment bed stores, and/or currently unidentified other point
sources. Therefore, a critical gap in the current analysis framework is that the extent, magnitude,
and impacts of offsite PFAS groundwater and soil contamination has not been evaluated.
Releases of contaminated groundwater, diffusion from contaminated sediment, and erosion of
contaminated soils may contribute PFAS to the CFPUA’s intake water following the
implementation of the proposed control strategies (Section 2.3). Additional offsite monitoring and
modeling is needed to understand the long-term implications on downstream water quality.

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Figure 2. PFAS Concentrations and Cape Fear River Flow (provided by CFPUA)
5. For offsite groundwater where airborne deposition is considered to be the mechanism for PFAS
transport to groundwater, prevailing wind directions should be utilized to estimate groundwater
concentrations and mass loading to the river through offsite groundwater discharge to the river
(see supplemental wind rose). For example, the predominant wind directions measured at
nearby Fayetteville are from the southwest and from the northeast, which generally correlates
with Figure E-2. For the area east and southeast of the site, however, there is very little data (few
residential wells) and a review of Figure E-2 suggests that PFAS loading to groundwater in this
area may be underestimated. The sampling data for wells west and northwest of the site (a much
larger data set) could, however, be used to project/estimate groundwater concentrations/mass
loading due to airborne deposition in the east-southeast area as the proportion of west and
northwest winds (from west to east) is similar to/slightly higher than east/southeast winds (1998 –
2019 data). As currently configured, it appears that offsite groundwater mass loading to the river
from east/southeast of the site may be underestimated.
6. A critical gap in the technical framework is that no sampling has been reported to characterize
PFAS contamination of sediment in the Cape Fear River bed or riparian wetlands. It is
anticipated that historic emissions and discharges from the facility have accumulated and caused
long-term residual contamination of the river and riparian wetlands. Diffusion from such
contaminant stores could provide a long-term source of PFAS contamination to the river.
Scouring of contaminated sediment from the river bed or banks during high flow events could also
elevate PFAS concentrations in downstream intake water. Sediment sampling along the
mainstem should be conducted to characterize the extent and magnitude of sediment bed and
riparian wetland contamination and the potential associated risks. Areas prone to excess build-
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up of organic matter, such as sluggish riverine swamps and pools behind the locks and dams,
face a higher risk of exhibiting elevated sediment PFAS concentrations. A comprehensive study
is needed to characterize sediment PFAS contamination in the Cape Fear River bed that includes
assessment of potential contamination hot-spots, such as the Kings Bluff intake canal situated
near the Cape Fear River Lock and Dam #1. In addition, onsite sediment sampling has been
sparse and should be extended to all concentrated surface flow pathways (e.g., open channel to
Outfall 002).
7. A flow-based PFAS loading curve prepared by CFPUA for 2019 is shown in Figure 3. Higher
PFAS loads are associated with higher flows, which indicates that stormwater and/or sediment
bed erosion (as described in the previous comment) contributes PFAS to the river. Yet, these
sources are poorly quantified, including both onsite and offsite stormwater contributions.

Figure 3. Flow-based PFAS Loading Rate (provided by CFPUA)
8. A mass balance evaluation of flow from the facility to the river is not provided in the Geosyntec
(2019) report and is needed to verify the overall annual flow balance applied in the MLM. Such
an evaluation should incorporate flow sources, storages, and discharges surface and subsurface
discharges from the facility study area.
9. The possibility of additional diffuse discharges from the perched zone/shallow aquifer in other
areas along the river should be investigated.
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2.3 LOADING REDUCTION PLAN AND STRATEGIES
Chemours has previously implemented PFAS loading control measures: 1) eliminating process
wastewater discharges (excluding those from site tenants Kuraray and DuPont), 2) air emission controls,
3) lining the facility’s cooling water channel and sediment ponds, and 4) extraction of groundwater
discarded offsite.
Seven new control strategies are proposed for the Chemours Fayetteville Works facility in the current plan
(Geosyntec, 2019): 1) capture and treat Old Outfall 002 water (within two years), 2) capture and treat
groundwater from seeps (within five years), 3) targeted sediment removal from conveyance network
(within one year), 4) develop a stormwater pollution prevention plan (within one year), 5) targeted
stormwater source control and/or treatment (within four years), 6) decommission and replacement of
remaining terracotta piping (that carried industrial process wastewater; within two years), and 7)
assessment of potential groundwater intrusion into the conveyance network (within five years). All
proposed actions are to be implemented within five years and are onsite controls (on the Fayetteville
Works property). Key comments regarding the plan and strategies follow.
1. It is stated on page v. regarding the control strategies that “Four of these actions would be
implemented within two years of Consent Order Amendment and three of the actions would be
implemented within five years of Consent Order Amendment (assuming all necessary permits
and authorizations are provided in a timely manner).” Control actions may not be implemented
on schedule due to the ambiguity of this statement, which poses a risk to downstream users.
2. The actions related to groundwater (#2 and #7) are set to take the longest time to implement yet
are the top loading sources according to the MLM. Plans to evaluate and address groundwater
and stormwater are still being developed, thus, loadings from these sources remain a vulnerability
to downstream water supplies.
3. No specific treatment option is listed for captured onsite surface and groundwater, nor is the
effectiveness of the proposed treatment methods demonstrated. Without these specifications it is
uncertain if the loading reduction plan will effectively mitigate PFAS pollution. An onsite study
evaluating the proposed treatment technologies and observed effectiveness (i.e., percent
removal, treated concentrations and loads) should be required.
4. The onsite perched zone pumping described in the report (Section 3; Completed Reduction
Actions) amounts to <0.1 gpm. Has there been any evaluation to determine whether the pumping
rate can be increased via more aggressive pumping or additional groundwater extraction points to
enhance capture of this highly impacted groundwater?
5. No manufacturing process changes have been required to date. Spills or unknown leaks or
emissions at the facility remain a risk to CFPUA’s source water. In paragraph 15 of the CO,
Chemours is to provide notification to downstream water utilities in the event of elevated PFAS
releases through Outfall 002. However, CFPUA should consider requesting spill (or other
contaminant release) notification requirements that are more comprehensive.
6. Discharge of Chemours’ process wastewater has been halted and the waste is injected into
subsurface storage out-of-state. However, elevated HFPO-DA and PFMOAA concentrations
were also observed in Kuraray process wastewater, which continues to be discharged from the
onsite WWTP (page 18 of the Outfall 002 Assessment) via Outfall 002. Sources causing
contamination of Kuraray process wastewater have not been identified and quantified.
Furthermore, control strategies have not been required or proposed for the Kuraray process
wastewater.
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7. No PFAS loading control strategies are recommended for contaminated offsite soils, offsite
groundwater, or river sediment due to the lack of evaluation of these sources (see Section 2.2).
Additional strategies may be needed following the evaluation of these sources to ensure
protection of downstream water quality.
All monitoring applied in the assessment appears to have been conducted by Geosyntec and contracted
labs for Chemours. DEQ can require split sampling (samples provided to DEQ for parallel testing) per the
Consent Order. Split sampling would be beneficial from the perspective of CFPUA for quality assurance
and control checking, therefore, CFPUA should inquire about completed split sampling and the findings,
or the rationale for why split sampling has not occurred to date.
3.0 REFERENCES
Barnes, G. (2019, July 30). PFAS shows up in Haw River, Pittsboro water, but gets limited local attention.
North Carolina Health News. Retrieved from https://www.northcarolinahealthnews.org/2019/07/30/pfas-
shows-up-in-haw-river-pittsboro-water-but-little-local-outcry/.
ERM. 2018. Modeling Report: HFPO-DA Atmospheric Deposition and Screening Groundwater Effects.
Prepared for Chemours Company FC, LLC. by Environmental Resources Management, Malvern,
Pennsylvania.
Giese, G.L., Eimers, J.L. and R.W. Coble. 1991. Simulation of Ground-water Flow in the Coastal Plain
Aquifer System of North Carolina. U.S. Geological Survey Open-File Report 90-372, 178 p.
Geosyntec. 2019. Cape Fear River PFAS Loading Reduction Plan. Prepared for Chemours Company FC,
LLC. by Geosyntec Consultants of NC, P.C., Raleigh, North Carolina.
Hopkins, Z. R., Sun, M., DeWitt, J.C. and D.R.U. Knappe. 2018. Recently Detected Drinking Water
Contaminants: GenX and Other Per- and Polyfluoroalkyl Ether Acids, American Water Works Association,
110(7), https://doi.org/10.1002/awwa.1073.
ITRC. 2018. Environmental Fate and Transport for Per- and Polyfluoroalkyl Substances. Interstate
Technology and Regulatory Council, Washington, DC.
Zevitas, C.D. and S. Zemba. 2018. Atmospheric deposition as a source of contamination at PFAS-
impacted sites [Powerpoint slides]. Retrieved from http://www.newmoa.org/events/docs/344_301/2018-
12-13_ZevitasZembaAtmosphericDepositionWebinar.pdf