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CAPE FEAR RIVER PFAS MASSLOADING ASSESSMENT - FIRSTQUARTER 2021 REPORT
Chemours Fayetteville Works
Prepared for

The Chemours Company FC, LLC
22828 NC Highway 87
Fayetteville, NC 28306
Prepared by
Geosyntec Consultants of NC, PC
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
Project Number TR0795A
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TABLE OF CONTENTS
1INTRODUCTION AND OBJECTIVES .............................................................. 1

2

SCOPE .................................................................................................................. 2
2.1 Sampling Activities in Q1 2021 .................................................................. 2
2.2 Cape Fear River PFAS Mass Load Sampling Program ............................... 3
2.3 Cape Fear River PFAS Mass Loading Model Sampling Program .............. 4
2.4 Laboratory Analyses .................................................................................... 4

3

PFAS MASS LOAD TO CAPE FEAR RIVER ................................................... 5
3.1 Q1 2021 Total PFAS Mass Load ................................................................. 6
3.2 Mass Discharge at Bladen Bluffs, Tar Heel Ferry Road Bridge andKings Bluff Intake Canal ...................................................................................... 7

4

CAPE FEAR RIVER PFAS MASS LOADING MODEL ................................... 8
4.1 PFAS Mass Loading Model Pathways ........................................................ 8
4.2 Mass Loading Model Results ...................................................................... 9
4.2.1 Reductions in Modeled Mass Discharge ......................................... 9
4.2.2 Modeled versus Measured Mass Discharge .................................. 10
4.2.3 Relative Contributions by Pathway ............................................... 11
4.3

Mass Loading Model Sensitives ................................................................ 11
4.3.1 Variability in Input Parameters ..................................................... 11
4.3.2 River Flows and Precipitation ....................................................... 125

SUMMARY ........................................................................................................ 12

6

REFERENCES ................................................................................................... 13

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LIST OF TABLES
Table 1:PFAS Analyte List

Table 2:

Surface Water Sample Collection and Flow Measurement Summary

Table 3:Groundwater Monitoring Well Sample Collection and Water Level
Measurement Summary

Table 4:

Summary of Calculated Total Mass Load in the Cape Fear River

Table 5A:

Cape Fear River PFAS Mass Load by Compound and Time Interval

Table 5B:

Old Outfall 002 Captured PFAS Mass Load by Compound and TimeInterval

Table 5C:

Seep C Flow Through Cell Captured Mass Load by Compound and TimeInterval

Table 6:

Summary of Total PFAS Mass Discharge at Tar Heel Ferry Road Bridge

Table 7:PFAS Mass Loading Model Potential Pathways

Table 8A:

Summary of Total PFAS Mass Discharge by Pathway Before Remedies– January 2021

Table 8B:

Summary of Total PFAS Mass Discharge by Pathway After Remedies –January 2021

Table 9A:

Summary of Total PFAS Mass Discharge by Pathway Before Remedies– February 2021

Table 9B:

Summary of Total PFAS Mass Discharge by Pathway After Remedies –February 2021

Table 10A:

Summary of Total PFAS Mass Discharge by Pathway Before Remedies– March 2021

Table 10B:

Summary of Total PFAS Mass Discharge by Pathway After Remedies –March 2021

Table 11:

Cape Fear River Total Table 3+ (17 Compounds) Relative Mass
Discharge Per Pathway

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LIST OF FIGURES
Figure 1:

Site Location Map

Figure 2:

Cape Fear River Watershed and Downstream Drinking Water Intakes

Figure 3:

Potential PFAS Transport Pathways to the Cape Fear River from Site

Figure 4A:

Sample and Flow Measurement Locations – January 2021

Figure 4B:

Sample and Flow Measurement Locations – February 2021

Figure 4C:

Sample and Flow Measurement Locations – March 2021

Figure 5:

Cape Fear River Sample Locations – Q1 2021

Figure 6:

Groundwater Wells for Mass Loading Assessment

Figure 7:

Total Table 3+ Concentrations (17 Compounds) Concentrations, Daily
Precipitation and Flow at Tar Heel Ferry Road Bridge

Figure 8:

Total Table 3+ Concentrations (17 Compounds) Mass Discharge, Daily
Precipitation and Flow at Tar Heel Ferry Road Bridge

Figure 9:Comparison of Modeled and Measured Total Table 3+ Mass Discharge
and Concentrations at Tar Heel Ferry Road Bridge
LIST OF APPENDICES

Appendix A: Sampling Results
Appendix B: Supplemental Tables
Appendix C: Field Forms
Appendix D: Laboratory Reports and DVM Report
Appendix E: Supporting Calculations – Onsite Groundwater Pathway
Appendix F: Supporting Calculations – Direct Aerial Deposition on Cape Fear River

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LIST OF ABBREVIATIONSCAPCorrective Action Plan

cfs

cubic feet per second

CFR-TARHEEL

Cape Fear River at Tar Heel Ferry Road Bridge

CO

Consent Order

CO Addendum

Addendum to Consent Order Paragraph 12

DVM

Data Verification Modulekg

kilograms

mg/s

milligrams per second

MT-1

mass per unit timeng/Lnanograms per liter

NCDEQ

North Carolina Department of Environmental Quality

PFAS

pe- and polyfluoroalkyl substances

PFHpA

perfluoroheptanoic acidQ1

first quarter

Q2

second quarter

Q3

third quarter

Q4

fourth quarter

RPD

relative percent difference

SOPstandard operating procedure

USGS

United States Geological Survey

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1

INTRODUCTION AND OBJECTIVES

Geosyntec Consultants of NC, P.C. (Geosyntec) has prepared this Cape Fear River PFAS
Mass Loading Assessment report for The Chemours Company, FC, LLC (Chemours).
Chemours operates the Fayetteville Works facility in Bladen County, North Carolina (theSite). This report provides monitoring and assessment results pursuant to therequirements of Paragraphs 1(a) and 1(b) of the Addendum to Consent Order Paragraph
12 (CO Addendum) and Paragraph 16 of the executed Consent Order (CO) dated 25
February 2019 among the North Carolina Department of Environmental Quality(NCDEQ), Cape Fear River Watch, and Chemours.
The purpose of this report is to describe the first quarter 2021 (Q1 2021) PFAS Mass
Loading Assessment of the Cape Fear River based on the findings of surface water, riverwater, and groundwater samples collected at and surrounding the Site. This is the seventh
assessment done since Q1 2020. Data collected were used to assess mass loading of total
per- and polyfluoroalkyl substances (PFAS) to the Cape Fear River. Total PFAS is a term
used to refer to PFAS detected in the environment for those PFAS compounds listed inTable 1 and analyzed by the Table 3+ standard operating procedure (SOP) analyticalmethod.
There are two primary objectives for this report:
1.

To assess Cape Fear River PFAS mass loads. Specifically:2.

a.

Mass loads measured in the Cape Fear River.

b.

Mass loads prevented from reaching the Cape Fear River by implemented
remedies.

c.

The total mass load to the Cape Fear River, i.e., the sum of the twoquantities above.

To assess the relative PFAS loadings from the different PFAS transport pathways
to the Cape Fear River during the reporting period1 using the Mass Loading
Model.

The CO Addendum requires sampling the Cape Fear River for PFAS compounds listed
in Attachment C of the CO (Cape Fear River Mass Loading Calculation Protocol

1

Starting in December 2020, Chemours commenced monthly sampling of the mass loading model
pathways as per CO Paragraph 1(b) and the associated protocol document Cape Fear River Mass
Loading Calculation Protocol Version 2 (Geosyntec 2020d). Monthly sampling of these pathways will
be conducted for one year and thereafter on a quarterly basis for the next four years.

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Version 2, Geosyntec 2020d). Accordingly, this report contains data from January 2021
through March 2021, and mass loading calculations and reporting are done on the set of
PFAS compounds listed in Table 1, i.e., both “Table 3+” and “Attachment C”.
The remainder of this report is organized as follows:•

Scope – This section describes the sampling programs performed in Q1 2021.

•

PFAS Mass Load to Cape Fear River – This section describes the assessmentsof Cape Fear River PFAS Mass Loads.

•

Cape Fear River PFAS Mass Loading Model – This section describes theassessment of the relative mass loading from the various PFAS transport
pathways.

•

Summary – This section summarizes report findings.

2

SCOPE

The Q1 2021 sampling was completed by Parsons of NC (Parsons) and Geosyntec fromJanuary through March 2021. The scope of the sampling programs is summarized below,
and complete descriptions of the field methods can be found in Appendix A.
2.1

Sampling Activities in Q1 2021

Q1 2021 (January to March 2021) sampling activities included:

2

1.

The Cape Fear River PFAS Mass Load Sampling Program consisted ofcollecting twice weekly composite samples at Cape Fear River at Tar Heel
Ferry Road Bridge (CFR-TARHEEL).

2.

The Cape Fear River PFAS Mass Loading Model Sampling Program event
which consisted of the following:a.

Collecting three synoptic rounds of groundwater elevations fromselect on and offsite monitoring wells.

b.

Collecting water samples for PFAS from 19 onsite and offsite
monitoring wells2.

c.

Collecting seep, surface water, and river water samples for PFAS.

Bladen-1D (damaged) and PW-11 (being pumped as part of the Pre-design Investigation activities)
could not be sampled in Q1 2021.

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d.

Measuring flow rates at specified seep and surface water locations.

Each program is described in further detail below.
2.2

Cape Fear River PFAS Mass Load Sampling Program

The Cape Fear River PFAS Mass Load Sampling Program consists of collecting twice
weekly composite samples from the sampling location at CFR-TARHEEL,
approximately 7 miles downstream of the Site (Figure 2). This location is situateddownstream of the Site such that water from the seeps, onsite groundwater, Outfall 002,
Old Outfall 002 and Georgia Branch Creek are well mixed in the river.
Composite samples were collected using an autosampler and were generally compositedover 24 hours with aliquots collected at one-hour intervals yielding seven samples per
week. Two samples per week were selected based on sample completeness and sent foranalysis. Collected samples were evaluated for the PFAS compounds listed in Table 1.
Interruptions to the sampling program may occur due to events such as vandalism,
equipment malfunction or a high river stage, which will flood the platform andnecessitates sampler removal. During interruptions, field protocol is to collect a grab
sample from the river twice per week at the CFR-TARHEEL location to continue
establishing a record of river concentrations over time.
During the reporting period between January 1, 2021 and March 31, 2021, high riverstages were recorded for 43 out of 89 total days. This resulted in 14 grab samples and 18
composite samples collected over the reporting period. The following provides further
details on the interruptions that occurred in the scheduled sampling program:•

January 1, 2021 to January 21, 2021 – High river stage was experienced at the
sampling location between these dates necessitating the removal of theautosampler to prevent damage. Instead, seven grab sampling events wereconducted on January 6, 7, 11 and 14, 2021.

•

January 28, 2021 to March 5, 2021 – High river stage was experienced at the
sampling location between these dates necessitating the removal of theautosampler to prevent damage. Instead, seven grab sampling events wereconducted on February 1, 4, 8, 16, 19, 22, 24 and 25 2021.

The data collected from the PFAS Mass Load Sampling Program were used to estimate
PFAS mass load in the Cape Fear River using concentrations from the CFR-TARHEEL
location and flows as reported by the United States Geological Survey (USGS) rivergauging station at the W.O. Huske Dam (Figure 2). Details of the sample collection
methods, flow measurement methods, and calculation methods were reported in the Cape

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Fear River PFAS Mass Loading Calculation Protocol Version 2 (Geosyntec, 2020d).
Mass load calculations are provided in Section 3 and sampling results are presented inAppendix A.
2.3

Cape Fear River PFAS Mass Loading Model Sampling Program

The Mass Loading Model Sampling Program for this reporting period consisted ofcollecting concentration and flow data from the various PFAS transport pathways in
January 2021, February 2021 and March 2021. Environmental media sampled include
surface water (seeps, creeks, Old Outfall, Outfall 002, and Cape Fear River) andgroundwater. Surface and river water sampling and flow gauging locations for the Q1
2021 Events are shown on Figures 4A, 4B, 4C and 5 and listed in Table 2. Groundwater
sampling locations for the Q1 2021 Events are shown on Figure 6 and listed in Table 3.
Collected samples were evaluated for the PFAS compounds listed in Table 1.
Due to high river flows and above average precipitation3 during Q1 2021, samples andflows were collected at alternate surface water locations as close as possible to thedesignated location. These alternate locations are noted in Figures 4A, 4B, 4C and
Table 2.
The data collected from these Q1 2021 field activities were then incorporated into theMass Loading Model to estimate PFAS mass discharge from the nine potential transport
pathways to the Cape Fear River (Figure 3), as identified in the Conceptual Site Model(Geosyntec, 2019b) and discussed in more detail in Section 4. These Mass Loading
Model estimates were compared to mass loading observed downstream at CFRTARHEEL.
Details of the sample collection methods, flow measurement methods, and calculation
methods were reported in the Cape Fear River PFAS Mass Loading Calculation Protocol
Version 2 (Geosyntec, 2020d). Mass Loading Model results are provided in Section 4.2
and sampling results are presented in Appendix A.
2.4

Laboratory Analyses

Samples were analyzed for PFAS by Table 3+ Laboratory SOP. The focus of this reportis on the set of PFAS originating from manufacturing activities at the Site; therefore,
results of sampling activities and assessments of mass loading were performed and3

USGS rain gauge 02105500 indicated approximately 1.5, 0.20, and 0.25 inches of precipitation
during the January, February, and March 2021 sample collection events, respectively.

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presented with respect to the PFAS groupings presented in Table 1: (i) Attachment C,(ii) Table 3+ (17 compounds)4, and (iii) Table 3+ (20 compounds).
For clarity, the text, tables and figures of this report describe the Total Table 3+ (17compounds), though the report tables also include results for Total Attachment C andTotal Table 3+ (20 compounds).
The calculations for Total Attachment C PFAS concentrations include the fluoroether
PFAS on the Attachment C list, i.e., excludes perfluoroheptanoic acid (PFHpA). As
presented in the Cape Fear River PFAS Mass Loading Assessment – Third Quarter 2020
Report (Geosyntec, 2020e), the presence of PFHpA upstream and offsite are unrelated to
the Site and is already present in the upstream river from other sources and is therefore
excluded from the attachment C sum. This represents a modification to the Cape Fear
River PFAS Mass Loading Calculation Protocol Version 2 submitted to NCDEQ on
November 18, 2020 (Geosyntec, 2020d).
3

PFAS MASS LOAD TO CAPE FEAR RIVER

This section presents results of the Cape Fear River PFAS mass loads for the present Q1
2021 reporting period of January 1, 2021 to March 31, 2021. Specifically, this section
discusses three types of mass loads defined in Equation 1.
Equation 1: Total PFAS Mass Load

𝑀𝐶𝐹𝑅 = 𝑚𝐶𝐹𝑅 + 𝑚𝑅𝑒𝑚𝑒𝑑𝑖𝑒𝑠
where,

4

𝑀𝐶𝐹𝑅 =

is the Mass Load of PFAS compounds in the Cape Fear River,including the mass load prevented from reaching the Cape Fear Riverby implemented remedies, measured in kilograms (kg).

𝑚𝐶𝐹𝑅 =

is the In-River Mass Load estimated using PFAS concentrations insamples taken in the Cape Fear River downstream of the Site where
the river is well mixed and using measured river flow volumes.

As reported in the Matrix Interference During Analysis of Table 3+ Compounds memorandum(Geosyntec, 2020a), matrix interference studies conducted by the analytical laboratory (TestAmerica,
Sacramento) have shown that the quantitation of three compounds (R-PSDA, Hydrolyzed PSDA, and
R-EVE) is inaccurate due to interferences by the sample matrix in both groundwater and surface water.
Total Table 3+ PFAS concentrations are calculated and presented two ways in this report: (i) summingover 17 of the 20 Table 3+ compounds “Total Table 3+ (17 compounds)”, i.e., excluding results of RPSDA, Hydrolyzed PSDA, and R-EVE, and (ii) summing over 20 of the Table 3+ compounds “Total
Table 3+ (20 compounds)”

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𝑚𝑅𝑒𝑚𝑒𝑑𝑖𝑒𝑠 = is the Captured Mass Load prevented from reaching the Cape Fear
River by remedies implemented by Chemours.
Remedies that have been implemented by Chemours through Q1 20215 include:•

Old Outfall 002 treatment system (October 1, 2020)•

Seep C flow through cell (December 16, 2020)

Both remedies prevent PFAS mass loads from reaching the Cape Fear River and were
quantified in the 𝑚𝑅𝑒𝑚𝑒𝑑𝑖𝑒𝑠 term of Equation 1. The specific methodology for estimating
the prevented mass per remedy was developed on a per remedy basis and details of thesecalculations are provided in the Cape Fear River PFAS Mass Loading Calculation
Protocol Version 2 (Geosyntec, 2020d). The goal of such calculations was to estimate the
Total PFAS mass diverted from reaching the Cape Fear River by the remedy that would
have otherwise reached the Cape Fear River.
3.1

Q1 2021 Total PFAS Mass Load

During the Q1 2021 reporting period, the Total Table 3+ mass load in the Cape Fear
River, including the mass load prevented from reaching the Cape Fear River byimplemented remedies, was estimated to be 122.5 kg (Tables 4, 5A, 5B, and 5C). The
total in-river mass load was estimated to be 93.8 kg, and the total remedy captured load
was 28.7 kg.
The total measured and estimated in-river mass load (122.5 kg) was based on the 43 massloading estimation intervals presented in Table 5A. The total measured and estimatedmass load captured by remedies implemented by Chemours (28.7 kg) was based on theconcentrations in samples collected at the influent and effluent (as reported inAppendix A) and measured flows at the Old Outfall 002 treatment system and the Seep C
flow through cell (Tables 5B and 5C).
For the Old Outfall 002 treatment system, a total of 23.4 kg was captured and prevented
from reaching the Cape Fear River. This estimate was based on three mass loading
estimation intervals between January 1, 2021 and March 31, 2021 (Table 5B). For the
Seep C flow through cell, a total of 5.4 kg was captured and prevented from reaching the5

There have been numerous other interim and permanent actions taken to limit PFAS reaching the Cape
Fear River prior to Q1 2021, i.e., air abatement measures (installation of the thermal oxidizer andcarbon beds, etc.), grouting of the terracotta pipe, sediment removal from onsite channels, among
others, and these may not be captured in these captured mass load calculations but should be consideredin the overall assessment of PFAS reductions.

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Cape Fear River. This estimate was based on 6 mass loading estimation intervals between
January 1, 2021 and March 31, 2021 (Table 5C).
The in-river Total PFAS mass discharges calculated from samples collected in Q1 2021
are provided in Table 6, while those from previous quarters are presented in Appendix A.
For Q1 2021, the Total Table 3+ mass discharge among samples with detected Total
Table 3+ PFAS concentrations ranged from 3.7 milligrams per second (mg/s) (CFRTARHEEL-010721) to 36 mg/s (CAP0221-CFR-TARHEEL-022421).
The plots of Total Table 3+ concentrations over time are presented in Figure 7 andindicate that, generally, concentrations in the Cape Fear River are inversely correlated toriver flow rate. That is, concentrations were higher when flow rates were lowest, while
concentrations were lower when river flow rates were higher. This trend is consistent withhigher river flow volumes diluting Table 3+ mass discharge into the river. Higher riverflows lead to a greater volume of water that the mass loads are distributed over leading
to a lower concentration value.
The plots of Total Table 3+ mass discharge since the beginning of the sampling program(March 28, 2020) are shown on Figure 8. Similar to the Q1 2021 mass discharges, therange of mass discharge across all samples with detected concentrations of Table 3+
PFAS was 2.7 mg/s (CFR-TARHEEL-9-100620) to 50.7 mg/s (CFR-TARHEEL-20111220), though the mass discharges are typically between 5 and 20 mg/s withapproximately 86% of the data falling within this range.
3.2

Mass Discharge at Bladen Bluffs, Tar Heel Ferry Road Bridge and Kings Bluff
Intake Canal

The Total Table 3+ concentrations and mass discharge values from the Q1 2021 events
are shown in the table below. Total Table 3+ concentrations at the three downstream river
locations ranged from 14 ng/L (CFR-BLADEN, CFR-TARHEEL) to 94 ng/L (CFRTARHEEL)..
The Total Table 3+ mass discharge ranged from 4.4 mg/s (CFR-BLADEN in
January 2021) to 24.4 mg/s (CFR-KINGS in January 2021). In previous assessments,
CFR-KINGS is sampled approximately three days after CFR-TARHEEL and CFRBLADEN to account for travel time between these two locations and CFR-KINGS.
During the Q1 2021 events, CFR-KINGS was sampled before the three days due to rising
river levels and rain events constraining field sampling activities. This sample collectionchange may contribute to the difference in mass discharges observed between CFRKINGS and the other two locations. Additionally, there is inherent variability associatedwith river sample collection due to changing flow rates, precipitation, sample collection
location, and grab sampling methods.

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Total Table 3+
Concentration
Mass Discharge(ng/L)(mg/s)
31
4.4

SampleLocation

Sample Collection
Date

Flow Rate(cfs)

CFR-BLADEN

01/26/2021

4,960

CFR-TARHEEL

01/26/2021

4,910

94

13.1

CFR-KINGS

01/28/2021

11,20077

24.4

CFR-BLADEN

02/24/2021

17,00017

8.2

CFR-TARHEEL

02/24/2021

16,90026

12.4

CFR-KINGS

02/25/2021

20,90030

17.8

CFR-BLADEN

03/29/2021

14,00014

5.6

CFR-TARHEEL

03/29/2021

14,00014

5.6

CFR-KINGS

03/30/2021

14,20024

9.7

4CAPE FEAR RIVER PFAS MASS LOADING MODEL

Where Section 3 presented the Total Table 3+ PFAS mass load in the Cape Fear River,this section presents an analysis evaluating the relative loadings from the identified PFAS
transport pathways to the observed in-river PFAS mass discharge. This evaluation
supports remediation planning to reduce the PFAS loading from the Transport Pathways
to the Cape Fear River. This evaluation was performed using the Mass Loading Model.
The following subsections describe the transport pathways and the results of the Mass
Loading Model assessment, including the sensitivity and the limitations of the Mass
Loading Model.
4.1

PFAS Mass Loading Model Pathways

The nine potential pathways representing compartments to the PFAS Mass Loading
Model are briefly described below and described in more detail in the Cape Fear RiverPFAS Mass Loading Calculation Protocol Version 2 (Geosyntec, 2020d). The following
pathways were identified as potential contributors of PFAS to the river PFAS
concentrations:•

Transport Pathway 1: Upstream Cape Fear River and Groundwater – This
pathway is comprised of contributions from non-Chemours related PFAS sourceson the Cape Fear River and tributaries upstream of the Site, and upstream offsite
groundwater with PFAS present from aerial deposition.

•

Transport Pathway 2: Willis Creek – Groundwater and stormwater discharge
and aerial deposition to Willis Creek and then to the Cape Fear River.

•Transport Pathway 3: Direct aerial deposition of PFAS on the Cape Fear River(see Appendix H for further details).

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Transport Pathway 4: Outfall 002 – Comprised of (i) water drawn from the Cape
Fear River and used as non-contact cooling water, (ii) treated non-Chemours
process water, (iii) Site stormwater, (iv) steam condensate, and (v) power
neutralization discharge, which are then discharged through Outfall 002.

•

Transport Pathway 5: Onsite Groundwater – Direct upwelling of onsite
groundwater to the Cape Fear River from the Black Creek Aquifer (seeAppendix G for further details).

•

Transport Pathway 6: Seeps – Onsite groundwater seeps A, B, C and D and
offsite Lock and Dam Seep above the Cape Fear River water level on the bluff
face from the facility that discharge into the Cape Fear River.

•Transport Pathway 7: Old Outfall 002 – Groundwater discharge to Old Outfall
002 and stormwater runoff that flows into the Cape Fear River.

•Transport Pathway 8: Adjacent and Downstream Offsite Groundwater – Offsite
groundwater adjacent and downstream of the Site upwelling to the Cape Fear
River (see Appendix I for further details).

•

Transport Pathway 9: Georgia Branch Creek – Groundwater, stormwater
discharge and aerial deposition to Georgia Branch Creek and then to the Cape
Fear River.

•

For the Q1 2021 Mass Loading Model assessments, data sources used as model
inputs for each potential pathway are described in Table 7. These data sources
included flow measurements, water levels and analytical results from the Q1 2020
sampling events (as discussed in Appendix A) and supplemental data provided inAppendices B, E, and F.

4.2

Mass Loading Model Results

For each monthly sampling event, the Total PFAS mass discharges are summarized inTables 8A, 8B, 9A, 9B, 10A, and 10B. Analyte-specific mass discharges estimated from
the Mass Loading Model and measured at CFR-TARHEEL are provided in Appendix A.
A comparison of relative contributions per pathway for the Q1 MLM assessments isprovided in Table 11.
4.2.1 Reductions in Modeled Mass Discharge
The model-estimated Before Remedies and After Remedies Total PFAS mass discharge
values from the Q1 2021 monthly events are provided in Tables 8A, 8B, 9A, 9B, 10A,
and 10B. The reduction in Total Table 3+ mass discharges after remedies is summarized

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in the table below. The mass discharges across the months are similar and relatively
stable. Additionally, the operation of the Old Outfall 002 treatment system and Seep C
flow through cell was effective at reducing the Total Table 3+ mass discharge, whichranged from 2.7 to 3.6 mg/s across the three months. More specifically, the reductions ofmass discharge from Old Outfall 002 ranged from 2.1 mg/s to 3.0 mg/s, while thereduction from Seep C ranged from 0.24 mg/s to 0.64 mg/s. The variability in reductions
at the Old Outfall and Seep C are expected due to variability in influent flows andconcentrations.
For example, at Seep C, the difference in reduction in
February compared to January and March is due to the lower concentrations observed at
the influent of the flow through cell (47,000 ng/L compared to 150,000 ng/L).
Pathway
All Pathways

After Remedies Reduction in Model-EstimatedTotal Table 3+ Mass Discharge (mg/s)
Jan-21
Feb-21
Mar-21
3.6

2.8

2.7

Old Outfall 002

3.0

2.6

2.1

Seep C

0.62

0.24

0.63

4.2.2 Modeled versus Measured Mass Discharge
The model-estimated After Remedies Total Table 3+ mass discharge values werecompared to the measured mass discharge at CFR-TARHEEL shown in the table below(Tables 8B, 9B, and 10B). The ranges in the lower and upper bounds for the modeled
mass discharge estimates are not wide and generally within 1.0 mg/s. The measured massdischarges at CFR-TARHEEL was higher than the modeled estimates in January andFebruary 2021 and lower than the modeled estimate in March 2021. However, whencompared to the measured mass discharges within a month, the model estimates fallwithin the range observed at CFR-TARHEEL (Figure 9; top plot).
Further, when the model-estimated mass discharges were used to estimate the Total
Table 3+ river concentrations, the modeled concentrations showed a good fit and tracks
closely to the trends in the observed Total Table 3+ concentrations measured at CFRTARHEEL (Figure 9; bottom plot). Therefore, despite the discrepancies between modeland measured mass discharges for the one snap-shot in time, overall the model shows
good agreement with the measured concentrations at CFR-TARHEEL during Q1 2021.
Nonetheless, several hypotheses are being explored to better understand the differences
between modeled and measured mass discharge and are further discussed in Section 4.3.

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4.2.3 Relative Contributions by Pathway
The relative contributions per pathway for the Q1 2021 MLM assessments is provided inTable 11. The most significant pathways continue to be the Seeps (approximately 35%
to 45%) and Onsite Groundwater (approximately 15% to 30%) for the three monthly
events, which is consistent with previous events (Geosyntec, 2020b; Geosyntec, 2020c;
Geosyntec, 2020e; Geosyntec, 2020f). Previous assessments showed that Old Outfall 002
was also a significant contributor; however, the Q1 2021 average contribution was
reduced from 25% to 7% with the implementation of the treatment system. Remedy
implementation at Seep C has also reduced the Q1 2021 average contribution of the Seeps
from 42% to 38%. The combined reductions from the Seeps are expected to increase
throughout 2021 after the installation of the flow through cells at Seeps A, B, and D.
4.3

Mass Loading Model Sensitives

As described in previous Cape Fear River PFAS Mass Loading Assessment reports(Geosyntec, 2020b; Geosyntec, 2020c; Geosyntec, 2020e), the Mass Loading Model is asuitable tool to evaluate which PFAS transport pathways are significant contributors ofmass to the Cape Fear River, but the results of the model either under or overestimate themass discharge observed in the Cape Fear River. These discrepancies are being evaluated
via a series of hypotheses as outlined in the second quarter 2020 (Q2 2020) report(Geosyntec, 2020c). In general, and as described in the following subsections, thesehypotheses relate to the (i) inherent variability in input parameters and (ii) the effect ofhigher levels of precipitation and river flows on flow measurement, sample collection
methods, and analytical results. With one year of twice weekly data now available fromthe CFR-TARHEEL sampling location, Chemours is assessing these hypotheses with thedata collected over the past year from all pathways. Future quarterly reports will provide
an update on the evaluation of these hypotheses.
4.3.1 Variability in Input Parameters
The Mass Loading Model assessments provide PFAS mass discharge estimates andrelative proportions of loadings for a ‘snapshot’ in time. While controlling for temporalvariability, the model-based mass discharge estimates contain some level of uncertainty
due to the inherent variability and measurement error in the input parameters, e.g., flow,
concentrations, etc. To better understand the sensitivity of the model to the various
pathway-specific input parameters, the uncertainties associated with the input parameters
were used to conduct a sensitivity analysis in the Q1 2020 report (Geosyntec, 2020b). An
updated sensitivity analysis will be conducted using the data collected over the past year.

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4.3.2 River Flows and Precipitation
The Q4 2020 and Q1 2021 sampling events were associated with higher river flows due
to above average levels of precipitation. This Q4 2020 assessment was the first wet eventin 2020 and the total flow volume recorded in Q4 2020 (4,100 MG) was much higher
than that recorded in previous events and this trend continued in Q1 2021. As such, themass discharge estimates could potentially be more sensitive to this increase in flow,
particularly in the river samples (e.g., CFR-TARHEEL). These sensitivities to thechanges in river conditions will be studied further using data collected over the past year
to better characterize the effect these varying conditions on river concentrations.
5

SUMMARY

Two sampling programs were conducted in Q1 2021:•

The PFAS Mass Load Sampling program consisting of 24 composite samples and
14 grab samples collected at the Tar Heel Ferry Road Bridge. The analyticalresults of these samples were used to calculate the in-river PFAS mass loads in
the Cape Fear River during the reporting period and to calculate the Baseline Mass
Load.

•

The Q1 2021 PFAS Mass Loading Model Sampling program consisting of threemonthly sampling events collected water samples from the PFAS transport
pathways (seeps, creeks, Old Outfall, Outfall 002, groundwater and Cape Fear
River) and paired water flow measurements and estimates. These data were used
to assess the relative loadings per transport pathway to the Cape Fear River using
the PFAS Mass Loading Model.

The Cape Fear River PFAS Mass Load assessment estimated the Total PFAS that waseither discharged or prevented from being discharged to the Cape Fear River over theload assessment period of December 30, 2020 to March 31, 2021. Over this period, theTotal PFAS mass load in the Cape Fear River, including the mass load prevented fromreaching the Cape Fear River by implemented remedies, was 122.5 kg, where 93.8 kg
was the in-river mass load measured at CFR-TARHEEL and 28.7 kg was the mass load
prevented from reaching the Cape Fear River due to the installation of remedies at Old
Outfall 002 and at Seep C. As additional remedies are implemented at the Site greater
quantities of mass will be prevented from reaching the Cape Fear River.
The Cape Fear River Mass Loading Model assessments showed that model estimates
were relatively consistent are in good agreement with the monthly trends at observed at
CFR-TARHEEL. In fact, when the model-estimated mass discharges were used toestimate the Total Table 3+ river concentrations, the modeled concentrations showed a

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good fit and tracks closely to the trends in the observed Total Table 3+ concentrations
measured at CFR-TARHEEL during Q1 2021. Overall, reductions in model-estimatedmass discharges ranged from 2.7 mg/s to 3.6 mg/s with the implementation of thetreatment system at the Old Outfall and the flow through cell at Seep C.
The measured mass discharges at CFR-TARHEEL was higher than the modeled estimatesin January and February 2021 and lower than the modeled estimate in March 2021.
However, when compared to the measured mass discharges within a month, the model
estimates show good agreement with the trends at CFR-TARHEEL (Figure 9; top plot).
In terms of relative contributions, the most significant pathways continue to be the Seeps(Transport Pathway 6) and Onsite Groundwater (Transport Pathway 5). Previous
assessments (Geosyntec, 2020b; Geosyntec, 2020c; Geosyntec, 2020e; Geosyntec,
2020f) indicated that Old Outfall 002 (Pathway 7) was also a significant contributor;
however, the Q1 2021 average contribution of this pathway was reduced from 25% to 7%
with the implementation of the treatment system. Reductions in mass discharge
associated with the Seep C flow through cell were also observed in Q1 2021; and further
reductions associated with the installation of the flow through cells at Seeps A, B, and D
are anticipated through 2021.
Sample collection will continue as outlined in the Cape Fear River Mass Loading
Calculation Protocol Version 2 (Geosyntec 2020d). Capture and treatment of water fromthe Old Outfall 002 and Seep C has begun and future sampling events will continue toevaluate PFAS mass loads and associated remedy facilitated at CFR-TARHEEL.
6REFERENCES

Geosyntec, 2019a. Cape Fear River PFAS Loading Reduction Plan – Supplemental
Geosyntec, 2019a. Seeps and Creeks Investigation Report. Chemours
Fayetteville Works. August 26, 2019.
Geosyntec, 2019b. On and Offsite Assessment. Chemours Fayetteville Works.
September 30, 2019.
Geosyntec, 2019c. Corrective Action Plan. Chemours Fayetteville Works.
December 31, 2019.
Geosyntec, 2020a. Matrix Interference During Analysis of Table 3+ Compounds.
Chemours Fayetteville Works. June 30, 2020.
Geosyntec, 2020b. Cape Fear River Table 3+ PFAS Mass Loading Assessment – First
Quarter 2020 Report, Chemours Fayetteville Works. July 31, 2020.

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Geosyntec, 2020c. Cape Fear River PFAS Mass Loading Assessment – Second Quarter2020 Report, Chemours Fayetteville Works. September 30, 2020.
Geosyntec, 2020d. Cape Fear River Mass Loading Calculation Protocol Version 2,
Chemours Fayetteville Works. November 18, 2020.
Geosyntec, 2020e. Cape Fear River PFAS Mass Loading Assessment – Third Quarter2020 Report, Chemours Fayetteville Works. December 23, 2020.
Geosyntec, 2020f. Cape Fear River PFAS Mass Loading Assessment – Fourth Quarter2020 Report, Chemours Fayetteville Works. March 31, 2021.
PubChem, 2020. Compound Summary: Perfluoroheptanoic acid; 8. Use andManufacturing. Viewed March 10, 2020. <https://pubchem.ncbi.nlm.nih.gov/compound/Perfluoroheptanoicacid#section=General-Manufacturing-Information>

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TABLES

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TABLE 1PFAS ANALYTE LIST
Chemours Fayetteville Works, North Carolina

Geosyntec Consultants NC P.C.

PFAS Grouping
1

CASN

Chemical Formula

Hexafluoropropylene oxide dimer acid13252-13-6

C6HF11O3✔

Perfluoro-2-ethoxypropionic acid267239-61-2

C5HF9O3✔

✔

Perfluoro-4-isopropoxybutanoic acid

801212-59-9

C12H9F9O3S

✔

✔

✔

Perfluoro-2-methoxyacetic acid674-13-5

C3HF5O3PFO2HxA✔

✔

✔

Perfluoro-3,5-dioxahexanoic acid39492-88-1

C4HF7O4PFO3OA✔

✔

✔

Perfluoro-3,5,7-trioxaoctanoic acid39492-89-2

C5HF9O5PFO4DA✔

✔

✔

Perfluoro-3,5,7,9-tetraoxadecanoic acid39492-90-5

C6HF11O6

PMPA

✔

✔

✔

Perfluoro-2-methoxypropionic acid

13140-29-9

C4HF7O3

Hydro-EVE Acid

--

✔

✔

2,2,3,3-tetrafluoro-3-({1,1,1,2,3,3-hexafluoro-3-[(1,2,2,2-tetrafluoroethyl)oxy]propan-2-yl}oxy)propionic acid773804-62-9

C8H2F14O4

EVE Acid--✔

✔

2,2,3,3-tetrafluoro-3-({1,1,1,2,3,3-hexafluoro-3-[(1,2,2-trifluoroethenyl)oxy]propan-2-yl}oxy)propionic acid

69087-46-3

C8HF13O4PFECA B--✔

✔

Perfluoro-3,6-dioxaheptanoic acid

151772-58-6

C5HF9O4

R-EVE

--

--

✔

Pentanoic acid, 4-(2-carboxy-1,1,2,2-tetrafluoroethoxy)-2,2,3,3,4,5,5,5-octafluoro-

2416366-22-6

C8H2F12O5

PFO5DA✔

✔

✔

Perfluoro-3,5,7,9,11-pentaoxadodecanoic acid39492-91-6

C7HF13O7

R-PSDA----✔

Pentanoic acid, 2,2,3,3,4,5,5,5-octafluoro-4-(1,1,2,2-tetrafluoro-2-sulfoethoxy)-2416366-18-0

C7H2F12O6S

R-PSDCA--✔

✔

Ethanesulfonic acid, 1,1,2,2-tetrafluoro-2-[1,2,2,3,3-pentafluoro-1-(trifluoromethyl)propoxy]-2416366-21-5

C6H2F12O4S

Hydrolyzed PSDA

--

--

✔

Acetic acid, 2-fluoro-2-[1,1,2,3,3,3-hexafluoro-2-(1,1,2,2-tetrafluoro-2-sulfoethoxy)propoxy]-2416366-19-1

C7H3F11O7S

NVHOS

--

✔

✔

1,1,2,2,4,5,5,5-heptafluoro-3-oxapentanesulfonic acid; or 2-(1,2,2,2-ethoxy)tetrafluoroethanesulfonic acid; or 11132933-86-8(1,1,2,2-tetrafluoro-2-sulfoethoxy)-1,2,2,2-tetafluoroethane

C4H2F8O4S

PES

--

✔

✔

Perfluoro-2-ethoxyethanesulfonic acid

113507-82-7

C4HF9O4S

PS Acid✔

✔

✔

29311-67-9

C7HF13O5S

Hydro-PS Acid

✔

✔

✔

Ethanesulfonic acid, 2-[1-[difluoro[(1,2,2-trifluoroethenyl)oxy]methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2tetrafluoroEthanesulfonic acid, 2-[1-[difluoro(1,2,2,2-tetrafluoroethoxy)methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2tetrafluoro-

749836-20-2

C7H2F14O5S

PFHpA2✔

----

Perfluoroheptanoic acid375-85-9

C7HF13O2

Common Name

Attachment C

Table 3+(17 compounds)

Table 3+(20 compounds)

HFPO-DA2

✔

✔

✔

PEPA

✔

✔

PFECA-G✔

PFMOAA

Chemical Name

Notes:
1 - Analyzed under analytical method Table 3+ Lab SOP.
2 - HFPO-DA and PFHpA can be analyzed under methods Table 3+ SOP and EPA Method 537 Mod.
EPA - Environmental Protection Agency
PFAS - Per- and Polyfluoroalkyl substances
SOP - Standard Operating Procedure

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TABLE 2
SURFACE WATER SAMPLE COLLECTION AND FLOW MEASUREMENT SUMMARY
Chemours Fayetteville Works, North Carolina

Pathway / Location

Upstream River Water and
Groundwater6

Location ID

Location Description

CFR-MILE-76

Cape Fear River Mile 76
Upstream of Cape Fear River
Mile 76
Upstream of Cape Fear River
Mile 76
Mouth of Willis Creek
Tributary to Seep C
Tributary to Seep C
Tributary to Seep C
Water Drawn Through theIntake Sampled at the Power
Area at the Site

CFR-DCO
CFR-2517BoatRamp

Willis Creek

WC-1
WC-2
WC-1-TR2
WC-5

Intake River Water at
Facility

Intake at Facility

Outfall 002

Outfall 002

Seep A

Seep C

Seep D

Lock and Dam Seep

March 2021
Sample Collection Method1
Flow Measurement Method2
---

--

--

Grab

USGS Data

--

--

--

--

--

--

Grab

USGS Data

24-hour composite----

Velocity Probe
----

-Grab
---

-----

--Grab
Grab*--Velocity Probe
Velocity Probe

24-hour composite

Facility DMRs

Grab

Facility DMRs

24-hour composite

Facility DMRs

24-hour composite

Facility DMRs

Grab

Facility DMRs

24-hour composite

Facility DMRs

24-hour composite

3

--

3

SEEP-B-1-C1
SEEP-B-1-C2
SEEP-B-1-C3
SEEP-CSEEP-C-EFF

Effluent Basin of Seep C FTC

24-hour composite--

24-hour composite--

24-hour composite--

SEEP-C-2
SEEP-D-1
SEEP-D-3
SEEP-D-C1
SEEP-D-D
SEEP-D-D1
SEEP-D2-B1

Upstream of Seep C FTCMouth of Seep D
Tributary to Seep D
Tributary to Seep D
Tributary to Seep D
Tributary to Seep D
Tributary to Seep D
Mouth of the Lock and Dam
Seep
Mouth of Old Outfall 002
Upstream of Mouth of Old
Outfall 002-Grab-------Flume------

Grab-Grab*
Grab
Grab
---

---3
---------Grab
-Grab
Grab*

---3
-----Manually Measured4

SEEP-A-IMP

SEEP-B-IMP

LOCK-DAM SEEPOLDOF-1

Old Outfall 002

February 2021
Sample Collection Method1
Flow Measurement Method2---

Impoundment Pond Before Seep
A FTCMouth of Seep B
Tributary to Seep B
Tributary to Seep B
Tributary to Seep B
Impoundment Pond Before Seep
B FTCTributary to Seep B
Tributary to Seep B
Tributary to Seep B
Mouth of Seep C

SEEP-B-1
SEEP-B-2
SEEP-B-TR1
SEEP-B-TR2
Seep B

Outfall 002 in open channel

January 2021
Sample Collection Method1
Flow Measurement Method2
Grab
USGS Data

Geosyntec Consultants of NC P.C.

OLDOF-2
GBC-1

Georgia Branch Creek
GBC-5
Tar Heel Ferry Road Bridge6

CFR-TARHEEL

Bladen Bluffs6

CFR-BLADEN

Kings Bluffs7

CFR-KINGS

Mouth of Georgia Branch Creek
Upstream of Mouth of Georgia
Branch Creek
Cape Fear River at Tar Heel
Ferry Road Bridge
Cape Fear River at Bladen
BluffsCape Fear River at Kings Bluff
Raw Water

Grab

--

24-hour composite

--3

Grab
----

3

-----

-Grab*Grab
Grab-Velocity Probe
Velocity Probe
Velocity Probe

-----

-----

--

--

--

--

24-hour composite

--

-----

---Flume----------3-----

Velocity Probe
Velocity Probe
Velocity Probe
--3

Grab

Manually Measured4

--5

--3

Grab

Grab

Velocity Probe

--

--

--

--

--

--

Grab

Velocity Probe

Grab

Velocity Probe

Grab

Velocity Probe

--

--

--

--

--

--

Grab

Velocity Probe

Grab

Velocity Probe

24-hour composite

USGS Data

Grab

USGS Data

Grab / Composite

USGS Data

Grab

USGS Data

Grab

USGS Data

Grab

USGS Data

Grab

USGS Data

Grab

USGS Data

Grab

USGS Data

Notes:
1 - Samples analyzed for PFAS by EPA Method 537 Mod and Table 3+ Lab SOP.
2 - Results of estimated flow at these locations are provided in Appendix A Table A6 and supplemental flow measurement data are included in Appendix B.
3 - Flow at this location could not be measured due to high river stages.
4 - Flow was measured at the Lock and Dam Seep manually using a volumetric container (e.g., five gallon bucket, two liter bottle, etc.) and recording the duration of flow.
5 - Sample at Lock and Dam Seep could not be collected in the February 2021 event due to high river stages.
6 - USGS data measurements are recorded from the USGS flow gauging station at the W.O. Huske Dam, ID 02105500 (USGS, 2021).
7 - USGS data measurements are recorded from the USGS flow gauging station at the Lock and Dam #1, ID 02105769 (USGS, 2021).
-- - not sampled or not measured* - this grab-sampled location represents the maximum Table 3+ concentration among the multiple locations that were sampled during these monthly events. This concentration was used in the mass loading model calculations.
DMRs - Discharge Monitoring Reports
EPA - Environmental Protection Agency
FTC - flow-through cell
PFAS - per- and polyfluoroalkyl substances
USGS - United States Geological Survey

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TABLE 3GROUNDWATER MONITORING WELL SAMPLE COLLECTION AND WATER LEVEL MEASUREMENT SUMMARY
Chemours Fayetteville Works, North Carolina

Area

Water Bearing
1
Unit

Well ID

Adjacent Surface Water
FeatureOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOnsiteOffsiteBlack Creek
Floodplain
Black Creek
Floodplain
Black Creek
Floodplain
Floodplain
Black Creek
Black Creek
Surficial
Surficial
Surficial
Black Creek
Black Creek
Surficial
Surficial
Black Creek
Floodplain
Surficial
Black Creek

PIW-3D
PIW-7S
PIW-7D
LTW-01
LTW-02
LTW-03
LTW-04LTW-05
PZ-22
PW-06
PW-07
PW-04
PW-112
PW-09
SMW-11
SMW-10
SMW-12
PIW-1S
PIW-1D
Bladen-1D2Cape Fear River
Cape Fear River
Cape Fear River
Cape Fear River
Cape Fear River
Cape Fear River
Cape Fear River
Cape Fear River
Cape Fear River
Georgia Branch Creek
Georgia Branch Creek
Old Outfall
Old Outfall
Willis Creek
Willis Creek
Willis Creek
Willis Creek
Cape Fear River / Willis Creek
Cape Fear River / Willis Creek
Georgia Branch Creek

January 2021

February 2021

Geosyntec Consultants of NC P.C.

March 2021

Sample Collection
Date

Synoptic Water
Level Date

Sample Collection
Date

Synoptic Water
Level Date

Sample Collection
Date

Synoptic Water
Level Date

1/29/2021
1/27/2021
1/27/2021
1/28/2021
1/27/2021
1/28/2021
1/19/2021
1/19/2021
1/19/2021
1/18/2021
1/18/2021
1/18/2021-1/27/2021
1/15/2021
1/28/2021
1/29/2021
1/27/2021
1/27/2021--

1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/14/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021
1/13/2021

2/8/2021
2/23/2021
2/23/2021
2/8/2021
2/11/2021
2/4/2021
2/23/2021
2/11/2021
2/23/2021
2/10/2021
2/10/2021
2/11/2021-2/4/2021
2/10/2021
2/8/2021
2/5/2021
2/8/2021
2/8/2021--

2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021
2/3/2021

3/16/2021
3/23/2021
3/23/2021
3/16/2021
3/16/2021
3/9/2021
3/9/2021
3/23/2021
3/23/2021
3/16/2021
3/9/2021
3/11/2021-3/12/2021
3/9/2021
3/11/2021
3/9/2021
3/11/2021
3/11/2021--

3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021
3/5/2021

Notes:
1 - Water Bearing Unit - refers to primary aquifer unit well screen is estimated to be screened within.
2 - Bladen-1D (damaged) and PW-11 (being pumped as part of the Pre-design Investigation activities) could not be sampled in December 2020.
-- - not applicable

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TABLE 4
Geosyntec Consultants of NC P.C.
SUMMARY OF CALCULATED TOTAL MASS LOAD IN THE CAPE FEAR RIVER
Chemours Fayetteville Works, North Carolina
Reporting Period Details
Reporting Peroid

Start Date

End Date

Days

River volume(m3)

2020-Q1 Report
2020-Q2 Report
2020-Q3 Report
2020-Q4 Report2021-Q1 Report

03/28/2020 1:00
05/09/2020 23:49
06/29/2020 16:06
10/01/2020 0:01
12/30/2020 10:56

05/09/2020 23:49
06/29/2020 16:06
10/01/2020 0:01
12/30/2020 10:56
03/31/2021 23:01

43
51
93
90
92

514,570,000
1,308,600,000
1,036,200,000
2,118,700,000
3,157,900,000

Total403/28/2020 1:00

03/31/2021 23:01

369

8,135,970,000

Total Attachment C1
Load in Cape
RemedyTotal Load toFear River
Reduction
Cape Fear
3,6
4,6
(kg)
Loads (kg)River (kg)5,6
45.1
0
45.1
79.1
0
79.1
77.3
0
77.3
75.8
25.5
101.3
93.8
28.3
122.1
371.1

53.8

424.9

Notes:
1 - Total Attachment C does not include Perfluorohepthanoic acid (PFHpA).
2 - Total table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed,
PSDA, and R-EVE.
3 - Calculated Cape Fear River loads represents loads measured in the Cape Fear
River at the CFR-TARHEEL sampling location downstream of the Site.
4 - Calculated remedy reduction loads represents loads from Old Outfall 002 andSeep C that were prevented from reaching the Cape Fear River.
5 - Total load to Cape Fear River represents the sum of the measured in-river load
and the remedy reduction load. This value represents the baseline load that would
reach the Cape Fear River in the absence of any remedies.
6 - Total values are rounded to two significant digits. Values in calculations
supporting totals are not rounded.
kg - kilograms
m3 - cubic meters

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TABLE 4
Geosyntec Consultants of NC P.C.
SUMMARY OF CALCULATED TOTAL MASS LOAD IN THE CAPE FEAR RIVER
Chemours Fayetteville Works, North Carolina
Reporting Period Details
Reporting Peroid

Start Date

End Date

Days

River volume(m3)

2020-Q1 Report
2020-Q2 Report
2020-Q3 Report
2020-Q4 Report2021-Q1 Report

03/28/2020 1:00
05/09/2020 23:49
06/29/2020 16:06
10/01/2020 0:01
12/30/2020 10:56

05/09/2020 23:49
06/29/2020 16:06
10/01/2020 0:01
12/30/2020 10:56
03/31/2021 23:01

43
51
93
90
92

514,570,000
1,308,600,000
1,036,200,000
2,118,700,000
3,157,900,000

Total403/28/2020 1:00

03/31/2021 23:01

369

8,135,970,000

Total Table 3+ (17 Compounds)2
Load in Cape
RemedyTotal Load toFear River
Reduction
Cape Fear
3,6
4,6
(kg)
Loads (kg)River (kg)5,6
45.8
0
45.8
79.7
0
79.7
78.5
0
78.5
76.7
25.8
102.5
93.8
28.7
122.5
374.5

54.5

429.0

Notes:
1 - Total Attachment C does not include Perfluorohepthanoic acid (PFHpA).
2 - Total table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed,
PSDA, and R-EVE.
3 - Calculated Cape Fear River loads represents loads measured in the Cape Fear
River at the CFR-TARHEEL sampling location downstream of the Site.
4 - Calculated remedy reduction loads represents loads from Old Outfall 002 andSeep C that were prevented from reaching the Cape Fear River.
5 - Total load to Cape Fear River represents the sum of the measured in-river load
and the remedy reduction load. This value represents the baseline load that would
reach the Cape Fear River in the absence of any remedies.
6 - Total values are rounded to two significant digits. Values in calculations
supporting totals are not rounded.
kg - kilograms
m3 - cubic meters

Page 2 of 3

June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 4
Geosyntec Consultants of NC P.C.
SUMMARY OF CALCULATED TOTAL MASS LOAD IN THE CAPE FEAR RIVER
Chemours Fayetteville Works, North Carolina
Reporting Period Details
Reporting Peroid

Start Date

End Date

Days

River volume(m3)

2020-Q1 Report
2020-Q2 Report
2020-Q3 Report
2020-Q4 Report2021-Q1 Report

03/28/2020 1:00
05/09/2020 23:49
06/29/2020 16:06
10/01/2020 0:01
12/30/2020 10:56

05/09/2020 23:49
06/29/2020 16:06
10/01/2020 0:01
12/30/2020 10:56
03/31/2021 23:01

43
51
93
90
92

514,570,000
1,308,600,000
1,036,200,000
2,118,700,000
3,157,900,000

Total403/28/2020 1:00

03/31/2021 23:01

369

8,135,970,000

Total Table 3+ (20 Compounds)
Load in Cape
RemedyTotal Load toFear River
Reduction
Cape Fear
3,6
4,6
(kg)
Loads (kg)River (kg)5,6
58.7
0
58.7
101.6
0
101.6
99.5
0
99.5
98.5
26.5
125.0
117.9
29.5
147.3
476.2

56.0

532.2

Notes:
1 - Total Attachment C does not include Perfluorohepthanoic acid (PFHpA).
2 - Total table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed,
PSDA, and R-EVE.
3 - Calculated Cape Fear River loads represents loads measured in the Cape Fear
River at the CFR-TARHEEL sampling location downstream of the Site.
4 - Calculated remedy reduction loads represents loads from Old Outfall 002 andSeep C that were prevented from reaching the Cape Fear River.
5 - Total load to Cape Fear River represents the sum of the measured in-river load
and the remedy reduction load. This value represents the baseline load that would
reach the Cape Fear River in the absence of any remedies.
6 - Total values are rounded to two significant digits. Values in calculations
supporting totals are not rounded.
kg - kilograms
m3 - cubic meters

Page 3 of 3

June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 5A
CAPE FEAR RIVER PFAS MASS LOAD BY COMPOUND AND TIME INTERVAL
Chemours Fayetteville Works, North Carolina

Calculated Mass Load2 (kg)PEPA

PS Acid (Formerly
PFESA-BP1)

Hydro-PS Acid (Formerly
PFESA-BP2)

R-PSDA (Formerly
Byproduct 4)

Hydrolyzed PSDA
(Foremerly Byproduct 5)

R-PSDCA (Formerly
Byproduct 6)

NVHOS

EVE AcidHydro-EVE Acid

R-EVE

PES

PFECA BPFECA-G

PFHpA

334,627,822
45,269,293
161,851,166
80,160,009
101,278,798
12,924,035
11,886,280
38,714,509
630,758
4,979,036
12,789,729
9,642,566
29,998,584
129,039,020
157,579,853
159,603,375
83,254,162
32,965,312
180,462,725
186,467,284
164,917,031
93,018,293
35,590,029
331,411,594
43,768,217
41,150,891
42,955,240
38,107,963
74,531,356
25,460,186
61,556,350
21,039,530
46,167,900
30,138,753
118,868,402
19,076,663
19,613,126
63,362,994
17,967,039
15,484,784
15,161,123
25,026,429
39,405,157
3,157,903,369

PMPA

1/6/21 12:10
1/7/21 11:00
1/11/21 10:30
1/14/21 12:40
1/21/21 0:01
1/22/21 0:01
1/22/21 23:01
1/26/21 15:00
1/26/21 16:10
1/27/21 0:01
1/27/21 15:10
1/28/21 0:01
1/28/21 23:01
2/1/21 10:05
2/4/21 16:35
2/8/21 16:00
2/11/21 0:01
2/12/21 14:01
2/16/21 12:00
2/19/21 13:35
2/22/21 9:35
2/24/21 15:15
2/25/21 12:20
3/5/21 0:01
3/6/21 0:01
3/6/21 23:01
3/8/21 0:01
3/8/21 23:01
3/11/21 0:01
3/11/21 23:01
3/15/21 0:01
3/15/21 23:01
3/18/21 0:01
3/18/21 23:01
3/24/21 0:01
3/24/21 23:01
3/25/21 23:01
3/29/21 0:01
3/29/21 12:50
3/29/21 23:01
3/30/21 8:50
3/31/21 0:01
3/31/21 23:01

PFO5DA

12/30/20 10:56
1/6/21 12:10
1/7/21 11:00
1/11/21 10:30
1/14/21 12:40
1/21/21 0:01
1/22/21 0:01
1/22/21 23:01
1/26/21 15:00
1/26/21 16:10
1/27/21 0:01
1/27/21 15:10
1/28/21 0:01
1/28/21 23:01
2/1/21 10:05
2/4/21 16:35
2/8/21 16:00
2/11/21 0:01
2/12/21 14:01
2/16/21 12:00
2/19/21 13:35
2/22/21 9:35
2/24/21 15:15
2/25/21 12:20
3/5/21 0:01
3/6/21 0:01
3/6/21 23:01
3/8/21 0:01
3/8/21 23:01
3/11/21 0:01
3/11/21 23:01
3/15/21 0:01
3/15/21 23:01
3/18/21 0:01
3/18/21 23:01
3/24/21 0:01
3/24/21 23:01
3/25/21 23:01
3/29/21 0:01
3/29/21 12:50
3/29/21 23:01
3/30/21 8:50
3/31/21 0:01

PFO4DA

2021_1_Q1
2021_2_Q1
2021_3_Q1
2021_4_Q1
2021_5_Q1
2021_6_Q1
2021_7_Q1
2021_8_Q1
2021_9_Q1
2021_10_Q1
2021_11_Q1
2021_12_Q1
2021_13_Q1
2021_14_Q1
2021_15_Q1
2021_16_Q1
2021_17_Q1
2021_18_Q1
2021_19_Q1
2021_20_Q1
2021_21_Q1
2021_22_Q1
2021_23_Q1
2021_24_Q1
2021_25_Q1
2021_26_Q1
2021_27_Q1
2021_28_Q1
2021_29_Q1
2021_30_Q1
2021_31_Q1
2021_32_Q1
2021_33_Q1
2021_34_Q1
2021_35_Q1
2021_36_Q1
2021_37_Q1
2021_38_Q1
2021_39_Q1
2021_40_Q1
2021_41_Q1
2021_42_Q1
2021_43_Q1
TotalsTotal River
Flow (m3)

PFO3OA

End Time1

PFO2HxA

1

PFMOAA

Start TimeHFPO-DAInterval Details

Interval ID

Geosyntec Consultants of NC P.C.

1.20
0.14
0.73
0.60
0.95
0.12
0.12
0.52
0.01
0.05
0.13
0.09
0.22
0.83
0.79
0.36
0.42
0.33
1.27
1.17
1.16
0.47
0.17
1.66
0.20
1.15
0.73
0.22
0.51
0.20
0.49
0.16
0.29
0.15
0.83
0.06
0.06
0.09
0.06
0.05
0.04
0.09
0.17
19

2.51
0.07
1.05
1.36
2.13
0.27
0.27
1.14
0.02
0.11
0.29
0.22
0.48
1.59
0.68
0.00
1.00
0.79
2.17
0.83
1.26
0.70
0.29
3.21
0.53
0.45
0.49
0.46
1.19
0.51
1.23
0.40
0.74
0.39
1.96
0.15
0.11
0.17
0.14
0.10
0.08
0.15
0.27
32

1.39
0.16
0.76
0.63
0.93
0.11
0.10
0.41
0.01
0.06
0.14
0.09
0.21
0.76
0.74
0.37
0.34
0.27
1.03
0.71
0.94
0.56
0.19
1.77
0.23
0.19
0.20
0.17
0.44
0.18
0.44
0.14
0.27
0.16
1.08
0.09
0.05
0.07
0.08
0.05
0.03
0.07
0.15
17

0.00
0.00
0.00
0.08
0.10
0.00
0.00
0.06
0.00
0.01
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.18
0.10
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.13
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.7

0
0
0
0.00
0.00
0.00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.0

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.0

0.00
0.00
0.00
0.00
0.71
0.18
0.17
0.66
0.01
0.09
0.23
0.16
0.42
1.74
1.81
0.80
0.83
0.66
3.16
2.89
2.31
0.95
0.36
1.99
0.00
0.00
0.00
0.00
0.52
0.36
0.86
0.25
0.53
0.33
1.66
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
25

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.6

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

1
0.00
0.32
0.34
0.52
0.07
0.08
0.51
0.01
0.05
0.10
0.07
0.18
0.38
0.00
0.00
0.21
0.17
0.46
0.45
0.98
0.55
0.14
1.67
0.32
0.26
0.22
0.14
0.31
0.11
0.28
0.09
0.18
0.11
1.53
0.00
0.14
0.23
0.00
0.06
0.11
0.10
0.00
12

0.72
0.00
0.23
0.28
0.58
0.09
0.09
0.34
0.01
0.04
0.09
0.06
0.14
0.49
0.57
0.35
0.25
0.20
0.54
0.28
0.51
0.26
0.08
1.18
0.21
0.16
0.13
0.09
0.24
0.11
0.26
0.08
0.15
0.09
1.00
0.08
0.04
0.07
0.07
0.05
0.03
0.07
0.12
10

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.0

0
0
0
0.00
0.00
0.00
0
0
0.00
0.00
0.00
0.00
0
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.1

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.0

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.0

0.47
0
0.00
0.00
0.00
0.00
0.00
0.08
0.00
0.02
0.04
0.03
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.17
0.10
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.32
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.2

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.0

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.0

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.0

0.59
0.00
0.00
0.00
0.12
0.03
0.03
0.09
0.00
0.02
0.03
0.02
0.07
0.35
0.43
0.51
0.31
0.12
0.55
0.24
0.00
0.00
0.06
1.11
0.15
0.16
0.17
0.15
0.28
0.09
0.22
0.09
0.19
0.11
0.42
0.04
0.07
0.12
0.04
0.05
0.06
0.08
0.11
7.3

Total
Total Table 3+
Total Table 3+
Attachment C3 (17 Compounds)4 (20 Compounds)

5.1
0.4
2.5
2.7
4.8
0.7
0.7
2.8
0.1
0.3
0.8
0.6
1.3
4.9
4.0
1.5
2.6
2.1
7.6
5.6
6.1
2.9
1.0
8.6
0.9
1.8
1.4
0.8
2.7
1.3
3.0
0.9
1.8
1.0
5.9
0.3
0.2
0.3
0.3
0.2
0.2
0.3
0.6
94

5.1
0.4
2.5
2.7
4.8
0.7
0.7
2.9
0.1
0.3
0.8
0.6
1.3
4.9
4.0
1.5
2.6
2.1
7.6
6
6.1
2.9
1.0
8.6
0.9
1.8
1.4
0.8
2.7
1.3
3.0
0.9
1.8
1.0
5.9
0.3
0.2
0.3
0.3
0.2
0.2
0.3
0.6
94

7.2
0.4
3.1
3.3
5.9
0.8
0.8
3.8
0.1
0.4
1.0
0.7
1.7
5.8
4.6
1.9
3.1
2.4
8.6
6
7.7
3.8
1.2
11.5
1.5
2.2
1.8
1.1
3.2
1.5
3.6
1.1
2.2
1.2
8.8
0.4
0.4
0.6
0.4
0.3
0.3
0.5
0.7
118

Notes:
1 - Start and end times are adjusted based on sampling times ± one hour to account for the total flow of the Cape Fear River.
2 - The calculated mass load is a product of weighted concentration and total river flow. Refer to the Cape Fear River PFAS Mass Loading Calculation Protocol Version 2 (Geosyntec, 2020d) for more details.
3 - Total Attachment C does not include Perfluorohepthanoic acid (PFHpA).
4 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.

TR0795

Page 1 of 1

June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 5B
OLD OUTFALL 002 CAPTURED MASS LOAD BY COMPOUND AND TIME INTERVAL
Chemours Fayetteville Works, North Carolina
Calculated Captured Mass Load (kg)1

PFMOAAPFO2HxAPFO3OAPFO4DAPFO5DAPMPA

PEPA

PS Acid

Hydro-PS Acid

R-PSDA

Hydrolyzed PSDA

R-PSDCANVHOSEVE AcidHydro-EVE Acid

R-EVE

PES

PFECA BPFECA-GInterval ID
OF003_2020_1_Q4
OF003_2020_2_Q4
OF003_2020_3_Q4
OF003_2021_1_Q1
OF003_2021_2_Q1
OF003_2021_3_Q1

HFPO-DAInterval Details

Total
Duration Flow(m3)(hours)Start Time
End Time
10/1/20 0:00 10/31/20 0:00
720
90,00011/1/20 0:00 11/30/20 0:00
696
80,00012/1/20 0:00 12/31/20 0:00
720
120,000
1/1/21 0:00 1/31/21 0:00
720
120,000
2/1/21 0:00 2/28/21 0:00
648
100,000
3/1/21 0:00 3/31/21 0:00
720
100,000
Total 610,000

Geosyntec Consultants of NC P.C.

0.41
0.52
0.53
0.67
0.53
0.75
3.4

4.98
4.86
5.89
4.72
4.84
4.36
30

1.24
1.00
1.42
1.11
1.30
1.18
7.2

0.34
0.33
0.34
0.31
0.37
0.32
2.0

0.10
0.12
0.11
0.09
0.13
0.10
0.64

0.06
0.06
0.07
0.05
0.07
0.06
0.36

0.47
0.50
0.55
0.37
0.48
0.45
2.8

0.12
0.16
0.17
0.12
0.18
0.17
0.91

0.02
0.08
0.10
0.10
0.09
0.11
0.51

0.02
0.03
0.04
0.03
0.04
0.03
0.19

0.05
0.03
0.08
0.11
0.06
0.07
0.40

0.13
0.15
0.24
0.15
0.13
0.17
0.97

0.00
0.00
0.00
0.00
0.00
0.00
0

0.05
0.05
0.05
0.04
0.05
0.04
0.28

0.00
0.00
0.01
0.01
0.01
0.01
0.03

0.02
0.02
0.02
0.02
0.02
0.02
0.10

0.02
0.02
0.03
0.03
0.02
0.03
0.14

0.00
0.00
0.00
0.00
0.00
0.00
0

0.00
0.00
0.00
0.00
0.00
0.00
0

0.00
0.00
0.00
0.00
0.00
0.00
0

Total
Total Table Total Table
Attachment
3+ (173+ (20C2,4
compounds)3 compounds)
7.73
7.82
8.00
7.62
7.70
7.87
9.20
9.31
9.67
7.55
7.67
7.90
8.02
8.14
8.26
7.55
7.55
7.90
48
48
50

Notes:
1 - The calculated captured mass load is a product of the concentration difference in the influent and the effluent samples and total flow at the influent for the sampling interval. Refer to the Cape Fear River PFAS Mass Loading Calculation Protocol
Version 2 (Geosyntec, 2020d) for more details.
2 - Total Attachment C does not include Perfluorohepthanoic acid (PFHpA).
3 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
OF003 - Outfall 003, i.e., Old Outfall 002 treatment system

TR0795

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DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 5CSEEP C FLOW THROUGH CELL CAPTURED MASS LOAD BY COMPOUND AND TIME INTERVAL
Chemours Fayetteville Works, North Carolina

PEPA

PS Acid

Hydro-PS Acid

R-PSDA

Hydrolyzed PSDA

R-PSDCA

0.011
0.001
0.013
0.012
0.025
0.001
0.040
0.019
0.12

0
0
0
0
0.000700.00086
0
0.002

0.050
0.005
0.037
0.043
0.066
0.003
0.101
0.076
0.38

0.017
0.002
0.014
0.012
0.026
0.001
0.041
0.028
0.14

0
0
0
0
0
0
0
0
0

0.002
0.00020.00180.00150.00290.00020.00500.00340.02

0.006
0.00040.00220.00390.00730.00040.00760.0066
0.03

0.007
0.001
0.003
0.006
0.009
0.001
0.009
0.008
0.04

0
0
0
0
0
0
0
0
0.001

0.005
0
0.000400.003400.003300.005900.0003 6.9E-05
0.009100.006800.03
0.0001

0.008
0.001
0.006
0.006
0.009
0.000
0.015
0.009
0.05

0.005
0
0.000500.003300.004000.0066 3.8E-05
0.000400.008600.006800.04 0.00004

PFECA-G

PMPA

0.042
0.004
0.029
0.029
0.061
0.003
0.083
0.062
0.31

PFECA BPFO5DA

0.149
0.012
0.094
0.120
0.216
0.009
0.279
0.198
1.1

PES

PFO4DA

0.529
0.039
0.287
0.421
0.611
0.024
0.917
0.633
3.5

R-EVE

PFO3OA

0.105
0.010
0.063
0.089
0.129
0.006
0.209
0.122
0.73

291
24
416
270
674
56
444
312

Hydro-EVE Acid

PFO2HxA

5513
522
4496
5571
8647
1068
11632
7632
Total 45,081

End Time
12/30/2020
12/31/2020
1/18/2021
1/29/2021
2/26/2021
2/28/2021
3/19/2021
3/31/2021

EVE Acid

PFMOAA

Start Time
12/17/2020
12/30/2020
1/1/2021
1/18/2021
1/29/2021
2/26/2021
3/1/2021
3/19/2021

Hfpo Dimer Acid

Interval ID

Total
Flow
(m3)

Duration(hours)

NVHOS

Calculated Captured Mass Load (kg) 1

Interval Details

SeepC_2020_1_Q4 4
SeepC_2020_2_Q4
SeepC_2021_1_Q1
SeepC_2021_2_Q1
SeepC_2021_3_Q1
SeepC_2021_4_Q1
SeepC_2021_5_Q1
SeepC_2021_6_Q1

Geosyntec Consultants of NC P.C.

0
0
0
0
0
0
0
0
0

0
0
0
0
0
0
0
0
0

Total
Total Table Total Table
Attachment
3+ (173+ (20C2
compounds)3 compounds)
0.88
0.07
0.54
0.75
1.12
0.05
1.63
1.14
6.2

0.93
0.07
0.54
0.75
1.12
0.05
1.74
1.14
6.4

0.93
0.07
0.54
0.75
1.21
0.05
1.74
1.14
6.4

Notes:
1 - The calculated captured mass load is a product of the concentration difference in the influent and the effluent samples and total flow recorded at the influent for the sampling interval. Refer to the Cape Fear River PFAS Mass Loading Calculation Protocol
Version 2 (Geosyntec, 2020d) for more details.
2 - Total Attachment C does not include Perfluorohepthanoic acid (PFHpA).
3 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
4 - Seep C was not operation for 47 hours between December 25 and 27, 2020 due to flooding.

TR0795

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DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 6SUMMARY OF TOTAL PFAS MASS DISCHARGE AT TARHEEL FERRY ROAD BRIDGE
Chemours Fayetteville Works, North Carolina

Quarter

Field Sample ID

Collection
Date

Hours
1
Composited

2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1
2021 Q1

CFR-TARHEEL-010621
CFR-TARHEEL-010721
CFR-TARHEEL-011121
CFR-TARHEEL-011421
CFR-TARHEEL-24-012121
CFR-TARHEEL-24-012221
CAP0121-CFR-TARHEEL-012621
CAP0121-CFR-TARHEEL-24-012721
CFR-TARHEEL-24-012721
CFR-TARHEEL-24-012821
CFR-TARHEEL-020121
CFR-TARHEEL-020421
CFR-TARHEEL-020821
CFR-TARHEEL-38-021221
CFR-TARHEEL-021621
CFR-TARHEEL-021921
CFR-TARHEEL-022221
CAP0221-CFR-TARHEEL-022421
CFR-TARHEEL-022521
CFR-TARHEEL-24-030521
CFR-TARHEEL-24-030621
CFR-TARHEEL-24-030821
CFR-TARHEEL-24-031121
CFR-TARHEEL-24-031521
CFR-TARHEEL-24-031821
CFR-TARHEEL-24-032421
CFR-TARHEEL-24-032521
CAP0321-CFR-TARHEEL-032921
CAP0321-CFR-TARHEEL-21-033021
CFR-TARHEEL-24-032921
CFR-TARHEEL-24-033121
CFR-TARHEEL-24-033121-D

1/6/21 12:10
1/7/21 11:00
1/11/21 10:30
1/14/21 12:40
1/21/21 23:01
1/22/21 23:01
1/26/21 15:00
1/27/21 15:10
1/27/21 23:01
1/28/21 23:01
2/1/21 10:05
2/4/21 16:35
2/8/21 16:00
2/12/21 14:01
2/16/21 12:00
2/19/21 13:35
2/22/21 9:35
2/24/21 15:15
2/25/21 12:20
3/5/21 23:01
3/6/21 23:01
3/8/21 23:01
3/11/21 23:01
3/15/21 23:01
3/18/21 23:01
3/24/21 23:01
3/25/21 23:01
3/29/21 12:10
3/30/21 8:50
3/29/21 23:01
3/31/21 23:01
3/31/21 23:01

0
0
0
0
23
23
0
23
23
23
0
0
0
38
0
0
0
0
0
23
23
23
23
23
23
23
23
0
20
23
23
23

Total
Attachment C2
9.3
7
24
42
53
55
91
67
58
44
32
19
0
62
22
38
36
71
30
22
44
22
49
45
34
65
58
14
11
16
15
15

Concentrations (ng/L)
Total Table 3+3(17 compounds)
9.3
7
24
42
53
55
94
67
58
44
32
19
0
62
22
38
36
75
30
22
44
22
49
45
34
75
61
14
11
16
15
15

Total Table 3+(20 compounds)
9.3
7
31
51
66
70
130
88
74
55
35
24
0
73
22
46
48
88
36
34
54
28
58
53
41
120
90
20
20
20
18
18

Total Volume(ft3)4

Instantaneous
Flow Rate
3
5(ft /s)----437,800,000
419,760,000-627,500,000
753,130,000
1,059,400,000---1,164,200,000-----1,481,400,000
1,453,200,000
1,345,800,000
899,120,000
743,000,000
1,064,300,000
673,680,000
663,150,000-1,082,200,000
1,181,300,000
1,391,600,000
1,391,600,000

19,90018,90014,6007,500--4,910---14,800
18,20017,900-25,000
24,20018,90016,90016,200--------14,000-----

Geosyntec Consultants NC P.C.

Total
2
Attachment C
5.2
3.7
9.9
8.9
7.9
7.9
13
14
15
16
13
9.8
0
15
16
26
19
34
14
11
22
10
15
11
12
15
13
5.6
4.7
6.5
7.1
7.1

Mass Discharge (mg/s)
Total Table 3+
Total Table 3+3(20 compounds)(17 compounds)
5.2
3.7
9.9
8.9
7.9
8
13
14
15
16
13
9.8
0
15
16
26
19
36
14
11
22
10
15
11
12
17
14
5.6
4.6
6.5
6.9
7.2

5.2
3.7
13
11
9.8
10
18
19
19
20
15
12
0
18
16
32
26
42
17
17
27
13
18
13
15
28
20
7.9
8.6
8.1
8.4
8.7

Notes:
1 - Samples with a compositing duration of zero (0) hours are grab samples.
2 - Total flow volume is determined based on measurements taken over the sample collection period.
3 - For samples with a duration of zero (0) hours, i.e., grab samples, the instantaneous flow rate was used to calculated the mass discharge.
4 - Total Attachment C does not include Perfluorohepthanoic acid (PFHpA).
5 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
-- - not applicable
ng/L - nanograms per liter
3

ft - cubic feetmg/s - milligrams per second

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DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 7PFAS MASS LOADING MODEL POTENTIAL PATHWAYS
Chemours Fayetteville Works, North Carolina

Geosyntec Consultants NC P.C.

Transport
Pathway
NumberPotential PFAS Transport Pathway

Analytical Data Source for Mass Loading Model1

Flow Data Source for Mass Loading Model1

1

Upstream River and Groundwater

Measured from Cape Fear River Mile 76 samples collected in January
2021, from Cape Fear DCO sample collected in February 2021, and from
Cape Fear 2517 Boat Ramp sample collected in March 2021 as reported inAppendix A Table A5.

Measured flow rates from USGS gauging station at W.O. Huske Damduring January, February, March 2021 volumetrically adjusted for flow
pathways between River Mile 76 and W.O. Huske Dam2.

2

Willis Creek

Measured from Willis Creek samples collected in January, February,
March 2021 as reported in Appendix A Table A5.

Measured flow rates through point velocity method during January,
February, March 2021 as reported in Appendix B.

3

Aerial Deposition on River

Estimated from air deposition modeling3.

Estimated from air deposition modeling3.

4

Outfall 002

Measured from Outfall 002 samples collected in January, February, March
2021 as reported in Appendix A Table A5.

Measured daily Outfall 002 flow rates recorded in Facility discharge
monitoring reports, summarized in Appendix B.

5

Onsite Groundwater

Measured from monitoring well samples collected in January, February,
March 2021 as reported in Appendix A Table A7.

Estimated as the sum of the mass flux from the Black Creek Aquifer
calculated from a transect along the Cape Fear River. Further details andsupporting calculations provided in Appendix E.

6

Seeps

Measured from Seeps A, B, C, and D samples collected in January,
February, March 2021 as reported in Appendix A Table A5.

Measured flow rates through point velocity method and flumes during
January, February, March 2021 as reported in Appendix B.

7

Old Outfall 002

Measured from Old Outfall 002 sample collected in January, February,
March 2021 as reported in Appendix A Table A5.

Measured flow rates through point velocity method during January,
February, March 2021 as reported in Appendix B.

8Adjacent and Downstream Groundwater

9

Georgia Branch Creek

Estimated using a scaling factor applied to upstream mass discharge. Refer Estimated using a scaling factor applied to upstream mass discharge. Refer
to Cape Fear River PFAS Mass Loading Calculation Protocol Version 2
to Cape Fear River PFAS Mass Loading Calculation Protocol Version 2(Geosyntec, 2020d) for details.
(Geosyntec, 2020d) for details.
Measured from Georgia Branch Creek sample collected in January,
February, March 2021 as reported in Appendix A Table A5.

Measured flow rates through point velocity method during January,
February, March 2021 as reported in Appendix B.

Notes:
1 - Flow and concentration data are multiplied together to estimate the PFAS mass discharge in the Cape Fear River originating from each pathway.
2 - Cape Fear River flow rates measured at USGS gauging station #02105500 located at William O Huske Lock & Dam accessed from https://waterdata.usgs.gov on 2021-04-30 at 12:00 EDT.
3 - ERM, 2018. Modeling Report: HFPO-DA Atmospheric Deposition and Screening Groundwater Effects. 27 April 2018.

TR0795

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DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Geosyntec Consultants of NC P.C.

TABLE 8A
SUMMARY OF TOTAL PFAS MASS DISCHARGE BY PATHWAY BEFORE REMEDIES -JANUARY 2021
Chemours Fayetteville Works, North Carolina

Total Flow
Volume on
Sample Date
(MG)1

Pathway

Pathway Name

1
2
3
4

Upstream River Water and Groundwater2
Willis Creek
Aerial Deposition on Water Features5

Outfall 0023
Onsite Groundwater (Lower Bound)44

Onsite Groundwater (Upper Bound)
6A
Seep A
6B
Seep B
6C
Seep C7
6D
Seep D
6E
Lock and Dam Seep
7
Old Outfall 0027
8
Offsite Adjacent and Downstream Groundwater
9
Georgia Branch Creek
Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Lower Bound)Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Upper Bound)
Measured Total Table 3+ Loading (mg/s) at Tar Heel

Total Attachment C5
Concentration Mass Loading(ng/L)(mg/s)

Total Table 3+ (17 compounds)6

Total Table 3+ (20 compounds)

Concentration(ng/L)

Mass Loading(mg/s)

Concentration(ng/L)

Mass Loading(mg/s)

4,407
15.69
-18

0.0
1,100
-800

0.0
0.76
0.01
0.63

0.0
1,100
-860

0.0
0.76
0.01
0.68

3.7
1,100
-1,700

0.7
0.76
0.01
1.34

--

--

2.29

--

2.29

--

2.31

-0.30
0.18
0.10
0.38
0.05
1.23
-11.84-91,000
170,000
150,000
140,000
40,00064,000-1,400-94,000
170,000
150,000
140,000
40,00065,000-1,500

67

3.3
1.25
1.36
0.63
2.36
0.09
3.51
0.00
0.78
13.7
14.7
14.4

-110,000
190,000
150,000
150,000
41,00067,000-1,600

4,890

3.3
1.21
1.36
0.63
2.36
0.09
3.46
0.00
0.73
13.5
14.5
14.4

3.3
1.46
1.52
0.63
2.52
0.09
3.62
0.27
0.83
16.1
17.1
18.9

67

88

Notes:
1 - Total flow volume is determined based on measurements taken over 24-hour sample
collection period for all locations except Seeps A and B, Lock and Dam Seep, Old Outfall 002,
Georgia Branch Creek and Willis Creek. At these locations, the total flow volume was estimatedbased on the instantaneous flow measurement.
2 - The volumetric flow rate for upstream river water and groundwater was estimated bysubtracting inflows from Willis Creek, upwelling groundwater, seeps to the river, and Outfall
002 and by adding the river water intake from Chemours to the flow rate measurement from the
W.O. Huske Dam.
3 - Total PFAS concentrations at the Intake River Water at Facility location are subtracted from
Outfall 002 concentrations to compute the mass discharge at Outfall 002.
4 - Mass Discharge for Onsite Groundwater was determined using calculations described inAppendix E. The lower and upper bounds on the mass discharge were calculated calculatedusing two different contour elevation differences in the vicinity of the river frontage: a ten-footelevation difference (between the 40 and 50 ft contours) and a twenty-foot elevation difference(between the 40 and 60 ft contours) as described in Appendix E.
5 - Mass dicharge calculations for Total Attachment C does not include Perfluorohepthanoic
acid (PFHpA).
6 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
7 - For January 2021, the concentrations from the influent samples collected at the Old Outfall
002 treatment system and Seep C flow-through cell were used to calculate the Before Remedy
mass discharge for these pathways.

Page 1 of 1

TR0795June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Geosyntec Consultants of NC P.C.

TABLE 8B
SUMMARY OF TOTAL PFAS MASS DISCHARGE BY PATHWAY AFTER REMEDIES - JANUARY 2021
Chemours Fayetteville Works, North Carolina
Total Attachment C

Total Flow
Volume on Sample Concentration Mass Loading1(ng/L)(mg/s)
Date (MG)

Pathway

Pathway Name

1
2
3
4

Upstream River Water and Groundwater
Willis Creek
Aerial Deposition on Water Features5

Outfall 002

52

Total Table 3+ (17 compounds)

6

Total Table 3+ (20 compounds)

Concentration(ng/L)

Mass Loading(mg/s)

Concentration(ng/L)

Mass Loading(mg/s)

4,407
15.69
-18

0.0
1,100
-800

0.0
0.76
0.01
0.63

0.0
1,100
-860

0.0
0.76
0.01
0.68

3.7
1,100
-1,700

0.7
0.76
0.01
1.34

4

--

--

2.29

--

2.29

--

2.31

4

-0.30
0.18
0.10
0.38
0.05
1.23
-11.84-91,000
170,000
1,400
140,000
40,0009,900-1,400-94,000
170,000
1,400
140,000
40,00010,000-1,500

67

3.3
1.25
1.36
0.01
2.36
0.09
0.54
0.00
0.78
10.1
11.1
14.4

-110,000
190,000
1,500
150,000
41,00010,000-1,600

4,890

3.3
1.21
1.36
0.01
2.36
0.09
0.53
0.00
0.73
10.0
11.0
14.4

3.3
1.46
1.52
0.01
2.52
0.09
0.54
0.27
0.83
12.4
13.4
18.9

3

Onsite Groundwater (Lower Bound)

Onsite Groundwater (Upper Bound)
6A
Seep A
6B
Seep B
7
6C
Seep C
6D
Seep D
6E
Lock and Dam Seep
7
7
Old Outfall 002
8
Offsite Adjacent and Downstream Groundwater
9
Georgia Branch Creek
Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Lower Bound)Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Upper Bound)
Measured Total Table 3+ Loading (mg/s) at Tar Heel

67

88

Notes:
1 - Total flow volume is determined based on measurements taken over 24-hour sample collection
period for all locations except Seeps A and B, Lock and Dam Seep, Old Outfall 002, Georgia
Branch Creek and Willis Creek. At these locations, the total flow volume was estimated based on
the instantaneous flow measurement.
2 - The volumetric flow rate for upstream river water and groundwater was estimated bysubtracting inflows from Willis Creek, upwelling groundwater, seeps to the river, and Outfall 002
and by adding the river water intake from Chemours to the flow rate measurement from the W.O.
Huske Dam.
3 - Total PFAS concentrations at the Intake River Water at Facility location are subtracted from
Outfall 002 concentrations to compute the mass discharge at Outfall 002.
4 - Mass Discharge for Onsite Groundwater was determined using calculations described inAppendix E. The lower and upper bounds on the mass discharge were calculated calculated using
two different contour elevation differences in the vicinity of the river frontage: a ten-foot elevationdifference (between the 40 and 50 ft contours) and a twenty-foot elevation difference (between the
40 and 60 ft contours) as described in Appendix E.
5 - Mass dicharge calculations for Total Attachment C does not include Perfluorohepthanoic acid
(PFHpA).
6 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
7 - For January 2021, the concentrations from the Old Outfall 002 sample collected downgradientfrom the treatment system and the Seep C sample collected downgradient from the Seep C flowthrough cell were used to calculate the After Remedy mass discharge for these pathways.

Page 1 of 1

TR0795June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Geosyntec Consultants of NC P.C.

TABLE 9A
SUMMARY OF TOTAL PFAS MASS DISCHARGE BY PATHWAY BEFORE REMEDIES-FEBRUARY 2021
Chemours Fayetteville Works, North Carolina

Total Flow
Volume on
Sample Date
(MG)1

Pathway

Pathway Name

1
2
3
4

Upstream River Water and Groundwater2
Willis Creek
Aerial Deposition on Water Features5

Outfall 0023

10,827
15.69
-11

4

--

4

-0.30
0.30
0.12
0.23
0.05
1.11
-5.28

Onsite Groundwater (Lower Bound)

Onsite Groundwater (Upper Bound)
6A
Seep A
6B
Seep B
6C
Seep C7
6D
Seep D
6E
Lock and Dam Seep
7
Old Outfall 0027
8
Offsite Adjacent and Downstream Groundwater
9
Georgia Branch Creek
Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Lower Bound)Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Upper Bound)
Measured Total Table 3+ Loading (mg/s) at Tar Heel

10,923

Total Attachment C5

Total Table 3+ (17 compounds)6

Total Table 3+ (20 compounds)

Concentration(ng/L)

Mass Loading(mg/s)

Concentration(ng/L)

Mass Loading(mg/s)

0.0
0.96
0.01
0.12

0.0
1,400
-275

0.0
0.96
0.01
0.13

0.0
1,600

0.0
1.10
0.01
0.20

2.34

--

2.34

3.2
2.52
1.60
0.24
1.20
0.09
3.30
0.00
0.39
12.8
13.6
12.4

-200,000
130,000
47,000120,000
40,00069,000

3.2
2.65
1.73
0.25
1.20
0.09
3.35
0.00
0.42
13.1
14.0
12.4

Concentration Mass Loading(ng/L)(mg/s)
01,400
255

190,000
120,000
46,000120,000
40,00068,000
1,700

26

1,800

26

403

2.35
220,000
140,000
48,000120,000
41,00070,000
1,900

34

3.2
2.91
1.86
0.25
1.20
0.09
3.40
0.00
0.44
13.8
14.7
16.3

Notes:
1 - Total flow volume is determined based on measurements taken over 24-hour sample
collection period for all locations except Seeps A through D, Lock and Dam Seep, Old Outfall
002, Georgia Branch Creek and Willis Creek. At these locations, the total flow volume wasestimated based on the instantaneous flow measurement.
2 - The volumetric flow rate for upstream river water and groundwater was estimated bysubtracting inflows from Willis Creek, upwelling groundwater, seeps to the river, and Outfall
002 and by adding the river water intake from Chemours to the flow rate measurement from the
W.O. Huske Dam.
3 - Total PFAS concentrations at the Intake River Water at Facility location are subtracted from
Outfall 002 concentrations to compute the mass discharge at Outfall 002.
4 - Mass Discharge for Onsite Groundwater was determined using calculations described inAppendix E. The lower and upper bounds on the mass discharge were calculated calculatedusing two different contour elevation differences in the vicinity of the river frontage: a ten-footelevation difference (between the 40 and 50 ft contours) and a twenty-foot elevation difference(between the 40 and 60 ft contours) as described in Appendix E.
5 - Mass dicharge calculations for Total Attachment C does not include Perfluorohepthanoic
acid (PFHpA).
6 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
7 - For February 2021, the concentrations from the influent samples collected at the Old Outfall
002 treatment system and Seep C flow-through cell were used to calculate the Before Remedy
mass discharge for these pathways.

Page 1 of 1

TR0795June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Geosyntec Consultants of NC P.C.

TABLE 9B
SUMMARY OF TOTAL PFAS MASS DISCHARGE BY PATHWAY AFTER REMEDIES -FEBRUARY 2021
Chemours Fayetteville Works, North Carolina
Total Attachment C

Total Flow
Volume on Sample Concentration Mass Loading1(ng/L)(mg/s)
Date (MG)

Pathway

Pathway Name

1
2
3
4

Upstream River Water and Groundwater
Willis Creek
Aerial Deposition on Water Features5

Outfall 002

5

2

3

10,838
15.69
-11

0
1,400
255

0.0
0.96
0.01
0.12

4

--

2.34

4

-0.30
0.30
0.12
0.23
0.05
1.11
-5.28

3.2
2.52
1.60
0.01
1.20
0.09
0.73
0.00
0.39
10.0
10.8
12.4

Onsite Groundwater (Lower Bound)

Onsite Groundwater (Upper Bound)
6A
Seep A
6B
Seep B
6C
Seep C
6D
Seep D
6E
Lock and Dam Seep
7
7
Old Outfall 002
8
Offsite Adjacent and Downstream Groundwater
9
Georgia Branch Creek
Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Lower Bound)Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Upper Bound)
Measured Total Table 3+ Loading (mg/s) at Tar Heel

10,923

190,000
120,000
1,000
120,000
40,00015,0001,700

26Total Table 3+ (17 compounds)

6

Total Table 3+ (20 compounds)

Concentration(ng/L)

Mass Loading(mg/s)

Concentration(ng/L)

Mass Loading(mg/s)

0.0
1,400
-275

0.0
0.96
0.01
0.13

0.0
1,600

0.0
1.10
0.01
0.20

--

2.34

-200,000
130,000
1,000
120,000
40,00015,000

3.2
2.65
1.73
0.01
1.20
0.09
0.73
0.00
0.42
10.3
11.1
12.4

1,800

26

403

2.35
220,000
140,000
1,000
120,000
41,00015,000
1,900

34

3.2
2.91
1.86
0.01
1.20
0.09
0.73
0.00
0.44
10.9
11.8
16.3

Notes:
1 - Total flow volume is determined based on measurements taken over 24-hour sample collection
period for all locations except Seeps A through D, Lock and Dam Seep, Old Outfall 002, Georgia
Branch Creek and Willis Creek. At these locations, the total flow volume was estimated based on
the instantaneous flow measurement.
2 - The volumetric flow rate for upstream river water and groundwater was estimated bysubtracting inflows from Willis Creek, upwelling groundwater, seeps to the river, and Outfall 002
and by adding the river water intake from Chemours to the flow rate measurement from the W.O.
Huske Dam.
3 - Total PFAS concentrations at the Intake River Water at Facility location are subtracted from
Outfall 002 concentrations to compute the mass discharge at Outfall 002.
4 - Mass Discharge for Onsite Groundwater was determined using calculations described inAppendix E. The lower and upper bounds on the mass discharge were calculated calculated using
two different contour elevation differences in the vicinity of the river frontage: a ten-foot elevationdifference (between the 40 and 50 ft contours) and a twenty-foot elevation difference (between the
40 and 60 ft contours) as described in Appendix E.
5 - Mass dicharge calculations for Total Attachment C does not include Perfluorohepthanoic acid
(PFHpA).
6 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
7 - For February 2021, the concentrations from the Old Outfall 002 sample collected
downgradient from the treatment system and effluent sample collected at the Seep C flow-throughcell were used to calculate the After Remedy mass discharge for these pathways.

Page 1 of 1

TR0795June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 10A
SUMMARY OF TOTAL PFAS MASS DISCHARGE BY PATHWAY BEFORE REMEDIES - MARCH 2021
Chemours Fayetteville Works, North Carolina
Total Flow
Volume on
Sample Date
1
(MG)

Pathway

Pathway Name

1
2
3
4

Upstream River Water and Groundwater2
Willis Creek
Aerial Deposition on Water Features5

Outfall 0023
Onsite Groundwater (Lower Bound)44

Onsite Groundwater (Upper Bound)
Seep A
Seep B

6A
6B
6C
Seep C7
6D
Seep D
6E
Lock and Dam Seep
7
Old Outfall 0027
8
Offsite Adjacent and Downstream Groundwater
9
Georgia Branch Creek
Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Lower Bound)Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Upper Bound)
Measured Total Table 3+ Loading (mg/s) at Tar Heel8

Total Attachment C5
Concentration Mass Loading(ng/L)(mg/s)

Geosyntec Consultants of NC P.C.

Total Table 3+ (17 compounds)6

Total Table 3+ (20 compounds)

Concentration(ng/L)

Mass Loading(mg/s)

Concentration(ng/L)

Mass Loading(mg/s)

0.0
900
-298

0.0
0.39
0.01
0.24

10,309
9.84
-18

0
900
-196

0.0
0.39
0.01
0.16

0.0
900
-216

0.0
0.39
0.01
0.17

--

--

2.77

--

2.77

--

2.81

-0.30
0.15
0.10
0.24
0.02
1.42
-2.42

-150,000
210,000
150,000
170,000
140,000
64,000-3,100-150,000
220,000
150,000
170,000
140,000
64,000-3,100

13

3.6
1.99
1.44
0.63
1.81
0.14
3.98
0.00
0.33
13.7
14.5
4.5

-160,000
260,000
150,000
180,000
150,000
67,000-3,100

8,290

3.6
1.99
1.38
0.63
1.81
0.14
3.98
0.00
0.33
13.6
14.5
4.5

3.7
2.12
1.71
0.63
1.92
0.15
4.17
0.00
0.33
14.5
15.3
7.3

13

20

Notes:
1 - Total flow volume is determined based on measurements taken over 24-hour sample
collection period for all locations except Seeps A through D, Lock and Dam Seep, Old Outfall
002, Georgia Branch Creek and Willis Creek. At these locations, the total flow volume wasestimated based on the instantaneous flow measurement.
2 - The volumetric flow rate for upstream river water and groundwater was estimated bysubtracting inflows from Willis Creek, upwelling groundwater, seeps to the river, and Outfall
002 and by adding the river water intake from Chemours to the flow rate measurement from the
W.O. Huske Dam.
3 - Total PFAS concentrations at the Intake River Water at Facility location are subtracted from
Outfall 002 concentrations to compute the mass discharge at Outfall 002.
4 - Mass Discharge for Onsite Groundwater was determined using calculations described inAppendix E. The lower and upper bounds on the mass discharge were calculated calculatedusing two different contour elevation differences in the vicinity of the river frontage: a ten-footelevation difference (between the 40 and 50 ft contours) and a twenty-foot elevation difference(between the 40 and 60 ft contours) as described in Appendix E.
5 - Mass dicharge calculations for Total Attachment C does not include Perfluorohepthanoic
acid (PFHpA).
6 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
7 - For March 2021, the concentrations from the influent samples collected at the Old Outfall
002 treatment system and Seep C flow-through cell were used to calculate the Before Remedy
mass discharge for these pathways.
8 - For the March 2021 sampling event, a 24-hr composite sample could not be collected
because of battery failure after 21 cycles. The average concentration between the grab sample
and partial 24-hr composite sample were used in the calculation of mass dischrage.

Page 1 of 1
TR0795June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 10B
SUMMARY OF TOTAL PFAS MASS DISCHARGE BY PATHWAY AFTER REMEDIES - MARCH 2021
Chemours Fayetteville Works, North Carolina
Total Flow
Volume on
Sample Date
(MG)1

Pathway

Pathway Name

1
2
3
4

Upstream River Water and Groundwater2
Willis Creek
Aerial Deposition on Water Features5

3

Outfall 002

Onsite Groundwater (Lower Bound)44

Onsite Groundwater (Upper Bound)
6A
Seep A
6B
Seep B
6C
Seep C
6D
Seep D
6E
Lock and Dam Seep
7
Old Outfall 0027
8
Offsite Adjacent and Downstream Groundwater
9
Georgia Branch Creek
Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Lower Bound)Calculated Total Table 3+ Loading (mg/s) at Tar Heel (Upper Bound)
Measured Total Table 3+ Loading (mg/s) at Tar Heel8

Total Attachment C5
Concentration Mass Loading(ng/L)(mg/s)

Geosyntec Consultants of NC P.C.

Total Table 3+ (17 compounds)6

Total Table 3+ (20 compounds)

Concentration(ng/L)

Mass Loading(mg/s)

Concentration(ng/L)

Mass Loading(mg/s)

10,309
9.84
-18

0
900
-196

0.0
0.39
0.01
0.16

0.0
900
-216

0.0
0.39
0.01
0.17

0.0
900
-298

0.0
0.39
0.01
0.24

--

--

2.77

--

2.77

--

2.81

-0.30
0.15
0.10
0.24
0.02
1.42
-2.42

-150,000
210,000
110
170,000
140,000
30,000-3,100-150,000
220,000
110
170,000
140,000
30,000-3,100

13

3.6
1.99
1.44
0.00
1.81
0.14
1.87
0.00
0.33
10.9
11.8
4.5

-160,000
260,000
110
180,000
150,000
31,000-3,100

8,290

3.6
1.99
1.38
0.00
1.81
0.14
1.87
0.00
0.33
10.8
11.7
4.5

3.7
2.12
1.71
0.00
1.92
0.15
1.93
0.00
0.33
11.6
12.5
7.3

13

20

Notes:
1 - Total flow volume is determined based on measurements taken over 24-hour sample
collection period for all locations except Seeps A through D, Lock and Dam Seep, Old Outfall
002, Georgia Branch Creek and Willis Creek. At these locations, the total flow volume wasestimated based on the instantaneous flow measurement.
2 - The volumetric flow rate for upstream river water and groundwater was estimated bysubtracting inflows from Willis Creek, upwelling groundwater, seeps to the river, and Outfall 002
and by adding the river water intake from Chemours to the flow rate measurement from the W.O.
Huske Dam.
3 - Total PFAS concentrations at the Intake River Water at Facility location are subtracted from
Outfall 002 concentrations to compute the mass discharge at Outfall 002.
4 - Mass Discharge for Onsite Groundwater was determined using calculations described inAppendix E. The lower and upper bounds on the mass discharge were calculated calculated using
two different contour elevation differences in the vicinity of the river frontage: a ten-footelevation difference (between the 40 and 50 ft contours) and a twenty-foot elevation difference(between the 40 and 60 ft contours) as described in Appendix E.
5 - Mass dicharge calculations for Total Attachment C does not include Perfluorohepthanoic acid
(PFHpA).
6 - Total Table 3+ (17 compounds) does not include R-PSDA, Hydrolyzed, PSDA, and R-EVE.
7 - For March 2021, the concentrations from the Old Outfall 002 sample collected downgradientfrom the treatment system and the Seep C sample collected downgradient from the Seep C flowthrough cell were used to calculate the After Remedy mass discharge for these pathways.
8 - For the March 2021 sampling event, a 24-hr composite sample could not be collected becauseof battery failure after 21 cycles. The average concentration between the grab sample and partial
24-hr composite sample were used in the calculation of mass dischrage.

Page 1 of 1
TR0795June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

TABLE 11CAPE FEAR RIVER TOTAL TABLE 3+ (17 COMPOUNDS)RELATIVE MASS DISCHARGE PER PATHWAY
Chemours Fayetteville Works, North Carolina
Pathway

1[1] Upstream River Water and Groundwater[2] Willis Creek[3] Aerial Deposition on Water Features[4] Outfall 002[5] Onsite Groundwater[6] Seeps
2
Seeps (After Remedies)[7] Old Outfall 002
Old Outfall 002 (After Remedies) 2[8] Offsite Adjacent and Downstream Groundwater[9] Georgia Branch Creek

January 2021
Lower
Upper
0%
0%
6%
5%
<1%
<1%
5%
5%
17%
23%
41%
39%
37%
34%
26%
24%
3.9%
3.7%
0%
0%
6%
5%

February 2021
Lower
Upper
0%
0%
7%
7%
<1%
<1%
1%
1%
18%
23%
45%
42%
43%
41%
25%
24%
5.5%
5.2%
0%
0%
3%
3%

Geosyntec Consultants of NC P.C.

March 2021
Lower
Upper
0%
0%
3%
3%
<1%
<1%
1%
1%
20%
25%
44%
41%
39%
37%
29%
27%
14%
13%
0%
0%
2%
2%

Notes:
1 - Relative contributions were calculated using the before remedies Total Table 3+ (17 compounds) model-estimated mass discharges (Tables 8A, 9A, and 10A). These relative
contributions are presented as a range, which represents the upper and lower bound model estimates. Relative contributions for Total Attachment C and Total Table 3+ (20 compounds)
are provided in Appendix A.
2 - For Old Outfall 002 and at Seep C, the relative contributions were also calcalated using the after remedies model-estimated mass discharges (Tables 8B, 9B, and 10B).

Page 1 of 1
TR0795June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

FIGURES

TR0795A

June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Cape Fear River

³

NC
Hig
hw
ay

87

Will is C
reek

Site River Water Intake ")Seep A

Seep B

Outfall 002)"

Seep C Flow-Through Cell)"

Seep C
Seep D)
W.O. Huske Dam "Old Outfall 002 Treatment System ")Old Outfall 002

Ge

or g

ia B

r an

ch C

re

ek

³

0

8 Miles

Areas at Site

"
)
)
"
)
"

Seep C Flow-Through Cell

Chemours Monomers IXM

Kuraray Trosifol®
Leased Area

Old Outfall 002 Treatment System

Chemours Polymer
Processing Aid Area

Wastewater Treatment Plant

DuPont Polyvinyl Fluoride
Leased Area

Power - Filtered and
Demineralized Water
Production

Former DuPont PMDF Area

Kuraray Laboratory

Site Features
Site Boundary
Nearby Tributary
Observed Seep (Natural Drainage)
Site Conveyance Network

500

01,000 Feet

Site Location Map
Chemours Fayetteville Works, North Carolina

Kuraray SentryGlas®
Leased Area

Notes:
1. The outline of Cape Fear River is approximate and is based on open data from ArcGIS Online and North Carolina Department ofEnvironmental Quality Online GIS (MajorHydro shapefile).
2. Basemap sources: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS
User Community

Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US

1,000

a ry 1

Legend

ut

4

Tri
b

8

FigureBC

Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Baseline Monitoring Workplan\TR0795_SiteLocation_MLM.mxd

Last Revised: 6/16/2021

Author: TIp

Site Location

G
Raleigh

June 2021

1DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54³
Virginia

Haw
ve r
Ri

Greensboro

River
Deep

RaleighStart ofCape FearRiver
L i t tleR

North
Carolina

iverFayettevilleiver

Tar Heel
Ferry Road
BridgeW.O. Huske Dam_^
Bladen Bluffs
IntakeCapKings BluffFe arRIntake Canale

South
Carolina

Chemours
FayettevilleWorks

Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Baseline Monitoring Workplan\TR0795_Cape Fear River Watershed and Downstream Intakes.mxd; TIp; 06/16/2021

Wilmington

20

Legend_^10020 MilesChemours Fayetteville Works
Upper Basin

Cape Fear River Watershed and Downstream
Drinking Water Intakes

Middle Basin

Chemours Fayetteville Works, North Carolina

Lower Basin
Note:
Basemap sources: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,
and the GIS User Community.
Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US

FigureRaleigh2

June 2021
Sources:Esri, Garmin, USGS, NPSDocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54(3) Aerial Deposition(4) Outfall 002 (Pipe to River)Non-contact cooling water from river
Non-Chemours treated process water
Stormwater

Rain

Chemours
Fayetteville Works
Manufacturing Area

(1) Upstream
Cape Fear River

Seep A

(2)
Wil
lis

Seep B

ne
ed Zo

h

Perc

cial

Perched Zone Clay

Surfi

ifer

Aqu

Black Creek
Confining Unit

und

wa

(7)

Seep D

ld

O

B

nc

Ou
tfa

Seep C

02
ll 0

a
gi
or

ra

c
ja
Ad ea
(8) nstrw
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Data/PRJ/Projects/TR0795/Database and GIS/Illustrator/3D CSM Illustration/ConceptualSiteModel_Dec2020.ai

te

(9
)G
e

hC
ree
k

ek

(6) Seeps

i
nS
O
(5)

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ter

pe

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ou

nd w

ater

ver

r Ri

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an (8) Ad D dja
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un
dw
ater

Potential PFAS Transport Pathways to theCape Fear River from Site
Chemours Fayetteville Works, North Carolina

FigureNote: Image is conceptual and is not to scale

3
Raleigh, NC

June 2021

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54³

k
Willis Cree³

LegendFlow Measurement Location#*! Sample Location
(

GF

1

Sample Location (alternate)") Seep C Flow-Through Cell)"

Old Outfall 002 Treatment System
Observed Seep

CFR-MILE-76(!

Nearby Tributary
Site BoundaryWC-1

Notes:* - Flow measurement was taken at W.O. Huske Dam - USGS
1. Flow at Seep C and Seep D was measured using a flume.
2. Flow at Old Outfall 002, Willis Creek, and Georgia Branch Creek,
were measured using flow velocity method. Seep A flume
measurements contained many negative values and were not usedin the mass loading model. Flow at Seep B could not be measured
during the January 2021 event. Due to low flow, the Lock and Dam
seep flow was manually measured using a stopwatch andvolumetric container.
3. For Seeps A and B, flows were estimated using median flows of wet
weather events measured at the flumes over 2020 historical periods.
4. Results of estimated flow at these locations are provided in Table A3.
5. The outline of Cape Fear River is approximate and is based on
open data from ArcGIS Online and North Carolina Department ofEnvironmental Quality Online GIS.
6. Basemap sources: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,
and the GIS User Community.

#
*
!
(
Cap
e Fe
i
ar R
ver
SEEP-A-IMP

³

GF

1

#
*
!
(

³

2

SEEP-B-1(!

SEEP-C-EFF

#
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(

SEEP-C

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)
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Old Outfall 002 Treatment System

ch
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*
!
(

2

Seep C Flow-Through Cell

OUTFALL 002

Gek

Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Baseline Monitoring Workplan\TR0795_StreamReaches_FlowMeasurements_Jan2021_Q1_2021.mxd

Last Revised: 6/22/2021

Author: TIp

Intake River Water at Facility

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# LOCK-DAM SEEP
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(

1

0.5

0

1 Miles

1,250 1,000625 500

0 0

1,250
1,000
FeetFeetSample and Flow Measurement
Locations - January 2021
Chemours Fayetteville Works, North Carolina# OLDOF-1*!
(
2,000 1,0000Figure2,000 Feet
Raleigh

Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US

June 2021

4A

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54³

k
Willis Cree³

LegendFlow Measurement Location (alternate)

W
X# Flow Measurement Location
*

GF

1

Sample Location (alternate)(!

Sample Location") Seep C Flow-Through Cell)"

Old Outfall 002 Treatment System
Observed Seep
Nearby Tributary
Site Boundary

GF

WC-2

Notes:* - Flow measurement was taken at W.O. Huske Dam - USGS** - This location represents the maximum concentration used in themass loading model calculations.
1. Flow at Old Outfall 002, Georgia Branch Creek, Seep A, Seep B,
Seep C, and Seep D were measured using flow velocity method.
Flow at Willis Creek could not be measured during the February 2021
event. Flow measurement and sample collection at Lock and Dam
could not be obtained during the February 2021 event.
2. For Seeps A and D, flows were estimated using median flows of wet
weather events measured at the flumes over 2020 historical periods.
3. Results of estimated flow at these locations are provided in Table A3.
4. The outline of Cape Fear River is approximate and is based on
open data from ArcGIS Online and North Carolina Department ofEnvironmental Quality Online GIS.
5. Basemap sources: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,
and the GIS User Community.

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SEEP-B-TR2

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W.O. Huske Dam*

1,250 1,000625 500

1,250
1,000
FeetFeetSample and Flow Measurement
Locations - February 2021
Chemours Fayetteville Works, North Carolina

ek

W
OLDOF-2 X
Figure2,000 Feet
Raleigh

Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US

0 0

GF

GF

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Author: TIp
Last Revised: 6/22/2021

#
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Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Baseline Monitoring Workplan\TR0795_StreamReaches_FlowMeasurements_FebToMar_Q1_2021.mxd

Intake River Water at Facility³

1SEEP-A-IMP

June 2021

4B

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54³

k
Willis Cree³

LegendFlow Measurement Location (alternate)

W
X# Flow Measurement Location
*

GF

1

Sample Location (alternate)(!

Sample Location") Seep C Flow-Through Cell

W
X

GF

)
"

WC-5

Old Outfall 002 Treatment System
Observed Seep
Nearby Tributary
Site Boundary

Notes:* - Flow measurement was taken at W.O. Huske Dam - USGS** - This location represents the maximum concentration used in themass loading model calculations.
1. Flow at Old Outfall 002, Willis Creek, Georgia Branch Creek, Seep A,
Seep B, Seep C, and Seep D were measured using flow velocity
method. Due to low flow, the Lock and Dam seep flow was manually
measured using a stopwatch and volumetric container.
2. For Seeps A, C, and D, flows were estimated using median flows of
wet weather events measured at the flumes over 2020
historical periods.
3. Results of estimated flow at these locations are provided in Table A3.
4. The outline of Cape Fear River is approximate and is based on
open data from ArcGIS Online and North Carolina Department ofEnvironmental Quality Online GIS.
5. Basemap sources: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,
and the GIS User Community.

GF

W
X

WC-1-TR2

Cap
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ar R
ver
SEEP-A-IMP

GF
SEEP-B-1-C3
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2

SEEP-B-IMP
OUTFALL 002

#
*
!
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Seep C Flow-Through Cell

(
!
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SEEP-C-EFF

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2

W
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Author: TIp

SEEP-D2-B1*

Old Outfall 002 Treatment System

0.5

01 Miles

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Old O

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*

SEEP-D-C1

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002

W.O. Huske Dam*

# LOCK-DAM SEEP
*
!
(

)
"

1,250 1,000625 500

0 0

1,250
1,000
FeetFeetSample and Flow Measurement
Locations - March 2021
Chemours Fayetteville Works, North Carolina

ek

W
X

GF

Br

GBC-5

1

SEEP-D-D1

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Last Revised: 6/23/2021

#
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Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Baseline Monitoring Workplan\TR0795_StreamReaches_FlowMeasurements_FebToMar_Q1_2021.mxd

Intake River Water at Facility³

1

OLDOF-2
2,000 1,0000Figure2,000 Feet
Raleigh

Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US

June 2021

4C

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

GF

CFR-DCO

³

LegendGF³

1

Sample Location (alternate)(!

Sample Location
Site Boundary
Cape Fear RiverGF

CFR-2517BoatRamp

Notes:
1. The outline of Cape Fear River is approximate and is based on
open data from ArcGIS Online and North Carolina Department ofEnvironmental Quality Online GIS.
2. CFR-MILE-76 could not be sampled in February and March 2021.
CFR-DCO was sampled in February 2021 and CFR-2517BoatRamp
was sampled in March 2021.
3. Basemap sources: Esri, DigitalGlobe, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN,
and the GIS User Community.

³
1

Author: TIp

CFR-MILE-76

Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Baseline Monitoring Workplan\TR0795_CapeFearRiverSampleLocations_Q12021.mxd

Last Revised: 6/16/2021(!

³

2 - Downstream

2
CFR-BLADEN
25

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025 Miles

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2

1

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CFR-TARHEEL

Cape Fear River Sample
Locations - Q1 2021(!

Chemours Fayetteville Works, North Carolina

Figure2

1

0

2 Miles
Raleigh

Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US

June 2021

5DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Willis Creek

³

PW-09

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A
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Cape

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PW-04

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Old Outfall 002

PW-06

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Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Baseline Monitoring Workplan\TR0795_BaselineGroundwaterMonitoringWellNetwork.mxd; TIp; 6/16/2021

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Floodplain Deposits!
'
A

Black Creek Aquifer!
'A

Damaged500

01,000 Feet

Observed Seep
Nearby Tributary
Site Boundary

Groundwater Wells for Mass Loading Assessment
Chemours Fayetteville Works, North Carolina

Notes:
1. Due to the scale of the map, pairs of wells that are in close proximity have been offset for visibility. Therefore, the placement ofthese wells on this map do not reflect their true geographic coordinates.
2. The outline of Cape Fear River is approximate and is based on open data from ArcGIS Online and North Carolina Departmentof Environmental Quality Online GIS.
3. Basemap source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the
GIS User Community.
Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US

FigureRaleigh

June 2021

6

7

350

6

300

5

250

4

200

3

150

2

100
50

1

0
400

0
35,000350

30,000300

25,000250

20,000200

15,000150

10,000

100
50

5,000

0

0

Composite Sample
Grab Sample

Notes:-Total Table 3+ concentrations calculated by summing over Attachment C compounds
and Table 3+ (20 compounds) are provided in Appendix A.
-Precipitation data are from the USGS monitoring site at the W.O. Huske Dam.
Abbrevations:in - inches
ng/L - nanograms per liter
ft3/s - cubic feet per seconds

Total Daily Precipitation (in)400Cape Fear River Flow (ft3/s)

Total Table 3+ (17)Concentration (ng/L)

Total Table 3+ (17)Concentration (ng/L)

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Total Table 3+ (17 Compounds) Concentrations, Precipitation
and Daily Flow at Tar Heel Ferry Road Bridge
Chemours Fayetteville Works, North Carolina

FigureRaleigh

June 2021

7

7

60

6

50

5

40

4

30

3

20

2

10

1

0
70

0
35,00060

30,00050

25,00040

20,00030

15,00020

10,000

10

5,000

0

0

Total Daily Precipitation (in)70

Cape Fear River Flow (ft3/s)

Total Table 3+ (17)Mass Discharge (mg/s)

Total Table 3+ (17)Mass Discharge (mg/s)

DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Composite Sample
Grab Sample
Notes:-Total PFAS mass discharges calculated by summing over Table 3+ compounds (20 compounds) areprovided in Table 6.
-Precipitation data are from the USGS monitoring site at the W.O. Huske Dam.
Abbrevations:in - inches
mg/s - milligrams per seconds
ft3/s - cubic feet per seconds

Total Table 3+ (17 Compounds) Mass Discharge, Precipitation
and Daily Flow at Tar Heel Ferry Road Bridge
Chemours Fayetteville Works, North Carolina

FigureRaleigh

June 2021

8DocuSign Envelope ID: E2A337B6-519B-4C07-A23B-CF0D8191CF54

Total Table 3+ (17)Mass Discharge (mg/s)

70Composite Sample
Grab Sample
MLM Lower Bound
MLM Upper Bound

60
50
40
30
20
10

Total Table 3+ (17)Concentration (ng/L)

0630

Modeled Concentration
Composite Sample
Grab Sample

560
490
420
350
280
210
140
70
0

Notes:
1. Modeled mass discharges and concentrations were estimated using the MLM. The Q1 2021 massdischarge estimates are reported in Tables 8A, 8B, 9A, 9B, 10A, and 10B. The modeled
concentrations are provided in Appendix A.
2. Measured mass discharges and concentrations at CFR-TARHEEL are reported in Table 6 andAppendix A, respectively.
mg/s - milligrams per seconds
MLM - mass loading modelng/L - nanograms per liter

Modeled versus Measured Total PFAS Mass Discharge andConcentration
Chemours Fayetteville Works, North Carolina

FigureRaleigh

June 2021

9