NC0003573_Application (Amendment)_20210624

The Chemours Company
t Chemours Fayetteville Works
1 22828 NC Highway 87 W
Fayetteville,NC 28306
June 13, 2021
RECEIVED
Sergei Chernikov SUN 2 4 2021
NCDEQ Division of Water Resources
NPDES Unit NCDEQ/DWR/NPDES
1617 Mail Service Center
Raleigh,North Carolina 27699-1679
sergei.chernikov a,ncdenr.gov
Re: Chemours Fayetteville Works NPDES Permit Application for the
Groundwater Treatment System
Dear Mr. Chernikov:
The Chemours Company—Fayetteville Works is submitting a National Pollutant Discharge
Elimination System (NPDES) permit application to North Carolina Department of
Environmental Quality (NCDEQ) for the above-referenced facility. This facility is required
under the Addendum to Consent Order Paragraph 12 to reduce mass loading of per- and
polyfluoroalkyl substances(PFAS)from seeps and groundwater to the Cape Fear River. The
Addendum to the Consent Order requires that Chemours commence full operation of the
proposed groundwater remedy no later than March 15, 2023. The Groundwater Treatment
System needs to be operational no later than April 1, 2022 to meet the Consent Order
obligations.
Your timely review of this application is therefore much appreciated. Chemours would like
to schedule a meeting in early July to review and discuss this application with you. In the
meantime, if you have any questions or need additional information, please contact Christel
Compton at(910) 678-1213.
Sincerely,
41144~-211• 411,-
Dawn M. Hughes
Plant Manager
Chemours—Fayetteville Works

Chemours Fayetteville Works
NPDES Permit Application Update
Groundwater Treatment System
June 2021

Chemours-
„,„,:
Chemours Fayetteville Works
NPDES Permit Application Update
GROUNDWATER TREATMENT SYSTEM
cProposed
new GWTS
location
k
'`M.
4
�d
—— 4
Legend Si
1.
S Extraction well 1
— Planned groundwater remedy route 4
June 2021

NPDES PERMIT APPLICATION —JUNE 13, 2021
Chemours Fayetteville Works NPDES Permit Application for the Groundwater
Treatment System
Table of Contents
Application Introduction
• General Discussion regarding NPDES Application
Attachment A— Groundwater Treatment System (GWTS)—Outfall 004
• Attachment A.1 GWTS— Form 2D
• Attachment A.2 Line Drawing
• Attachment A.3 Justification for Presence of Pollutants
• Attachment A.4 Chemours Fayetteville Works—Groundwater and Seeps Water Quality
Assessment
• Attachment A.5 Engineering Report—Treatment of Groundwater and Upgradient Seeps
Water
• Attachment A.6 Engineering Alternatives Analysis—Treatment of Groundwater and
Upgradient Seeps Water
2

NPDES PERMIT APPLICATION—JUNE 13, 2021
Chemours Fayetteville June 13, 2021 NPDES Permit Application for the Groundwater
Treatment System
The Chemours Company FC, LLC (Chemours) is providing this National Pollutant Discharge
Elimination System (NPDES) permit application for discharges from a Groundwater Treatment
System (GWTS) at Fayetteville Works. The GWTS is required under the Addendum to Consent
Order (CO) between Chemours and the North Carolina Department of Environmental Quality
(NCDEQ). The objective of the GWTS is to reduce mass loading of per- and polyfluoroalkyl
substances (PFAS) from seeps and groundwater to the Cape Fear River, as measured by three
indicator PFAS.1 The GWTS will discharge into the pipe that conveys effluent from Outfall 002
from Chemours Fayetteville Works Site (the Site)to the Cape Fear River.
This will be the third NPDES permit associated with the Site.The first permit authorizes discharges
to the Cape Fear River through Outfall 002 under NC003573. Chemours is also authorized under
NC0089915 to discharge effluent from Outfall 003 to the Cape Fear River. The design of the
GWTS is similar to the design of the treatment system for Outfall 003. The effluent data that has
been submitted to NCDEQ with EPA Form 2C for permit number NC0089915 is therefore
considered to be suitable to estimate the expected effluent data for the GWTS.
The application for this new discharge consists of Form 2D and its various attachments.
1 The three indicator PFAS are hexafluoropropylene oxide-dimer acid (HFPO-DA), perfluoro-2-methoxypropanoic
acid(PMPA),and perfluoro-l-methoxyacetic acid (PFMOAA).
3

Attachment A. 1 — Form 2D Outfall 004

EPA Identification Number NPDES Permit Number Facility Name Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works OMB No.2040-0004
U.S.Environmental Protection Agency
Form Application for NPDES Permit to Discharge Wastewater
2D
NPDES CO EPA NEW MANUFACTURING,COMMERCIAL,MINING,AND SILVICULTURAL OPERATIONS
THAT HAVE NOT YET COMMENCED DISCHARGE OF PROCESS WASTEWATER
SECTION 1.EXPECTED OUTFALL LOCATION(40 CFR 122.21(k)(1))
1.1 Provide information on each of the facility's outfalls in the table below.
= Outfall Receiving Water
Number Name Latitude Longitude
as
0 004 Cape Fear River 34° 50' 19.28" N 78° 49' 32.70" W
0
0
SECTION 2.EXPECTED DISCHARGE DATE(40 CFR 122.21(k)(2))
a, 2.1 Month Day Year
COy
w y April 01 2022
SECTION 3.AVERAGE FLOWS AND TREATMENT(40 CFR 122.21(k)(3)(i))
3.1 For each outfall identified under Item 1.1, provide average flow and treatment information.Add additional sheets as
necessary.
**Outfall Number** 004
Operations Contributing to Flow
Operation Average Flow
Groundwater extraction wells and seeps 1.756 mgd
mgd
mgd
R
mgd
I-
-o
mgd
U)
o Treatment Units
Description Code from Final Disposal of Solid or Liquid
co (include size,flow rate through each treatment unit,
a retention time,etc.) Exhibit 2D-1 Wastes Other Than by Discharge
Chemical precipitation,1,000-1,500 gpm 2-C N/A
Flocculation, 1,000-1,500 gpm 2-D N/A
Sedimentation,1,000-1,500 gpm 1-U N/A
Ultrafiltration,1,000-1,500 gpm 1-Q N/A
Carbon adsorption,1,000-1,500 gpm 2-A N/A(See Page 2 for continuation)
EPA Form 3510-2D(Revised 3-19) Page 1

EPA Identification Number NPDES Permit Number Facility Name Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works OMB No.2040-0004
3.1 **Outfall Number** 004
Cont. Operations Contributing to Flow
Operation Average Flow
mgd
mgd
mgd
mgd
mgd
Treatment Units
Description Code from Final Disposal of Solid or Liquid
(include size,flow rate through each treatment unit, Exhibit 2D-1 Wastes Other Than by Discharge
retention time,etc.)
Discharge to surface water 4-A N/A
Gravity thickening(sludge from sedimentation) 5-L N/A
"a
m
= Belt filtration or centrifugation(sludge) 5-C or 5-D Certified landfill
0
0
a
is
1--
a
N **Outfall Number**
o Operations Contributing to Flow
Operation Average Flow
a)
d mgd
mgd
mgd
mgd
mgd
Treatment Units
Description Code from Final Disposal of Solid or Liquid
(include size,flow rate through each treatment unit, Exhibit 2D-1 Wastes Other Than by Discharge
retention time,etc.)
EPA Form 3510-2D(Revised 3-19) Page 2

EPA Identification Number NPDES Permit Number I Facility Name i Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works I OMB No.2040-0004
SECTION 4. LINE DRAWING(40 CFR 122.21(k)(3)(ii))
a> 4.1 Have you attached a line drawing to this application that shows the water flow through your facility with a water
.3 balance?(See instructions for drawing requirements. See Exhibit 2D-2 at end of instructions for example.)
t
a ❑✓ Yes ❑ No
SECTION 5. INTERMITTENT OR SEASONAL FLOWS(40 CFR 122.21(k)(3)(iii))
5.1 Except for stormwater runoff, leaks, or spills. are any expected discharges described in Sections 1 and 3 intermittent
or seasonal?
0 Yes ❑✓ No 4 SKIP to Section 6.
5.2 Provide information on intermittent or seasonal flows for each applicable outfall.Attach additional pages, if
necessary.
Outfall Operations Frequency Rate and Volume
Number (list) Average Average Maximum Daily Maximum Total Duration
Days/Week 1 Months/Year Discharge Volume
1
days/week months/year mgd gallons ' days
o days/week months/year mgd gallons days
W
c days/week months/year mgd gallons days
0
cn
a) Outfall Operations Frequency Rate and Volume
`o Number (list) Average Average Maximum Daily Maximum Total Duration
Days/Week Months/Year Discharge Volume
.a'
a>
days/week months/year mgd gallons days
E
m
c days/week months/year mgd gallons days i
days/week months/year mgd gallons days
Outfall Operations Frequency Rate and Volume
Number (list) Average Average Maximum Daily Maximum Total Duration ,
Days/Week Months/Year Discharge Volume
days/week months/year mgd gallons days
days/week . mgd gallons days
days/week • mgd gallons days
SECTION 6. PRODUCTION (40 CFR 122.21(k)(4))
6.1 Do any effluent limitation guidelines(ELGs)promulgated by EPA under CWA Section 304 apply to your facility?
❑ Yes p No 4 SKIP to Section 7.
c 6.2 Provide the following information on applicable ELGs.
0
.0 ELG Category ELG Subcategory Regulatory Citation
-a
2
n_
EPA Form 3510-2D(Revised 3-19) Page 3

EPA Identification Number Pe
rmit NPDES Perm t Number Facility Name Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works OMB No.2040-0004
6.3 Are the limitations in the applicable ELGs expressed in terms of production(or other measure of operation)?
❑ Yes ❑ No 4 SKIP to Section 7.
6.4 Provide an expected measure of average daily production expressed in terms and units of applicable ELGs.
Expected Actual Average Daily Production for First Three Years
Outfall Year Operation,Product,or Material Quantity per Day Unit of Measure
Number (note basis if applicable)
Year 1
a Year2
a)
c Year3
0
U
c
O
Year 1
0
n- Year 2
Year 3
Year 1
Year 2
Year3
SECTION 7.EFFLUENT CHARACTERISTICS(40 CFR 122.21(k)(5))
See the instructions to determine the parameters and pollutants you are required to monitor and, in turn,the tables you must
complete. Note that not all applicants need to complete each table.
Table A.Conventional and Non-Conventional Parameters
7.1 Are you requesting a waiver from your NPDES permitting authority for one or more of the Table A parameters for any
of your outfalls?
❑ Yes ❑✓ No 4 SKIP to Item 7.3.
7.2 If yes,indicate the applicable outfalls below.Attach waiver request and other required information to the application.
Outfall number Outfall number Outfall number
7.3 Have you have provided estimates or actual data for all Table A parameters for each of your outfalls for which a
waiver has not been requested and attached the results to this application package?
No; a waiver has been requested from my
❑✓ Yes ❑ NPDES permitting authority for all parameters at
all outfalls.
2 Table B.Certain Conventional and Non-Conventional Pollutants
7.4 Have you checked"Believed Present"for all pollutants listed in Table B that are limited directly or indirectly by an
applicable ELG?
ElYes ❑ No
7.5 Have you checked`Believed Present"or"Believed Absent"for all remaining pollutants listed in Table B?
❑✓ Yes ❑ No
7.6 Have you provided estimated data for those Table B pollutants for which you have indicated are`Believed Present"
in your discharge?
❑✓ Yes ❑ No
EPA Form 3510-2D(Revised 3-19) Page 4

EPA Identification Number NPDES Permit Number Facility Name Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works OMB No.2040-0004
Table C.Toxic Metals,Total Cyanide,and Total Phenols
7.7 Have you indicated whether pollutants are"Believed Present or"Believed Absent"for all pollutants listed on Table C
for all outfalls?
Yes ❑ No
7.8 Have you completed Table C by providing estimated data for pollutants you indicated are"Believed Present,"
including the source of the information,for each applicable outfall?
Q Yes ❑ No
Table D.Organic Toxic Pollutants(GC/MS Fractions)
7.9 Do you qualify for a small business exemption under the criteria specified in the Instructions?
❑ Yes 4 Note that you qualify at the top of No
Table D,then SKIP to Item 7.12.
7.10 , Have you indicated whether pollutants are"Believed Present"or`Believed Absent"for all pollutants listed on Table D
co
for all outfalls?
❑✓ Yes ❑ No
ci 7.11 Have you completed Table D by providing estimated data for pollutants you indicated are"Believed Present,"
including the source of the information,for each applicable outfall?
CD ❑✓ Yes 0 No
2,3,7,8-Tetrachlorodibenzo-p-Dioxin(TCDD)
2 7.12 Does the facility use or manufacture one or more of the 2,3,7,8-TCDD congeners listed in the Instructions,or do you
= know or have reason to believe that TCDD is or may be present in effluent from any of your outfalls?
❑ Yes ❑✓ No
Table E.Certain Hazardous Substances and Asbestos
7.13 Have you indicated whether pollutants are"Believed Present"or"Believed Absent"for all pollutants listed in Table E
for all outfalls?
❑ Yes ❑✓ No
7.14 Have you completed Table E by reporting the reason the pollutants are expected to be present and available
quantitative data for pollutants you indicated are`Believed Present"for each applicable outfall?
❑ Yes ❑✓ No
Intake Credits,Tables A through E
7.15 Are you applying for net credits for the presence of any of the pollutants on Tables A through E for any of your
outfalls?
❑ Yes 4 Consult with your NPDES permitting ❑✓ No
authorit
SECTION 8. ENGINEERING REPORT(40 CFR 122.21(k)(6))
8.1 Do you have any technical evaluations of your wastewater treatment, including engineering reports or pilot plant
studies?
Q ❑✓ Yes ❑ No 4 SKIP to Item 8.3.
a, 8.2 Have you provided the technical evaluation and all related documents to this application package?
✓❑ Yes ❑ No
8.3 Are you aware of any existing plant(s)that resemble production processes,wastewater constituents,or wastewater
w treatment at your facility?
❑✓ Yes 0 No 4 SKIP to Section 9.
EPA Form 3510-2D(Revised 3-19) Page 5

EPA Identification Number NPDES Permit Number Facility Name Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works ! OMB No.2040-0004
8.4 Provide the name and location of the similar plants.
Q Name of Similar Plants Location of Similar Plants
Treatment System for Outfall 003(Old Outfall 002) Fayetteville Works,Old Outfall 002 Channel
o
C V
•ca
c
uJ
SECTION 9.OTHER INFORMATION(40 CFR 122.21(k)(7))
9.1 ! Have you attached any optional information that you would like considered as part of the application review process
(i.e.,material beyond that which you have already noted in the application as being attached)?
❑✓ Yes ❑ No —) SKIP to Section 10.
0 9.2 List the additional items and briefly note why you have included them.
1. Attachment A.4 Chemours Fayetteville Works—Groundwater and Seeps Water Quality Assessment
0
2. Attachment A.5 GWTS Engineering Report and Data Analysis
I
m
O 3.Attachment A.6 Engineering Alternatives Analysis—GWTS Discharge
4.
5.
SECTION 10.CHECKLIST AND CERTIFICATION STATEMENT(40 CFR 122.22(a)and(d))
10.1 In Column 1 below, mark the sections of Form 2D that you have completed and are submitting with your application.
For each section,specify in Column 2 any attachments that you are enclosing to alert the permitting authority. Note
that not all applicants are required to complete all sections or tables,or provide attachments.
Column 1 Column 2
❑ Section 1: Expected Outfall ❑ w/attachments(e.g., responses for additional outfalls)
Location
❑✓ Section 2: Expected ❑ w/attachments
Discharge Date
❑ Section 3:Average Flows El attachments
and Treatment
E
:' ❑✓ Section 4: Line Drawing ❑✓ w/line drawing ❑ w/additional attachments
Co
`" ❑ Section 5: Intermittent or ❑
g Seasonal Flows w/attachments
w ❑ Section 6: Production ❑ w/attachments
w/Table A waiver
El request or ✓❑ Table A
approval
ElSection 7: Effluent El Table B ❑✓ Table C
CD
U Characteristics
❑✓ Table D ❑ Table E
w/other Attachment A.5(Engineering Report)identifies PFAS
attachmentscompounds in the intake and potentially in the outfal.
❑ Section 8: Engineering ✓❑ w/technical evaluations and related attachments
Report
❑ Section 9:Other Information ❑ w/optional information
❑ Section 10: Checklist and ❑ w/attachments
Certification Statement
EPA Form 3510-2D(Revised 3-19) Page 6

EPA Identification Number NPDES Permit Number Facility Name Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works OMB No.2040-0004
10.2 Certification Statement
1 certify under penalty of law that this document and all attachments were prepared under my direction or supervision
;a in accordance with a system designed to assure that qualified personnel properly gather and evaluate the
information submitted.Based on my inquiry of the person or persons who manage the system,or those persons
Rdirectly responsible for gathering the information,the information submitted is, to the best of my knowledge and
al
belief,true,accurate,and complete. I am aware that there are significant penalties for submitting false information,
'c including the possibility of fine and imprisonment for knowing violations.
o
Name(print or type first and last name) Official title
-13
as Dawn M.Hughes Plant Manager
Signature Date signed
n
/(1�,,,,. In • �r��Zo2t
EPA Form 3510-20(Revised 3-19) Page 7

This page intentionally left blank.

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE A.CONVENTIONAL AND NON CONVENTIONAL PARAMETER ESTIMATES(40 CFR 122.21(k)(5)(i))1
Effluent Data Intake Water
Waiver Units Maximum Daily Average Daily Believed Present?
Pollutant Requested Discharge Discharge Source of Information (check only one response per
(if applicable) (use codes in instructions)
(required) (if available) parameter)
El Check here if you have applied to your NPDES authority for a waiver for all of the pollutants listed on this table for the noted outfall.
Biochemical oxygen Concentration mg/L >30.8 5.6 3
1 demand(BODS) ❑ 0 Yes ❑ No
Mass
Chemical oxygen demand Concentration mg/L <25,000 3
2. (COD) 0 0 Yes 0 No
Mass
Total organic carbon Concentration mg/L <6.2 4
3. (TOC) 0 0 Yes 0 No
Mass
Total suspended solids Concentration mg/L 6.6 3
4. (TSS) El 0 Yes 0 No
Mass
Concentration mg/L 0.051 3
5. Ammonia(as N) 0 0 Yes 0 No
Mass
6. Flow ❑ Rate MGD 1.756 1 0 Yes ❑ No
Temperature(winter) ❑ °C °C 22.3 3
7. D Yes ❑ No
Temperature(summer) 0 °C °C 23.0
pH(minimum) ❑ Standard units s.u. 6.12 3
8. O Yes ❑ No
pH (maximum) 0 Standard units s.u. 8.85 3
1 Sampling shall be conducted according to sufficiently sensitive test procedures(i.e., methods)approved under 40 CFR 136 for the analysis of pollutants or pollutant parameters or
required under 40 CFR chapter I, subchapter N or 0. See instructions and 40 CFR 122.21(e)(3).
Effluent data(with exception of flow and TOC)are from EPA Form 2C for Outfall 003(04/01/21).Attachment 4 includes TOC data
EPA Form 3510-2D(Revised 3-19) measured in the untreated groundwater and seeps-TOC will be reduced after being treated with GAC. Page 1

This p � intentionally page left blank.

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE B.CERTAIN CONVENTIONAL AND NON CONVENTIONAL POLLUTANTS(40 CFR 122.21(k)(5)(ii))1
Presence or Absence Estimated Data for Pollutants Expected to be Present or Limited by an ELG
(check one) (Provide both concentration and mass estimates for each pollutant.)
Pollutant _ Effluent _ Intake Water
Believed Believed Maximum DailyAverage DailyBelieved Present?
g Source of Information
Present Absent Units Discharge Discharge (use codes in instructions) (check only one
(required) (if available) response per item)
❑ Check(✓)here if you believe all pollutants listed to be absent from the discharge.You need not complete Table B for the noted outfall unless you have quantitative data available.
1 Bromide 0 ❑ Concentration mg/L <1.3 p 3 ❑ Yes ✓❑ No
(24959-67-9) Mass
2 Chlorine,total El Concentration mg/L 0.13 p 3 ❑ Yes ❑ No
residual Mass
Concentration
3. Color 0 0 PCU <5.0 p . 3 0 Yes ❑ No
Mass
Concentration #/1o0mL <1.0 :I3
4. Fecal coliform 0 El El Yes 0 No
Mass
Fluoride Concentration mg/L <0.25 p 3
5. (16984 48 8) 0 0 Mass 0 Yes 0 No
Concentration mg/L <0.04 p 3
6. Nitrate-nitrite 0 0 0 Yes ❑ No
Mass
7 Nitrogen,total 0 ❑ Concentration mg/L 0.7 p 3 0 Yes ❑ No
organic(as N) Mass
Concentration
8. Oil and grease 0 El El
2.1 p 3 ✓❑ Yes ❑ No
Mass
Phosphorus(as P), Concentration mg/L 0.96 p 3
9. total(7723 14 0) 0 ❑ Mass 0 Yes 0 No
10. Sulfate(as SO4) 0 ❑ Concentration mg/L 77.0 if 3 ❑✓ Yes El No
(14808-79-8) Mass
Concentration
11. Sulfide(as S) Ill El El
<0.70 p 3 0 Yes ❑ No
Mass
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 3

EPA Identification Number Facility Name Outfall Number I Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE B.CERTAIN CONVENTIONAL AND NON CONVENTIONAL POLLUTANTS(40 CFR 122.21(k)(5)(ii))1
Presence or Absence Estimated Data for Pollutants Expected to be Present or Limited by an ELG
(check oneJ -_ (Provide both concentration and mass estimates for each pollutant.)
Pollutant Effluent Intake Water
Believed Believed Maximum Daily Average Daily Source of Information Believed Present?
Present Absent Units Discharge Discharge (check only one
(required) (if available) (use codes in instructions) — response per item)
Sulfite(as SO3) Concentration mg/L <2 II
12' (14265 45 3) 0 Mass ❑ Yes ElNo
13. Surfactants 0 ✓❑ Concentration ug/L p <40 p 3 0 Yes ✓❑ No
Mass
14. Aluminum,total El ❑ Concentration ug/L o 36 p 3 ❑✓ Yes ❑ No
(7429-90-5) Mass
15. Barium,total © 0 Concentration ug/L ill 50 p 3 ❑✓ Yes ❑ No
(7440-39-3) Mass
16. Boron,total ❑✓ 0 Concentration ug/L p <12.0 p 3 ✓❑ Yes 0 No
(7440-42-8) Mass
Cobalt,total Concentration ug/L p 13 p 3
17. (7440 48 4) 0 ❑ ❑✓ Yes 0 No
Mass
18 Iron,total 0 ❑ Concentration ug/L p <23 CI 3 ❑✓ Yes 0 No
(7439-89-6) Mass
Magnesium,total Concentration ug/L p 1,600 p 3
19. (7439 95 4) ❑✓ Mass ❑✓ Yes ❑ No
20 Molybdenum,total 0 ❑ Concentration ug/L o <0.13 p 3 0 Yes ❑✓ No
(7439-98-7) Mass
21 Manganese,total 0 ❑ Concentration ug/L p 95 p 3 ❑✓ Yes ❑ No
(7439-96-5) Mass
22 Tin,total ❑ ❑✓ Concentration ug/L p <0.60 El ❑ Yes ❑✓ No
(7440-31-5) Mass
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 4

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No,2040-0004
TABLE B.CERTAIN CONVENTIONAL AND NON CONVENTIONAL POLLUTANTS(40 CFR 122.21(k)(5)(ii))1
Presence or Absence Estimated Data for Pollutants Expected to be Present or Limited by an ELG
(check one) (Provide both concentration and mass estimates for each pollutant.)
Pollutant Effluent Intake Water
Believed Believed Maximum Daily Average Daily Believed Present?
Present Absent Units Discharge Discharge Source of Information (check only one
(required) . (if available) (use codes in instructions) response per item)
Titanium,total ❑ Concentration ug/L <6.0 a 3 ❑✓ Yes 0 No
23. (7440-32-6) Mass
24. Radioactivity
Concentration
24.1 Alpha,total 0 pCi/L <1.83 p 3 ❑✓ Yes ❑ No
Mass
24.2 Beta, total 0 Concentration pCi/L 2.42 ,3 ✓❑ Yes 0 No
Mass
24.3. Radium,total Concentration pCi/L <0.208 3 ❑ Yes 0 No
Mass
24.4 Radium 226, total 0 Concentration pCi/L <0.826 3 ❑ Yes ElNo
Mass
1 Sampling shall be conducted according to sufficiently sensitive test procedures(i.e., methods)approved under 40 CFR 136 for the analysis of pollutants or pollutant parameters or
required under 40 CFR chapter 1,subchapter N or 0. See instructions and 40 CFR 122.21(e)(3).
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 5

This page intentionally left blank.

1
EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE C.TOXIC METALS,TOTAL CYANIDE,AND TOTAL PHENOLS(40 CFR 122.21(k)(5)(iii)(A))1
Presence or Absence Estimated Data for Pollutants Expected to be Present in Discharge
(check one) (Provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Maximum Average
Present Absent Units Daily Daily Source of Information Believed Present?
Discharge Discharge (Use codes in Instructions.) {Check only one
(required) (if available) response per pollutant.)
❑ Check(✓)here if you believe all pollutants listed to be absent from the discharge. You need not complete Table C for the noted outfall unless you have quantitative data
available.
1. Antimony,Total El ❑ Concentration ug/L <u.41 3 El Yes No
(7440-36-0) Mass
2. Arsenic,Total Concentration ug/L <0.68 3
(7440 38 2) El ❑ Mass ❑ Yes El No
3. Beryllium,Total ❑ ❑ Concentration ug/L <0.12 3 0Yes El No
(7440-41-7) Mass
4. Cadmium,Total Concentration ug/L <10
3
(7440-43-9) Mass ID Yes El No
5. Chromium,Total Concentration ug/L <0.33El 0 3 ✓
(7440-47-3) Mass Yes El No
6. Copper,Total Concentration ug/L <10 3
(7440 50 8) El El Mass ❑ Yes El No
7. Lead, Total Concentration ug/L <10
El El 3
(7439-92-1) Mass-
❑ Yes El No
8. Mercury,Total Concentration ng/L 1.13
(7439 97 6) ✓❑ El Mass 3 El Yes ❑ No
9. Nickel,Total Concentration ug/L 3.10 El 3
(7440-02-0) Mass ❑✓ Yes ❑ No
10. Selenium,Total Concentration ug/L <10
3
(7782-49-2) Mass 0 Yes El No
11. Silver, Total Concentration ug/L <0.48
(7440 22 4) ❑ ❑✓ Mass 3 ElYes CINo
12. Thallium,Total Concentration ug/L <10
(7440 28 0) ❑✓ ❑ Mass 3 El Yes 0No
13. Zinc,Total Concentration ug/L <6.2
(7440 66 6) 0 El Mass 3 0Yes El No
14. Cyanide,Total Concentration ug/L <5
(57 12 5) El El Mass 3 El Yes El No
15. Phenols,Total Concentration ug/L <10
Mass 3 ❑ Yes ElNo
1 Sampling shall be conducted according to sufficiently sensitive test procedures(i.e.,methods)approved under 40 CFR 136 for the analysis of pollutants or pollutant parameters or +
required under 40 CFR chapter I, subchapter N or 0. See Instructions and 40 CFR 122.21(e)(3).
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 7

This page intentionally left blank.

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No,2040-0004
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Units Maximum Average Source of Believed Present?
Present Absent Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
0 Check here if all pollutants listed in Table D are expected to be absent from your facility's discharge.
0 Check here if the facility believes it is exempt from Table D reporting requirements because it is a qualified small business. See the instructions for exemption criteria and for a list
of materials you must attach to the application.
Note: If you check either of the above boxes, you do not need to complete Table D for the noted outfall unless you have quantitative data available.
1.Organic Toxic Pollutants(GCIMS Fraction—Volatile Compounds)
1.1 Acrolein Concentration ug/L <1.0
(107 02 8) ❑ ❑ 3 0 Yes ❑✓ No
Mass
1.2 Acrylonitrile Concentration ug/L <0.2
(107-13-1) ❑ ✓❑ Mass 3 ❑ Yes ❑✓ No
1.3 Benzene Concentration ug/L <0.05 3
(71 43 2) El El Mass El Yes ❑✓ No
1.4 Bromoform Concentration ug/L <0.10
(75 25 2) ❑ El Mass 3 El Yes ❑✓ No
1.5 Carbon tetrachloride Concentration ug/L <0.10
(56 23 5) ❑ Mass 3 El Yes ❑✓ No
1.6 Chlorobenzene Concentration ug/L <0.10
(108 90 7) ❑ El Mass 3 0 Yes ❑✓ No
1.7 Chlorodibromomethane Concentration ug/L <0.10
(124 48 1) ❑ Mass 3 El Yes ❑✓ No
1.8 Chloroethane Concentration ug/L <0.10
(75 00 3) 0 Mass 3 ❑ Yes 0 No
1.9 2-chloroethylvinyl ether Concentration ug/L <0.05
(110 75 8) 0 0 Mass 3 ❑ Yes ❑✓ No
1.10 Chloroform(67-66-3) El ❑ Concentration ug/L <0.10 3 0 Yes ❑ No
Mass
1.11 Dichlorobromomethane Concentration ug/L <0.20
(75-27-4) ❑ ✓❑ Mass 3 El Yes ❑✓ No
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 9

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GCIMS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Units Maximum Average Source of Believed Present?
Present Absent Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
1.12 1,1-dichloroethane Concentration ug/L <0.10 3
(75-34-3) ❑ ✓❑ 0 Yes ❑✓ No
Mass
1.13 1,2-dichloroethane Concentration ug/L <0.30 3
(107-06-2) ✓❑ 0 ✓❑ Yes ❑ No
Mass
1.14 1,1-dichloroethylene Concentration ug/L <0.20 3
(75-35-4) 0 ❑✓ 0 Yes ✓❑ No
Mass
1.15 1,2-dichloropropane Concentration ug/L <0.20
(78-87-5) 0 ❑ 3 0 Yes 0 No
Mass
1.16 1,3-dichloropropylene Concentration ug/L <0.08
(542 75 6) 0 El Mass 3 0 Yes 0No
1.17 Ethylbenzene Concentration ug/L <0.10
(100 41 4) 0 El Mass 3 0 Yes 0No
1.18 Methyl bromide Concentration ug/L <0.10
(74 83 9) ❑✓ ❑ Mass 3 0Yes El No
1.19 Methyl chloride Concentration ug/L <0.30
(74 87 3) El 0 Mass 3 0Yes El No
1.20 Methylene chloride Concentration ug/L <0.30
(75 09 2) ❑ Mass 3 ❑ Yes 0No
1.21 1,1,2,2-tetrachloroethane Concentration ug/L <0.05
(79 34 5) ❑ El Mass 3 ❑ Yes 0No
1.22 Tetrachloroethylene Concentration ug/L <0.20
(127 18 4) ❑ El Mass 3 0 Yes 0No
1.23 Toluene Concentration ug/L <0.05
(108 88 3) ❑✓ 0 Mass 3 ❑ Yes El No
1.24 1,2-trans-dichloroethylene Concentration ug/L <0.10
(156 60 5) 0 1:1 Mass 3 El Yes 0No
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 10

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) _ (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number.if available) Believed Believed Units Maximum Average Source of Believed Present?
Present Absent Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
1.25 1,1,1-trichloroethane Concentration ug/L <0.10
(71 55 6) 0 0Mass 3 ❑ Yes 0No
1.26 1,1,2-trichloroethane Concentration ug/L <0.20
(79 00 5) 0 0Mass 3 ❑ Yes ❑✓ No
1.27 Trichloroethylene Concentration ug/L <0.20
(79-01-6) 0 ❑✓ Mass 3 ❑ Yes 0No
1.28 Vinyl chloride Concentration ug/L <0.30
(75 01 4) 0 0Mass 3 ❑✓ Yes El No
2.Organic Toxic Pollutants(GC/MS Fraction—Acid Compounds)
2.1 2-chlorophenol Concentration ug/L <0.20 3
(95-57-8) 0 CIMass 0 Yes 0No
2.2 2,4-dichlorophenol Concentration ug/L <0.10 3
(120-83-2) ❑ ❑✓ Mass ❑ Yes 0No
2.3 2,4-dimethylphenol Concentration ug/L <0.20
(105-67-9) 0 0Mass 3 0 Yes ❑✓ No
2.4 4,6-dinitro-o-cresol Concentration ug/L <1.0
(534-52-1) 0Mass 3
0 0❑ Yes No
2.5 2,4-dinitrophenol Concentration ug/L <1.0 3
(51-28-5) 0 0 Mass ❑ Yes 0No
2.6 2-nitrophenol Concentration ug/L <0.30 3
(88-75-5) 0 ❑✓ Mass El Yes ❑✓ No
2.7 4-nitrophenol Concentration ug/L <0.91 3
(100-02-7) ❑ ❑✓ Mass ❑ Yes 0No
2.8 p-chloro-m-cresol Concentration ug/L <0.30
(59-50-7) 0 0Mass 3 ElYes ❑✓ No
2.9 Pentachlorophenol Concentration ug/L <0.81 3
(87-86-5) 0 0 Mass 0 Yes 0No
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 11

EPA Identification Number Facility Name Outfall Number Form Approved 03/05119
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Units Maximum Average Source of Believed Present?
Present Absent Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
2.10 Phenol Concentration ug/L <0.40
(108-95-2) ❑ 0 Mass 3 ❑ Yes 0No
2.11 2,4,6-trichlorophenol Concentration ug/L <0.20
(88-05-2) 0 0 Mass 3 ❑ Yes 0No
3.Organic Toxic Pollutants(GC/MS Fraction—Base/Neutral Compounds)
3.1 Acenaphthene Concentration ug/L <0.091
(83-32-9) 0 0 Mass 3 ✓❑ Yes ❑ No
3.2 Acenaphthylene Concentration ug/L <0.081
(208-96-8) 0 Mass 3 ❑ Yes ❑✓ No
3.3 Anthracene Concentration ug/L <0.071
(120-12-7) 0 0 Mass 3 ❑✓ Yes ❑ No
3.4 Benzidine Concentration ug/L <6.1
(92 87 5) 0 0 Mass 3 El Yes 0No
3.5 Benzo(a)anthracene Concentration ug/L <0.20
(56-55-3) 0 0 Mass 3 0Yes ❑ No
3.6 Benzo(a)pyrene Concentration ug/L <0.20
(50-32-8) 0 ❑ Mass 3 0Yes ❑ No
3.7 3,4-benzofluoranthene Concentration ug/L <0.20
(205-99-2) 0 0 Mass 3 ❑✓ Yes ❑ No
3.8 Benzo(ghi)perylene Concentration ug/L <0.10
(191-24-2) 0 0 Mass 3 ❑ Yes 0No
3.9 Benzo(k)fluoranthene Concentration ug/L <0.10
(207-08-9) 0 0 Mass 3 0Yes ❑ No
3.10 Bis(2-chloroethoxy)methane Concentration ug/L <0.20
(111-91-1) ❑ 0 Mass 3 ❑ Yes ElNo
3.11 Bis(2-chloroethyl)ether Concentration ug/L <0.10
(111-44-4) 0 0 Mass 3 ❑ Yes ❑✓ No
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 12

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
I
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Units Maximum Average Source of Believed Present?
Present Absent Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
3.12 Bis(2-chloroisopropyl)ether Concentration ug/L <0.30
(102 80 1) Mass 3 0 Yes ❑✓ No
3.13 Bis(2-ethylhexyl)phthalate Concentration ug/L <1.0
(117-81-7) ❑ ✓❑ Mass 3 ❑ Yes 0No
3.14 4-bromophenyl phenyl ether Concentration ug/L <0.20
(101 55 3) 0 0Mass 3 0 Yes 0No
3.15 Butyl benzyl phthalate Concentration ug/L <1.0
(85 68 7) 0 ID
Mass 3 0 Yes 0No
3.16 2-chloronaphthalene Concentration ug/L <0.61
(91 58 7) 0 0Mass 3 ❑ Yes ElNo
3.17 4-chlorophenyl phenyl ether Concentration ug/L <0.20
(7005 72 3) 0 CIMass 3 0 Yes 0No
3.18 Chrysene Concentration ug/L <0.20
(218 01 9) El ElMass 3 ❑✓ Yes ❑ No
3.19 Dibenzo(a,h)anthracene Concentration ug/L <0.10
(53-70-3) ❑ ❑✓ Mass 3 0 Yes 0No
3.20 1,2-dichlorobenzene Concentration ug/L <0.20
(95 50 1) El 0Mass 3 ❑ Yes 0No
3.21 1,3-dichlorobenzene Concentration ug/L <0.10 3
1 ✓
(541-73-1) 0 ❑ Yes ❑ No
Mass
3.22 1,4-dichlorobenzene Concentration ug/L <0.20
(106 46 7) El 0Mass 3 El Yes ❑✓ No
3.23 3,3-dichlorobenzidine Concentration ug/L <0.30
(91 94 1) El El
Mass 3 ❑ Yes ✓❑ No
3.24 Diethyl phthalate Concentration ug/L <0.30
(84 66 2) El 0Mass 3 0 Yes 0No
-
3.25 Dimethyl phthalate Concentration ug/L <0.51
(131-11-3) ❑ ✓❑ 3 ❑ Yes ❑✓ No
Mass
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 13

EPA Identification Number Facility Name I Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GCIMS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Maximum Average Source of Believed Present?
Present Absent Units
Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
3.26 Di-n-butyl phthalate Concentration ug/L <1.0
(84-74-2) 0 ❑✓ Mass 3 ❑ No
Yes El
3.27 2,4-dinitrotoluene Concentration ug/L <0.10
(121-14-2) ❑ ✓❑ Mass . 3 ElYes ✓❑ No
3.28 2,6-dinitrotoluene Concentration ug/L <0.20
(606-20-2) 0 0 Mass , 3 ElYes ElNo
3.29 Di-n-octyl phthalate Concentration ug/L <0.51
(117-84-0) 0 0 3 ❑ Yes ✓❑ No
Mass
3.30 1,2-diphenylhydrazine Concentration ug/L <0.10
(as azobenzene)(122-66-7) 0 0 Mass 3 0 Yes ElNo
3.31 Fluoranthene Concentration ug/L <0.20
(206-44-0) 0 0 Mass 3 ❑✓ Yes 0 No
3.32 Fluorene Concentration ug/L <0.20
(86-73-7) 0 0 Mass 3 ❑ Yes El No
3.33 Hexachlorobenzene Concentration ug/L <0.51
(118-74-1) 0 ❑� Mass 3 El Yes Yes El
3.34 Hexachlorobutadiene Concentration ug/L <0.20
(87-68-3) 0 0 Mass 3 El Yes Yes El
3.35 Hexachlorocyclopentadiene Concentration ug/L <0.20
(77-47-4) 0 0 Mass 3 El Yes Yes El
3.36 Hexachloroethane Concentration ug/L <0.10
(67-72-1) ❑ ✓❑ Mass 3 El Yes
Yes ✓❑
3.37. Indeno(1,2,3-cd)pyrene Concentration ug/L <0.20
(193-39-5) ❑ 0 Mass 3 El Yes Yes El
3.38 Isophorone Concentration ug/L <0.20
(78-59-1) ❑ ✓❑ Mass 3 0 Yes ❑✓ No
3.39 Naphthalene Concentration ug/L <0.10
(91-20-3) ❑✓ ❑ Mass 3 El Yes El No
EPA Form 3510-2D(Revised 3-19) Page 14
Effluent data are from EPA Form 2C for Outfall 003(04/01/21).

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Units Maximum Average Source of Believed Present?
Present Absent Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
3.40 Nitrobenzene Concentration ug/L <0.20
(98 95 3) 0 0 Mass 3 ❑ Yes ❑✓ No
3.41 N-nitrosodimethylamine Concentration ug/L <0.40
(62-75-9) 0 0 Mass 3 0 Yes 0No
3.42 N-nitrosodi-n-propylamine Concentration ug/L <0.20
(621-64-7) 0 0Mass 3 0 Yes ❑✓ No
3.43 N-nitrosodiphenylamine Concentration ug/L <0.10
(86-30-6) 0 ❑✓ Mass 3 0 Yes 0No
3.44 Phenanthrene Concentration ug/L <0.10
(85-01-8) 20 Mass 3 0Yes ❑ No
3.45 Pyrene Concentration ug/L <0.20
(129-00-0) El 0 Mass 3 ❑✓ Yes 0 No
3.46 1,2,4-trichlorobenzene Concentration ug/L <0.20
(120-82-1) ❑ ❑ 3 ❑ Yes ✓❑ No
Mass
4.Organic Toxic Pollutants(GC/MS Fraction—Pesticides)
4.1. Aldrin Concentration ug/L <0.0051
(309-00-2) ❑ ❑ 3 ❑ Yes ❑✓ No
Mass
•
4.2 a-BHC Concentration ug/L <0.012
(319 84 6) El El
Mass 3 0 Yes ❑✓ No
4.3 13-BHC Concentration ug/L <0.047
(319-85-7) 0 0 Mass 3 El Yes 2No
4.4 y-BHC Concentration ug/L <0.0053
(58-89-9) 0 ❑✓ Mass 3 0 Yes 2No
4.5 o-BHC Concentration ug/L <0.011
(319-86-8) ❑ ❑✓ Mass 3 El Yes 2No
•
4.6 Chlordane Concentration ug/L <0.24
(57-74-9) ❑ ❑ Mass 3 ❑ Yes ❑✓ No
EPA Form 3510-2D(Revised 3-19) Page 15
Effluent data are from EPA Form 2C for Outfall 003(04/01/21).

EPA Identification Number I Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co Fayetteville Works 004 OMB No.2040-0004
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Units Maximum Average Source of Believed Present?
Present Absent Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
4.7 4.4'-DOT Concentration ug/L <0.010
(50-29-3) 0 0 Mass 3 ❑ Yes 0No
4.8 4,4'-DDE Concentration — ug/L <0.020
(72-55-9) El 0 Mass 3 ❑ Yes 0No
4.9 4,4'-DDD Concentration ug/L <0.0092
(72-54-8) 0 ❑ Mass 3 El Yes ❑✓ No
4.10 Dieldrin Concentration ug/L <0.0082
(60-57-1) El 0 Mass 3 ❑ Yes IDNo
4.11 a-endosulfan Concentration ug/L <0.0031 3
(115-29-7) ❑ 0 ❑ Yes ❑✓ No
Mass
4.12 13-endosulfan Concentration ug/L <0.010 3
(115-29-7) ❑ ❑✓ ❑ Yes El No
Mass
4.13 Endosulfan sulfate Concentration ug/L <0.010 3
(1031-07-8) 0 E✓ 0 Yes El No
Mass
4.14 Endrin Concentration ug/L <0.0092 3
(72-20-8) 0 ❑✓ 0 Yes ❑✓ No
Mass
4.15 Endrin aldehyde Concentration ug/L <0.0093 3
(7421-93-4) 0 E✓ ❑ Yes ❑✓ No
Mass
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 16

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19 1
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))1
Presence or Absence Estimated Data for Pollutants Expected to Be Present in Discharge
(check one) (provide both concentration and mass estimates for each pollutant)
Pollutant Effluent Intake Water
(CAS Number,if available) Believed Believed Maximum Average Source of Believed Present?
Present Absent Units
Daily Daily Information (check only one response per
Discharge Discharge (use codes in instructions) pollutant)
4.16 Heptachlor Concentration ug/L <0.0082
(76-44-8) ❑ 0 Mass 3 ❑ Yes 0No
4.17 Heptachlor epoxide Concentration ug/L <0.0051
(1024-57-3) ✓❑ 0 Mass 3 DYes ❑ No
4.18 PCB-1242 Concentration ug/L <0.076
(53469-21-9) 0 ❑✓ Mass 3 ❑ Yes 0No
4.19 PCB-1254 Concentration ug/L <0.076
(11097 69 1) 0 ElMass 3 ❑ Yes 0No
4.20 PCB-1221 Concentration ug/L <0.076
(11104-28-2) 0 0 Mass 3 ❑ Yes 0No
4.21 PCB-1232 Concentration ug/L <0.076
(11141 16 5) 0 E3Mass 3 El Yes 0No
4.22 PCB-1248 Concentration ug/L <0.076
(12672-29-6) 0 0 Mass 3 ❑ Yes ❑✓ No
4.23 PCB-1260 Concentration ug/L <0.076
(11096-82-5) 0 0 Mass 3 ❑ Yes 0No
4.24 PCB-1016 Concentration ug/L <0.076
(12674-11-2) 0 0 Mass 3 ❑ Yes ❑✓ No
4.25 Toxaphene Concentration ug/L <0.36
(8001-35-2) 0 0 Mass 3 ❑ Yes 0No
1 Sampling shall be conducted according to sufficiently sensitive test procedures(i.e., methods)approved under 40 CFR 136 for the analysis of pollutants or pollutant parameters or
required under 40 CFR chapter I,subchapter N or 0. See instructions and 40 CFR 122.21(e)(3).
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003(04/01/21). Page 17

This page intentionally left blank.

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE E.CERTAIN HAZARDOUS SUBSTANCES AND ASBESTOS(40 CFR 122.21(k)(5)(v))1
Presence or Absence
Pollutant gieck one) Available Quantitative Data
Believed Believed Reason Pollutant Believed Present in Discharge (specify units)
Present Absent
✓❑ Check(✓)here if you believe all pollutants listed to be absent from the discharge.You need not complete Table E for the noted outfall unless you have quantitative data available.
1. Asbestos ❑ ❑
2. Acetaldehyde ❑ ❑
3. Allyl alcohol ❑ ❑
4. Allyl chloride ❑ ❑
5. Amyl acetate ❑ ❑
6. Aniline 0 ❑
7. Benzonitrile ❑ ❑
8. Benzyl chloride 0 ❑
9. Butyl acetate 0 ❑
10. Butylamine 0 ❑
11. Captan ❑ ❑
12. Carbaryl 0 ❑
13. Carbofuran 0 ❑
14. Carbon disulfide 0 ❑
15. Chlorpyrifos 0 ❑
16. Coumaphos ❑ ❑
17. Cresol ❑ ❑
18. Crotonaldehyde ❑ 0
EPA Form 3510-2D(Revised 3-19) Page 19

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE E.CERTAIN HAZARDOUS SUBSTANCES AND ASBESTOS(40 CFR 122.21(k)(5)(v))l
Presence or Absence i
Pollutant _ (check one) Available Quantitative Data
Believed Believed Reason Pollutant Believed Present in Discharge (specify units)
Present Absent
19. Cyclohexane ❑ ❑
20. 2,4-D(2,4-dichlorophenoxyacetic acid) 0 0
21. Diazinon 0 0
22. Dicamba 0 ❑
23. Dichlobenil 0 0
24. Dichlone 0 0
25. 2,2-dichloropropionic acid 0 0
26. Dichlorvos ❑ ❑
27. Diethyl amine 0 ❑
28. Dimethyl amine 0 0
29. Dintrobenzene ❑ 0
30. Diquat 0 ❑
31. Disulfoton ❑ 0
32. Diuron 0 0
33. Epichlorohydrin ❑ 0
34. Ethion 0 0
35. Ethylene diamine 0 0
36. Ethylene dibromide ❑ ❑
37. Formaldehyde 0 0
EPA Form 3510-2D(Revised 3-19) Page 20

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE E.CERTAIN HAZARDOUS SUBSTANCES AND ASBESTOS(40 CFR 122.21(k)(5)(v))1
Presence or Absence
Pollutant (check one) Available Quantitative Data
Believed Believed Reason Pollutant Believed Present in Discharge (specify units)
Present Absent
38. Furfural ❑ ❑
39. Guthion ❑ 0
40. Isoprene 0 ❑
41. Isopropanolamine 0 ❑
42. Kelthane ❑ 0
43. Kepone ❑ ❑
44. Malathion ❑ ❑
45. Mercaptodimethur ❑ ❑
46. Methoxychlor 0 ❑
47. Methyl mercaptan ❑ ❑
48. Methyl methacrylate ❑ ❑
49. Methyl parathion 0 ❑
50. Mevinphos ❑ ❑
51. Mexacarbate ❑ ❑
52. Monoethyl amine ❑ ❑
53. Monomethyl amine ❑ ❑
54. Naled ❑ ❑
55. Naphthenic acid ❑ ❑
56. Nitrotoluene 0 ❑
EPA Form 3510-2D(Revised 3-19) Page 21

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE E.CERTAIN HAZARDOUS SUBSTANCES AND ASBESTOS(40 CFR 122.21(k)(5)(v))1
Presence or Absence
Pollutant (check one) Available Quantitative Data
Believed Believed Reason Pollutant Believed Present in Discharge (specify units)
Present Absent
57. Parathion ❑ ❑
58. Phenolsulfonate ❑ ❑
59. Phosgene ❑ ❑
60. Propargite ❑ 0
61. Propylene oxide 0 ❑
62. Pyrethrins ❑ ❑
63. Quinoline ❑ ❑
64. Resorcinol ❑ ❑
65. Strontium ❑ ❑
66. Strychnine ❑ ❑
67. Styrene ❑ ❑
68 2,4,5-T(2,4,5-trichlorophenoxyacetic ❑ ❑
acid)
69. TDE(tetrachlorodiphenyl ethane) ❑ ❑
70. 2,4,5-TP[2-(2,4,5-trichlorophenoxy) ❑ ❑
propanoic acid]
71. Trichlorofon 0 ❑
72. Triethanolamine ❑ ❑
73. Triethylamine ❑ ❑
74. Trimethylamine 0 ❑
75. Uranium ❑ ❑
EPA Form 3510-2D(Revised 3-19) Page 22

EPA Identification Number Facility Name Outfall Number Form Approved 03/05/19
NCD 047 368 642 Chemours Co-Fayetteville Works 004 OMB No.2040-0004
TABLE E.CERTAIN HAZARDOUS SUBSTANCES AND ASBESTOS(40 CFR 122.21(k)(5)(v))'
Presence or Absence
Pollutant (check one) Available Quantitative Data
Believed Believed Reason Pollutant Believed Present in Discharge (specify units)
Present Absent
76. Vanadium ❑ ❑
77. Vinyl acetate ❑ ❑
78. Xylene ❑ ❑
79. Xylenol ❑ ❑
80. Zirconium 0 ❑
Sampling shall be conducted according to sufficiently sensitive test procedures(i.e., methods)approved under 40 CFR 136 for the analysis of pollutants or pollutant parameters or
required under 40 CFR chapter I,subchapter N or 0. See instructions and 40 CFR 122.21(e)(3).
EPA Form 3510-2D(Revised 3-19) Effluent data are from EPA Form 2C for Outfall 003. Page 23

Attachment A.2 — Line Drawing Water Balance

Chemours Company-Fayetteville Works Groundwater Treatment System
ATTACHMENT A.02
OUTFALL 004 FORM 2C SECTION 2 :LINE DRAWING
WATER BALANCE(06-10-2021)
Cape Fear River
Groundwater
from Black Groundwater
Creek Aquifer 950 gpm — ► Treatment —+ 1,219 gpm'2
& Surficial System (GWTS)
•
Baseflow and
Surface Runoff
from Seeps A ' 269 gpm
& B 12,517 gpm
•
Outfall 002
NOTES:
1)gpm=gallons per minute
2)All flow rates are estimated maximum daily discharges.
June 2021

Attachment A.3 — Rationale for Presence of
Compounds in Intake Water

Chemours Company-Fayetteville Works Groundwater Treatment System
Attachment A.3
Form 2D Attachment - Justification for Presence of Pollutants
The pollutants below were identified as being present in the intake water (influent) to the Groundwater Treatment
System (GWTS).
The effluent concentrations and presence/absence on EPA Form 2D are from EPA Form 2C for Outfall 003 from the
April 1, 2021 submittal.
Parameter Name Rationale for Presence
Table A.Conventional and Non-conventional Parameters(40 CFR 122.21(k)(5)(i))
Biochemical oxygen demand Detected in Outfall 003
Chemical oxygen demand Detected in seep (Mar/Apr 2021)
Total organic carbon Detected in groundwater (GW) and seeps (Mar/Apr 2021)
Total suspended solids Detected in GW and seeps (2018-2020 data)
Ammonia Detected in GW and seeps (2018-2020 data)
pH Detected in GW and seeps (Mar/Apr 2021)
Table B. Certain Conventional and Non-conventional parameters(40 CFR 122.21(k)(5)(ii))
Chlorine (total Residual) Detected in GW and seeps (Mar/Apr 2021)
Color Detected in GW and seeps (Mar/Apr 2021)
Fecal Coliform Detected in GW and seeps (2018-2020 data)
Fluoride (16984-48-8) Detected in GW and seeps (Mar/Apr 2021)
Nitrate-Nitrite Detected in GW and seeps (Mar/Apr 2021)
Nitrogen (total Organic as N) Engineering judgment
Oil and grease Detected in Outfall 003
Phosphorous (as P). Total (7723-14-0) Detected in GW and seeps (2018-2020 data)
Sulfate (as SO4) (14808-79-8) Detected in GW and seeps (Mar/Apr 2021)
Sulfide Detected in GW and seeps (2018-2020 data)
Aluminum,Total (7429-90-5) Detected in GW and seeps (Mar/Apr 2021)
Barium,Total (7440-39-3) Detected in GW and seeps (Mar/Apr 2021)
Boron,Total (7440-42-8) Detected in seep (Mar/Apr 2021)
Cobalt,Total (7440-48-4) Detected in GW and seeps (Mar/Apr 2021)
Iron,Total (7439-89-6) Detected in GW and seeps (Mar/Apr 2021)
Magnesium,Total (7439-95-4) Detected in GW and seeps (Mar/Apr 2021)
Manganese,Total (7439-96-5) Detected in GW and seeps (Mar/Apr 2021)
Titanium,Total (7440-32-6) Detected in GW and seeps (Mar/Apr 2021)
Alpha,Total Detected in seeps (2018-2020)
Beta,Total Detected in seeps (2018-2020)
Radium,Total Detected in GW and seeps (Mar/Apr 2021)
Radium 226, TotalDetected in GW and seeps (Mar/Apr 2021)
Table C. Toxic Metals,Total Cyanide, and Total Phenols(40 CFR 122.21(k)(5)(iii)(A))
Arsenic Detected in GW and seeps (Mar/Apr 2021)
Beryllium Detected in GW and seeps (Mar/Apr 2021)
Chromium Detected in GW and seeps (Mar/Apr 2021)
Page 1 of 2 June 2021

Chemours Company-Fayetteville Works Groundwater Treatment System
Parameter Name Rationale for Presence
Copper Detected in GW and seeps (Mar/Apr 2021)
Lead Detected in GW and seeps (Mar/Apr 2021)
Mercury Detected in seeps (Mar/Apr 2021)
Nickel Detected in seeps (Mar/Apr 2021)
Selenium Detected in seeps (2018-2020 data)
Zinc Detected in seeps (Mar/Apr 2021)
Cyanide Detected in seeps (Mar/Apr 2021)
Table D.1 Organic Toxic Pollutants(GC/MS Fraction-Volatile Compounds)
Chloroform Detected in GW (2018-2020 data)
1,2-dichloroethane Detected in GW (2018-2020 data)
Methyl bromide Detected in GW (2018-2020 data)
Methyl chloride Detected in GW (2018-2020 data)
Toluene Detected in GW (2018-2020 data)
Vinyl chloride Detected in GW and seeps (Mar/Apr 2021)
Table D.2 Organic Toxic Pollutants(GC/MS Fraction-Base/Neutral Compounds)
Acenapthene Detected in GW (Mar/Apr 2021)
Anthracene Detected in GW (Mar/Apr 2021)
Benzo(a)Anthracene Detected in GW (Mar/Apr 2021)
Benzo(a)Pyrene Detected in GW (Mar/Apr 2021)
Benzo(b)Fluoranthene Detected in GW (Mar/Apr 2021)
Benzo(K)Fluoranthene Detected in GW (Mar/Apr 2021)
Chrysene Detected in GW (Mar/Apr 2021)
Fluoranthene Detected in GW (Mar/Apr 2021)
Fluorene Detected in GW (Mar/Apr 2021)
Napthalene Detected in GW (Mar/Apr 2021)
Phenanthrene Detected in GW (Mar/Apr 2021)
Pyrene Detected in GW (Mar/Apr 2021)
Table D.4 Organic Toxic Pollutants(GC/MS Fraction-Pesticides)
Heptachlor epoxide Detected in GW and seeps (2018-2020 data)
Page 2 of 2 June 2021

Attachment A.4 - Groundwater and Seeps Water
Quality Assessment

Geosyntec `f y 2501 Blue Ridge Road,Suite 430
Raleigh,NC 27607
PH 919.870.0576
consultants FAX [phone]
www.geosyntec.com
Geosyntec Consultants of NC,P.C.
NC License No.:C-3500 and C-29:7,
Memorandum
Date: June 13, 2021
To: Chemours Company FC, LLC
Subject: Chemours Fayetteville Works - Groundwater and Seeps Water Quality
Assessment
1 INTRODUCTION
Geosyntec Consultants of NC, P.C. (Geosyntec) has prepared this memorandum for The
Chemours Company FC, LLC (Chemours). This document summarizes a water quality
assessment of groundwater and seep data intended to represent the influent to a
groundwater extraction and treatment system (Groundwater Treatment System or
GWTS). The GWTS is a requirement of the Addendum to Consent Order paragraph 12
(CO Addendum) amongst Chemours, the North Carolina Department of Environmental
Quality (NCDEQ), and Cape Fear River Watch entered by the court on October 12, 2020.
The GWTS will discharge to the pipe that conveys the effluent from Outfall 002 at the
Fayetteville Works site to the Cape Fear River. The discharge will enter the pipe
approximately 870 feet downstream of Outfall 002 and is expected to be designated as
Outfall 004. The combined discharge from Outfalls 002 and 004 will then enter the river.
As part of the National Pollutant Discharge Elimination System (NPDES) permit
application for the GWTS, Chemours is required to complete EPA Application Form 2D
New Manufacturing, Commercial, Mining, and Silvicultural Operations That Have Not
Yet Commenced Discharge of Process Wastewater. EPA Form 2D requires information
on whether a compound is believed present in the intake water for the treatment system
and the maximum concentrations expected in the treatment system discharge for a
number of different compounds.This water quality assessment was conducted to provide
this information. Results are summarized herein. For compounds where the averages of
the untreated groundwater and seeps water were calculated to be greater than a water
quality criterion, information has been incorporated into the Engineering Report
(Geosyntec, 2021).
TR0795A108D102/A-04a_Chemours FW 004-Form 2C-Att 4 GWTS WQ Assessment-06-13-2021.docx

Groundwater and Seeps Water Quality Assessment Geosyntec p
June 13, 2021 consultants
Page 2 (;eosynter Consukanta of NC,P.C.
NC,Lwense Nu;C-343OO and C-293
2 SAMPLING PROGRAMS
Data from untreated groundwater and seep sampling that occurred from 2018 through
2020 were evaluated to determine what compounds should be further sampled for
inclusion on the EPA Form 2D:
a) where any untreated groundwater or seep concentration was greater than North
Carolina's most stringent, applicable surface water quality criteria (including the
North Carolina 15A NCAC 02B Water Quality Standards for Surface Waters, US
EPA National Recommended Water Quality Criteria for Aquatic Life & Human
Health, and North Carolina In-Stream Target Values for Surface Waters);
b) where the reporting limits were greater than the applicable surface water quality
criteria; and
c) where data did not exist.
The evaluation of the 2018 through 2020 data was used to inform sampling that Chemours
conducted in March and April 2021. This untreated groundwater and seep sampling was
conducted to provide representative data to complete the intake information on EPA Form
2D and to inform the engineering analysis of the GWTS.
Figure 1 provides the locations of the 2018-2020 sampling and the March/April 2021
sampling. Figure 2 shows the location of the March/April 2021 sampling. This included
four groundwater locations (EW-1, EW-3, PIW-10S, and PIW-5S) and two seep locations
(SEEP-A-WALL and SEEP-B-WALL). Concentrations from SEEP-A-TR4 were not
included in the water quality assessment for EPA Form 2D as this sample was artificially
disturbed to produce results necessary for the engineering analysis.
3 2018 THROUGH 2020 SAMPLING RESULTS
The 2018 through 2020 sampling results include data from September 27, 2018 to
October 23, 2020. Table 1 provides the comparison of the 2018 to 2020 groundwater data
to the surface water quality criteria. Table 2 provides the comparison of the 2018 through
2020 seep data to the surface water quality criteria. Of the compounds that were analyzed,
the following had at least one result that was greater than the surface water quality criteria:
• Beryllium
• Fluoride
• Iron
• Lead
June 2021

Groundwater and Seeps Water Quality Assessment GeOSynteC
June 13, 2021 consultants
Page 3 Geosyntec t:onsultsnLs of NC.P.C.
NC License Nu..C-1500 and C 29
• Manganese
• Mercury
• Methyl bromide
• Radium, total
• Selenium
• Sulfide
• Total residual chlorine
These parameters were analyzed in the March/April 2021 sampling program. A number
of compounds had insufficient reporting limits for comparison to the water quality criteria
and were also included in the March/April 2021 sampling program. Additionally, some
parameters on the EPA 2D Form had not previously be analyzed for in the untreated
groundwater or seeps and were therefore included for analysis in the March/April 2021
sampling program.
4 MARCH/APRIL 2021 SAMPLING RESULTS
Samples for the March/April 2021 sampling were collected from the four representative
groundwater extraction wells and two seep locations. Sampling was conducted on March
3, 2021 for all parameters. Further samples were collected on additional dates in March
and April of 2021 based on the need determined by the 2018 through 2020 sampling
results or the requirements for the engineering study.Flow-weighted mean concentrations
(FWMCs) were calculated for each day based on the expected maximum daily flow from
each source, as shown in Table 3. Table 3 also includes the average daily discharge for
Outfall 002, which was used to provide an estimate of the combined concentration from
Outfall 002 and the GWTS, prior to discharge to the Cape Fear River.
4.1 Flow-weighted Mean Concentrations (FWMC)
Table 4 provides the concentrations for compounds where a single sample was collected,
along with an estimated load in pounds per day (lb/d) and a FWMC. For some
compounds, all of the concentrations were less than the reporting limit and it is assumed
that there is no reasonable potential for the GWTS discharge to cause or contribute to an
exceedance of the water quality criterion in the Cape Fear River.No additional evaluation
was performed on this data. When some of the concentrations were above the reporting
limit, the FWMC in Table 4 was calculated assuming concentrations below the reporting
limit were equal to the reporting limit.
June 2021

GeoYnS t>
tec
Groundwater and Seeps Water Quality Assessment
June 13,2021 consultants
Page 4 Geosyntec Consultants af?:C,P.C:
NC Lkenst'Nu.:C-Y500 and C-2.95
Table 5 provides the concentrations for compounds where multiple samples were
collected, along with an estimated load and a FWMC for each day. The load and FWMC
calculations were performed assuming that values less than the reporting limit were equal
to the reporting limit. For some pollutants, all of the concentrations were less than the
reporting limit and it is assumed that there is no reasonable potential for the GWTS
discharge to cause or contribute to an exceedance of the water quality criterion in the
Cape Fear River. No additional evaluation was performed for these data. If any of the
concentrations were above the reporting limit, an average load and FWMC was then
calculated across all of the sampling events.
4.2 Comparison to Surface Water Quality Criteria
As many of the results at individual wells or seeps were below the reporting limit,
FWMCs were calculated assuming concentrations below the reporting limit were set to
(1) the reporting limit, (2) one half of the reporting limit, and (3) zero. Table 6 (which
integrates information from Tables 4 and 5) shows the results of these calculations
compared to the surface water quality criteria. FWMCs that are greater than the water
quality criterion are highlighted.
For the highlighted compounds, calculations for iron and manganese were insensitive to
these varied assumptions about reporting limits and the estimated concentrations did not
change. The varied assumptions did result in decreases in the estimated concentrations of
total residual chlorine, cyanide, mercury, anthracene, fluoranthene, phenanthrene,
polycyclic aromatic hydrocarbons (PAHs), and heptachlor epoxide. PAHs included in the
analysis are benzo(A)anthracene, benzo(A)pyrene, benzo(B)fluoranthene,
benzo(K)fluoranthene, and chrysene.
The samples were analyzed for total chromium and total cyanide to meet the needs of the
EPA Form 2D; however, the criteria are for Chromium III and free cyanide, respectively.
The estimated total cyanide concentration met the free cyanide water quality criterion
when concentrations below the reporting limit were assumed to be equal to one-half of
the reporting limit or zero. The total chromium concentration met the Chromium III
criteria in all assumptions.
It should also be noted that EPA approved the removal of the North Carolina aquatic life
standards for both iron and manganese due to high natural occurrence in North Carolina's
surface waters.The iron and manganese concentrations are compared to the EPA National
Recommended Water Quality Criteria for Aquatic Life & Human Health in Table 6
strictly for guidance.
For the comprehensive Site permit application, Chemours conducted a mixing zone
assessment to determine that there was an 8:1 dilution available in the Cape Fear River
June 2021

Groundwater and Seeps Water Quality Assessment Geosyntec
June 13,2021 consultants
Page 5 t;eos}ntec Consultants of NC,PC.,
NC License Nu.:C:1500 and C 295
for Outfall 002 (Geosyntec, 2019). Table 7 provides the comparison of the FWMC for
Outfall 004 with the 8:1 dilution applied to the water quality criteria. Results indicate that
total residual chlorine, PAHs, and heptachlor epoxide may have reasonable potential to
exceed surface water quality criteria without treatment or mixing with effluent from
Outfall 002.
A mass balance was conducted using the loads calculated with the FWMC for Outfall
004 after mixing with the effluent from Outfall 002. An average daily flow of 18.025
million gallons per day (MGD) was used for Outfall 002, consistent with the line drawing
for the NPDES permit application submitted on June 4, 2021 (see Table 3).
Concentrations for Outfall 002 include the long-term average from EPA Form 2C (when
available) or the daily maximum. Table 8 provides the loads calculated for Outfalls 002
and 004.
Table 9 shows the mass balance for Outfalls 002 and 004 and mixing zone assessment
combined results for total residual chlorine, the PAHs, and heptachlor epoxide, as these
compounds were identified in Table 7 as possibly having have reasonable potential to
exceed surface water quality criteria. The results show that the total residual chlorine is
well below the criterion. Only heptachlor epoxide and PAHs therefore warrant
consideration as additional pollutants targeted for removal by the GWTS.
5 SUMMARY
Heptachlor epoxide was only detected in one well (PIW-5S) and one seep (SEEP-A-
WALL) at low levels. Heptachlor is a breakdown product of an insecticide that is not
used at the Site. The PAH compounds were only detected at low levels in one (PIW-5S)
of the six untreated groundwater and seep sources. There is no asphalt present nearby that
would serve as a source of PAHs. PAHs and heptachlor epoxide are also not present in
the wastewater from the manufacturing operations (see the EPA Form 2C for Outfall 002
with the NPDES permit application dated June 4, 2021). In addition, flow from the PIW-
5S well is only 7% of the total flow and flow from Seep-A-Wall is only 4% of the total
flow. Finally, the Chemours river intake, Outfall 002 and Outfall 003 analytical results
for these compounds were non-detect. Chemours intends to resample PIW-5S and SEEP-
A-WALL for PAHs and heptachlor epoxide.
As indicated in the Engineering Report (Geosyntec, 2021),it is anticipated that the GWTS
will reduce the contaminant levels of these potential pollutants so that the discharge from
Outfall 004 will not cause or contribute to exceedances of the surface water quality
criteria in the Cape Fear River, if they are present.
June 2021

Groundwater and Seeps Water Quality Assessment Geosynte&
June 13,2021 consultants
Page 6 i.,eosyntec f:onsuftants of NC,PC;
NC License Nu;C 15O0 and C 29a
References
Geosyntec, 2021. Engineering Report-Treatment of Groundwater and Upgradient Seeps
Water Prepared for the Chemours Company FC, LLC.June 10, 2021.
Geosyntec, 2019. Mixing Zone Report, Addendum. Chemours Fayetteville Works
Outfall 002, Fayetteville, North Carolina.Prepared for the Chemours Company FC,LLC.
October 2019.
June 2021

N
. ..
Y -......„.„,,,1„......,\,,,,,
.,.
. /
See Figure 2
A SEEPA-TR-N
<SMW OSB _;
SMW-07
BCA-03R PZ-11
MW-15DRR
}� redPZ-21 R--�Y
MW-16D PZ OR —SEEPA-V ALL
NAf-
FTA-01 PZ-35 -,$
°'x PZ-lc'.' PZ N
FTA-02
P.W-13 FTA-03 AF-1
MW-12S M'dv i :_ \
_ PW 03 myn�.t
MW-24 . ' +�. -
MW-13U
MW-1 S
Y „ L SEEPS- ALL
.- MW-141-3 MW-8S ''. MW 25 I
MW-2S , - PZ 25 !'
i MW-2, 1
.PZ-17 1,
MWY-11� BGA 02
FM
5' •:MW-26 P
N \27 � ,
.
BC.
A 0
Pilot Test Area for PlumeStop'" v
.til\\\IN -,
d� m
:„,
ti
mommotommin
\11411.411.
\0000.\\\
Legend
Locations Sampled along Barrier 1,000 500 0 1,000 Feet
Wall Alignment in March 2021
e1 Surficial Aquifer Perched Zone Sample Location ■ Seep Sample Location
tJ Monitoring Well Sample
Location Planned Groundwater
Black Creek Aquifer -S.- Surficial Aquifer Sample Location m ' ' ' Remedy Route Onsite Surface Water and Groundwater
<J Monitoring Well Sample Observed Seep Sample Locations - Past 5 Years
Location 4.. Floodplain Deposits Sample Location
Site Boundary Chemours Fayetteville Works, North Carolina
OSeep Sample Location + Black Creek Aquifer Sample Location
Notes:
1.Topographic surface was generated using LiDAR scans performed on December 1,2019 and December 19,2019
by Spectral Data Consultants,Inc Geosyntec Figure
2.Due to the scale of the map,pairs of wells that are in close proximity have been offset for visibility. Therefore,the placement of Gcosynlec Consultants of NC,P.C. ry
these wells on this map do not reflect their true geographic coordinates. NC License No.:C 3500 and C 295 7
consultants
3.The outline of the River shown on this figure is approximate(River outline based on compilation of open data sources from ArcGIS
online service and North Carolina Department of Environmental Quality Online GIS-Major Hydro shapefile). 1
4.Basemap source:Esri,DigitalGlobe,GeoEye,Earthstar Geographies,CNES/Airbus DS,USDA,USGS,AeroGRID,IGN,and the Raleigh June 2021
GIS User Community.

- N1
L'. '' -l7;'.",i.b1*''''1iP'1.".-.7.-1. e-,*-t.."..-.1.'',i.'.,'07.:-.. . ----.-.1.4•,t•t
Ii.. -
5.,„.tt.k 10_,44.
-
- tt.a 1 •..,, >'`SEEP A-TR4 1 . *•.-
°" b'� �: ra # SEEP-A-TR3 1 si:0*,, '' •'
Aler
n
.+. - • 0♦ 1
,.u. ram , T ' ii
p
♦ 1. $�
SEEP A I2 r�» a
u4
' E A TR2 1� ,, S E P '` �+�' t`�
s.
llAls,$.41:,..77_,,• . ,
,r � Y iY .
'' ` t . dimimiSEEP-A-TR �`
. : +/ ; i . , SEEP-A3 ► �
kc i i.• • SEEP-A-11 . . -v-a �-. • u,.
n SEEP-A 10 .. • SEEP-A-2
=s, ,PIW r3S ' • SEEP-A-1 4#4_,A• °`' °2 '
, ,_ ...:—: ,,,
4414 f „,. SEEP-A 9 1 1l /� ;`:r SEEP A 4 yP,. 1a I .m°
lilA ,,•-:x,,, d t 4 "*.` t`. -SEEP A 5 1 . `. ,�i
t SEEPA7itj ''
t �*' SEEP-A-8 r t
I �,, SEEP-A-6lit* , • d
. '''' 011010) ' t,' - - ::1•1':":.'di.: SEEP AA WALL ' ' ....
't+ . 4 > y,* ,.. 14,,
' - '''. ..: ..,.e4'. . i1,,ii',1., ' i-,. ..-,_•..... „. -• ''.!A:. 11,i'i' . ."-'.**-*i.,4r•''..f V I
1
i' SEEP-B-TR1 ��` '' , ,
SE C P B-2 %\ :SEEP-B-1 ,dd ' m -
SEEP BWALL `'" '14*7 --, t
C) T SELF-B-ERA'
-.,, SI LPB-3 '. _ -
SI_CP-B-4 '_ , J
t �� ♦ _ sE f P-B-3A
— 'iY` li `4 y,,tot SEEP-B-3 11 • r t
- V4- .
'
LEP_C-1
s.
r
d, /
l F l)
. Y` 1•
V
t „ . i .) 1
*"..t4
ii
# - *s- ,
` a
T # _ rojj '.1-,4- - --' -li.lf t ,„
•
`< .` •
Legend 400 200 0 400 Feet
Locations Sampled along Barrier
Wall Alignment in March 2021 olim iiim
Surficial Aquifer
/1 Monitoring Well Sample Seep Location — — to Observed Seep
�J Location
Black Creek AquiferIIIIII Cape Fear River r a w a Planned Groundwater Remedy Route Seep Sample Locations Past 5 Years
r� Monitoring Well Sample
No Location Chemours Fayetteville Works, North Carolina
® Nearby Tributary Site Boundary
Seep Sample Location
Notes: GQOc teC D
Nt Topographic surface was generated using LiDAR scans performed on December 1,2019 and December 19,2019 e s `e Gcosyn,ec Consultants of NC,l>.c. Figure
by Spectral Data Consultants,Inc NC License No.:C 3500 and C 24',,
2.The outline of the River shown on this figure is approximate(River outline based on compilation of open data sources from ArcGIS consultants
online service and North Carolina Department of Environmental Quality Online GIS-Major Hydro shapefile).
3.Basemap source:Esri,DigitalGlobe,GeoEye,Earthstar Geographies,CNESIAirbus DS,USDA,USGS,AeroGRID,IGN,and the 2
GIS User Community. Raleigh June 2021

1 able 1 Geosyntec Consultants of NC P.C.
Onsite Untreated Groundwater Data Summary for 2018 to 2020
Chemours Fayetteville Works,North Carolina
Minimum Greater Than No.Total Source Data
Parameter name(as used in data analysis) CAS Number Units Regulatory Criteria No.Total No.Total Non- Maximum Minimum beginning Source Data
Criteria (Y/N) Results of Detects Detects date end date
TABLE A.CONVENTIONAL AND NON CONVENTIONAL PARAMETER ESTIMATES(40 CFR 122.21(k)(5)(i)) _
Biochemical Oxygen Demand(BOD)-5 Day BOD mg/L NA No 41 0 4 ND ND 5/27/2020 5/28/2020
Chemical Oxygen Demand(COD) COD mg/L NA No 4 2 2 8.6 6.6 5/28/2020 5/28/2020
Total Organic Carbon TOC mg/L NA No 8 7 1 6.2 0.52 9/27/2018 5/28/2020 _
Total Suspended Solids TSS mg/I. NA No ' 4 2 2 87 13 5/28/2020 5/28/2020
Ammonia mg/L pH and Temp No I 2 2 2.7 2.7 5/27/2020 5/27/2020
Dependent
TABLE B.CERTAIN CONVENTIONAL AND NON-CONVENTIONAL POLLUTANTS(40 CFR 122.21(k)(5)(ii))
Bromide mg/L NA No 8 0 8 ND ND 9/27/2018 5/28/2020
Fluoride(16984-48-8) 16984-48-8 mg/L 1.8 Yes ' 8 3 5 5.1 0.033 9/27/2018 3/6/2020
Oil and Grease mg/L NA No _ 4 0 4 ND ND 5/27/2020 5/28/2020
Phosphorous(as P),Total(7723-14-0) 7723-14-0 mg/L NA 10, No 4 3 1 0.099 0.04 5/27/2020 5/28/2020
Sulfate(as SO4) (14808-79-8) 14808-79-8 mg/L 250 N, �3`_ 8 8 0 68 3.5 9/27/2018 5/28/2020
Aluminum,Total(7429-90-5) 7429-90-5 mg/L 6.5 a'd 8 8 0 1.4 0.088 9/27/2018 5/28/2020
Barium,Total(7440-39-3) 7440-39-3 mg/L 1 No ' 4 4 0 0.057 0.043 5/27/2020 5/28/2020
Cobalt,Total(7440-48-4) 7440-48-4 mg/L 0.0016 No `!? 4 3 1 0.00089 0.00071 5/27/2020 5/28/2020
Iron,Total(7439-89-6) 7439-89-6 mg/L I Yes, g`� 12 11 1 11 0.0487 9/27/2018 5/28/2020
Magnesium,Total(7439-95-4) 7439-95-4 mg/L NA 8 8 0 5.1 0.39 9/27/2018 5/28/2020
Manganese,Total(7439-96-5) 7439-96-5 mg/L 0.05 8 8 0 0.366 0.0041 9/27/2018 5/28/2020
Radioactivity
TABLE C.TOXIC METALS,TOTAL CYANIDE,AND TOTAL PHENOLS(40 CFR 122.21(k)(5)(iii)(A))1
Antimony 7440-36-0 mg/L 0.0056 No 1 0 4 ND ND 5/27/2020 5/28/2020
Arsenic 7440-38-2 mg/L 0.01 No I 1 3 0.0013 0.0013 5/28/2020 5/28/2020
Beryllium 7440-41-7 mg/L 0.0065 Yes I 4 0 0.0067 0.00014 5/27/2020 5/28/2020 _
Cadmium 7440-43-9 mg/L 0.00042 No 4 0 4 ND ND 5/27/2020 5/28/2020
Chromium 7440-47-3 mg/L 0.011 No 4 4 0 0.0055 0.0019 5/27/2020 5/28/2020
Copper 7440-50-8 mg/L 0.00896 No 4 4 0 0.0038 0.00064 5/27/2020 5/28/2020
Lead 7439-92-1 mg/L 0.00252 Yes 4 4 0 0.0029 0.00048 5/27/2020 5/28/2020
Mercury 7439-97-6 mg/L 0.000012 Yes 4 2 2 0.00019 0.00013 5/28/2020 5/28/2020
Nickel 7440-02-0 mg/L 0.025 No 4 4 0 0.0032 0.0011 5/27/2020 5/28/2020 _
Selenium 7782-49-2 mg/L 0.005 No 4 0 4 ND ND 5/27/2020 5/28/2020 _
Silver 7440-22-4 mg/L 0.00006 No ` 4 0 4 ND ND 5/27/2020 5/28/2020
Thallium 7440-28-0 mg/L 0.002 No 4 0 4 ND ND 5/27/2020 5/28/2020 _
Zinc 7440-66-6 mg/L 0.11718 No 4 3 1 0.091 0.01 5/27/2020 5/28/2020
Organic Toxic Pollutants(GC/MS Fraction-Volatile Compounds)
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))
Acrolein 107-02-8 ug/L 3 No 28 0 28 ND ND 5/2/2019 8/12/2019
Acrylonitrile 107-13-1 ug/1. 0.061 No 28 0 28 ND ND 5/2/2019 8/12/2019 _
Benzene 71-43-2 ug/I. 1.19 No 32 0 32 ND ND 5/2/2019 5/28/2020
Bromoform 75-25-2 uk%1 7 No 32 0 32 ND ND 5/2/2019 5/28/2020
Carbon Tetrachloride 56-23-5 - u3'I 0.259 No 32 0 32 ND ND 5/2/2019 5/28/2020 _
Chlorobezene 108-90-7 ug/1. 140 No 32 0 32 ND ND 5/2/2019 5/28/2020
Chlorodibromomethane 124-48-1 ug%l. 0.8 No 32 0 32 ND ND 5/2/2019 5/28/2020
Eth !Chloride 75-00-3 tit;I NA b o .` 32 0 32 ND ND 5/2/2019 5/28/2020
TR0795A Page 1 of 28 June 2021

Table 1 Geosyntec Consultants of NC P.C.
Onsite Untreated Groundwater Data Summary for 2018 to 2020
Chemours Fayetteville Works,North Carolina
Minimum Greater Than No.Total Source Data
Parameter name(as used in data analysis) CAS Number Units Regulatory Criteria No.Total No.Total Non- Maximum Minimum beginning Source Data
Criteria (Y/N) Results of Detects Detects date end date
Chloroform 67-66-3 ug/L 60 - 32 19 13 2 0.16 5/2/2019 8/12/2019
Dichlorobromomethane 75-27-4 ug/L 0.55 32 0 32 ND ND 5/2/2019 5/28/2020
1,1-dichloroethane 75-34-3 ug/L 6 No -A. 32 0 32 ND ND 5/2/2019 5/28/2020 _
1,2-dichloroethane 107-06-2 ug/L 9.9 No :' 32 3 29 0.18 0.14 5/2/2019 5/3/2019
1,1-dichloroethylene 75-35-4 ug/L 300 t No ''.. 32 0 32 ND ND 5/2/2019 5/28/2020
1,2-dichloropropane 78-87-5 ug/L 0.9 ` No 32 0 32 ND ND 5/2/2019 5/28/2020
Ethylbenzene 100-41-4 ug/L 68 No 32 0 32 ND ND 5/2/2019 5/28/2020
Methyl bromide 74-83-9 ug/L 0.04 Yes 32 1 31 0.3 0.3 8/9/2019 8/9/2019
Methyl chloride 74-87-3 ug/L 2.6 No 32 1 31 0.41 0.41 6/18/2019 6/18/2019
Methylene chloride 75-09-2 ug/L 20 No 32 0 32 ND ND 5/2/2019 5/28/2020
1,1,2,2-tetrachloroethane 79-34-5 ug/L 0.17 No 32 0 32 ND ND 5/2/2019 5/28/2020
Tetrachloroethylene 127-18-4 ug/L 0.7 No 32 0 32 ND ND 5/2/2019 5/28/2020
Toluene 108-88-3 ug/L 11 No 32 1 31 0.27 0.27 7/18/2019 7/18/2019 _
1,2-trans-dichloroethylene 156-60-5 ug/L 100 No 32 0 32 ND ND 5/2/2019 5/28/2020
1,1,1-trichloroethane 71-55-6 ug/L 2500 No 32 0 32 ND ND 5/2/2019 5/28/2020
1,1,2-trichloroethane 79-00-5 ug/L 0.55 No 32 0 32 ND ND 5/2/2019 5/28/2020 —
Trichloroethylene 79-01-6 ug/L 2.5 No 32 0 32 ND ND 5/2/2019 5/28/2020
Vinyl chloride 75-01 1 ug/L 0.025 No 32 0 32 ND ND 5/2/2019 5/28/2020
Organic Toxic Pollutants(GC/MS Fraction-Acid Compounds)
Organic Toxic Pollutants(GC/MS Fraction-Base/Neutral Compounds)
1,2dichlorobenzene 95-50-1 ugil. -170 No 1 0 4 ND ND _ 5/27/2020 5/28/2020
1,3dichlorobenzene 541-73-1 ugil. 390 No t2 0 32 ND ND 5/2/2019 5/28/2020
-
1,4-dichlorobenzene 106-46-7 ug/L hlorinated' No -1 0 1 ND ND 5/27/2020 5/28/2020
1,2,4-trichlorobenzene 120-82-1 ug/L 61 No I 0 1 ND ND 5/27/2020 5/28/2020
Organic Toxic Pollutants(GC/MS Fraction-Pesticides)
E E.CERTAIN HAZARDOUS SUBSTANCES AND ASBESTOS(40 CFR 122.21(k)(5)(v))
Allyl chloride ug/L NA No 28 0 28 ND ND 5/2/2019 8/12/2019
Carbon disulfide _ ug/L 100 No 32 4 28 0.64 0.38 5/2/2019 5/2/2019
Cyclohexane ug/L 230 No 4 0 4 ND ND 5/27/2020 5/28/2020
Methyl methacrylate ug/L 9600 No 28 0 28 ND ND 5/2/2019 8/12/2019
Styrene ug/L NA No 32 0 32 ND ND 5/2/2019 5/28/2020
Vanadium mg/L NA ` No 4 4 0 _ 0.01 0.0003 5/27/2020 5/28/2020
Vinyl acetate ug/L NA No 28 0 28 ND ND 5/2/2019 8/12/2019
SABLE E.2,3,7,8 TETRACHLORODIBENZO P DIOXIN(2,3,7,8 TCDD)(40 CFR 122.21(g)(7)(viii))
Notes
ND-Not Detected mg/L-milligrams per liter NC 02B Standards
NR-Not Recorded ug/L-microgram per liter EPA NRWQC
NA-No Applicable Standard In-Stream Target Values
TR0795A Page 2 of 28 June 2021

Table 2 Geosyntec Consultants of NC P.C.
Onsite Untreated Seep Data Summary for 2018 to 2020
Chemours Fayetteville Works,North Carolina
Minimum Greater Than No.Total No.Total of No.Total Non- Source Data Source Data
Parameter name(as used in data analysis) CAS Number Units Regulatory Maximum Minimum
Crites Criteria(YIN) Results Detects Detects beginning date end date
TABLE A.CONVENTIONAL AND NON CONVENTIONAL PARAMETER ESTIMATES(40 CFR 122.21(k)(5)(i))_
Biochemical Oxygen Demand(BOD)-5 Day BOD mg/L NA No 4 0 4 ND ND 10/23/2020 10/23/2020
Chemical Oxygen Demand(COD) COD mg/L NA No 4 0 4 ND ND 10/23/2020 10/23/2020 -
Total Organic Carbon TOC mg/I. NA N 26 25 1 10.4 1 2/5/2019 10/23/2020
Total Suspended Solids TSS mg/L NA No 32 32 0 3740 3.1 2/5/2019 10/23/2020
Ammonia mg2 pH and Temp No 26 12 14 0.13 0.052 2/5/2019 10/23/2020
Dependeni -
Ph STD Units 6 No 4 4 0 6.5 6.5 10/23/2020 10/23/2020
Ph STD Units 9 No 4 4 0 6.5 6.5 10/23/2020 10/23/2020
TABLE B.CERTAIN CONVENTIONAL AND NON-CONVENTIONAL POLLUTANTS(40 CFR 122.21(k)(5)(ii))
Bromide mg/L NA No I 0 I ND ND 10/23/2020 10/23/2020 -
total residual chlorine mg/L 0.017 Yeti I 4 0 0.19 0.08 10/22/2020 10/22/2020
colonies
Fecal Coliform per 200 No 4 3 1 180 45 10/22/2020 10/22/2020
100mL
Fluoride(16984-48-8) 16984-48-8 mg/L 1,8 No 4 0 4 ND ND 10/23/2020 10/23/2020
Total Kjeldahl Nitrogen mg/L NA No 4 0 4 ND ND 10/23/2020 10/23/2020
Oil and Grease mg/L NA No 4 0 4 ND ND 10/22/2020 10/22/2020
Phosphorous(as P),Total(7723-14-0) 7723-14-0 mg/L NA Nn 4 2 2 0.14 0.1 10/23/2020 10/23/2020 -
Sulfate(as SO4)(14808-79-8) 14808-79-8 mg/L 250 No 26 26 0 34 5.2 2/5/2019 10/23/2020
Sulfide mg/L 0.00021 l es 4 1 3 1.6 1.6 10/23/2020 10/23/2020
Sulfite(as S03)(14265-45-3) 14265-45-3 mg/I. NA No, " 4 0 4 ND ND 10/22/2020 10/22/2020 _
Aluminum,Total(7429-90-5) 7429-90-5 mg/L 6.5 Noo 30 30 0 5.23 0.392 2/5/2019 10/23/2020
Barium,Total(7440-39-3) 7440-39-3 mg/L 1 No 4 4 0 0.086 0.059 10/23/2020 10/23/2020
Boron,Total(7440-42-8) 7440-42-8 mg/L 0.15 No 4 1 3 0.012 0.012 10/23/2020 10/23/2020
Iron,Total(7439-89-6) 7439-89-6 mg/L 1 Yes 30 30 0 21.4 0.227 2/5/2019 10/23/2020
Magnesium,Total(7439-95-4) 7439-95-4 mg/L NA No 26 26 0 1.55 0.506 2/5/2019 10/23/2020
Molybdenum,Total(7439-98-7) 7439-98-7 mg/L 0.16 No 4 0 4 ND ND 10/23/2020 10/23/2020
Manganese,Total(7439-96-5) 7439-96-5 mg/I. 0.05 Ye, 30 30 0 0.434 0.0095 2/5/2019 10/23/2020
Tin,Total(7440-31-5) 7440-31-5 mg/L 0.77 No 4 0 4 ND ND 10/23/2020 10/23/2020
Titanium,Total(7440-32-6) 7440-32-6 mg/L NA No I 3 1 0.023 0.0053 10/23/2020 10/23/2020
Radioactivity
Gross Alpha pCi/L _ 15 No I 1 (1 3.67 2.25 10/23/2020 10/23/2020
Gross Beta pCi/L 50 No I 4 (1 11.5 5.34 10/23/2020 10/23/2020
Radium(Total) pCi/L 5 Yes 4 4 (1 9.32 4.72 10/23/2020 10/23/2020
Radium-226 pCi/L 5 No I 3 I 2.03 0.701 10/23/2020 10/23/2020
TABLE C.TOXIC METALS,TOTAL CYANIDE,AND TOTAL PHENOLS(40 CFR 122.21(k)(5)(iii)(A))1
Antimony 7440-36-0 mg/L 0.0056 No 7 0 7 ND ND 2/6/2019 10/23/2020
Arsenic 7440-38-2 mg/L 0.01 No 7 0 7 ND ND 2/6/2019 10/23/2020
Beryllium 7440-41-7 mg/L 0.0065 No 7 3 4 0.0013 0.001 10/23/2020 10/23/2020 -
Cadmium 7440-43-9 mg/L 0.00042 No r 0 7 ND ND 2/6/2019 10/23/2020
Chromium 7440-47-3 mg/L 0.011 No 7 0 7 ND ND 2/6/2019 10/23/2020
Copper 7440-50-8 mg/L 0.00896 No 7 O 7 ND ND _ 2/6/2019 10/23/2020 -
Lead 7439-92-1 mg/L 0.00252 No 7 0 7 ND ND 2/6/2019 10/23/2020
Mercury 7439-97-6 mg/L 0.000012 Yes 7 1 6 0.00008 0.00008 10/23/2020 10/23/2020
Nickel 7440-02-0 mg/L 0.025 No 7 4 3 0.0045 0.0028 _ 2/7/2019 10/23/2020
Selenium 7782-49-2 mg/L 0.005 # Yes 11 1 10 0.0248 0.0248 2/6/2019 2/6/2019
TR0795A Page 3 of 28 June 2021

Table 2 Geosyntec Consultants of NC P.C.
Onsite Untreated Seep Data Summary for 2018 to 2020
Chemours Fayetteville Works,North Carolina
Minimum Greater Than No.Total No.Total of No.Total Non- Source Data Source Data
Parameter name(as used in data analysis) CAS Number Units Regulatory Maximum Minimum
Critera Criteria(Y/N) Results Detects Detects beginning date end date
Silver 7440-22-4 mg/L 0.00006 11 0 11 ND ND 2/6/2019 10/23/2020
Thallium 7440-28-0 mg/L 0.002 No 1 0 4 ND ND 10/23/2020 10/23/2020
Zinc 7440-66-6 mg/L 0.11718 No 7 6 1 0.0181 0.016 2/7/2019 10/23/2020
Cyanide 57-12-5 mg/L 0.004 No I 0 4 ND ND 10/22/2020 10/22/2020
Total Phenols mg/L NA No 1 0 4 NI) ND 10/22/2020 10/22/2020
TABLE D.ORGANIC TOXIC POLLUTANTS(Gas Chromatography/Mass Spectrometry or GC/MS Fractions)(40 CFR 122.21(k)(5)(iii)(B))
Organic Toxic Pollutants(GC/MS Fraction-Volatile Compounds)
Acrolein 107-02-8 ug/L 3 No 10 _ 0 10 ND ND 2/5/2019 10/22/2020
Acrylonitrile 107-13-1 ug/L 0.061 No 10 0 10 ND ND 2/5/2019 10/22/2020
Benzene 71-43-2 ug/L 1.19 No 6 0 6 ND ND 2/5/2019 2/7/2019
Bromoform 75-25-2 ug/L 7 No 6 0 6 ND ND 2/5/2019 2/7/2019
Carbon Tetrachloride 56-23-5 ug/L 0.254 No 6 0 6 ND ND 2/5/2019
_ 2/7/2019
Chlorobezene 108-90-7 ug/L 140 No 6 0 6 ND ND 2/5/2019 2/7/2019
Chlorodibromomethane 124-48-1 ug/L 0.8 No 6 0 6 ND ND _ 2/5/2019 2/7/2019
Ethyl Chloride 75-00-3 ug/L NA No 6 0 6 ND ND 2/5/2019 2/7/2019
2-chloroethylvinyl ether 110-75-8 ug/L NA No 10 0 10 ND ND 2/5/2019 10/22/2020
Chloroform 67-66-3 ug/L 60 No 6 0 6 ND ND _ 2/5/2019 2/7/2019
Dichlorobromomethane 75-27-4 ug/L 0.55 No 6 0 6 ND ND 2/5/2019 2/7/2019
1,1-dichloroethane 75-34-3 ug/L 6 No 6 0 6 ND ND 2/5/2019 2/7/2019
1,2-dichloroethane 107-06-2 ug/L 9.9 No 6 0 6 ND ND 2/5/2019 2/7/2019 I
1,1-dichloroethylene 75-35-4 ug/L 300 i No 6 0 6 ND ND 2/5/2019 2/7/2019
1,2-dichloropropane 78-87-5 ug/L 0.9 No 6 0 6 ND ND 2/5/2019 2/7/2019
Ethylbenzene 100-41-4 ug/L 68 No 6 0 6 ND ND 2/5/2019 2/7/2019
Methyl bromide 74-83-9 ug/L 0.04 No 6 0 6 ND ND 2/5/2019 2/7/2019
Methyl chloride 74-87-3 ug/L 2.6 No 6 0 6 ND ND 2/5/2019 2/7/2019
Methylene chloride 75-09-2 ug/L 20 No 6 0 6 ND ND 2/5/2019 2/7/2019
1,1,2,2-tetrachloroethane 79-34-5 ug/L 0.17 No 6 0 6 ND ND 2/5/2019 2/7/2019
Tetrachloroethylene 127-18-4 ug/L 0.7 No 6 0 6 ND ND 2/5/2019 2/7/2019
Toluene 108-88-3 ug/L 11 No 6 0 6 ND ND 2/5/2019 2/7/2019
1,2-trans-dichloroethylene 156-60-5 ug/L 100 No 6 0 6 ND ND 2/5/2019 2/7/2019
1,1,1-trichloroethane 71-55-6 ug/L 2500 ., ,o ,„ 6 0 6 ND ND 2/5/2019 2/7/2019
1,1,2-tichloroethane 79-00-5 ug/L 0.55 6 0 6 ND ND 2/5/2019 2/7/2019
Trichloroethylene 79-01-6 ug/L 2.5 ..,._ .- - ; 6 0 6 ND ND 2/5/2019 2/7/2019
Vinyl chloride 75-01-4 tut I 0 025 No 6 0 6 NI) ND 2/5/2019 2/7/2019
Organic Toxic Pollutants(GC/MS Fraction-Acid Com sounds)
2-chlorophenol 95-57-8 ug/L chlorinated No 10 0 10 \I) ND 2/5/2019 10/23/2020
phenols
g/l -total
2,4-dichlorophenol 120-83-2 ug/L -chlorinated No 10 0 I0 ND ND 2/5/2019 10/23/2020
2,4-dimethylphenol 105-67-9 ug/L 100 No 10 0 10 ND ND 2/5/2019 10/23/2020
4,6-dinitro-o-cresol 534-52-1 ug/L 10 0 _ 10 ND ND 2/5/2019 10/23/2020
2,4-dinitrophenol 51-28-5 ug/l. 1010 0 10 ND ND 2/5/2019 10/23/2020
2-nitrophenol 88-75-5 ug/L NA No 10 0 10 ND ND 2/5/2019 10/23/2020
4-nitro.henol 100-02-7 ug/L 10 0 10 ND ND 2/5/2019 10/23/2020
TR0795A Page 4 of 28 June 2021

Table 2 Geosyntec Consultants of NC P.C.
Onsite Untreated Seep Data Summary for 2018 to 2020
Chemours Fayetteville Works,North Carolina
Minimum Greater Than No.Total No.Total of No.Total Non- Source Data Source Data
Parameter name(as used in data analysis) CAS Number Units Regulatory Maximum Minimum
Critera Criteria(Y/N) Results Detects Detects beginning date end date
p-chloro-m-cresol 59-50-7 ug/L No 10 0 10 ND ND 2/5/2019 10/23/2020
Pentachlorophenol 87-86-5 (ig/LNo 10 0 10 ND ND 2/5/2019 10/23/2020
Phenols 108-95-2 ug/L. 4000 No '' 10 _ 0 10 ND ND 2/5/2019 10/23/2020
2,4,6-trichlorophenol 88-06-2 ug,'I_ No 10 1 U 10 ND ND 2/5/2019 10/23/2020
Organic Toxic Pollutants(GC/MS Fraction-Base/Neutral Compounds)
Acenapthene 83-32-9 ug/L 60 No 10 0 11) NI) ND 2/5/2019 10/23/2020 _
Acenapthylene 208-96-8 ug/L NA No 10 0 10 ND ND 2/5/2019 10/23/2020
Anthracene 120-12-7 ug/L 0.05 No 10 0 10 ND ND 2/5/2019 10/23/2020_
Benzidine 92-87-5 ug/L 0.00014 No 10 0 10 ND ND 2/5/2019 10/23/2020
Benzo(a)anthracene 56-55-3 ug/L 0.1 No 10 0 10 ND ND 2/5/2019 10/23/2020
Benzo(a)pyrene 50-32-8 ug/L 0.05 No 10 0 10 ND ND 2/5/2019 10/23/2020
3,4-benzofluoranthene 205-99-2 ug/L No 10 0 10 ND ND 2/5/2019 10/23/2020
Benzo(ghi)perylene 191-24-2 ug/L NA No 10 0 10 ND ND 2/5/2019 10/23/2020
Benzo(k)fluoranthene 207-08-9 ug/L No 10 0 10 ND ND 2/5/2019 10/23/2020
Bis(2 cttlorcethoxy)methane 111-91-1 ug/L 100 No 10 0 10 ND ND 2/5/2019 10/23/2020
Bis(2-chloroethyl)ether 111-44-4 ug/L 0.03 No 10 0 10 ND ND 2/5/2019 10/23/2020 _
Bis(2-chloroisopropyl)ether 39638-32-9 ug/L NA No 6 0 6 ND ND 2/5/2019 2/7/2019
Bis(2-ethylhexyl)phthalate 117-81-7 ug/L 0.32 No 10 0 10 ND ND 2/5/2019 10/23/2020
4-bromophenyl phenyl ether 101-55-3 ug/L 2 No 10 0 10 ND ND 2/5/2019 10/23/2020
Butyl benzyl phthalate 85-68-7 ug/L 0.1 No 10 0 _ 10 ND ND 2/5/2019 10/23/2020
2-chloronaphthalene 91-58-7 ug/L 110 N 10 0 10 ND ND 2/5/2019 10/23/2020
4-chlorophenyl phenyl ether 7005-72-3 ug/L NA Now" 10 0 10 ND ND 2/5/2019 10/23/2020
Chrysene 218-01-9 ug/L No 10 0 10 ND ND 2/5/2019 10/23/2020
Dibenzo(a,h)anthracene 53-70-3 ug/L i No 10 0 l0 ND ND 2/5/2019 10/23/2020
1,2-dichlorobenzene 95-50-1 ug/L hlortnated No 10 0 10 ND ND 2/5/2019 10/23/2020
benzenes ,
:ug/L total
1,3-dichlorobenzene 541-73-1 ug/L \o I0 0 10 ND ND 2/5/2019 10/23/2020
1,4-dichlorobenzene 106-46-7 ug/L blot mated No 10 0 10 NI) ND 2/5/2019 10/23/2020
3,3-dichlorobenzidine - 91-94-1 ug/L 0.099 No 10 0 10 ND ND 2/5/2019 10/23/2020
Diethyl phthalate 84-66-2 ug/L 600 No. 10 0 10 ND ND 2/5/2019 10/23/2020
Dimethyl phthalate 131-11-3 ug/L 2000 N - 10 0 10 ND ND 2/5/2019 10/23/2020
Di-n-butyl phthalate 84-74-2 ug/L N i 10 4 6 3.5 2.5 10/23/2020 10/23/2020 _
2,4-dinitrotoluene 121-14-2 ug/L 10 0 10 ND ND 2/5/2019 10/23/2020
TR0795A Page 5 of 28 June 2021

table 2 Geosyntec Consultants of NC P.C.
Onsite Untreated Seep Data Summary for 2018 to 2020
Chemours Fayetteville Works,North Carolina
Minimum Greater Than No.Total No.Total of No.Total Non- Source Data Source Data
Parameter name(as used in data analysis) CAS Number Units Regulatory Maximum Minimum
Criteria(Y/N) Results Detects Detects beginning date end date
Critera
2,6-dinitrotoluene 606-20-2 ug/L 0.048 V. 10 0 10 ND ND 2/5/2019 10/23/2020
Di-n-octyl phthalate 117-84-0 ug/L NA No 10 0 10 ND ND 2/5/2019 10/23/2020 _
1,2-diphenylhydrazine 122-66-7 ug/L 0.03 No 10 0 10 ND ND 2/5/2019 10/23/2020 _
Fluoranthene 206-44-0 ug/L ') !I No 10 0 10 ND ND 2/5/2019 10/23/2020
Fluorene 86-73-7 ug/L i,, No 10 0 10 ND ND 2/5/2019 10/23/2020
8 ug/I. total
Hexachlorobenzene 118-74-1 ug/L Itlorinatod No 10 0 10 ND ND 2/5/2019 10/23/2020
benzene,
Hexachlorobutadiene 87-68-3 ug/L n I I No 10 0 10 ND ND 2/5/2019 10/23/2020 _
Hexachlorocyclopentadiene 77-47-4 ug/L )0", No 10 0 10 ND ND 2/5/2019 10/23/2020
Hexachloroethane 67-72-1 ug/L 0.1 No 10 0 10 ND ND 2/5/2019 10/23/2020
Indeno(1,2,3-cd)pyrene 193-39-5 ug/I. No • 10 0 10 ND ND 2/5/2019 10/23/2020
Isophorone 78-59-1 ug/L 34 No 10 0 10 ND ND 2/5/2019 10/23/2020
Napthalene 91-20-3 ug/L 12 No 10 0 10 ND ND 2/5/2019 10/23/2020
Nitrobenzene 98-95-3 ug/L 10 No 10 0 10 ND ND 2/5/2019 10/23/2020 _
N-nitrosodimethylamine 62-75-9 ug/L 17000 No ._ 10 0 10 ND ND 2/5/2019 10/23/2020
N-nitrosodi-n-propylamine 621-64-7 ug/L 0.005 N . 10 0 10 ND ND 2/5/2019 10/23/2020 _
N-nitrosodiphenylamine 86-30-6 ug/L 0.00069 No`''- 10 0 10 ND ND 2/5/2019 10/23/2020
Phenanthrene 85-01-8 ug/L 0-7 No 10 0 10 ND ND 2/5/2019 10/23/2020
Pyrene 129-00-0 ug/L 20 No 10 0 10 ND ND 2/5/2019 10/23/2020
1,2,4-trichlorobenzene 120-82-1 ug/L 61 No 10 0 10 ND ND 2/5/2019 10/23/2020
Organic Toxic Pollutants(GC/MS Fraction-Pesticides)
Aldrin 309-00-2 ug/L 0.00005 No I 0 I ND ND 10/23/2020 10/23/2020
a-BHC 319-84-6 ug/L 0.00036 No I 0 1 ND ND 10/23/2020 10/23/2020
13-BHC 319-85-7 ug/L 0.008 No 4 0 I ND ND 10/23/2020 10/23/2020 _
y-BHC 58-89-9 ug/L 0.01 No 4 0 1 ND ND 10/23/2020 10/23/2020
S-BHC 319-86-8 ug/L 40 No 4 0 I ND ND 10/23/2020 10/23/2020
Chlordane 57-74-9 ug/L 0.0008 No 4 0 I ND ND 10/23/2020 10/23/2020
9,4-DDT 50-29-3 ug/L 0.0002 No 4 0 I ND ND 10/23/2020 10/23/2020_
4,4-DDE 72-55-9 ug/L 0.000018 No 4 4 0 1 ND ND 10/23/2020 10/23/2020_
4,9-DDD 72-54-8 ug/L 0.00012 No 4 0 1 ND ND 10/23/2020 10/23/2020_
Dieldrin 60-57-1 ug/L 0.00005 No 4 0 I ND ND 10/23/2020 10/23/2020 _
a-endosulfan 959-98-8 ug/L 20 No I 0 I ND ND 10/23/2020 10/23/2020
p-endosulfan 33213-65-9 ug/L 0.05 No I 0 I ND ND 10/23/2020 10/23/2020
Endosulfan sulfate 1031-07-8 ug/L 0.05 No I 0 I ND ND 10/23/2020 10/23/2020
Endrin 72-20-8 ug/L 0.002 No I 0 I ND ND 10/23/2020 10/23/2020
Endrin aldehyde 7421-93-4 ug/L I No I 0 1 ND ND 10/23/2020 10/23/2020 _
Heptachlor 76-44-8 ug/L 0.00008 No I 0 I ND ND 10/23/2020 10/23/2020
Heptachlor epoxide 1024-57-3 ug/L 0.000032 No I 0 I ND ND 10/23/2020 10/23/2020
PCB-1242 53469-21-9 ug/L ,'`PC'-h, No 1 0 4 ND ND 10/23/2020 10/23/2020
PCB-1254 11097-69-1 ug/L l I up/1.-total No I 0 4 ND ND 10/23/2020 10/23/2020
PC'Os
11 u_,L-total
PCB-1221 11104-28-2 ug/L Na 1 0 1 ND ND 10/23/2020 10/23/2020
TR0795A Page 6 of 28 lune 21121

Table 2 Geosyntec Consultants of NC P.C.
Onsite Untreated Seep Data Summary for 2018 to 2020
Chemours Fayetteville Works,North Carolina
Minimum Greater Than No.Total No.Total of No.Total Non- Source Data Source Data
Parameter name(as used in data analysis) CAS Number Units Regulatory Maximum Minimum
Crites Criteria(Y/N) Results Detects Detects beginning date end date
PCB-1232 11141-16-5 ug/L No 4 0 4 ND ND 10/23/2020 10/23/2020
5 ..
PCB-1248 12672-29-6 ug/L rt l ug L total No 1 4 0 4 ND ND 10/23/2020 10/23/2020
PCBs
PCB-1260 11096-82-5 ug/L 11 ug/L-total Nt 4 0 4 ND ND 10/23/2020 10/23/2020
PCBs
PCB-1016 12674-11-2 ug/L ,11ug/L-total No 4 0 4 ND ND 10/23/2020 10/23/2020
Toxaphene 8001-35-2 ug/L 0.0002 No 4 0 4 ND ND 10/23/2020 10/23/2020
TABLE E.CERTAIN HAZARDOUS SUBSTANCES AND ASBESTOS(40 CFR 122.21(k)(5)(v))
TABLE E.2,3,7,8 TETRACHLORODIBENZO P DIOXIN(2,3,7,8 TCDD)(40 CFR 122.21(g)(7)(viii))
2,3,7,8 TCDD I I pg/L I 0.000005 L., is ,0,a,i i 0 4 ND ND 10/23/2020 I 10/23/2020
Notes
ND-Not Detected mg/L-milligrams per liter -NC 02B Standards
NR-Not Recorded ug/L-microgram per liter -EPA NRWQC
NA-No Applicable Standard pCi/L-picocuries per liter -In StreamTarget Values
pg/L-picogram per liter No Exceedance
NC 02B Standards are for total compounds
TR0795A Page 7 of 28 June 2021

Table 3 Geosyntec Consultants of NC P.C.
Flows used for the Water Quality Assessment
Chemours Fayetteville Works, North Carolina
Source' Flow (MGD)
EW-1 0.703
EW-3 0.449
PM-1 OS 0.091
PIW-5S 0.125
SEEP-A-WALL 0.155
SEEP-B-WALL 0.233
Total 1.756
Outfall 002 18.025
Notes
MGD - million gallons per day
i Flows for the groundwater and seeps represent
maximum daily estimates.
2 Outfall 002 is the average annual daily flow
estimate.
TR0795A Page 8 June 2021

Table 4 Geosyntec Consultants of NC P.C.
Results for Single Samples of Untreated Groundwater and Seeps from March 3, 2021
Chemours Fayetteville Works, North Carolina
SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter Units EW-1 EW-3 PIW-10S PIW-5S WALL WALL Load (lb/d) FWMCa
Table A. Conventional and Non-Conventional Parameters
Ammonia mg/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 < 0.73 < 0.05
Biochemical Oxygen Demand (BUD) -5 Day MG/L <1.5 <1.5 <1.5 <1.5 <1.5 <1.5 < 22 < 1.5
Chemical Oxygen Demand (COD) MG/L <25 <25 <25 <25 27 <25 < 369 < 25
Table B. Certain Conventional and Non-Conventional Parameters
Aluminum MG/L 0.035 0.41 1.2 0.96 14 _ 0.65 23 1.57
Barium MG/L 0.056 0.05 0.036 0.038 0.04 0.021 0.68 0.046
Magnesium MG/L 1.3 5.4 0.61 0.84 1.2 0.69 32 2.19
Molybdenum _ _ _ _ _ _ MG/L <0.00013 <0.00013 <0.00013 <0.00013 0.00043 <0.00013 < 0.0023 < 0.00016
Oil and Grease _ MG/L <1.5 <1.5 <1.6 <1.6 <1.5 <1.6 < 22 < 1.5
Tin MG/L <0.0006 <0.0006 <0.0006 <0.0006 <0.0006 <0.0006 < 0.009 < 0.0006
Titanium MG/L <0.006 <0.006 0.017 <0.006 0.55 0.012 < 0.810 < 0.055
total residual chlorine MG/L 0.21 0.14 <0.01 0.12 <0.01 0.19 < 2.3 < 0.16
Hazardous Parameter
2,3,7,8-TCDD PG/L <0.073 <0.093 <0.084 <0.12 <0.091 <0.037 < 1.16E-09 < 0.079
Metals
Antimony _ _ MG/L <0.00041 <0.00041 <0.00041 <0.00041 <0.00041 <0.00041 < 0.006 < 0.00041
Arsenic MG/L <0.00068 <0.00068 0.002 <0.00068 0.0013 <0.00068 < 0.012 < 0.00080
Chromium MG/L <0.00033 0.00035 0.0011 <0.00033 0.012 0.00047 < 0.021 < 0.0014
Nickel MG/L 0.0011 <0.0006 0.0025 0.0046 0.0047 0.0018 < 0.025 < 0.0017
Total Phenols MG/L <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 < 0.147 < 0.01
Zinc MG/L 0.017 0.09 <0.0062 0.009 0.021 <0.0062 < 0.491 < 0.033
Organic Toxic Pollutants (GC/MS Fraction-Acid Compounds)
2,4,6-Trichlorophenol UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
2,4-Dichlorophenol _ UG/L <0.1 <0.11 <1.1 <0.1 <0.1 <0.11 < 0.002 < 0.16
2,4-Dimethylphenol UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
2,4-Dinitrophenol _ UG/L <1 <1.1 <11 <1 <1 <1.1 < 0.023 < 1.6
2-Chlorophenol UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
TR0795A Page 9 of 28 June 2021

Table 4 Geosyntec Consultants of NC P.C.
Results for Single Samples of Untreated Groundwater and Seeps from March 3, 2021
Chemours Fayetteville Works, North Carolina
SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter Units EW-1 EW-3 PIW-10S PIW-5S WALL WALL Load (lb/d) FWMC"
2-Nitrophenol _ _ UG/L <0.31 <0.32 <3.4 _ <0.31 <0.31 _ <0.33 < 0.007 < 0.47
4,6-Dinitro-2-Methylphenol _ _ UG/L <1 <1.1 <11 <1 <1 _ <1.1 < 0.023 _ < 1.6
4-Chloro-3-Methylphenol UG/L <0.31 <0.32 <3.4 <0.31 <0.31 <0.33 < 0.007 < 0.47
Pentachlorophenol UG/L <0.82 <0.86 <9.1 <0.83 <0.83 <0.88 < 0.019 < 1.27
Phenol UG/L <0.41 <0.43 <4.6 <0.42 <0.41 <0.44 < 0.009 < 0.64
Organic Toxic Pollutants (GC/MS Fraction- Base/Neutral Compounds)
1,2,4-Trichlorobenzene UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
2,4-Dinitrotoluene UG/L <0.1 <0.11 <1.1 <0.1 <0.1 <0.11 < 0.002 < 0.16
2,6-Dinitrotoluene UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
2-Chloronaphthalene UG/L <0.61 <0.65 <6.8 <0.62 <0.62 <0.66 < 0.014 < 0.95
3,3'-Dichlorobenzidine UG/L <0.31 <0.32 <3.4 <0.31 <0.31 <0.33 < 0.007 < 0.47
4-Bromophenyl Phenyl Ether UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
4-Chlorophenyl Phenyl Ether UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
Acenaphthene UG/L <0.092 <0.097 <1 4 <0.093 <0.099 < 0.006 < 0.42 1
Acenaphthylene UG/L <0.082 <0.086 <0.91 <0.083 <0.083 <0.088 < 0.002 < 0.13
Anthracene UG/L <0.071 <0.075 <0.8 1.2 <0.073 <0.077 < 0.003 < 0.19
Benzo(A)Anthracene UG/L <0.2 <0.22 <2.3 1 <0.21 <0.22 < 0.005 < 0.37
Benzo(A)Pyrene UG/L <0.2 <0.22 <2.3 0.24 <0.21 <0.22 < 0.005 < 0.32
Benzo(B)Fluoranthene UG/L <0.2 <0.22 <2.3 0.36 <0.21 <0.22 < 0.005 < 0.33
Benzo(G,H,1)Perylene UG/L <0.1 <0.11 <1.1 <0.1 <0.1 <0.11 < 0.002 < 0.16
Benzo(K)Fluoranthene UG/L <0.1 <0.11 <1.1 0.2 <0.1 <0.11 < 0.002 < 0.16
Bis(2-Chloroethoxy)Methane UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
Bis(2-Chloroethyl)Ether UG/L <0.1 <0.11 <1.1 <0.1 <0.1 <0.11 < 0.002 < 0.16
Bis(2-Ethylhexyl)Phthalate UG/L <1 <1.1 <11 <1 <1 <1.1 < 0.023 < 1.56
Butyl Benzyl Phthalate UG/L <1 _ <1.1 <11 <1 <1 <1.1 < 0.023 < 1.56
Chrysene UG/L <0.2 <0.22 <2.3 0.84 <0.21 <0.22 < 0.005 < 0.36
Dibenz(A,H)Anthracene UG/L <0.1 <0.11 <1.1 <0.1 <0.1 <0.11 < 0.002 < 0.16
Diethyl Phthalate UG/L <0.31 <0.32 <3.4 <0.31 <0.31 <0.33 < 0.007 < 0.47
TR0795A Page 10 of 28 June 2021

Table 4 Geosyntec Consultants of NC P.C.
Results for Single Samples of Untreated Groundwater and Seeps from March 3, 2021
Chemours Fayetteville Works, North Carolina
SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter Units EW-1 EW-3 PIW-10S PIW-5S WALL WALL Load (lb/d) FWMCa
Dimethyl Phthalate _ _ _ UG/L <0.51 <0.54 <5.7 <0.52 <0.52 <0.55 < 0.012 < 0.79
Di-N-Butyl Phthalate _ _ UG/L <1 <1.1 <11 <1 <1 <1.1 < 0.023 < 1.56
Fluoranthene _ UG/L <0.2 <0.22 <2.3 6.4 <0.21 <0.22 < 0.011 < 0.76
Fluorene _ UG/L <0.2 <0.22 <2.3 5.4 <0.21 <0.22 < 0.010 < 0.69
Hexachlorobenzene UG/L <0.51 <0.54 <5.7 <0.52 <0.52 <0.55 < 0.012 < 0.79
Hexachlorobutadiene _ UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
Hexachlorocyclopentadiene _ UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
Hexachloroethane UG/L <0.1 <0.11 <1.1 <0.1 <0.1 <0.11 < 0.002 < 0.16
Indeno(1,2,3-CD)Pyrene UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
Isophorone UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
Naphthalene UG/L <0.1 <0.11 <1.1 7.4 <0.1 <0.11 < 0.010 < 0.68
N-Dioctyl Phthalate UG/L <0.51 <0.54 <5.7 <0.52 <0.52 <0.55 < 0.012 < 0.79
Nitrobenzene UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
N-Nitrosodi-N-Propylamine UG/L <0.2 <0.22 <2.3 <0.21 <0.21 <0.22 < 0.005 < 0.32
N-Nitrosodiphenylamine UG/L <0.1 <0.11 <1.1 <0.1 <0.1 <0.11 < 0.002 < 0.16
Phenanthrene UG/L <0.1 <0.11 <1.1 16 <0.1 <0.11 < 0.019 < 1.29
Pyrene UG/L <0.2 <0.22 <2.3 3.5 <0.21 <0.22 < 0.008 < 0.55
Organic Toxic Pollutants (GC/MS Fraction - Pesticides)
4,4'-DDD UG/L <0.0096 <0.0095 <0.01 <0.0095 <0.0093 <0.0093 < 0.0001 < 0.010
4,4'-DDE UG/L <0.021 <0.021 <0.023 <0.021 <0.021 <0.021 < 0.0003 < 0.021
4,4'-DDT UG/L <0.011 <0.011 <0.011 <0.011 <0.01 <0.01 < 0.0002 _ < 0.011
Aldrin UG/L <0.0053 <0.0053 <0.0056 <0.0053 <0.0051 ' <0.0052 < 0.0001 < 0.005
Alpha-BHC UG/L <0.013 <0.013 <0.014 <0.013 <0.012 <0.012 < 0.0002 < 0.013
beta-BHC UG/L <0.049 <0.049 <0.052 <0.048 <0.047 <0.048 < 0.001 < 0.049
Chlordane UG/L <0.25 <0.25 <0.26 <0.24 <0.24 <0.24 < 0.004 < 0.248
delta-BHC UG/L <0.012 <0.012 <0.012 <0.012 <0.011 <0.011 < 0.0002 < 0.012
Dieldrin UG/L <0.0085 <0.0085 <0.009 <0.0084 <0.0082 <0.0083 < 0.0001 < 0.008
Endosulfan I UG/L <0.0032 <0.0032 <0.0034 <0.0032 0.037 <0.0031 < 0.0001 < 0.006
TR0795A Page 11 of 28 June 2021

Table 4 Geosyntec Consultants of NC P.C.
Results for Single Samples of Untreated Groundwater and Seeps from March 3, 2021
Chemours Fayetteville Works, North Carolina
SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter Units EW-1 EW-3 PIW-10S PIW-5S WALL WALL Load (lb/d) FWMC
Endosulfan II UG/L <0.01 <0.01 <0.011 <0.01 <0.01 <0.01 < 0.0001 < 0.010
Endosulfan Sulfate UG/L <0.011 <0.011 <0.011 <0.011 <0.01 <0.01 < 0.0002 < 0.011
Endrin UG/L <0.0096 <0.0095 <0.01 <0.0095 <0.0093 <0.0093 < 0.0001 < 0.010
Endrin Aldehyde UG/L <0.0097 <0.0096 <0.01 <0.0096 <0.0094 <0.0094 < 0.0001 < 0.010
Heptachlor UG/L <0.0085 <0.0085 <0.009 <0.0084 <0.0082 <0.0083 < 0.0001 < 0.008
Heptachlor Epoxide UG/L <0.0053 <0.0053 <0.0056 0.0094 0.018 <0.0052 < 0.0001 < 0.007
PCB 1016 UG/L <0.079 <0.078 <0.083 <0.078 <0.076 <0.077 < 0.001 < 0.078
PCB 1221 UG/L <0.079 <0.078 <0.083 <0.078 <0.076 <0.077 < 0.001 < 0.078
PCB 1232 UG/L <0.079 <0.078 <0.083 <0.078 <0.076 <0.077 < 0.001 < 0.078
PCB 1242 UG/L <0.079 <0.078 <0.083 <0.078 <0.076 <0.077 < 0.001 < 0.078
PCB 1248 UG/L <0.079 <0.078 <0.083 <0.078 <0.076 <0.077 < 0.001 < 0.078
PCB 1254 UG/L <0.079 <0.078 <0.083 <0.078 <0.076 <0.077 < 0.001 _ < 0.078
PCB 1260 _ UG/L <0.079 <0.078 <0.083 <0.078 <0.076 <0.077 < 0.001 < 0.078
Toxaphene UC/L <0.38 <0.38 <0.4 <0.37 <0.37 <0.37 < 0.006 < 0.38
Other Parameters
Alpha Chlordane UG/L <0.0064 <0.0064 <0.0068 <0.0063 0.036 <0.0062 < 0.000 _ < 0.01
Bis(2-Chloro-l-Methylethyl) Ether UG/L <0.31 <0.32 <3.4 <0.31 <0.31 <0.33 < 0.007 < 0.47
Calcium MG/L 2.7 9.3 0.46 2 6.4 0.86 63 4.3
Lindane UG/L <0.0055 <0.0055 <0.0059 <0.0055 <0.0053 <0.0054 < 0.000 < 0.01
Total Kjeldahl Nitrogen MG/L <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 < 7 < 0.5
Notes
FWMC - flow-weighted mean concentration
lb/d - pounds per day
TR0795A Page 12 of 28 June 2021

Table 5 Geosyntec Consultants of NC P.C.
Results for Multiple Samples of Untreated Groundwater and Seeps from March/April 2021
Chemours Fayetteville Works,North Carolina
Date in SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter 2021 Units EW-1 EW-3 PIW-10S PIW-5S WALL WALL Load(lb/d) FWMC
Table A.Conventional and Non-Conventional Parameters
Ph 3-Mar SU 6.8 6.5 6.3 6.5 6.8 6.5
28-Apr SU 7 7 7 7 7 _ 7
Total Organic Carbon 3-Mar mg/L <0.5 <0.5 0.78 0.96 4.3 4.5 < 20.71 < 1.41
8-Mar mg/L <0.5 <0.5 0.73 0.88 3 3.2 < 16.38 < 1.12
10-Mar mg/L <0.5 _ 0.5 0.91 1.1 3.4 3.7 < 18.23 < 1.24
12-Mar mg/L <0.5 <0.5 <0.5 <0.5 1.6 _ 2.6 < 12.83 < 0.9
15-Mar mg/L <0.5 <0.5 <0.5 0.52 0.58 2.7 < 11.73 < 0.80
17-Mar mg/L <0.5 <0.5 0.68 0.91 4.3 4.2 < 20.00 < 1.36
19-Mar mg/L - <0.5 <0.5 0.67 0.87 3.6 4.5 < 19.63 < 1.34
22-Mar mg/L <0.5 <0.5 0.9 1 2 4.1 < 17.09 < 1.2
24-Mar mg/L <0.5 _ 0.93 0.9 1.1 4.2 5.3 < 23.99 < 1.6
26-Mar mg/L <0.5 <0.5 <0.5 0.59 0.96 3.8 < 14.44 < 0.99
28-Apr mg/L <0.5 0.76 1 1.1 1.4 5.5 < 20.20 < 1.4
3-Mar mg/L 7.5 3.3 6 2 89 23 222.60 15.2
28-Apr mg/L , 5.9 20 3.9 2.9 4.7 11 143.07 _ 9.8
Total Organic Carbon 43.15 2.94
Table B.Certain Conventional and Non-Conventional Parameters
Boron 3-,Mar mg/L 0.012 <0.012 <0.012 <0.012 0.014 <0.012 < 0.18 < 0.012
28-Apr mg/L <0.012 <0.012 <0.012 . <0.012 <0.012 , <0.012 < 0.18 < 0.012
Boron 0.18 0.012
Bromide 3-Mar mg/L <1.3 <1.3 <1.3 <1.3 <1.3 <1.3
8-Mar mg/L <1.3 <1.3 <1.3 <1.3 <1.3 <1.3
10-Mar mg/L <1.3 <1.3 <1.3 <1.3 _ <1.3 <1.3
12-Mar mg/L <1.3 <1.3 <1.3 <1.3 <1.3 _ <1.3
15-Mar mg/L <1.3 <1.3 _ <1.3 <1.3 <1.3 <1.3
17-Mar mg/L <1.3 <1.3 <1.3 <1.3 <1.3 <1.3
19-Mar mg/L <1.3 <1.3 <1.3 <1.3 <1.3 <1.3
22-Mar mg/L <1.3 <1.3 <1.3 <1.3 <1.3 <1.3
24-Mar mg/L <1.3 <1.3 <1.3 <1.3 _ <1.3 <1.3
26-Mar mg/L <1.3 <1.3 _ <1.3 <1.3 <1.3 <1.3
28-Apr mg/L <1.3 <1.3 <1.3 <1.3 <1.3 <1.3
Cobalt 3-Mar mg/L <0.00016 <0.00016 0.0027 0.0037 0.0016 0.0017 < 0.01 < 0.00088
8-Mar mg/L <0.00016 <0.00016 0.0027 0.0035 0.0007 0.0018 < 0.01 < 0.00079
10-Mar mg/L <0.00016 <0.00016 0.003 0.0038 0.00073 0.0018 < 0.01 < 0.00083
12-Mar mg/L <0.00016 <0.00016 0.0027 0.0034 0.001 0.0018 < 0.01 < 0.00081
15-Mar mg/L <0.00016 <0.00016_ 0.0029 0.0038 _ 0.0029 0.0019 < 0.02 < 0.00103
17-Mar mg/L <0.00016 <0.00016 0.0026 0.0035 0.001 0.0017 < 0.01 < 0.00080
19-Mar mg/L <0.00016 <0.00016 0.0027 0.0035 0.001 0.0018 < 0.01 < 0.00082
22-Mar mg/L <0.00016 <0.00016 0.0026 0.0034 0.0025 0.0017 < 0.01 < 0.00093
24-Mar mg/L <0.00016 0.0002 _ 0.0027 0.0045 0.00074 0.0018 < 0.01 < 0.00088
26-Mar mg/L <0.00016 <0.00016 0.0027 0.0035 0.0027 0.002 < 0.01 < 0.00100
28-Apr mg/L <0.00016 0.00017 0.0028 0.0031 0.002 0.002 < 0.01 < 0.00092
Cobalt 0.01 0.00088
COLOR TRUE 3-Mar PCU <5 <5 30 <5 60 35
28-Apr PCU <5 <5 <5 <5 <5 30
Fluoride 3-Mar mg/L <0.25 0.32 <0.25 <0.25 0.41 <0.25 < 4.13 < 0.28
28-Apr mg/L <0.25 <0.25 <0.25 <0.25 <0.25 <0.25 < 3.66 , < 0.25
Fluoride 3.90 0.27
Iron 3-Mar mg/L 2.1 10 2.6 0.31 5.2 0.71 60.21 4.1
8-Mar mg/L 1.6 10 0.45 0.18 0.96 0.57 49.77 3.40
10-Mar mg/L 1.6 9.9 0.16 0.098 0.69 0.63 48.85 3.33
12-Mar mg/L 1.6 11 0.15 0.18 0.69 0.63 53.06 3.62
15-Mar mg/L 1.7 12 0.061 1 0.45 0.73 58.07 3.96
TR0795A Page 13 of 28 June 2021

m 4 G - s z 4 0
COV c,� ;..b .., O Gi W
yDa
❑ O
Y c y co o w •p
3 2
g w
z 'w
o•
tD
eo
0
CV IV IV CD V Cn N O O c'`) C7) .P N CD V Cn N O C� C'`) N N N. N O W N W N W N N N N 00 W N N N N .... d r
y y zz C,4 00 C7) «yP yN CD V CA N O `� , ca 00 00 O .A. N CD V C.n Ny COO , z 00 a) .A• Ny CO V N
y rmp��. d py� y444444444y py� py� ,� «1 rpp.�� .yyA p� p�� y„0 al
.d y^ .b p�� p�� p�� rm� m� rp�.� r� pj y ry1. w rye m� O r'
•f •f n •t •f •f •f n �i •f •f �i �i Pi' n n �t n �n �-f `-f �-f �i �-f �-f �i ~ `t n N n �-f �-f
o
4
3 3 3 3o 3 3 3 3 3o 3 3a 3 3o 3 3� 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 33c 3 3a 3a 3 3 30 3c 3 3 3 3a 3a 3 3a 3 30
fir rtarar' rrat- rarra rrrrrrr� r' rrrrar rr r' t- r' r' rrr� r� r� r� t� tar� r� r� r� r' y a.
H
0 Co 0 0 0 0 Co A A A A o o o 0 0 0 0 0 C. C. o Cif n
0 0 0 o c o Co A A A n n n A n n nC A'o
0 Co 0 0 0 0 0 O O O O O O O O O O co O O co C C_ b _O CD C CD O_ O_ b b r i r N N G B A
O co co co co O O V to V. O) .P .P Q) Cn Gn C7) .P cn 0 0 O Co �` N N Ni Ni .+ Ni C) CO C7) p H
C) Cr) W W W W Q) al C.n V. V. CD CD C. CD 00 V. r CO CD CD D) ►-
V C75 W V. V. .. 00 ' G
1
O O o 0 0 o w '*
O C7 b O O b O AAAAAAAAAA ,p coC.n V O O Cr) O) O) O Cr)C) C) 0) C) C) C) © O O Co O coO O O O O O O O O a) .... v) .- .- A A
Co O co O co co co O O O O O O O O O O • .. w
"U CO CO CD 00 V V �' .--. .P O .P 'P CO CD ►+ CA V) 0 0 O Ni Ni N Ni CV rC-. CD .r
C•- (Si Ni W CO CS) V Cn C.n 0 W CD Cn Ni CD CD CD CD r .P Ni O eli a
C. 0 0 0 0 0 0 A co
° o 0 o c o 0 o A A A A A A A A n n A A Co Co O o 0 o 0 Co 0 0 0 0 0 Ni0 co a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 cri
O O •" CO Cp "" CO CD •" O O CO CO 0 •0 C'D C C O CD O O O Co C C C�7 O O C O C�.7 < •'1 4.
00 co O co O O co co C.n C7) •" C) '-" CD co .-' v C7) O O CO CD W
.A. Ni Ni .Ca Ni Ni Ni V Cn Cn .-• V N .. .- .- N — W N .- .- CV N N V W Cr) N 0
CA z mat
N
0 Co 0 0 0 0 0 �
O O © O O O O n n n n n n n n AA A A O O 0 0 0 0 0 0 0 0 0 0 0 O .„ 0 O ,by w
O O O O co O O O O O O O O O O Ni Ni Ni N N Ni Ni Ni Ni Ni Ni O co O_ O O C_ C O C O C C "' O co C� a
0 0 0 0 0 © 0 V O O (Si W O W .P W .A. .P W O O .--
coO . — N Ni N N Ni Ni Ni N N CD .A. N w
CA
S . W .P .A. Cw) W as Cn Cn 00 00 V cD .- .- .-. .A. r W r C.n
C.n O) CO y 0 A
2 �„
O O O O O 0 0 g V) w ,4
b o r n © © © A A A A A A A A A _ _ _ _ co no _ _ A n :* n © 0 o O o o O O o 0 0 0 co o _ o ,rtil e
coco O co O O O co O N 0 0 0 0 0 0 0 0 coiv OD ►- V coCp O N N .- co O O O C © O O CD CD O CD O C CD
N O O N .+ .+ W '"' •' 00 O O O V W N N N .A. N N N O) V N O W .- C'' r , 9
Ni N T .P Cn .P V Cn Cn • .A V .+ CD V 00 Cn C.n O 00 1..,
w
0 0 0 0 0 0 o z Cl)
C O O C C'D n n n n n n n n n /� C/1 n n O O 0 0 0 0 0 0 0 0 0 0 0 ,... 0 0 0 0 0 C�
O O OD OD CD Do V CO Do CD CO Co ScO O C7 .-y 6© O O O O C C O O O O y C>y 'U
00 0 oO o 0000000oOc C� � � � � y
O O O CO O O O �, W O) .P .A ... 00 CO �) O .� O O O o) ,,, ,� w . a
w v Ca N w W is.) y to cn Q w eq CO ao Cr) V CD O V V V 00 00 W V T P P
.- .� O R p ©
C" 'N" co
A A A A A
000000o wwcaw .A. ww .A. .4. www .+ .- .- 000 .-- ., 0 .- .- Oo .- cnwv, v. 0) 0)
O inC O O co b 00 .+ V a) V CD CVCD CO CD in b.) .A O CD CD CD i-- O CO O O CD CD O W CD .A. C7) W O W G
.4. .4. Ca Ca Ca Ca W C) Ca00 O .P C7) O) N CVO Ca .-. O) C O Cn O -400 .A. CT) cD Cn .A. O faN N CJI W C7) 00 CD 00_ m
0.) O Cn 00 .P Ni .A Ni W Cr) ivLc) V Ni in .P O �A. Ni V. 4.. V .P Ni W 0077
C.n 00 .D. 00 Cn CD Ca 00 00 O .-. 00 C
C
. C
n A A A A CT17
O O O O O O O Ni Ni Ni Ni Ni Ni Ni Ni Ni Ni Ni Ni O O co O O O O O O O O O O O O W Ni W W .P .P W -.
0 0 0 0 0 Co 0 O •- C.n C.n 00 rn 00 Oo O O O) ).. �, 0 0 Co 0 0 0 0 Co 0 0 0 0 o a) a) v W Cr) o,
O O O O O O O .A 4, OO W .+ 00 N a) 00 -) CO CD C7) C7) O) O V V O) V C7) co co V C.n V ,.- OD O O V
CD V .P C7) W Ni W C) 4, CD 00 Cr) --.I .4. CO Cn C.n .+ OD Ca Ca O C� A C7
O 4 '0
N- - C)

Table 5 Geosyntec Consultants of NC P.C.
Results for Multiple Samples of Untreated Groundwater and Seeps from March/April 2021
Chemours Fayetteville Works,North Carolina
Date in SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter 2021 Units EW-1 EW-3 P1W-10S PIW-5S WALL WALL Load(Ib/d) FWMC
22-Mar mg/L 0.00032 0.011 0.0002 0.00037 0.00051 0.00032 0.045 0.0031
24-Mar mg/L 0.00055 0.0075 0.00021 0.00044 0.00016 0.00027 0.033 0.0022
26-Mar mg/L 0.00033 0.0091 0.00024 0.00036 0.00063 0.0003 0.038 0.0026
28-Apr mg/L 0.0003 0.0081 0.00024 0.00036 0.0005 0.00037 < 0.034 < 0.0023
Beryllium 0.037 0.0025
Cadmium 3-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 _
8-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015
10-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015
12-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015
15-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 _
17-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015
19-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 _
22-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015
24-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015
26-Mar mg/L <0.00015 <0.00015 <0.00015 <0.00015 <0.00015 <0.00015
28-Apr mg/L <0.00015 <0.00016 <0.00015 <0.00015 <0.00015 <0.00015
Copper 3-Mar mg/L 0.00036 <0.00036 0.00045 <0.00036 0.0043 0.00047 < 0.011 _ < 0.00073
8-Mar mg/L <0.00036 <0.00036 <0.00036 <0.00036 0.0012 0.00037 < 0.006 < 0.00044
10-Mar mg/L <0.00036 <0.00036 <0.00036 <0.00036 0.00097 0.00047 < 0.006 < 0.00043
12-Mar mg/L 0.00044 <0.00036 0.0004 <0.00036 0.0011 0.00049 < 0.007 < 0.00048
15-Mar mg/L <0.00036 <0.00036 <0.00036 0.00051 0.00051 0.00042 < 0.006 < 0.00039
17-Mar mg/L <0.00036 <0.00036 <0.00036 0.00081 0.0015 <0.00036 < 0.007 < 0.00049
19-Mar mg/L 0.0012 <0.00036 <0.00036 <0.00036 0.0014 <0.00036 < 0.012 < 0.00079
22-Mar mg/L <0.00036 <0.00036 <0.00036 <0.00036_<0.00036 <0.00036 < 0.005 < 0.00036
24-Mar mg/L 0.0004 <0.00036 <0.00036 0.0027 0.0021 0.00043 < 0.010 < 0.00071
26-Mar mg/L <0.00036 <0.00036 <0.00036 <0.00036 0.00055 0.00054 < 0.006 < 0.00040
28-Apr mg/L 0.003 0.00066 <0.00036 <0.00036 0.0004 0.00039 < 0.022 < 0.0015
Copper 0.009 0.00061
Cyanide 3-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 < 0.073 < 0.0050
8-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 _ <0.005 < 0.073 < 0.0050
10-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 < 0.073 < 0.0050
12-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 < 0.073 < 0.0050
15-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 < 0.073 < 0.0050
17-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 < 0.073 < 0.0050
19-Mar mg/L <0.005 <0.005 <0.005 <0.005 0.0078 <0.005 < 0.077 < 0.0052
22-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 , <0.005 < 0.073 < 0.0050
24-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 < 0.073 < 0.0050
26-Mar mg/L <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 < 0.073 < 0.0050
Cyanide 0.074 0.005
Lead 3-Mar mg/L 1<0.000071 0.00015 0.0012 0.00025 0.0055 10.00047 < 0.010 < 0.0007
8-Mar mg/L '<0.000071 <0.000071 0.00093 0.00025 0.0012 0.00031 < 0.004 < 0.00026
10-Mar mg/L <0.000071 <0.000071 0.00098 0.0003 0.001 0.0004 < 0.004 < 0.00026
12-Mar mg/L <0.000071 <0.000071 0.00095 0.00027 0.001 0.0004 < 0.004 < 0.00026
15-Mar mg/L <0.000071 <0.000071 0.001 0.00049 0.00097 0.00044 < 0.004 < 0.00028
17-Mar mg/L 0.000077 <0.000071 0.001 0.00053 0.0022 0.00056 < 0.006 < 0.00041
19-Mar mg/L _ 0.00013 <0.000071 0.001 0.00034 0.0016 _ 0.00055 < 0.005 < 0.00036
22-Mar mg/L <0.000071 <0.000071 0.00095 0.00028 0.0016 0.00038 < 0.004 < 0.00031
24-Mar mg/L _<0.000071 <0.000071 0.00097 0.0029 0.0028 0.00054 < 0.009 < 0.00062
26-Mar mg/L <0.000071 <0.000071 0.00097 0.00033 0.0016 0.00055 < 0.005 < 0.00033
28-Apr mg/L 0.000088 0.00032 0.0011 0.00037 0.00096 0.00053 < 0.005 < 0.00036
Lead 0.006 0.00038
Mercury 3-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 0.000088 0.000086 < 0.001 < 0.00008
8-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
10-Mar mg/L <0.000079 0.000081 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
TR0795A Page 15 of 28 June 2021

Table 5 Geosyntec Consultants of NC P.C.
Results for Multiple Samples of Untreated Groundwater and Seeps from March/April 2021
Chemours Fayetteville Works,North Carolina
Date in SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter 2021 Units EW-1 EW-3 PIW-10S PIW-5S WALL WALL Load(lb/d) FWMC
12-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
15-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
17-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
19-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079_<0.000079 < 0.001 < 0.00008
22-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
24-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
26-Mar mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
28-Apr mg/L <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 <0.000079 < 0.001 < 0.00008
Mercury 0.001 0.00008
Selenium 3-Mar mg/L <0.00028_<0.00028 <0.00028 <0.00028 0.00039 <0.00028
8-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
10-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
12-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
15-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
17-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
19-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
22-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
24-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
26-Mar mg/L <0.00028 <0.00028 <0.00028 <0.00028 <0.00028 <0.00028
28-Apr mg/L <0.00028 <0.00029 <0.00028 <0.00028 <0.00028 <0.00028
Silver 3-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
8-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
10-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
12-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
15-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
17-Mar mg/L <0.00017 <0.00017_ <0.00017 <0.00017 <0.00017 <0.00017
19-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
22-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
24-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
26-Mar mg/L <0.00017 <0.00017 <0.00017 <0.00017 <0.00017 <0.00017
28-Apr mg/L <0.00017 <0.00018 <0.00017 <0.00017 <0.00017 <0.00017
Thallium 3-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013
8-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013
10-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013
12-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013
15-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013
17-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 _
19-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 _ -
22-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013
24-Mar mg/L <0.00013 <0.00013 <0.00013_<0.00013 <0.00013 <0.00013 _
26-Mar mg/L <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 <0.00013 _
28-Apr mg/L <0.00013 <0.00013 <0.00013 , <0.00013 <0.00013 <0.00013
Organic Toxic Pollutants(GC/MS Fraction-Base/Neutral Compounds)
1,2-Dichlorobenzene 3-Mar ug/L <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 L
8-Mar ug/L <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 _ _
10-Mar ug/L <0.07 <0.07 <0.07 <0.07 <0.07 <0.07
12-Mar _ ug/L <0.07 <0.07 <0.07 <0.07 <0.07 <0.07
15-Mar ug/L <0.07 _ <0.07 <0.07 <0.07 <0.07 <0.07
17-Mar _ ug/L <0.07 <0.07 <0.07 <0.07 <0.07 <0.07
19-Mar ug/L <0.07 <0.07 <0.07 <0.07 <0.07 <0.07
22-Mar ug/L <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 _
24-Mar ug/L I <0.07 <0.07 <0.07 I <0.07 <0.07 <0.07
26-Mar ug/L <0.07 <0.07 <0.07 <0.07 <0.07 <0.07
TR0795A Page 16 of 28 June 2021

Table 5 Geosyntec Consultants of NC P.C.
Results for Multiple Samples of Untreated Groundwater and Seeps from March/April 2021
Chemours Fayetteville Works,North Carolina
Date in I SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter 2021 Units EW-1 EW-3 P1W-10S PIW-5S WALL WALL Load(Ib/d) FWMC
1,3-Dichlorobenzene 3-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
8-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
10-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
12-Mar ug/L <0.06 <0.06 <0.06 <0.06 _ <0.06 <0.06
15-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
17-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
19-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
22-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
24-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
26-Mar ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06
1,4-Dichlorobenzene 3-Mar ug/L <0.1 <0.1 _ <0.1 <0.1 <0.1 <0.1
8-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
10-Mar ug/L _ <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
12-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
15-Mar ug/L _ <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 _
17-Mar ug/L _ <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
19-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
22-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
24-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
26-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
Organic Toxic Pollutants(GC/MS Fraction-Volatile Compounds)
1,1,1-Trichloroethane 3-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
8-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
10-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
12-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
15-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
17-Mar ug/L <0.1 _ <0.1 <0.1 <0.1 <0.1 <0.1
19-Mar ug/L <0.1 <0.1 _ <0.1 <0.1 <0.1 <0.1
22-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
24-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
26-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
1,1,2,2-Tetrachloroethane 3-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
8-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
10-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
12-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
15-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
17-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
19-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
22-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
24-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
26-Mar ug/L <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
1,1,2-Trichloroethane 3-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
8-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
10-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
12-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
15-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
17-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
19-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
22-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
24-Mar ug/L <0.2 _ <0.2 <0.2 <0.2 <0.2 <0.2
26-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
1,1-Dichloroethane 3-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
8-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
10-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
TR0795A Page 17 of 28 June 2021

-
iU D D N - - N --, .j
- ^O
C7 C7 6 °c
cn
D ° S T o
r.
q. F o F as
b co
C m
N 0, co CD
CD
IV NDIVND IV IV IV ND IV CV ND IVCVIV NDCJ y
CO p73 cn N pO�� O �, per) t. N 9 77 c.n yN O O w yO) ab. N cm V Cyyn `v co O c.4 Oy) .yP N CO -) (DI yN yO O C4 Qy) .P Na CO y�l Gpir7 t co O �''� C) .P yN CO �y7 ()I N O y G
o
C G C G G G G G C C G" C G G C G G C G C C G C C G C C C C C C C C G C C C G G G C C C C C C C C C C C G G G
Pr�- r� r� r� t�- t�- c� t- r' r� r� r� r� r� r� r� r� r� r� r� r� r��rr� r� r� r��r r� r� r�- r� r� r� r� r� r� r� r� c� r� r� r� H
A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A ir
O O O O O O O A A A A A A A A A A O O O o 0 0 0 0 0 o O o 0 0 CO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 H
NI CV IV IV CV CV ND ND IV IV N ND ND IV IV N N W W W 42 W Ca Ca co 42 42 iv iv iv N iv iv iv iv iv iv — rc
A A A A A A A AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA A A
O O o O O O O A A A A A A A A A A O O O O O O O O O O O O O O o 0 o O O O O O O O O O o O O O O O O O O O O �i = .w..
N ND ND IV CV ND ND CV ND IV ND IV IV ND ND NJ N N 42 42 to42 co coco 42 co 42 N N iv iv iv iv iv iv iv is.) CN G
A A
ao S.
A
eT
o
A A A A A A A AA A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A 0 e
r.: 0 0 0 0 0 0 0 A A A A A A A A A A 0 0 0 0 0 0 0 o O o 0 0 0 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 "'
cc N N N CV IV ND ND N N N iv N iv iv iv iv iv W W W Cwl 42 W co co W W iv iv iv iv iv iv iv iv iv ivG 6.
y z
o -,
b 4, 5
A A A A A A A AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
O O O O O O O A A A A A A A A A A O O o O O O O O 0 0 0 O O O O O O O O o O O o 0 0 0 0 0 0 o O O O O O O O (10..
NDIVIVNDIVIVND N N N N N N N N N N co 4.2 co co co W co co W W co N Na N N N N N N N . . . . . . . 6n M A
co
y O CD
y
°S'
A A A A A A A AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAtri 0
0 0 0 0 0 0 o A A A A A A A A A A O o 0 0 C. 0 0 0 0 0 p 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o O O p p p p p p 0 Y „,ti E
ND ND ND NJ IV IV IV ND IV IV IV N IV IV N IV IV CA W W W Id.) IA) W Cw7 W Cw) IV N IV IV IV N N IV N IVr y
w
c
n
A A A A A A A AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA CC G Y
A A A A A A A A A A
0 O O O O O O 'O
N ND CV ND ND ND ND IV IV ND IV IV IV N IV IV IV 42 W W W 42 W W La CN W iv iv iv iv iv iv iv iv iv ivr ^�I
N
N CD
r ~
a
a.
a & 0
0
V1
� y
CC
C 0
4d z
neD ci
N. 0. ro
N, - - n

r
V N
o.' 'C N
z G
w 7
O F
O W k'
0
U 4
I
y rs
Q0 — w a
©
N
' a N N N un un 47 un un un un un to un N N N „ N N N N N N
O O O O O O O O O O
O. W O O O O O O Ov O O O O O Ov Ov Ov Ov Ov O O O O O O O O O O Ov Ov Ov Ov Ov O O O O O O Ov Ov O O O O O O O O O O O O CDQ W 3
v
v
x V
H
Q a N N14") it) IllLC) Le) LI" N N N N N N N N N N•
E r. CD CD o 0 0 0 0 0 0 0 0 0 CD CD o 0 0 0 0 0 0 0 0 0 0 o c o 0 0 0 0 0 0 0 0 0 0 0 o CD CD 0 o c c o 0 o CD CD 0
to A r.4 Q aD 3 v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v
o CU 1
t;UP) O u? N N N O 2 O O O O O O O O N N N N N N N N N N
.: U 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 v
a v v v v v v v v v v
a
t!f to to to to to tf) IC) It) u)
: rl N " N O O O O O O O O O O N N N N N N N N N N
i. O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O co O O O O O O O O O O O O O O O O O O O O O N
O 7 O ' V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V 0
� � a
F M N N N °op
)
• •y tf) tf) Le' tf) If) tf) t000Le' N N N N N N N N N N M
t t l
O O w
7,1 01 300000O00O0O cc:00O0 O O00cc::: 000000000000000000000000000000000000000V
� W v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v v
w 6
O 0 - N N N O O O O O O O O O O
N N N N N N N N N N
A E 3 O O O OCOOOOCOOOO C O O C = G C 7 = O O 7 G C O C O C C O C7 C C C 7 O 7 O 7 7 O O C CD D C7 CD C CS
EW V V V V V V V V V v V V v V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V
, U
CA
o
O.
7
a 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 0 7 7
4.O .C.J' ., `t tt `td 't 't `t tt tt t t t tt tt `td tt t tt t tt `ta `td `t `t� t `t t t t t tt t t t t t t `t t tt t`a t tee t tt `t tt� tt tt tt t t t`d `td
0
M N N C CD Ch 00 O Cam) O l� tT N ' CD Ch Cb O N t1' t� O N ' CD M 00 O N LP) IS:. N �' tD M 00 O N lA N tT N d' CD
N N N N N N N N N N N N N N CO.
N N N
a
I
0
to
0)as E
•0
6, 0 c
= N N
0.)
C 77 w 0 0 C .0 to
O co
0 E O O 0 O
C.) CO W GO _ _ U U

50 5 0 0 S. E
C �e S. o 'c
n a c o 3 ro
fD M
0 0 o @: Er
m �o
o M �d
A CD C "wS
0 w
m
5 ::
"s
P7
N N N N N N N N N N N N N N N
N O �z W D) .4. N �C CD Vy cn N yO 'CO W'' cn oil. N CO V U9 N Oy 90 w Oy .P N co V CCD N yO W Oy Se. yN CCD V cm DJ yO z° WW " " N CO Vy Gyyn �Nyy- O `� W'�"' N e
kk4kk
kkkkk
N N - N N N N N N N N N N N N N N n N N N N N N N N N n N N N N N N N N N N N N N N N N N N N N N N N N N Imo+ 'J C
b4
C C C C C C C C C C C C G G C C G G G C G G G G C C C C C C C C C C C C G G G G C C C C C C G C G G G C G C G"
eti
cn
c.
n n n n n n n n cnn n cmn cnn cnn n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n 5 co b
O 0 0 O O O O O O O O O O O O O O 0 O 0 O O 0 O 0 O 0 0 O O O O C O O O O O O O O O O O O O O O O O O O O O A
wwwwo0666666664wWwwwww4) - a ;
n n n n o 0 0 0 0 o n0 n0 n0 o n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 '+ w
.ti is w C ( o 0 0 0 0 0 0 o c o c cn C.J W CC7 W W CJ W W CJ C. w e
cn v, c n c n cn cn cn c n
ago 5 n V
0
° A n n n o 0 0 0 0 0 0 0 0 o n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n 0 = cn
N 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 "'!
a.
0o W W W W C C O C O O C C O O W co co W CO W W Lal W LO r er $
CT CJ7 CT CT CJ7 C.Tf U7 U7 „ Cll
z
G ti
n n n n AA n n A n n n A A n AAA n A n A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A W
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0"
W is W w c o c c c c o c c c w w is is w is to is i.a w w Cl
cn u, cr, cr, ca, cn cn cn cn v,
P H
n n n n n n n n n n w 'o
n n n n o 0 0 0 0 0 0 0 0 0 n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n n 8
0 0 0 0 © 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o O PPP 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o a b
C4 GO GO CW to cal cn to v, to cn cn C„ C„ W W W W W W W Cw7 W W y
aw
y n
o00000000000000000000000000000000000000000005D000000000a � z
w www � � � cm � � � � �o„ � wiawiaw CO Ww W is — t.l
til
O
N n
F+ m
O H
n
w
as c
0
N
C
fti y
N
gDt 0
^
0 W
NJ Ena
CD
tv
i--. n

Table 5 Geosyntec Consultants of NC P.C.
Results for Multiple Samples of Untreated Groundwater and Seeps from March/April 2021
Chemours Fayetteville Works,North Carolina
Date in SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter 2021 Units EW-1 EW-3 PIW-10S PIW-5S WALL WALL Load(lb/d) FWMC
15-Mar ug/L <0.3 <0.3 <0.3 <0.3 <0.3 <0.3
17-Mar ug/L <0.3 <0.3 <0.3 <0.3 <0.3 <0.3
19-Mar ug/L <0.3 <0.3 <0.3 <0.3 <0.3 <0.3
22-Mar ug/L <0.3 <0.3 <0.3 <0.3 <0.3 <0.3
24-Mar ug/L <0.3 <0.3 <0.3 <0.3 <0.3 <0.3
26-Mar ug/L <0.3 <0.3 <0.3 <0.3 <0.3 <0.3
Radioactivity
Radium(total) 3-Mar pCi/L <0.308 <0.315 2.84 5.69 <1.9 ' <0.48 < 0.0139 ' < 0.95
8-Mar pCi/L <0.531 <0.606 2.77 4.46 <0.867 <0.32 < 0.0219 < 1.50
10-Mar pCi/L <1.15 2.36 3.1 3.21 <0 <0.314 < 0.0183 < 1.25
12-Mar pCi/L <0.885 <0.598 3.86 4.76 <0.688 <1.05 < 0.0260 < 1.77
15-Mar pCl/L <1.11 <1.18 4.12 4.71 3.27 - <1.43 < 0.0225 < 1.54
17-Mar pCi/L _ <0.7 <1.46 4.74 - 5.57 <0.753 _ <1.31 < 0.0235 < 1.60
19-Mar pCi/L <1.83 <0.648 4.12 _ 4.14 <1.15 <0.7 < 0.0222 < 1.51
22-Mar pCi/L <1.35 <0.548 4.49 4.29 2.61 <0.483 < 0.0045 < 0.31
Radium(total) 0.0191 1.3022
Radium-226 3-Mar pCi/L <0.203 <0 <0.354 <0.699 1.58 <0.131 < 0.0098 < 0.67
8-Mar pCi/L <0.107 <0.528 0.467 <0.308 <0.193 <0.118 < 0.0047 < 0.32
10-Mar pCi/L 0.615 1.31 <0.56 <0.488 <0 <0.169 < 0.0017 < 0.12
12-Mar pCi/L <0.18 <0.324 0.949 <0.8 <0.121 <0.369 < 0.0025 < 0.17
15-Mar pCi/L <-0.305 <0.22 <0.543 0.784 <0.431 0.456 < 0.0086 < 0.58
17-Mar pCi/L <-0.0278 _ <0.188 0.984 <0.434 <-0.0586 <0.43 < 0.0051 < 0.35
19-Mar pCi/L <0.79 <0.354 <0.756 <0.578 <0.0725 <0.683 < 0.0100 < 0.68
22-Mar pCi/L <0.521 <0.0652 <0.799 <0.841 <0.157 <0.0663 < 0.0101 < 0.69
Radium-226 0.0066 0.45
Radium-228 3-Mar pCi/L <0.105 <0.315 2.49 4.99 <0.323 <0.349 < 0.0136 < 0.93
8-Mar pCi/L <0.424 <0.078 2.3 4.15 <0.674 <0.202 < 0.0225 < 1.53
10-Mar pCi/L <0.535 1.05 2.54 2.72 _ <-0.061 <0.145 < 0.0198 < 1.35
12-Mar pCi/L <0.705 <0.274 2.91 3.96 <0.567 <0.679 < 0.0149 < 1.02
15-Mar pCi/L <1.11 <0.962 3.58 3.93 2.84 <0.972 < 0.0170 < 1.16
17-Mar pCi/L <0.7 <1.27 3.76 5.14 <0.753 <0.876 < 0.0000 < 0.00
19-Mar pCi/L <1.04 <0.294 3.36 3.56 1.08 <0.0173 < 0.0015 < 0.10
22-Mar pCi/L <0.829 <0.483 3.69 3.45 2.45 <0.417 < 0.0015 < 0.10
Radium-228 0.0113 0.77
Other Parameters
1,3-Dichloropropane 3-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
8-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
10-Mar ug/L <0.1 _ <0.1 <0.1 <0.1 <0.1 <0.1
12-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 __ _
15-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
17-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 _
19-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
22-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
24-Mar ug/L <0.1 _ <0.1 <0.1 <0.1 _ <0.1 <0.1
26-Mar ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
Bicarbonate 3-Mar mg/L 3.1 <2.6 <2.6 <2.6 16 <2.6 < 58.323 < 4.0
28-Apr mg/L 3.3 <2.6 <2.6 <2.6 <2.6 <2.6 < 42.202 < 2.9
Bicarbonate 50.263 3.4
Carbonate I 3-Mar I mg/L l <2.6 I <2.6 <2.6 <2.6 _ <2.6 I <2.6
28-Apr mg/L <2.6 <2.6 <2.6 <2.6 <2.6 <2.6
Chloride 3-Mar mg/L 6.6 13 3.7 5.4 5 5 112.088 7.6
8-Mar mg/L 6.7 14 4.1 5.9 5.3 5.7 119.000 8.1
10-Mar mg/L 6.8 14 3.9 5.9 4.8 5.5 118.401 8.1
12-Mar mg/L 6.3 14 4 5.5 4.2 6.5 116.298 7.9
TR0795A Page 21 of 28 June 2021

R •-3 •� 1n .0 [=7 C7 (l C)
O g o o E. c 5 y O c
EL 2 . ,e o r a
a N 0 T 2 PO _.
q g o 2 0 0. a
. O b
co a 0 , Y m
w
0 Y c 0 3
A
n
C) o
W c
N N N N N N N N N N N N N N N N N N N .+ .+ •+
00 W 00 W W W W 00 W W O d C
O �P N CO V Cyyn N O 00 O �P N O V Cn N O C10 00 00 `� CO 4, N CO V cn Ny O 00 00 00 .t r. N C-O V Cn N
.1 ,0 .� .�. „� „d „d y^ it it r� it ,�,� ,�� r� ram. �N,,, a
�i �i �i �i �i �i �i �i n �i �i �i �i �i n n n n g �i N N N N N N Ni n n �'� n g �i �i �i �i wi EJ'. -,
4
S B g s g g g c c c c c c c c c c c -0 .0 C Cccccccccc CCCC CC CC CC C r H
43
CA
AN
A A A A A A A A A A A A A A A A A A A A A A Cb7 A ID
0 0 0 0 0 0 0 0 0 0 cn cnN C" CD CD 0 0 0 0 0 0 0 0 0 0 A A QD v O 0 0t v C A
N �+ CD ►+ N �-+ N N �--• .+ N W ►+ N N N N cn col 4, CO 00 -.4 cn cmO H
co cn .. 0 O
N •9
co
�P W �P .P �P W co �P co �P �P „n,,, "' N O O A A A A A A A A A A O 01 C A A
O O O O O O O O O O N O O O O O O O O O OA A G .+ 0�
rb N CO O N W CO O N 00 .P cn N O OO .P lV is., 00 cn cn .+ W .+ W N 4P 4, A R
0 Ln cn
(�
00 P1
Ni A
Ni , or
rrtlyy O
N O O O O O O O O O O 'P W CA W W W :A W W C'`� W W N O O O O O O O O O O O O O co ,p '.�'' ,p !I'' W n '0 Gn
CL
00 N V N C.n CO bn .+ bn O Cn V CA V O O N N cn 0 Cn Co .+ .-. .+ 'Y.
cn cn cn ~ A
y z
O n
_ _ N
AAAAAAAAAA OO � � o, cO pD CO 00 00 00 00 cn ^o o A A A A A A A A A A A A cm cm cn O Cl cm �, n a 0000000000 0000000000
�] Co O V 4P .-, r Co C) W Cn Cn co O 00 N nj . Cn cm Co 00 V Co N V Cn
61
0 cm cm C r
"O
x cm 00
o � D 0I
A A A A A A A A A A _ n n A A A A A A A A A A tT m
0 0 0 0 0 0 0 0 0 0 0 00 OOO W O CT 4P O Cn V N N d W W 00 N N 0 0 0 0 0 0 0 0 0 0 cAJ� c0 Cn il
W tp "p ,a O
A A A A A A A A A A f� B' n n A A A A A A A A A A n a
O O O O O O O O O O W ;A :P C) to .1' Cn 'p Cn '-n Cr cn N T nw 0~ 5n 0 0 0 O O O O O o O O O co co EC CO V cn Cr cn cn cn y try ,b
() V CO .+ 4P CO V CO .+ V N N O Cn O CO 00 O 00 Cn W N r b
C) p, cn cn .O. r '..
W O fait N
. p
N
A A A A r pi �- 0
N N N N N N N Ni N N N N V O CO N N N O C! c'
CD cm 4, 4, al -4cnCD cmCn -.400 CD W 4, H7 CJ Cn .► ... N O .+ N O.
A. CO N co 00 0. O W 00 O 00 -.4 N CT CC 00 00 CO Cl 00 4, -.4 cn O .+ 4, g CD
N V 4P OO 00 N N W Cm O O W .+ Cn C1 O N N foD N Cn O Co O Cn S E, n
00 co CO N CO W Cl CD CD CO CO N Cn Cl Ci7 cm Cl .+ ...4 4, W CD .+ -.400 4. iir C)
H1 CO 00 cn CO 4, W 4, co r CO -4 CM CD N 00 cn N .+ -4 4, -.4 W Cn .+ CO O
0
N
A A A A �1 N
Fip
00 -.4 CO CO ...4OO V CD00 ..4CO CO iP W 4, .4 -.4 -.4V 00 00 -.4 -.4 -.4 00 -4O 0 V Cn O V V .+ O W •+ O O M+ W 00 V O V r-+ Cn W CO LA Co 00
Ni n a ro
Ni C)

Table 5 Geosyntec Consultants of NC P.C.
Results for Multiple Samples of Untreated Groundwater and Seeps from March/April 2021
Chemours Fayetteville Works,North Carolina
Date in SEEP-A- SEEP-B- Estimated Estimated
Grouping/Parameter 2021 Units EW-1 EW-3 PIW-10S PIW-5S WALL WALL Load (lb/d) FWMC
Trichloroethene 3-Mar , ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
8-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
10-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
12-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
15-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
17-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
-
19-Mar _ ug/L <0.2 <0.2 <0.2 _ <0.2 <0.2 <0.2
22-Mar _ ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
24-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
26-Mar ug/L <0.2 <0.2 <0.2 <0.2 <0.2 <0.2
Notes
mg/L-milligrams per liter
ug/L-microgram per liter
pCi/L-picocuries per liter
TR0795A Page 23 of 28 June 2021

Table 6 Geosyntec Consultants of NC P.C.
Comparison of Flow-Weighted Mean Concentrations to Water Quality Criteria
Chemours Fayetteville Works, North Carolina
FWMC for Outfall 004 (Untreated)
March/April 2021 Sampling
Grouping/Parameter Units At Reporting At 1/2 RL RL set to 0 Water Quality3
Limit (RL) Criterion ' '
Table A. Conventional and Non-Conventional Parameters
Chemical Oxygen Demand (COD) mg/L L 25 8 1 NA
Total Organic Carbon mg/L I 2.94 1.60 1.53 I NA
Table B. Certain Conventional and Non-Conventional Parameters
Aluminum mg/L 1.57 0.89 0.89 6.5
Barium mg/L _ 0.046 0.026 0.026 1.0
Boron mg/L 0.012 0.008 0.003 0.15
Cobalt mg/L 0.0009 0.0008 0.0008 0.0016
Flouride mg/L 0.27 0.16 0.06 1.8
Iron mg/L 3.65 3.65 3.65 1.0
Magnesium mg/L 2.19 1.25 1.25 NA
Manganese mg/L 0.07 0.07 0.07 0.05
Nitrate/Nitrite Nitrogen mg/L 0.11 0.09 0.08 10
Sulfate mg/L 26 26 26 250
Titanium mg/L 0.055 0.030 0.029 NA
total residual chlorine mg/L 0.155 0.088 0.088 0.017
Radium (total) _ pCi/L 1.302 0.001 0.001 5
Radium-226 pCi/L 0.448 0.000 0.000 5
Metals
Arsenic mg/L 0.0008 0.0003 0.0001 0.01
Beryllium mg/L 0.0025 0.0025 0.0025 0.0065
Chromium mg/L 0.0014 0.0008 0.0007 0.0238
Copper mg/L 0.00061 0.00050 0.00040 0.00274
Cyanide mg/L 0.005 0.003 0.000 0.004
Lead _ mg/L 0.00038 0.00036 0.00034 0.00054
Mercury mg/L 0.000079 0.000041 0.000019 0.000012
Nickel mg/L 0.0017 0.0009 0.0009 0.0161
Zinc mg/L 0.033 0.019 0.018 0.037
Organic Toxic Pollutants (GC/MS Fraction- Base/Neutral Compounds)
Acenaphthene ug/L 0.42 0.20 0.16 60
Anthracene ug/L 0.19 0.14 0.086 0.05
Benzo(A)Anthracene ug/L 0.37 0.22 0.071 0.0028
Benzo(A)Pyrene ug/L 0.32 0.17 0.017 0.0028
Benzo(B)Fluoranthene ug/L 0.33 0.18 0.026 _ 0.0028
Benzo(K)Fluoranthene ug/L 0.16 0.09 0.014 0.0028
Chrysene ug/L 0.36 0.21 0.06 0.0028
Fluoranthene ug/L 0.76 0.61 0.46 0.11
Fluorene ug/L 0.69 0.54 0.39 30
TR0795A Page 24 of 28 June 2021

Table 6 Geosyntec Consultants of NC P.C.
Comparison of Flow-Weighted Mean Concentrations to Water Quality Criteria
Chemours Fayetteville Works, North Carolina
FWMC for Outfall 004 (Untreated)
March/April 2021 Sampling
Grouping/Parameter Units At Reporting At 1/2 RL RL set to 0 Water Quality
Limit (RL) Criterion . '
Naphthalene _ ug/L 0.68 0.60 0.53 12
Phenanthrene ug/L 1.29 1.22 1.14 0.7
Pyrene ug/L 0.55 0.40 0.25 20
Organic Toxic Pollutants (GC/MS Fraction - Pesticides)
Endosulfan I ug/L 0.006 0.005 0.003 20
Heptachlor Epoxide ug/L 0.007 0.004 0.002 0.000032
Notes
Hardness based metals (chromium, copper, lead, nickel, and zinc) criteria calculated assuming 25 mg/L CaCO3.
2 Total of all PAHs (benzo(A)anthracene, benzo(A)pyrene, benzo(B)fluoranthene, and benzo(K)fluoranthene, and
chrysene) should not exceed 2.8 ng/L.
3 Iron and manganese concentrations are provided for guidance purposes
mg/L -milligrams per liter
ug/L -microgram per liter
pCi/L -picocuries per liter
TR0795A Page 25 of 28 June 2021

Table 7 Geosyntec Consultants of NC P.C.
Comparison of Flow-Weighted Mean Concentrations to Water Quality Criteria with an 8:1 Dilution
Chemours Fayetteville Works, North Carolina
FWMC for Outfall 004 (Untreated)
March/April 2021 Sampling
At Water
Reporting Quality
Grouping/Parameter Units Limit (RL) At 1/2 RL RL set to 0 Criterion',z
Table B. Certain Conventional and Non-Conventional Parameters
total residual chlorine mg/L 0.155 0.088 0.088 0.136
Organic Toxic Pollutants (GC/MS Fraction- Base/Neutral Compounds)
Benzo(A)Anthracene ug/L 0.37 0.22 0.07 0.0224
Benzo(A)Pyrene ug/L 0.32 0.17 0.017 0.0224
Benzo(B)Fluoranthene ug/L 0.33 0.18 0.03 0.0224
Benzo(K)Fluoranthene _ ug/L 0.16 0.09 0.01 0.0224
Chrysene ug/L 0.36 0.21 0.06 0.0224
Organic Toxic Pollutants (GC/MS Fraction- Pesticides)
Heptachlor Epoxide ug/L 0.007 0.004 0.002 0.000256
Notes
1 Criterion increased by factor of 8 to account for 8:1 dilution with Cape Fear River.
2 Total of all PAHs (benzo(A)anthracene, benzo(A)pyrene, benzo(B)fluoranthene, benzo(K)fluoranthene,
and chrysene) should not exceed 2.8 ng/L (22.4 ng/L at an 8:1 dilution).
mg/L - milligrams per liter
ug/L - microgram per liter
TR0795A Page 26 of 28 June 2021

Table 8 Geosyntec Consultants of NC P.C.
Load Calculations for Mass Balance of GWTS(Outfall 004)with Outfall 002
Chemours Fayetteville Works,North Carolina
Load for Untreated Outfall 004 Outfall 002 Max Conc or Outfall 002 Load(lb/d)
(lb/d) LTA(Form 2C)
Grouping/Parameter At Reporting At 1/2 RL RL set to Conc. Units At Reporting At 1/2 RL RL set to
Limit(RL) 0 Limit(RL) 0
Table A.Conventional and Non-Conventional Parameters
Chemical Oxygen Demand(COD) _ 369 202 35 35.8 mg/L 5,385 5,385 5,385
Total Organic Carbon 43.1 41.3 39.4 5.3 mg/L 797.3 797.3 797.3
Table B.Certain Conventional and Non-Conventional Parameters
Aluminum 23 23 23 0.222 mg/L _ 33 33 33
Barium 0.7 0.7 0.7 0.0235 mg/L 3.5 3.5 3.5
Boron _ 0.2 _ 0.1 0.0 0.0262 mg/L 3.9 3.9 3.9
Cobalt 0.013 _ 0.012 0.011 0.00064 mg/L 0.10 0.10 0.10
Flouride 3.9 2.4 0.9 0.1 mg/L 15.0 15.0 15.0
Iron 54 54 54 1.05 mg/L 158 158 158
Magnesium 32 32 32 2.79 mg/L 420 420 420
Manganese 1.0 1.0 1.0 0.121 mg/L .i 18.2 18.2 18.2
Nitrate/Nitrite Nitrogen 1.6 1.4 1.2 0.46 mg/L 69.2 69.2 69.2
Sulfate 386 386 386 32.1 mg/L 4,829 4,829 4,829
Titanium 0.8 0.8 0.7 0.0078 mg/L 1.2 1.2 1.2
total residual chlorine 2.3 2.3 2.3 0.00036 mg/L 0.1 0.1 0.1
Radium(total) 0.019 0.014 0.009 < 1.39 pCi/L 0.2 0.1 0
Radium-226 0.007 0.005 0.003 1.15 pCi/L 0.2 0.2 0.2
Metals
Arsenic 0.012 0.007 0.003 0.00075 mg/L 0.1 0.1 0.1
Beryllium 0.04 0.04 0.04 < 0.000091 mg/L 0.01 0.01 0
Chromium 0.02 0.02 0.02 0.0011 mg/L 0.2 0.2 0.2
Copper 0.01 0.01 0.01 < 0.0099 mg/L 1.5 0.7 0
Cyanide 0.07 0.04 0 < 0.005 mg/L 0.8 0.4 0
Lead 0.01 0.01 0 < 0.0011 mg/L 0.2_ 0.1 0
Mercury 0.0012 0.0006 0.00005 0.00000471 mg/L 0.0007 0.0007 0.0007
Nickel 0.02 0.02 0.02 0.0016 mg/L 0.2 0.2 0.2
Zinc 0.5 0.5 0.5 0.0094 mg/L 1.4 1.4 1.4
Organic Toxic Pollutants(GC/MS Fraction-Base/Neutral Compounds)
Acenaphthene 0.006 0.005 0.004 < 0.08 ug/L 0.012 0.006 0
Anthracene 0.003 0.0020 0.0013 < 0.07 ug/L 0.011 0.005 0
Benzo(A)Anthracene 0.005 0.003 0.001 < 0.2 ug/L 0.030 0.015 0
1 Benzo(A)Pyrene 0.005 0.0025 0.0003 < 0.2 ug/L 0.030 0.015 0
Benzo(B)Fluoranthene 0.0048 0.0026 0.0004 < 0.07 ug/L 0.011 0.005 0
Benzo(K)Fluoranthene 0.002 0.001 0.0002 < 0.09 ug/L 0.014 0.007 0
Chrysene 0.005 0.003 0.001 < 0.2 ug/L 0.030 0.015 0
Fluoranthene 0.011 0.009 0.007 < 0.2 ug/L 0.030 0.015 0
Fluorene 0.010 0.008 0.006 < 0.08 ug/L 0.012 0.006 0
Naphthalene 0.01 0.01 0.01 < 0.09 ug/L 0.014 0.007 0
Phenanthrene 0.019 0.018 0.017 < 0.09 ug/L 0.014 0.007 0
Pyrene 0.008 0.006 0.004 < 0.2 ug/L 0.030 0.015 0
Organic Toxic Pollutants(GC/MS Fraction-Pesticides)
Endosulfan I 0.0001 0.0001 0.0000 < 0.0028 ug/L 0.0004 0.0002 0
Heptachlor Epoxide 0.00010 0.00007 0.00003 < 0.00466 ug/L 0.0007 0.0004 0
Notes
mg/L-milligrams per liter
ug/L-microgram per liter
pCi/L-picocuries per liter
TR0795A Page 27 of 28 June 2021

Table 9 Geosyntec Consultants of NC P.C.
Comparison of Flow-Weighted Mean Concentrations for Combined Outfalls 002 and 004 to Water Quality
Criteria with an 8:1 Dilution
Chemours Fayetteville Works, North Carolina
FWMC for Outfalls 002 (Treated) and
004 (Untreated)
At Reporting Water
Grouping/Parameter Units Limit (RL) At 1/2 RL RL set to 0 Quality
Criterionl'2
Table B. Certain Conventional and Non-Conventional Parameters
total residual chlorine mg/L - 0.014 0.014 0.014 0.136
Organic Toxic Pollutants (GC/MS Fraction -Base/Neutral Compounds)
Benzo(A)Anthracene ug/L 0.22 0.11 0.0063 0.0224
Benzo(A)Pyrene ug/L 0.21 0.11 0.0015 0.0224
Benzo(B)Fluoranthene ug/L 0.09 0.05 0.0023 0.0224
Benzo(K)Fluoranthene ug/L 0.096 0.049 0.0013 0.0224
Chrysene ug/L 0.214 0.110 0.0053 0.0224
Organic Toxic Pollutants (GC/MS Fraction - Pesticides)
Heptachlor Epoxide ug/L I 0.00484 I 0.00252 I 0.0002 0.000256
Notes
Criterion increased by factor of 8 to account for dilution with Cape Fear River.
2 Total of all PAHs (benzo(A)anthracene, benzo(A)pyrene, benzo(B)fluoranthene, benzo(K)fluoranthene, and
fluorene) should not exceed 2.8 ng/L (22.4 ng/L at an 8:1 dilution).
mg/L - milligrams per liter
ug/L -microgram per liter
Page 28 June 2021

Attachment A.5 - Engineering Report —
Treatment of Groundwater and Upgradient
Seeps Water

Geosyritec '
consultants
Geosyntec Consultants of NC,P.C.
NC License No.:C-3500 and C-295
ENGINEERING REPORT -
TREATMENT OF GROUNDWATER
AND UPGRADIENT SEEPS WATER
Prepared for
The Chemours Company FC, LLC
1007 Market Street
PO Box 2047
Wilmington, DE 19899
Prepared by
Geosyntec Consultants of NC, P.C.
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
Geosyntec Project Number TR0795
June 2021

Geosyntec°
consultants
CeWynlec Consultants u(NC,K-
an,License No:C and C-295
TR0795 i Jun('"2oz1

Geosyntec
C(St19iSh i,
TABLE OF CONTENTS
1. INTRODUCTION AND BACKGROUND 5
1.1 Site History and Overview 5
1.2 Process Overview 6
2. DESIGN BASIS 8
2.1 Aquifer Location 8
2.2 Influent Water Quality 10
2.3 Groundwater and Seeps Outfall 13
2.4 Influent Untreated Water Quality - Comparison to Water Quality Criterial3
2.5 Pilot Studies 15
2.6 Pumping & Conveyance Design 15
3. PROPOSED TREATMENT DESIGN 16
3.1 Overall Narrative 16
3.2 Individual Unit Operations 19
3.2.1 Metals Oxidation 19
3.2.2 Filtration 19
3.2.3 Granular Activated Carbon Adsorption 19
3.2.4 Solids Handling and Dewatering 20
3.3 Operability and Maintenance Considerations 20
3.4 Process Monitoring 21
4. SUMMARY 21
5. REFERENCES 21
TR0795 ii June 2021

Geosyntec°
consultants
t.'evmnnr.Canto.of Nr,PC.
M LI 1'nse Yu:S:L iO and t 295
LIST OF TABLES
Table 1: Hydraulic Loading of Representative Groundwater and Seep Sources
Table 2: Representative Well and Seep Locations and Estimated Flowrates
Table 3: Influent Design Basis for the Groundwater Treatment System
LIST OF FIGURES
Figure 1: Remedy Alignment and Proposed Groundwater Treatment System Location
Figure 2: Groundwater Flow Direction and Seep Locations
Figure 3: Comparison of Carbon Isotherms for Heptachlor Epoxide, Two PAHs, and HFPO-
DA
Figure 4: Conceptual Process Flow Diagram of Primary Treatment Train and Solids Recovery
Process
LIST OF APPENDICES
Appendix A: Analytical Data for Groundwater & Seep Sources for the Engineering Design
TR0795 iii June 2021

Geosyntec°
consultants
l:entnIrc(:urtupianao(NC,P.C.
NC License Nu:C-M Mock-295
ACRONYMS AND ABBREVIATIONS
BCA Black Creek Aquifer
CO Consent Order
GAC granular activated carbon
GPM gallons per minute
GWTS groundwater treatment system
HDPE high density polyethylene
HFPO-DA hexafluoropropylene oxide-dimer acid
HRT hydraulic retention time
mg/L milligrams per liter
MTZ mass transfer zone
NCDEQ North Carolina Department of Environmental Quality
ND Non-detect
NPDES National Pollutant Discharge Elimination System
PAH polycyclic aromatic hydrocarbons
PFAS per- and polyfluoroalkyl substances
PFMOAA perfluoro-1-methoxyacetic acid
PMPA perfluoro-2-methoxypropanoic acid
STD standard
TSS total suspended solids
ug/L micrograms per liter
TR0795 iv June 2021

Geosyntec
vonsultanft
4e.xptee4 Ctat ,WTh'n4NC.P.C.
,at t Rvn,su"Wa„C:3MO andl:4E4E
1. INTRODUCTION AND BACKGROUND
This Engineering Report was prepared by Geosyntec Consultants of NC, P.C.
(Geosyntec) for the Chemours Company FC, LLC (Chemours) to provide a description
of the future treatment works to be installed for the collection and treatment of
groundwater and surface water from locations along the proposed groundwater remedy
alignment at the Chemours Fayetteville Works, North Carolina site (the Site). The
groundwater remedy includes a barrier wall, water extraction network, and treatment
system (Groundwater Treatment System or GWTS) is a requirement of the Addendum to
the Consent Order paragraph 12 (CO Addendum) amongst Chemours, the North Carolina
Department of Environmental Quality (NCDEQ), and Cape Fear River Watch entered by
the court on October 12, 2020.
The goal of the GWTS is to achieve a removal efficiency of 99%, as measured by
indicator parameters hexafluoropropylene oxide-dimer acid (HFPO-DA), perfluoro-2-
methoxypropanoic acid (PMPA), and perfluoro-1-methoxyacetic acid (PFMOAA). The
remedy is to commence operation by March 15, 2023 per paragraph 3(b) of the
Addendum to the CO. To meet this requirement, Chemours intends to complete
construction of the GWTS by April 1, 2022. Chemours will need to pump and treat the
water collected by the remedy to protect the barrier wall's structural integrity.The GWTS
therefore needs to be operational prior to the remedy's construction in June 2022.
This document provides the conceptual design and engineering assumptions for the
GWTS, in accordance with the National Pollutant Discharge Elimination System
(NPDES) permit application requirements. The permit application requires that
Chemours identify effluent characteristics of those parameters identified in the EPA
Application Form 2D New Manufacturing, Commercial, Mining, and Silvicultural
Operations That Have Not Yet Commenced Discharge of Process Wastewater(EPA Form
2D).
1.1 Site History and Overview
The Site is located on NC Highway 87, 15 miles southeast of the City of Fayetteville, and
south of the Bladen-Cumberland County line. The Site encompasses 2,177 acres of
relatively flat undeveloped open land and sloping woodland bounded on the east by the
Cape Fear River, on the west by NC Highway 87, and on the north and south by farmland.
The ground on which the Site is situated slopes East towards the Cape Fear River. The
proposed treatment facility is to be located on the southeastern portion of the Site just
north of the William 0. Huske Lock & Dam.
E.I. du Pont de Nemours and Company (DuPont) purchased the property in parcels from
several families in 1970. The Site's first manufacturing area was constructed in the early
TR0795 5 June 2021

Geosyntec°
consultants
<,.NY , Pl
Nt I:,cu.r'w,.:t..:+100 unit r+5
1970s. Currently, the Site manufactures plastic sheeting, fluorochemicals, and
intermediates for plastics manufacturing. A former manufacturing area, which was sold
in 1992, produced nylon strapping and elastomeric tape.
DuPont sold its Butacite® and SentryGlas® manufacturing units to Kuraray America,
Inc. in June 2014; these are now a tenant operation. In July 2015, DuPont separated its
specialty chemicals business into a new publicly traded company named The Chemours
Company FC, LLC.With this separation, Chemours became the owner of the entire 2,177
acres of the Fayetteville Works along with the Fluoromonomers, Nation® membranes,
and Polymer Processing Aid (PPA) manufacturing units. The polyvinyl fluoride (PVF)
resin manufacturing unit remained with DuPont as a tenant operation.
In addition to the manufacturing operations, Chemours operates two natural gas-fired
boilers and a biological wastewater treatment plant for the treatment of DuPont and
Kuraray process wastewater and sanitary wastewaters from DuPont, Kuraray, and
Chemours.
1.2 Process Overview
Groundwater at the Site currently flows east towards the Cape Fear River. The extraction
and conveyance portion of the treatment design proposes to capture the groundwater flow
via the installation of a network of groundwater extraction wells and to capture the
baseflow of seeps originating upgradient of the remedy and flows during rainfalls up to
0.5 inches in depth. The extracted groundwater and seeps water will then be collected and
conveyed to be treated by the GWTS which is proposed to be located in the southeast
corner of the Site. The proposed location is shown in Figure 1.
TR0795 6 June 2021

Geosyntec°
consultants
t:a nwynrcc conarrw»sorNt:.PC..
341!11b6 Nu.;L:4SM!land t'495
SS'S
SyS
4 Proposed
new GWTS
location
Legend
!ri Extraction well I
Planned groundwater remedy route
Figure 1:Remedy Alignment and Proposed Groundwater Treatment System Location
The GWTS will be comprised of a series of chemical and physical separation steps.
Chemical oxidation and pH adjustment will first be employed to precipitate metals, such
as iron, to prevent downstream contamination or fouling of the granulated activated
carbon (GAC) media. The precipitated metals and other particles above an appropriate
control threshold will be removed via ultrafiltration membranes or some other suitable
separation technology. The filtered effluent will then be treated for per- and
polyfluoroalkyl substances (PFAS) by GAC adsorption.The reject from the filtration and
GAC systems will undergo dewatering through a thickening tank and filter press or
centrifugation, from which the sludge cake will be disposed of offsite and the press water
will be recycled to the influent of the thickening tanks. Periodic backwashing will extend
membrane and carbon media life, and the carbon will be removed and replaced based on
breakthrough monitoring of several three-vessel carbon trains in a lead-middle-lag
arrangement. Associated design elements such as pumps, piping, electrical,
instrumentation and control for interlocks, mechanical and civil/structural elements will
be finalized during the detailed design phase. This design concept may be optimized
based on ongoing benchtop studies and data acquisition.
TR0795 7 June 2021

Geosyntec°
consultants
Ceo3y„aec: unna,w+,x of\C.P.C.
.lac.,.iwpnee r,,,.C-4600 and 1196
2. DESIGN BASIS
2.1 Aquifer Location
The ground on which the Site is situated slopes east from the facility towards the Cape
Fear River. The main groundwater aquifers therefore also flow towards the Cape Fear
River. Furthermore, there are four seeps that also contribute surface water flow to the
Cape Fear River, as identified in Figure 2.
TR0795 8 June 2021

Geosyntec°
consultants
G4447017e443cCuw11e1441%ufNC.P.G.
SC S,icerm Na:C-4500 and s-295
y
WIMS creek
� µ
,� .
4
4�Id t)u
Legend
•r**r a Proposed groundwater remedy alignment
. Seep
onommon Nearby tributary to river
General direction of groundwater flow
Site boundary
Figure 2: Groundwater Flow Direction and Seep Locations
TR0795 9 June 2021

Geosyntec
consultants
f:eoa?ntn'l;onudnw$Of NI:P.C.
Nt.I even..Nu:1.4,50D and I'•29b
The groundwater originates from two main aquifers, known as the Black Creek Aquifer
(BCA) and the Surficial Aquifer. These two zones are separated by the Black Creek
Confining Unit along most of the length of the proposed groundwater remedy alignment,
and the BCA is underlain by the Upper Cape Fear Confining unit, which is a layer of
competent clay.
The groundwater daylights near the Cape Fear riverbank as various seeps. There are four
seeps (Seeps A through D), although only two of these are major hydraulic contributors
(A and B) which will require collection for treatment.The estimated hydraulic loading in
gallons per minute (gpm) from the two aquifers and four seeps, post remedy construction,
is shown in Table 1.
Table 1:Hydraulic Loading of Representative Groundwater and Seep Sources
Water Source Approximate Flow Rate
°
Seeps Baseflow 161 gpm
*
Seeps Stormflow 108 gpm
°
Groundwater from Surficial Aquifer 150 gpm
Groundwater from Black Creek Aquifer 800 gpm
Total Flow 1,219 gpm
* Seeps stormflow represents maximum increase over baseflow averaged over 24-hour period.
0 Seeps baseflow and Shallow Groundwater may include some double counting.Seeps baseflow represents the 95th
percentile instantaneous flow from each of Seeps A and B at location representative of the remedy capture location.
Actual flows may vary from these model results due to variability in rainfall. The largest
rainfall effect is expected to be seen in the seeps stormflow parameter in Table 1;the cited
108 gpm value is the 24-hour average flow for a 0.5 inch storm event.The seeps' baseflow
quantity is also a conservative estimate (i.e. high-end). For this reason, the extraction
system and the GWTS will be designed to handle reasonable expected flow variations
and the GWTS currently has a planned capacity safety factor such that a maximum design
flow of 1,500 gpm has been selected.
2.2 Influent Water Quality
The source water to the GWTS will be the extracted groundwater and captured seep
water. The groundwater will be extracted from a series of approximately 60 extraction
wells installed along the length of the proposed groundwater remedy alignment. Water
will also be captured from seeps originating upgradient of the barrier wall (Seeps A and
B). Since the GWTS has not yet been installed, the influent water quality presented in
this report is from representative wells in the associated aquifers and the seeps. The
TR0795 10 June 2021

Geosyntec°
consultants
GeNotwee imwdeutxs W NC.P.C.
Alt:laeens4 No.(.- OPebit C4PP
currently available non-PFAS analytical data from the individual untreated groundwater
and seep sources, or their closest analogs, has been collected and is summarized in the
memorandum Chemours Fayetteville Works — Groundwater and Seeps Water Quality
Assessment (Geosyntec, 2021). Relevant analytical data for the engineering design,
including the PFAS data, is provided in Appendix A.
Groundwater sampling was completed at four representative groundwater wells and three
seep locations. The seep locations are shown relative to the site in Figure 2. The
groundwater wells are analogs for the various groundwater sources to be collected by the
new extraction network along the groundwater remedy alignment, as described in Table
2. Two of the seep locations (Seep A at Wall Point and Seep B at Wall Point) are analogs
for the seep baseflow and surface runoff that will be intercepted by the groundwater
remedy. The samples collected at the location Seep A minor tributary are not analogs of
seep water as the location was artificially disturbed prior to sample collection to introduce
sediment into the sample. The results from Seep A minor tributary were, however,
included in the engineering design as a safety factor.
Table 2:Representative Well and Seep Locations and Estimated Flowrates
r Flowrate Flowrate Proportion
Representative Water Location Tag (gpd) (gpm) (%)
Black Creek Aquifer at North EW-1 668,794 464 47%
Black Creek Aquifer at South EW-3 428,198 297 30%
Surficial Aquifer at North PIW-5S 104,760 73 7%
Surficial Aquifer at South PIW-10S 75,773 53 5%
Seep A minor tributary* SEEPA-TR-N 31,522 22 2%
Seep A at Wall Point SEEP-A-WALL 50,501 35 4%
Seep B at Wall Point SEEP-B-WALL 67,133 47 5%
* Samples were artificially disturbed at SEEP-A-TR-N prior to collection to introduce turbidity.
The dataset used for the GWTS design is inclusive of untreated water data collected
during sampling events from 2019 and 2020 and a series of 11 sampling events that
occurred during March and April 2021. PFAS compounds were specifically sampled for
on March 3, March 26 and April 28, 2021. Appendix A provides a detailed overview of
the average, maximum, and minimum concentrations of all untreated water parameters
sampled for treatment design. The water collected at these wells (EW-1, EW-3, PIW-5S
and PIW-10S) and two seep locations (SEEP-A-WALL and SEEP-B-WALL) is assumed
to be representative of the total groundwater and seep flow that will be extracted and
treated by the GWTS.
TR0795 11 June 2021

Geosyntec>
CkanyroecComukaotstriNtl P.C.
vc;urw.,C-3ana,104C-as
In addition to PFAS analyses, a variety of supporting analytes such as total suspended
solids (TSS), and metals (such as aluminum and iron) were sampled as they were
considered key parameters of concern that would inform the pre-treatment system
upstream of the PFAS removal stage. Flow-weighted composite concentrations for each
parameter were developed for each of the groundwater and surface water groupings, as a
design aid for the development of the influent design basis. The average, minimum and
maximum mass loading of each untreated water parameter and Table 3+ compound was
estimated using the average, minimum, and maximum concentrations from the analytical
data and the flow rates in Table 1. Thus, the flow-weighted, mass-based composition for
the untreated water groundwater sources was estimated by summing the mass loadings
from PIW-5S, PIW-10S, EW-1, and EW-3. The flow-weighted average composition for
the seeps was estimated by summing the mass loadings from SEEP-A-WALL, SEEP-B-
WALL, and SEEP-A-TRN.
The projected concentrations in the combined influent to the GWTS were estimated from
the flow-weighted concentrations groundwater and surface water groupings. Upon
construction completion of the groundwater remedy, it is estimated that the total dry-
weather groundwater and surface water flows will be 950 gpm and 161 gpm, respectively.
The groundwater and surface water groupings were combined by flow-weighting the
average, minimum, and maximum concentrations using these estimated post-construction
flows. The design of the GWTS is based on the contaminant profile in Table 3.
Table 3:Influent Design Basis for the Groundwater Treatment System
Projected Concentrations
Influent Design
Constituent Units Basis
Avg. Min. Max. Min. Max.
HFPO Dimer ug/L 12.2 8.22 18.9 4.11 28.3
Acid
PFMOAA ug/L 64.3 17.5 192 8.73 288
PMPA ug/L 13.2 8.38 22.5 4.19 33.8
Total table 3+ ug/L 139 54.9 352 27.4 528
(20 compounds)
Aluminum, total mg/L 1.52 1.16 2.20 0.58 3.30
Bromide mg/L ND ND ND ND ND
Calcium, total mg/L 4.07 3.74 4.55 1.87 6.82
Carbonate mg/L ND ND ND ND ND
Alkalinity
Chloride, total' mg/L 8.30 4.85 11.6 2.42 17.4
Fluoride, total mg/L 0.11 0.11 0.11 0.06 0.17
Hardness mg/L ND ND ND ND ND
TR0795 12 June 2021

Geosyntec
Projected Concentrations
Influent Design
Constituent Units Basis
Avg. Min. Max. Min. Max.
Iron, total mg/L 4.86 2.28 8.56 1.14 12.8
Magnesium, mg/L 2.37 2.27 2.53 1.13 3.80
total
Manganese, mg/L 0.08 0.06 0.15 0.03 0.23
total
pH Std units 6.61 6.50 6.80 6.5 8.5
Phosphate mg/L ND ND ND ND ND
Sulfate (as SO4) mg/L 24.7 13.3 33.9 6.66 50.9
Total Dissolved mg/L 78.5 66.8 93.3 33.4 140
Solids
Total Organic mg/L 1.11 0.57 2.01 0.29 3.01
Carbon
TSS2 mg/L 59.2 38.4 120 19.2 180
I SEEP-A-WALL and SEEP-B-WALL each had one observation above 30,000 milligrams per liter(mg/L)chloride.
Data has been excluded and can be considered an outlier for the basis of design.
2 Potentially 250 mg/L during peak storm events (see below).This also does not include the total suspended solids
(TSS) contribution from solids generated during pretreatment.
2.3 Groundwater and Seeps Outfall
The treated groundwater and seeps water will be discharged to the Chemours Fayetteville
Site Outfall 002 discharge line to the Cape Fear River. The average flow rate from the
Outfall 002 is 18.025 million gallons per day. The water quality assessment accounted
for the combination of loads from Outfalls 004 and 002. In addition, the water quality
assessment accounted for the mixing zone analysis that was conducted for Outfall 002
that documented a river dilution of 8:1 (Geosyntec, 2019).
2.4 Influent Untreated Water Quality- Comparison to Water Quality Criteria
The groundwater and seep data for non-PFAS compounds were compared to North
Carolina's surface water quality criteria. This screening-level exercise was conservative
as no treatment was assumed. Results are documented in a memorandum - Chemours
Fayetteville Works - Groundwater and Seeps Water Quality Assessment (Geosyntec,
2021). After flow-weighting the groundwater and seeps' concentrations, incorporating
the load from Outfall 002, and applying an 8:1 dilution from the Outfall 002 mixing zone,
heptachlor epoxide and polycyclic aromatic hydrocarbons (PAHs) warrant consideration
as additional pollutants targeted for removal by the GWTS.
Heptachlor epoxide was only detected in one well (PIW-5S) and one seep (SEEP-A-
WALL) at low levels.The PAH compounds were only detected at low levels in one (PIW-
TR0795 13 June 2021

7
Geosyntec°
consultants
Geo./mot(:uuudnuurucN(:..PC.
NC lfrcn�e Nu.:C•fino+out C-C#S
5S) of the six untreated groundwater and seep sources. As detailed in the Groundwater
and Seeps Water Quality Assessment (Geosyntec, 2021), Chemours will be resampling
these locations to confirm the presence of these compounds.
However, if these compounds are occasionally present in the influent to the GWTS it is
unlikely that they will pass-through the GWTS. Heptachlor epoxide is extremely well
adsorbed by activated carbon due to its size, double bonds, and the presence of chlorine
atoms in the structure. PAHs tend to have strong sorptive interactions with carbon due to
their hydrophobic nature and size. Activated carbon itself is composed largely of
graphene plates, and this molecular similarity strengthens the binding energies via n-Tt
dispersive forces. A thorough review of the use of activated carbon (as well as other
adsorbents) for removal of PAHs from water can be found in Chemosphere 148 (2016),
336-353. A number of other literature sources are also available that include adsorption
equibria (i.e. isotherms), kinetics, and the combined effects in traditional packed bed
adsorbers which give rise to dynamic capacities for various PAHs on activated carbons.
Sorption of Various Organic Compounds on Activated Carbon
1 iln[f0
Heptachlor epoxide
-+-Benzo(k}fluoranthene
-
Ben zo(b)ftuoranthene
+HFPJ-DA
Cu0 iICI
La
en
o �-
_ r i
-14 n 3 ib ion
Concentration, mg/L
TR0795 14 June 2021

Geosyntec°
consultants
Gnxcnu`1(nnudl,u,lc W Nl:.r 1.
1,-,;(x)and l 1'1
Figure 3.. Comparison of Carbon Isotherms for Heptachlor Epoxide, two PHAs, and
HFPO-DA. Data from "Carbon Adsorption Isotherms for Toxic Organics" (EPA-
600/8-80-023, April 1980).
The PFAS compounds this system is designed to treat adsorb to carbon more weakly than
PAHs, as shown in Figure 3. Additionally, they are present in the water at concentrations
roughly two orders of magnitude higher than the PAHs (and roughly four orders of
magnitude higher than the heptachlor epoxide) that may be present in the intake water.
As this treatment system will be run to prevent breakthrough of the three indicator PFAS,
it is expected that heptachlor epoxide and the PAHs will be readily sorbed by the GAC
and therefore are not expected to cause or contribute to exceedances of water quality
criteria in the Cape Fear River if present in the wastewater.
2.5 Pilot Studies
Pilot studies have been completed by vendors to verify the effectiveness of their proposed
pretreatment methods and confirm performance of their selected carbon media to remove
the required constituents and loadings from representative feed water. Tests were
performed using bulk water collected from the sources in Table 2, which was
proportionally blended based on collected flow contribution. The vendors were also
furnished influent water quality data for each source. These pilot studies are being used
to inform the efficacy of proposed full-scale treatment design, including pretreatment
dosing chemistry and residuals characterization (for solids separation and solids-handling
designs).
2.6 Pumping & Conveyance Design
Groundwater modeling remedy development presently indicates a total of approximately
50 new BCA and extraction wells and 10 surficial aquifer extraction wells will be required
to intercept groundwater. The combined maximum total flow rate produced from these
wells is expected to be approximately 950 gpm.
Each well pump is expected to extract approximately 5 to 30 gpm and will be sized to
have additional flow capacity for contingency.The extraction wells are currently planned
as high-density polyethylene (HDPE) construction below finished grade, whereas the
wellhead will be of polyvinyl chloride construction.
Each wellhead will then tee into their corresponding conveyance line (i.e.,North or South
Force mains), constructed of HDPE. Approximately two thirds of the required extraction
wells will convey groundwater through the North Force main while the remaining third
is conveyed via the South Force main. The conveyance lines will be sized to
TR0795 15 June 2021

Geosyntec°
consultants
f eoa�tinec l.imadlontt of NI,Pt:.
.4(Llecrtsarw,.:C-teoaandc-ru
accommodate the total collected flow of the extraction with added contingency to allow
for increased extraction rates if required. Extracted groundwater will be conveyed to a
surge tank prior to being treated by the GWTS.
The seep flow will be impounded at or near seep capture locations (impoundment storage)
to provide equalization storage during rainfall events and remove readily
settleable/suspended solids prior to being conveyed to a break tank and treated by the
GWTS.
The total maximum dry weather flow to the GWTS after the groundwater remedy is fully
operational, including seep flow, is estimated to be 1,111 gpm. Total flow over a 24-hour
period with rainfall is estimated to average 1,219 gpm (see Table 1).The design flow rate
for the GWTS was selected to be 1,500 gpm to allow for increased groundwater extraction
from the extraction wells and potential uncertainty in post-installation flow behavior from
the seeps.
At the break tank, the influents from the extracted groundwater and the seeps will be
combined. The effluent of the tank will then be drawn on demand by the GWTS. The
impoundment storage will be dredged periodically, and solids characterized and disposed
of at an appropriately designated facility.
3. PROPOSED TREATMENT DESIGN
3.1 Overall Narrative
Based on turnkey vendor proposals currently under consideration, the GWTS is assumed
to be comprised of the following series of treatment units:
1. Metals oxidation;
2. Ultrafiltration (UF) or similar solids separation technology;
3. Granular Activated Carbon (GAC) adsorption;
4. Solids Handling & Dewatering; and
5. Ancillary processes for backwashing and residuals handling.
The influent oxidation system will be designed to help ensure complete oxidation of
reduced iron species (or other dissolved metals), by means of pH adjustment and possible
addition of inorganic coagulant and/or flocculant. Following oxidation, flow will proceed
to the solids separation unit in which particle sizes above an appropriate control threshold
will be removed. The filtrate will then be pumped to the GAC adsorption process, which
will remove the PFAS and other contaminants from the water. Influent flow to the carbon
beds may be pH adjusted to improve treatment performance. The GAC effluent will
undergo further pH adjustment back to near-neutral conditions and then be discharged to
the Cape Fear River via the pipe that conveys existing flows from Outfall 002 to the river.
TR0795 16 June 2021

Geosyntec°
consultants
Coowyntet(Amuli uhrfNC,P.CNC Weise 1.460Deult`40$
The solids separation unit reject, solids separation unit cleaning, and GAC backwash
water will collect in one or more thickener tanks. The thickened solids will be dewatered
using a filter press or centrifuge. Sludge cake will be transferred into hoppers that will be
trucked off-site for disposal at a permitted waste disposal facility. The dewatering filtrate
will be returned to the head of the plant and blended with the influent downstream of the
oxidation tanks. A backwash water tank will store a limited volume of treated water to
supply GAC backwash, polymer dilution, and other process water requirements. A GAC
backwash waste tank will collect backwash water and bleed it back into the treatment
process downstream of the oxidation tanks. Process design considerations for each unit
operation are further described in Section 3.2.
Based on vendor experience, Chemours' current operational experience at Outfall 003
elsewhere at the facility, and outcomes of past treatability pilot studies, it is anticipated
that a treatment design consisting of these elements will successfully address treatment
requirements. In addition, Chemours is currently performing treatability studies based on
anticipated wastewater characteristics of the groundwater and seeps.
A conceptual process flow diagram (PFD) of the GWTS and the associated sludge
handling system is shown in Figure 4.
TR0795 17 June 2021

Geosyntec
Cl.nisulranrs
Geacymec Catwalwms nr NC.P.C.
NC ticure NW C2 50P and C-296
H2SO4 12'diameter vessels
pH to 3.5
UF — --. GAC --4. GAC r GAC
- Vessel
► Frac tank —i Frac tank —
Feed UF To Outfall
♦ i Vessel H
—► GAC I--► GAC i—r GAG ► r► Frac tank P
I
Frac tank Frac tank .--,
UF
- Vessel . CPP i GAC —► GAC —. GAG
ifCaustic
--. UF SBS Caustic To GAC B/W,
Caustic Vessel pH to 6 9 Rinse,Sluice
Chlorine
Coagulant
UF
Vessel hot
Frac tank. 4
4 1 GAC
Backwash
4 Out
Anionic N- Frac tank i
polymer .__+
OF Reject
i
Cone Cone
Decant Bottom Bottom
Tank Tank Decant
GAC
Sludge System
Filtrate
Anionic polymer . I
Solids handling
Filter Solids
Press Solids II. roll-off Pre-and post-treatment
Cationic polymer
Figure 4: Conceptual Process Flow Diagram of Primary Treatment Train and Solids Recovery Process System
TR0795 18 June 2021

Geosyntec°
consultants
f 4a.1yxvxtr=l i',1?lxaittttuHc td Ni w Pt
3.2 Individual Unit Operations
3.2.1 Metals Oxidation
One or more influent oxidation retention tanks will be selected to allow for a hydraulic
retention time (HRT) of 30 minutes at the design flow of 1,500 gpm. The HRT has been
selected to achieve the optimal pH range of 6.5 to 7.5 and allow for the oxidation and
coagulation of ferrous iron (Fe2+) to the less soluble ferric iron (Fe3+). Multiple tanks may
be configured in a duty, active-standby configuration, with the capability to take one or
more tanks offline for maintenance and still process the total plant flow of 1,500 gpm.
Upstream of the tanks, chemical augmentation via an inorganic coagulant, sodium
hydroxide, and sodium hypochlorite will be performed to adjust the pH, limit biofouling,
and promote metals coagulation in the retention tanks. pH adjustment chemicals (sodium
hydroxide and sulfuric acid) will be added to reach the target pH based on feedback from
one or more pH probes.
3.2.2 Filtration
Effluent from the oxidation process is pumped to the solids separation operation, via two
or more pumps in duty-standby configuration.
Ultrafiltration membranes or a similar solids separation process will be used to remove
fine solids and turbidity down an appropriate control threshold upstream of the GAC beds
to prevent fouling and extend runtimes between carbon backwashes or media
replacement. The currently proposed OF system will be comprised of parallel banks of
submerged membranes, provided as a prefabricated system, including the vessels,
influent, effluent and backwash manifolds, automatic open/close valves, and any other
ancillary equipment required.
The filtered effluent from the solids separation process will be directed to a pH adjustment
tank where sulfuric acid can be dosed to lower the pH to approximately 3.5 prior to being
transferred to the GAC system. This pH adjustment is expected to improve GAC
performance and extend service life. The reject and backwash from the solids separation
process will routed to the sludge handling system to be dewatered prior to disposal.
3.2.3 Granular Activated Carbon Adsorption
PFAS removal will be accomplished using GAC adsorption. Filtered effluent will be
pumped from the pH adjustment tank to the GAC system and will enter three GAC
adsorption trains, each designed to treat one third of the design flow (500 gpm). Each
vessel will be configured as a down-flow process where water enters the top of the
adsorber and exits through the bottom. In this configuration, adsorption of contaminants
TR0795 19 June 2021

•
Geosyntec
((n suItantS
#;xrxpawrrr:te01z01I004 PC.
(i.e., PFAS) will begin in the upper portion of the GAC bed. The mass transfer zone
(MTZ) will move from the top of the bed downwards as each portion of the bed becomes
saturated with the contaminants. Eventually,breakthrough will occur wherein the effluent
of the tower contains the contaminant. Multiple carbon adsorbers will be arranged in
series to capture the breakthrough.
A three-column, lead/middle/lag, configuration per train is proposed for the GWTS. It is
assumed that complete saturation of the lead column will occur prior to the initiation of a
carbon changeout. During routine operation the lead column will act as the primary
contaminant remover. The MTZ will travel from the top of the bed to the bottom until
breakthrough of a contaminant of concern occurs. The spent GAC in the lead column will
then be replaced with new GAC and the previous lead column will be placed in the lag
column position. The expired GAC will be shipped offsite for disposal and if appropriate,
regeneration of the carbon. The previous middle column will then become the lead
column and the previous lag/third position column will become the second position
column. It is expected that this operating the system in this manner will result in
significant operations and maintenance savings without compromising removal
efficiencies.
Preliminary sizing for this application indicates that a series of 12-foot diameter vessels
that can hold 20,000 pounds of carbon each will provide for the required hydraulic
loading rate and Empty Bed Contact Time for PFAS removal.
Effluent from the GAC trains will be transferred to a storage tank, where caustic will be
dosed to the effluent upstream of the tank to adjust the pH back to neutral prior to
discharge. This tank is sized to provide an appropriate retention time for the pH
adjustment step.
The used backwash water will be collected and transferred to the thickening process for
dewatering and disposal.
3.2.4 Solids Handling and Dewatering
The thickened sludge from the bottom of the thickening operation will be pumped to a
filter press or similar technology for dewatering. The supernatant decanted from the top
of the sludge thickening operation will be recycled to the influent of the initial chemical
oxidation step for reprocessing.
3.3 Operability and Maintenance Considerations
Process equipment has been selected from established vendors who maintain available
inventory of critical spare parts, and the turnkey service provider should also have access
to spares inventory based on duplication of unit operations in their commercial fleet. The
TR0795 20 June 2021

Geosyntec a'
modular nature of the process train means that it is readily expanded or modified to adjust
to future changes in process conditions or treatment requirements.
3.4 Process Monitoring
The treatment process will be instrumented to monitor process performance consistent
with industry best practices. Process data will be recorded in a remotely accessible
database with an extended storage capacity and uninterruptible power supply.
Regulatory compliance will be maintained by means of routine sampling and analytical
testing of the untreated influent and treated water discharge points. Once a week, the
influent to each train and the effluent of each vessel will be sampled and tested at the Site
internal laboratory. Percent breakthrough is calculated for each PFAS indicator species.
First PMPA, and then PFMOAA, breakthrough values are used to determine when a bed
replacement is triggered. Generally once breakthrough begins to be observed in the
middle vessel, the lead vessel's media is changed out. The former lead vessel, filled with
new media, then becomes the lag vessel, former lag becomes the middle vessel, and
former middle vessel becomes the new lead vessel.
4. SUMMARY
In summary, the groundwater and seep flow associated with the proposed groundwater
remedy will be collected and treated (by physical/chemical precipitation, filtration and
carbon adsorption). It is anticipated that the environmental impacts associated with the
groundwater and seep water will be significantly diminished and the treated water will
exhibit a significant reduction in PFAS target compounds, total suspended solids and
dissolved metals. PAHs, and heptachlor epoxide will also be treated if present. This will
reduce the impact of these pollutants in the Cape Fear River.
5. REFERENCES
Geosyntec, 2019. Mixing Zone Report, Addendum, Chemours Fayetteville Works
Outfall 002. October 2019.
Geosyntec, 2021. Memorandum to Chemours. Chemours Fayetteville Works —
Groundwater and Seeps Water Quality Assessment. June 10, 2021.
TR0795 21 June 2021

Geosyntec°
consultants
CaNnynics=S..+m ml auhwiMC,AC.
VC:4.tN!n:k NDO 3608MH11:=a.95
APPENDIX A
Analytical Data for Groundwater & Seep Sources
for the Engineering Design
TR0795 June 2021

ME
June zuz1
Table Al:EW-1 Table 3+Compound Summary
Location: EW-1
Table 3+Compounds #of Results #of Non-Detects Average(ug/L) Min(ug/L) Max(ug/L) Range(ug/L) Std Dev(ug/L)
EVE Acid 9 9 ND ND ND ND ND
Hfpo Dimer Acid 6 _ 0 3.30 1.60 6.90 5.30 1.94
Hydro-EVE Acid 9 8 0.05 0.05 0.05 0.00 ND
Hydrolyzed PSDA 9 3 0.48 0.02 1.60 1.58 0.69
Hydro-PS Acid 10 9 0.03 0.03 0.03 0.00 ND
OS 8 0 0.26 0.11 0.59 0.48 0.20
PEPA 10 0 0.48 0.06 1.70 1.65 0.61
PES 9 8 0.01 0.01 0.01 0.00 ND
PFECA B 9 9 ND ND ND ND ND
PFECA-G 10 10 ND ND ND ND ND
PFMOAA 10 0 34.20 13.00 74.00 61.00 24.13
PFO2HxA 10 0 10.64 2.90 32.00 29.10 10.08
PFO3OA 10 0 1.16 0.10 4.20 4.10 1.53
PFO4DA 10 8 1.04 0.08 2.00 1.92 1.36
'PFOSDA 10 10 ND ND ND ND ND
PMPA 10 0 2.79 1.10 7.50 6.40 2.27
PS Acid 10 10 ND ND ND ND ND
R-EVE 9 3 0.13 0.04 0.35 0.32 0.13
R-PSDA 9 3 0.17 0.04 0.47 0.43 0.17
R-PSDCA 9 9 ND ND ND ND ND
Table A2:EW-1 Treatment Parameter Summary
Treatment Parameter #of Results #of Non-Detects Average(mg/L) Min(mg/L) Max(mg/L) Range(mg/L) Std Dev(mg/L)
Aluminum 3 1 0.06 0.04 0.09 0.05 0.04
Bromide 12 12 ND ND ND ND ND
Calcium 3 0 2.70 2.60 2.80 0.20 0.10
Carbonate Alkalinity 0 0 - - - - -
Chloride 12 0 7.19 6.30 10.00 3.70 1.00
Fluoride 3 3 ND ND ND ND ND
Hardness 0 0 - - -- -- -
Iron 24 0 1.73 1.40 2.10 0.70 0.23
Magnesium 3 0 1.37 1.30 1.50 0.20 0.12
Manganese 23 0 0.02 0.02 0.03 0.01 0.00
pH 2 0 6.90 -- -- -- 0.14
Phosphate 1 1 ND ND ND ND ND
Sulfate 12 0 15.08 14.00 17.00 3.00 1.00
Total Dissolved Solids 3 0 64.00 51.00 78.00 27.00 13.53
Total Organic Carbon 12 12 ND ND ND ND ND
Total Suspended Solids _ 3 0 8.80 5.90 13 00 7 10 3.72
�e
*pH expressed in standard units
Legend:
ug/L=micrograms per liter
mg/L=milligrams per liter
Min=minimum
Max=maximum
Range=difference between max and min
Std Dev=standard deviation
Prepared by:Geosyntec Consultants of NC,P.C.
Engineering Report-Groundwater and Seeps Treatment System

June 2021
Table A3:EW-3 Table 3+Compound Summary
Location: E W-3
Table 3+Compounds #of Results #of Non-Detects Average(ug/L) Min(ug/L) Max(ug/L) Range(ug/L) Std Dev(ug/L)
EVE Acid 15 12 0.097 0.095 0.1 0.005 0.002645751
Hfpo Dimer Acid 10 0 13.03 9.30 16.00 6.70 2.15
Hydro-EVE Acid 15 0 0.75 0.42 1.10 0.68 0.20
Hydrolyzed PSDA 15 0 4.25 1.50 6.50 5.00 1.85
Hydro-PS Acid 15 0 0.51 0.16 0.98 0.82 0.36
NVHOS 13 0 1.52 0.43 4.80 4.37 1.36
PEPA 15 0 2.85 1.80 4.90 3.10 0.77
PES 15 11 0.00 0.00 0.01 0.00 0.00
PFECA B 15 15 ND ND ND ND ND
PFECA-G 15 15 ND ND ND ND ND
PFMOAA 15 0 132.13 27.00 470.00 443.00 129.07
PFO2HxA 15 0 32.53 14.00 91.00 77.00 20.87
PFO3OA 15 0 14.77 5.20 43.00 37.80 11.94
PFO4DA 15 0 6.76 1.20 20.00 18.80 6.66
PFOSDA 15 6 0.91 0.01 2.40 2.39 0.77
PMPA 15 0 8.41 5.70 12.00 6.30 1.78
PS Acid 15 8 0.42 0.23 0.56 0.33 0.12
R-EVE 15 2 0.73 0.17 1.20 1.03 0.33
R-PSDA 15 0 1.21 0.65 1.70 1.05 0.33
R-PSDCA 15 3 0.04 0.01 0.10 0.09 0.03
Table A4 EW-3 Treatment Parameter Summary
Treatment Parameter #of Results #of Non-Detects Average(mg/L) Min(mg/L) Max(mg/L) Range(mg/L) Std Dev(mg/L)
Aluminum 3 0 0.75 0.41 1.40 0.99 0.56
Bromide 22 22 ND ND ND ND ND
Calcium 3 0 8.43 7.70 9.30 1.60 0.81
Carbonate Alkalinity 0 0 - - - - -
Chloride 22 0 12.42 3.00 16.00 13.00 2.67
Fluoride 4 3 0.32 0.32 0.32 -- -
Hardness 0 0 -- -- -- -- -
Iron 44 0 9.37 2.60 14.00 11.40 3.10
Magnesium 3 0 5.10 4.80 5.40 0.60 0.30
Manganese 43 0 0.20 0.16 0.25 0.09 0.02
pH 3 0 6.83 -- -- -- 0.29
Phosphate 1 1 ND ND ND ND ND
Sulfate 22 0 59.95 14.00 72.00 58.00 12.44
Total Dissolved Solids 4 1 123.33 120.00 130.00 10.00 5.77
Total Organic Carbon 22 16 0.74 0.50 0.98 0.48 0.20
Total Suspended Solids 4 0 31.08 3.30 87.00 83.70 37.92
*pH expressed in standard units
Legend.
ug/L=micrograms per liter
mg/L=milligrams per liter
Min=minimum
Max=maximum
Range=difference between max and min
Std Dev=standard deviation
Engineering Report-Groundwater and Seeps Treatment System Prepared by:Geosyntec Consultants of NC,P.C.

June 2021
Table A5:PIW-l0S Table 3+Compound Summary
Location: P1 W-l 0 S
Table 3+Compounds #of Results #of Non-Detects Average(ug/L) Min(ug/L) Max(ug/L) Range(ug/L) Std Dev(ug/L)
EVE Acid 7 7 ND ND ND ND ND
Hfpo Dimer Acid 6 0 3.23 2.80 3.90 1.10 0.45
Hydro-EVE Acid 7 1 0.01 0.01 0.01 0.00 0.00
Hydrolyzed PSDA 7 7 ND ND ND ND ND
Hydro-PS Acid 7 0 0.11 0.09 0.15 0.06 0.02
NVHOS 6 1 0.03 0.02 0.04 0.01 0.01
PEPA 7 0 1.69 1.50 2.10 0.60 0.23
PES 7 7 ND ND ND ND ND
PFECA B 7 7 ND ND ND ND ND
PFECA-G 7 7 ND ND ND ND ND
PFMOAA 7 0 2.99 1.50 4.70 3.20 1.14
PFO2HxA 7 0 3.70 2.40 5.40 3.00 1.03
PFO3OA 7 0 0.70 0.45 0.99 0.54 0.20
PFO4DA 7 0 0.26 0.16 0.37 0.21 0.08
PFO5DA 7 2 0.02 0.01 0.03 0.02 0.01
PMPA 7 0 4.91 4.00 5.70 1.70 0.71
PS Acid 7 7 ND ND ND ND ND
R-EVE 7 0 0.15 0.09 0.20 0.11 0.04
R-PSDA 7 0 0.31 0.19 0.42 0.23 0.10
R-PSDCA 7 7 NI) ND ND ND ND
Table A6:PIW-10S Treatment Parameter Summary
Treatment Parameter #of Results #of Non-Detects Average(mg/L) Min(mg/L) Max(mg/L) Range(mg/L) Std Dev(mg/L)
Aluminum 4 0 0.84 0.62 1.20 0.58 0.28
Bromide 12 12 ND ND ND ND ND
Calcium 4 0 0.44 0.43 0.46 0.03 0.02
Carbonate Alkalinity 0 0 -- - - - -
•
Chloride 12 0 4.13 3.10 5.50 2.40 0.66
Fluoride 3 3 ND ND ND ND ND
Hardness 0 0 - - -- - --
Iron 24 13 0.52 0.04 2.60 2.56 0.78
Magnesium 4 0 0.60 0.58 0.61 0.03 0.01
Manganese 24 0 0.01 0.01 0.01 0.00 0.00
pH 3 0 6.77 - -- - 0.25
Phosphate 0 0 - 0.00 0.00 - --
Sulfate 12 0 9.94 9.00 11.00 2.00 0.67
Total Dissolved Solids 3 0 30.67 27.00 33.00 6.00 3.21
Total Organic Carbon 12 3 0.85 0.67 1.10 0.43 0.15
Total Suspended Solids 3 0 9.63 3.90 19.00 15.10 8.18
*pH expressed in standard units
Legend:
ug/L=micrograms per liter
mg/L=milligrams per liter
Min=minimum
Max=maximum
Range=difference between max and min
Std Dev=standard deviation
Engineering Report-Groundwater and Seeps Treatment System Prepared by:Geosyntec Consultants of NC,P.C.

June 2021
Table A7,PIW-5S Table 3+Compound Summary
Location: PIW-5 S
Table 3+Compounds #of Results #of Non-Detects Average(ug/L) Min(ug/L) Max(ug/L) Range(ug/L) Std Dev(ug/L)
EVE Acid 6 0 0,986666667 0.57 1.8 1.23 0.478567306
Hfpo Dimer Acid 5 0 33.80 25.00 41.00 16.00 5.97
Hydro-EVE Acid 6 0 1.55 0.82 2.00 1.18 0.40
Hydrolyzed PSDA 6 0 15.67 5.00 28.00 23.00 8.26
Hydro-PS Acid 6 0 1.25 0.58 1.40 0.82 0.33
NVHOS 5 0 0.70 0.65 0.77 0.12 0.04
PEPA 6 0 26.00 17.00 44.00 27.00 10.16
PES 6 6 ND ND ND ND ND
PFECA B 6 6 ND ND ND ND ND
PFECA-G 6 6 ND ND ND ND ND
PFMOAA 6 0 38.00 31.00 61.00 30.00 11.42
PFO2HxA 6 0 31.17 27.00 38.00 11.00 4.07
PFO3OA 6 0 8.58 7.50 10.00 2.50 0.97
PFO4DA 6 0 7.05 4.70 8.70 4.00 1.34
PFO5DA 6 0 5.23 1.90 6.60 4.70 1.76
PMPA 6 0 60.67 39.00 100.00 61.00 23.53
PS Acid 6 0 2.32 1.30 4.30 3.00 1.13
R-EVE 6 0 2.42 1.90 3.00 1.10 0.42
R-PSDA 6 0 3.70 2.90 4.70 1.80 0.63
R-PSDCA 6 0 0 05 0.04 0 07 0.03 0.01
Table A8:PIW-5S Treatment Parameter Summary
Treatment Parameter #of Results #of Non-Detects Average(mg/L) Min(mg/L) Max(mg/L) Range(mg/L) SW Dev(mg/L)
Aluminum _ 0 0.91 0.86 0.96 0.10 0.07
Bromide 11 I ND ND ND ND ND
Calcium _ 0 1.95 1.90 2.00 0.10 0.07
Carbonate Alkalinity 0 0 - - - - -
Chloride II 0 5.80 5.40 6.30 0.90 0.28
Fluoride 2 2 ND ND ND ND ND
Hardness 0 0 - - -- -- --
Iron 22 0 0.79 0.04 12.00 11.96 2.52
Magnesium 2 0 0.82 0.79 0.84 0.05 0.04
Manganese 22 0 0.02 0.02 0.03 0 01 0.00
pH 2 0 6.75 -- -- -- 0.35
Phosphate 0 0 -- 0.00 0.00 -- -
Sulfate 11 0 22.36 20.00 24.00 4.00 1.63
Total Dissolved Solids 2 0 51.00 46.00 56.00 10.00 7.07
Total Organic Carbon 11 1 0.90 0.52 1.10 0.58 0.20
Total Suspended Solids 2 0 2.45 2.00 2.90 0.90 0.64
*pH expressed in standard units
Legend:
ug/L=micrograms per liter
mg/L=milligrams per liter
Min=minimum
Max=maximum
Range=difference between max and min
Std Dev=standard deviation
Engineering Report-Groundwater and Seeps Treatment System Prepared by:Geosyntec Consultants of NC,P.C.

June 2021
Table A9:SEEPA-TR-N Table 3+Compound Summary
Location: SEEPA-TR-N
Table 3+Compounds #of Results #of Non-Detects Average(ug/L) Min(ug/L) Max(ug/L) Range(ug/L) Std Dev(ug/L)
EVE Acid 7 7 ND ND ND ND ND
Hfpo Dimer Acid 4 0 12.85 8.40 19.00 10.60 4.51
• Hydro-EVE Acid 7 2 0.08 0.06 0.10 0.04 0.02
Hydrolyzed PSDA 7 4 0.05 0.03 0.08 0.05 0.03
Hydro-PS Acid 7 2 0.28 0.24 0.33 0.09 0.04
NVHOS 6 2 0.09 0.07 0.12 0.05 0.03
PEPA 7 2 4.52 2.90 6.80 3.90 1.68
PES 7 7 ND ND ND ND ND
PFECA B 7 7 ND ND ND ND ND
PFECA-G 7 7 ND ND ND ND ND
PFMOAA 7 2 6.20 5.00 7.90 2.90 1.16
PFO2HxA 7 2 12.54 9.70 16.00 6.30 2.49
PFO3OA 7 2 2.12 1.70 2.80 1.10 0.43
PFO4DA 7 2 1.44 1.20 1.80 0.60 0.25
PFOSDA 7 2 0.35 0.32 0.38 0.06 0.02
PMPA 7 2 13.02 9.10 17.00 7.90 3.36
PS Acid 7 7 ND ND ND ND ND
R-EVE 7 2 0.50 0.26 0.89 0.63 0.26
R-PSDA 7 2 0.96 0.48 1.60 1.12 0.47
R-PSDCA 7 4 0.01 0.00 0.01 0.00 0.00
Table A10:SEEPA-TR-N Treatment Parameter Summary
Treatment Parameter #of Results #of Non-Detects Average(mg/L) Min(mg/L) Max(mg/L) Range(mg/L) Std Dev(mg/L)
Aluminum 2 0 14.14 0.27 28.00 27.73 19.61
Bromide 11 10 0.27 0.27 0.27 - -
Calcium 2 0 1.30 1.00 1.60 0.60 0.42
Carbonate Alkalinity 0 0 - - -- -- --
Chloride 11 0 4.16 3.50 5.40 1.90 0.54
Fluoride 2 2 ND ND ND ND ND
1 lardness 0 0 -- -- -- -- --
Iron 22 0 13.90 0.74 44.00 43.26 14.73
Magnesium 2 0 1.46 0.82 2.10 1.28 0.91
Manganese 22 0 0.17 0.05 0.55 0.50 0.12 _
pH 2 0 6.75 -- -- - -- 0.35
Phosphate 0 0 -- 0.00 0.00 -- -
Sulfate 11 0 10.73 10.00 12.00 2.00 0.79
Total Dissolved Solids 2 0 106.00 42.00 170.00 128.00 90.51
Total Organic Carbon 11 0 12.88 5.30 24.00 18.70 5.74
Total Suspended Solids 2 0 1100.00 1 100 00 1100.00 -- 0.00
*pH expressed in standard units
Legend:
ug/L=micrograms per liter
mg/L=milligrams per liter
Min=minimum
Max=maximum
Range=difference between max and min
Std Dev=standard deviation
Engineering Report-Groundwater and Seeps Treatment System Prepared by:Geosyntec Consultants of NC,P.C.

June 2021
Table All SEEPA-WALL Table 3+Compound Summary
Location: SEEPA-WALL
Table 3+Compounds #of Results #of Non-Detects Average(ug/L) Min(ug/L) Max(ug/L) Range(ug/L) Std Dev(ug/L)
EVE Acid 24 0 1.219166667 0.14 9.1 8.96 1.728462289
Hfpo Dimer Acid 11 0 28.36 19.00 41.00 22.00 5.94
Hydro-EVE Acid 24 0 1.60 0.14 3.50 3.36 0.72
Hydrolyzed PSDA 24 0 24.05 3.30 72.00 68.70 16.10
Hydro-PS Acid 29 3 1.35 0.01 3.50 3.49 0.57
NVHOS 23 0 1.03 0.23 1.70 1.47 0.44
PEPA 28 0 11.75 6.90 22.00 15.10 4.75
PES 24 24 ND ND ND ND ND
PFECA B 24 24 ND ND ND ND ND
PFECA-G 29 29 ND ND ND ND ND
PFMOAA 29 0 70.93 15.00 130.00 115.00 41.13
PFO2HxA 29 0 35.38 18.00 55.00 37.00 11.30
PFO3OA 29 0 11.44 4.40 18.00 13.60 4.16
PFO4DA 29 0 6.91 1.40 11.00 9.60 2.28
PFOSDA 29 1 4.47 0.25 7.10 6.85 1.54
PMPA 28 0 27.25 17.00 46.00 29.00 7.94
PS Acid 29 2 4.56 0.02 _ 31.00 30.98 5.92
R-EVE 24 0 1.36 0.80 3.60 2.80 0.53
R-PSDA 24 0 2.47 0.32 8.30 7.98 1.42
R-PSDCA 24 5 0.06 0.02 012 010 0.02
Table Al2:SEEPA-WALL Treatment Parameter Summary
Treatment Parameter I #of Results #of Non-Detects Average(mg/L) Alin(mg/L) Max(mg/L) Range(mg/L) Std Dev(mg/L)
Aluminum 7 0 3.48 0.11 14.00 13.89 4.93
Bromide 12 12 ND ND _ ND ND ND
Calcium 7 0 3.14 1.31 6.40 5.09 2.24
Carbonate Alkalinity _ 5 5 ND - - - ND
Chloride 18 0 5.56 4.00 12.20 8.20 2.07
Fluoride 3 2 0.41 0.41 0.41 -- -- _
Hardness 0 0 -- -- -- -- --
Iron 27 0 1.63 0.07 21.40 21.33 4.10
Magnesium 7 0 0.89 0.51 1.50 0.99 0.36
Manganese 27 0 0.05 0.02 0.42 0.40 0.08
pH 3 0 6.77 -- -- -- 0.25
Phosphate 5 4 1.00 1.00 1.00 -- -
Sulfate 16 0 14.88 8.60 30.30 21.70 5.96
Total Dissolved Solids 7 0 62.64 39.50 113.00 73.50 26.15
Total Organic Carbon 16 0 2.98 0.58 10.40 9.82 2.31
Total Suspended Solids 9 0 124.26 4.70 712.00 707.30 223.19
*pH expressed in standard units
Legend:
ug/L=micrograms per liter
mg/L=milligrams per liter
Min=minimum
Max=maximum
Range=difference between max and min
Std Dev=standard deviation
Engineering Report-Groundwater and Seeps Treatment System Prepared by:Geosyntec Consultants of NC,P.C.

June 2021
Table A13:SEEPB-WALL Table 3+Compound Summary
Location. SEEPB-WALL
Table 3+Compounds #of Results #of Non-Detects Average(ug/L) Min(ug/L) Max(ug/L) Range(ug/L) Std Dev(ug/L)
EVE Acid 29 0 8.624137931 1.4 46 44.6 11.3600382
Hfpo Dimer Acid 17 0 37.47 25.00 85.00 60.00 18.93
Hydro-EVE Acid 29 0 3.30 0.85 11.00 10.15 2.77
Hydrolyzed PSDA 29 0 43.93 21.00 120.00 99.00 22.31
Hydro-PS Acid 33 2 1.63 0.49 4.70 4.21 1.32
NVHOS 28 0 3.57 1.80 8.50 6.70 1.88
PEPA 31 0 22.13 12.00 50.00 38.00 11.69
PES 29 25 0.07 0.01 0.21 0.20 0.10
PFECA B 29 27 0.11 0.05 0.17 0.12 0.09
PFECA-G 33 31 0.11 0.00 0.21 0.21 0.15
PFMOAA 33 0 118.08 4.80 200.00 195.20 80.31
PFO2HxA 33 0 34.76 11.00 50.00 39.00 13.64
PFO3OA 33 0 7.20 2.50 12.00 9.50 2.80
PFO4DA 33 0 1.95 0.79 7.70 6.91 1.20
PFO5DA 33 5 0.72 0.13 1.90 1.77 0.62
PMPA 31 0 47.19 32.00 87.00 55.00 17.18
PS Acid 33 1 7.56 0.04 31.00 30.96 8.97
R-EVE 29 0 4.38 2.00 13.00 11.00 3.45
R-PSDA 29 0 5.81 2.50 16.00 13.50 3.64
R-PSDCA 29 2 0.11 0.05 0.38 0.33 0.10
Table A14:SEEPB-WALL Treatment Parameter Summary
Treatment Parameter #of Results #of Non-Detects Average(mg/L) Min(mg/L) Max(mg/L) Range(mg/L) Std Dev(mg/L)
Aluminum 6 0 0.80 0.39 1.45 1.06 0.46
Bromide 12 12 ND ND ND ND ND
Calcium 6 0 0.96 0.69 1.58 0.89 0.32
Carbonate Alkalinity 4 4 ND - - - ND
Chloride 20 0 7.67 5.00 16.20 11.20 2.97
Fluoride 3 3 ND ND ND ND ND
Hardness 0 0 -- -- -- -- -
Iron 26 0 0.85 0.37 3.75 3.38 0.68
Magnesium 6 0 0.82 0.67 1.31 0.64 0.25
Manganese 26 0 0.03 0.02 0.41 0.40 0.08
pH 3 0 6.67 -- _ -- - 0.29
Phosphate 4 4 ND ND ND ND ND
Sulfate 15 0 10.70 7.00 24.40 17.40 4.70
Total Dissolved Solids 6 0 46.33 26.00 74.00 48.00 15.64
Total Organic Carbon 15 0 3.92 2.60 5.50 2.90 0.87
Total Suspended Solids 10 0 93.60 11.00 1 300.00 289.00 113.50
*pH expressed in standard units
Lend:
ug/L=micrograms per liter
mg/L=milligrams per liter
Min=minimum
Max=maximum
Range=difference between max and min
Std Dev=standard deviation
Engineering Report-Groundwater and Seeps Treatment System Prepared by:Geosyntec Consultants of NC,P.C.

Attachment A.6 - Engineering Alternatives
Analysis — Treatment of Groundwater and
Upgradient Seeps Water

Geosyntec
consultants
Geosyntec Consultants of NC,P.C.
NC License No.:C-3500 and C-295
ENGINEERING ALTERNATIVES
ANALYSIS (EAA) - TREATMENT OF
GROUNDWATER AND UPGRADIENT
SEEPS WATER
Prepared for
The Chemours Company FC, LLC
1007 Market Street
PO Box 2047
Wilmington, DE 19899
Prepared by
Geosyntec Consultants of NC, P.C.
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
Geosyntec Project Number TR0795
June 2021

Geosyntec°
a,ll5a��l,e�
Cgosyutoci;omulauMsurNC,P.C.
NC UeenseN C-3600atr*C-$
Applicant's Information:
Applicant Name: The Chemours Company FC, LLC
Facility Name: Fayetteville Works
Facility Mailing Address: 22828 NC Highway 87 W, Fayetteville NC 28306
County: Bladen
Phone Number: [phone]
Preparer's Information:
EAA Preparer: Geosyntec Consultants of NC, PC
Mailing Address: Atrium at Blue Ridge, 2501 Blue Ridge Road, Suite 430, Raleigh, NC
27607
Phone Number: [phone]
Contact Person: Adrienne Nemura, P.E.(M1,NC,OH)
TR0795 ii June 2021

Geosyntec a
TABLE OF CONTENTS
1. SITE HISTORY AND BACKGROUND 1
2. PROJECT SUMMARY 4
3. STEP 1 — ALLOWABILITY OF PROPOSED DISCHARGE 5
3.1 Analysis of Allowable Discharge Criteria 5
3.1.1 Applicability of the Local Government Review 5
3.1.2 EAA Guidance on Potential Restrictions 5
4. STEP 2: TREATMENT SYSTEM FLOW PROJECTION 10
4.1 Geological Descriptions 10
4.2 Extracted Groundwater Flow Estimate 12
4.3 Captured Seep Water Flow Estimate 12
4.4 Combined Flow Estimate 13
4.5 Pumping and Conveyance Design 16
5. STEP 3 ALTERNATIVES 16
5.1 Technologically Feasible Discharge Alternatives 17
5.1.1 Connection to Existing Public Treatment Plant 17
5.1.2 Wastewater Reuse 17
5.1.3 Direct Discharge 18
6. STEP 4 ECONOMICS 21
6.1 Economic Feasibility of Alternatives 21
6.1.1 PVCA Calculation Method 22
6.1.2 PVCA Summary 22
7. CONCLUSION AND PATH FORWARD 23
8. REFERENCES 24
TR0795 iii June 2021

Geosyntec°
consultants
G.eo. „ c, xktsof��P�..
NCU N -:
LIST OF TABLES
Table 1: Hydraulic Loading of Representative Groundwater and Seep Sources
Table 2: Present Value Cost Analysis Summary Table
LIST OF FIGURES
Figure 1: Site Location Map
Figure 2: Remedy Alignment & Proposed Groundwater Treatment System Location
Figure 3: Cape Fear River Classification
Figure 4: High Resolution Cross Section with Interpreted Geology
Figure 5: Numerical Modeling Simulated Groundwater Levels
Figure 6: Seep Flume and Proposed Capture Locations
Figure 7: Conceptual Process Flow Diagram of Primary Treatment Process and Solids
Recovery Process
LIST OF APPENDICES
Appendix A: PWC Refusal to Accept Treated Wastewater
Appendix B: Cost Estimates
TR0795 iv June 2021

Geos tec°
ACRONYMS AND ABBREVIATIONS
7Q10 seven-day, 10-year average low flow
BCA Black Creek Aquifer
cfs cubic feet per second
CO Consent Order
DWR Division of Water Resources
EAA Engineering Alternatives Analysis
ECOS Environmental Conservation Online System
EPA U.S. Environmental Protection Agency
GAC Granular Activated Carbon
gpm gallons per minute
GWTS Groundwater Treatment System
HDPE high density polyethylene
HFPO-DA hexafluoropropylene oxide-dimer acid
IPaC Information from the Planning and Consultation
NCDEQ North Carolina Department of Environmental Quality
NPDES National Pollutant Discharge Elimination System
PFAS per- and polyfluoroalkyl substances
PFD process flow diagram
PFMOAA perfluoro-1-methoxyacetic acid
PMPA perfluoro-2-methoxypropanoic acid
POTW Publicly Owned Treatment Works
TMDL Total Maximum Daily Load
WRF Water Reclamation Facility
WWTP wastewater treatment plant
TR0795 v June 2021

GeosYn tec°
consultants
uei�tdteuus n1 NAY,PC_
N.A C;-lRtp attd i0'96
1. SITE HISTORY AND BACKGROUND
In accordance with 15A NCAC 2H.0105(c)(2), Chemours Company FC, LLC (Chemours) has
prepared this Engineering Alternatives Analysis (EAA) for review by the North Carolina
Department of Environmental Quality (NCDEQ). The EAA supports the National Pollutant
Discharge Elimination System (NPDES) permit application for the discharge of groundwater
and surface water from locations along the proposed groundwater remedy alignment at the
Fayetteville Works Facility (the Site), Bladen County, North Carolina.
Pursuant to paragraphs 2(c)(i) and 3(b) of the signed Addendum to the Consent Order paragraph
12 (CO Addendum) entered by the court on October 12, 2020, Chemours will install a
groundwater extraction remedy supported by a barrier wall and capture seep flow originating
upgradient of the remedy and treat these waters prior to discharge. The Groundwater Treatment
System (GWTS) is to have a removal efficiency of 99%,as indicated by the three indicator per-
and polyfluoroalkyl substances (PFAS) constituents PFMOAA, PMPA and HFPO-DA 1 from
this flow to meet the requirements and criteria stipulated in the Addendum to the CO. A
NPDES permit application and supporting EAA is a pre-requirement for the construction and
operation of the GWTS to treat water from the groundwater and upgradient seep flow.
The remedy, which includes groundwater extraction and a GWTS, is to commence operation
by March 15, 2023 per paragraph 3(b) of the Addendum to the CO. To meet this requirement,
Chemours intends to complete construction of the GWTS by April 1, 2022. Chemours will
need to pump and treat the water collected by the remedy. The GWTS therefore needs to be
operational prior to commencement of remedy and extraction network construction in June
2022 to protect the integrity of the barrier wall.
The Site is located on NC Highway 87, 15 miles southeast of the City of Fayetteville, and south
of the Bladen-Cumberland County line. The Site encompasses 2,177 acres of relatively flat
undeveloped open land and woodland bounded on the east by the Cape Fear River, on the west
by NC Highway 87, and on the north and south by farmland. The site's location is shown in
Figure 1.
E.I. du Pont de Nemours and Company (DuPont) purchased the property in parcels from
several families in 1970.The Site's first manufacturing area was constructed in the early 1970s.
Currently, the Site manufactures plastic sheeting, fluorochemicals, and intermediates for
plastics manufacturing. A former manufacturing area,which was sold in 1992, produced nylon
strapping and elastomeric tape.
PFMOAA-perfluoro-2-methoxyacetic acid
PMPA-perfluoro-2-methoxypropionic acid
HFPO-DA-hexafluoropropylene oxide-dimer acid
TR0795 1 June 2021

Geosyntec°
consultants
G i (%c QC.
tamor Nu't,WiM:n.4 4 n;
DuPont sold its Butacite® and SentryGlas® manufacturing units to Kuraray America, Inc. in
June 2014. In July 2015, DuPont separated its specialty chemicals business into a new publicly
traded company named The Chemours Company FC, LLC. With this separation, Chemours
became the owner of the entire 2,177 acres of the Fayetteville Works along with the
Fluoromonomers, Nafion® membranes, and Polymer Processing Aid (PPA) manufacturing
units. The polyvinyl fluoride (PVF) resin manufacturing unit remained with DuPont.
In addition to the manufacturing operations, Chemours operates two natural gas-fired boilers
and a biological wastewater treatment plant (WWTP) for the treatment of DuPont and Kuraray
process wastewater and sanitary wastewaters from DuPont, Kuraray, and Chemours.
TR0795 2 June 2021

Geosyntec C>
consultants
<:r ar7"raN�:�.A/TNiH101r4k el NC,P,C
Limpai No..:t;-351V and t'-295
fN
t r
rW3 t
fit,....
Old OUEfaFf 002
Legend A....
Sae B.wrltlnry ...__
Near.Tnauaary
1.�.1 Ma./acMieg Area Sae Location Map
Nce-MartJact,ng Area Chances Fayetterdle works.North Carolnra
�.. an,/'w ov ny maex aau 9na in:+v,e Srla l�+ C amour'utraYe�OUVW"JGY:�rn¢��pG��. �.A - aiTeomie'psuiN'tln xeYa. \.l�GeitVi.Ai s Figure
Cap4 KaliaeWrwn rs. 4les1 d.tanAreGN 0,Ime NA NSF'Cram Ovaatmnd
3N— Et09�G GviE kar LevyarNcs CNESAAaw03 USDA 000$Aeo0Po0.I.sr.* 1
GS lw CcnmanN Ratemh JyW 2020
Figure 1:Site Location Map
TR0795 3 June 2021

Geosyntec°
consultants
Gr umec mwiasettie,ec.
2. PROJECT SUMMARY
The groundwater and upgradient seep flow will be captured west of a newly constructed
groundwater remedy consisting of extraction wells and supported by a barrier wall.The location
of the GWTS is also anticipated to be in the vicinity of the Site's Outfall 002 discharge. The
preliminary location is shown in Figure 2.
S
S
S
Proposed
new GWTS
location
S
Legend
!Q Extraction well
Planned groundwater remedy route as
Figure 2:Remedy Alignment&Proposed Groundwater Treatment System Location
The GWTS will be comprised of a series of chemical and physical separation steps. Chemical
oxidation and pH adjustment will first be employed to precipitate metals, such as iron, to
prevent downstream contamination or fouling of the granulated activated carbon (GAC) media.
The precipitated metals and other particles above an appropriate control threshold will be
removed via ultrafiltration membranes or some other suitable separation technology. The
filtered effluent will then be treated for per- and polyfluoroalkyl substances (PFAS) by GAC
adsorption. The reject from the filtration and GAC systems will undergo dewatering through a
thickening tank and filter press or centrifugation, from which the sludge cake will be disposed
of offsite and the press water will be recycled to the influent of the thickening tanks. Periodic
backwashing will extend membrane and carbon media life, and the carbon will be removed and
replaced based on breakthrough monitoring of several three-vessel carbon trains in a lead-
middle-lag arrangement. Associated design elements such as pumps, piping, electrical,
instrumentation and control for interlocks, mechanical and civil/structural elements will be
finalized during the detailed design phase. This design concept may be optimized based on
ongoing benchtop studies and data acquisition.
TR0795 4 June 2021

Geosyntec a
c t�rR4ttlo�tr�tti
GernyukvCuMd toTt4C;PC.
Additional process details associated with the treatment system are discussed later in this
document, under the "Direct Discharge Evaluation" section. A conceptual Process Flow
Diagram (PFD) showing the treatment schematic is also discussed in the same section.
3. STEP 1 - ALLOWABILITY OF PROPOSED DISCHARGE
3.1 Analysis of Allowable Discharge Criteria
Based on the CO, the remedy will intercept groundwater and capture dry weather flow plus
stormwater from 0.5-inch or less storm events from seeps daylighting upgradient of the remedy
alignment. The water will be treated and discharged through the pipe which conveys the
existing Outfall 002 effluent to the Cape Fear River. All the intercepted and captured waters'
streams were flowing towards either the Cape Fear River or one of its tributaries of Willis
Creek and the Old Outfall. Therefore, no new flow will be added to the Cape Fear River that
would not have been introduced under the current conditions.
Applicability of the local government review and a stepwise assessment for each potential
restriction of the receiving waterbody per the NCDEQ EAA guidance document is addressed
below. The NCDEQ EAA guidance language is in italics, and a discussion follows.
3.1.1 Applicability of the Local Government Review
Per the EAA guidance document, the North Carolina General Statute 143-215.1 (c)(6) allows
input from local governments regarding the issuance of NPDES permits for new non-municipal
domestic wastewater treatment facilities. As this facility is intended to treat groundwater and
surface water containing PFAS at an existing industrial facility due to a consent order, local
government review form does not need to be completed.
3.1.2 EAA Guidance on Potential Restrictions
EAA Guidance:Zero flow stream restrictions[15A NCAC 2B.0206(d)(2)1 apply to oxygen-consuming
waste in zero flow streams. In order to determine streamflow at the proposed discharge location,
contact the U.S. Geological Survey at 919-571-4000.
EAA Guidance on Streamllow:Low flow data (specifically, drainage area, summer and winter 7Q10,
average flow and 30Q2 flow statistics) are required to support the EAA.
The Cape Fear River is the receiving body for the discharge from the GWTS. This discharge
will mix with effluent from Outfall 002 in the outfall's discharge pipe prior to reaching the
river. The river's hydrologic unit code is 03030005. Based on available data from the U.S.
Geological Survey at the William O. Huske Lock and Dam (Station ID 02105500), the annual
average streamflow from January 2011 to January 2021 was 4,424 cubic feet per second (cfs);
the Cape Fear River is a perennially flowing river. The seven-day, 10-year average low (7Q10)
flow is 467 cfs. As such, the Cape Fear River is not a zero-flow stream, and zero-flow stream
restrictions do not apply.
TR0795 5 June 2021

Geosyntec°yn
consultants
4nnslttrc Lama IW t$of W,Pc.
;vcLiwnsr •(.4504 Andt-205
The proposed discharge will consist of ground water and surface water collected, treated (by
physical/chemical precipitation and carbon adsorption), and discharged into the pipe that
conveys Outfall 002 effluent to the Cape Fear River.The discharge therefore will be of a higher
quality than the existing flows of groundwater and surface water and also have a lower amount
of oxygen consuming constituents than are currently present. There will also be no addition of
any external flow or constituents since this water is currently discharging to the Cape Fear
River. As previously stated, zero flow discharge restrictions are not applicable to the current
scenario because the Cape Fear River is not a zero-discharge stream. Additionally, the organic
compounds in this water will exert limited oxygen demand and will be further reduced due to
the GWTS.See Engineering Report—Treatment of Groundwater and Seeps Water(Geosyntec,
2021) for 5-day biological oxygen demand analytical results. Furthermore, this document
provides details of the unit processes for the GWTS.
EAA Guidance: Receiving stream classification restrictions [e.g., ORW, WS, SA, NSW, and HQ class
waters have various discharge restrictions or require stricter treatment standards]. Stream
classifications are available on the DWR Classification and Standards/Rule Review Branch website:
(http://portalncdenr.org/web/wq/ps/csu), while wastewater discharge restrictions for various stream
classifications are presented in state regulations[15A NCAC 2B.0200].
A review of publicly available resources, such as the NCDEQ Surface Water Classifications
maps, indicates the Cape Fear River is classified as WS-IV. WS-IV waters represent waters
used as sources of water supply for drinking, culinary, or food processing purposes for
moderately to highly developed watersheds. These waters are also protected for Class C uses
(fishable/swimmable). Figure 3 shows the Cape Fear River and its classification.
TR0795 6 June 2021

Geosynkec
cc�+wam t.atvr,.rc.
...arena,th F:;9 itaiam1c.:c5
•
r-
■.n„ =
p, . 4, ,..- vi,:' . x
au l 1'''.
"'w.r
��'n coyv.+i ea
a „) 4
6
� ,� Te•^c mar me xis E1�352
m
' ,'e .. w 1
,+ 3, '` -.
0.
- ' +
m
•
a..=u
r
s
a .: fir
1
1.
w h R
c.
F
t:3fi.11?
527,2021.3:41 32 PM
Classincatimn rhrS-IV
.i2 a?
I r , ti
)5 P v�
Figure 3: Cape Fear River Classification
As previously stated, the level of treatment expected from the GWTS will be such that negative
water quality impacts are not anticipated as a result of the proposed discharge.
TR0795 7 June 2021

GeosyntecD
consultants
Gxwssknlav:.t:.ufutllutasa7 t9t:.PC.
vc,Iscrwx Nu;C-4ROA nndt%.t9s
EAA Guidance: Basinwide Water Quality Plans. These basin-specific plans list NPDES permitting
strategies that may limit wastewater discharges to particular streams within the basin due to lack of
stream assimilative capacity, etc. Basin plans are available on the DWR website, or you may contact
the DWR Basinwide Planning Branch (http.//portalncdenr.org/web/wq/ps/bpu).
The 2005 Cape Fear River Basinwide Water Quality Plan2 is the most recent water quality plan
available. Details for Subbasin 03-06-15, which includes assessment unit 18-(26)c, are found
in Chapter 15. According to the water quality plan, the assessment unit is impaired for aquatic
life because of high levels of chlorophyll-a. Nutrient levels behind Lock and Dam 3 (i.e. the
W.O. Huske Dam) were high enough to support nuisance algal growth and during the drought
of 2001 and 2002, dissolved oxygen levels behind the structure dropped below the standard.
When stream flow conditions returned to normal, the dissolved oxygen levels recovered.
Chapter 15 of the report did not include the NPDES permit for Chemours (formerly DuPont);
however, DuPont was listed in Chapter 16 as discharging to Subbasin 03-06-16. The specific
location of the discharge from the DuPont WWTP was not given.According to the water quality
plan, the Cape Fear River mainstem in Subbasin 03-06-16, assessment unit 18(26)d also
experiences high levels of chlorophyll-a and low levels of dissolved oxygen. However, it
appears these segments were not included on the state list of impaired waters, due to lack of
data.
Based on the available data, the proposed discharge will be low in organic carbon and organic
nitrogen and should not cause a dissolved oxygen reduction.The discharge will include treated
flow from groundwater seeps that are currently discharging directly into the Cape Fear River.
The treatment of the seep flow will improve water quality conditions in the receiving water
body.
EAA Guidance:Impaired waters and[total maximum daily loads or] TMDLs. Certain
waterbodies listed as impaired on the 303(d)list and/or subject to impending TMDLs may
have wastewater discharge restrictions. The list of 303(d)impaired waters is located on the
DWR website, or you may contact the DWR Modeling and Assessment Branch
(h ttp://portal n cdenr.org/web/wq/ps/mtu)
Based on the latest available 303(d) list for the Cape Fear River Basin (North Carolina 2020
Draft 303(d) List3) the Lower Cape Fear River assessment unit 18-(26.25)b, where the
Chemours facility is located, is not impaired. This assessment unit stretches from Grays Creek
to the Lock and Dam 3 and receives a rating of BLUE, indicating all assessments are meeting
criteria. The assessment unit 18-(26.25)c, beginning at Lock and Dam 3 to approximately 0.5
2 https://deq.nc.gov/about/divisions/water-resources/planning/basin-planning/water-resource-plans/cape-fear-
2005,accessed 2/27/2021
3 NC 2020 DRAFT 303D LIST PR.pdf,accessed 2/26/2021
TR0795 8 June 2021

Geosyntec°
consultants
�c r c. ima%avc.Pc.
Sac License Nu:C-INOO and C 293
miles upstream of Smithfield Packing Company's intake, is rated GRAY indicating that the
available data are inconclusive. This stream segment is located immediately downstream of
the Chemours facility. The Cape Fear River is not listed on the 303(d) list as impaired at this
location, and there are no approved TMDLs that apply to the Cape Fear River at this location
that would impose discharge restrictions on a future permitted discharge.
EAA Guidance:Presence of Endangered Species. If endangered species are present in the
proposed discharge location, there may be wastewater discharge restrictions. Endangered
species information may be included in the Basinwide Water Quality Plan, or you may
contact the U.S. Fish and Wildlife Service (919-856-4520), N.C. Wildlife Resources
Commission (919-733-3633), or the N.C. Natural Heritage Program (919-733-7701).
The Environmental Conservation Online System (ECOS) was reviewed to determine if any
there are any endangered species present near the proposed discharge location. ECOS lists
endangered species by county. The list for Bladen County includes one aquatic species, the
Atlantic pigtoe clam, Fusconaia mason, as a proposed threatened species. However, further
review using the Information from the Planning and Consultation4 (IPaC) online planning tool
did not identify the Atlantic pigtoe clam at the location. It should be noted that while there are
no critical habitats at this location the online lists include two endangered flowering plants:
American chaffseeed (Schwalbea americana), and rough-leaved loosestrife (Lysimachia
asperulaefolia) that could be found in the area. The northern long-eared bat (Myotis
septentrionalis), wood stork (Mycteria americana), and American alligator (Alligator
mississippiensis) are listed as threatened and the red-cockaded woodpecker (Picoides borealis)
is listed as endangered. The monarch butterfly (Danaus plexippus) is listed as a candidate
species by ECOS. Given the lack of critical habitat and the transient (mobile) nature of many
of these species, it is highly unlikely they would be impacted by the proposed discharge.
4 https://ecos.fws.gov/ipac/location/VDIGH7JAVJCIXEDEUW450L3YKU/resources, accessed 2/27/2021
TR0795 9 June 2021

Geosyntec a
4. STEP 2: TREATMENT SYSTEM FLOW PROJECTION
Extracted groundwater and captured seep water will come from three water bearing units
present at Site listed in order from topmost to bottom most: the Perched Zone, the Surficial
Aquifer, and the Black Creek Aquifer. The total estimated flows are from the various sources
are described below in Table 1. Extracted groundwater will come primarily from the Black
Creek Aquifer with a relatively minor component of flow originating from the Surficial
Aquifer. The seeps captured at the barrier wall will receive flow from both the Perched Zone
and Surficial Aquifer. Figure 4 depicts the cross section of the remedy alignment and shows
the thicknesses of the Surficial and Black Creek Aquifer locations, and a description of each
water bearing until described below.
Fate and transport analyses at the Site demonstrated groundwater and onsite seeps as two
primary PFAS transport pathways to the Cape Fear River (Geosyntec, 2019a, 2021a).
Groundwater seeps, a common hydrogeological feature in sloping terrain such as that at the
Site, has also been determined to be one of the PFAS release mechanisms to surface water
receptors. The remainder of this sub-section provides a geological description of the water
bearing units and the methods by which conservative estimates (i.e. high end) flow rates for
extracted groundwater and seeps were developed.
4.1 Geological Descriptions
Perched Zone: The Perched Zone is a relatively thin, spatially limited layer of groundwater
present in silty sands to a depth of about 20 feet below ground surface. Groundwater in the
Perched Zone is recharged through precipitation onsite. Groundwater flows radially away from
a groundwater mound in the Perched Zone. This leads to groundwater discharge to the east at
seeps on the edge of the bluff (i.e. towards the river), to the south toward the Old Outfall 002,
and to the north and to the west downwards through the geological sequence towards the
Surficial and Black Creek Aquifers (BCA)
Surficial Aquifer: The Surficial Aquifer is an unconfined silty sand aquifer lying atop the
Black Creek Confining Unit and is present beneath the Perched Clay Unit. Groundwater in the
Surficial Aquifer flows towards the bluff faces at the Site (i.e. towards the river) —It flows both
north, east and west toward surface water bodies (Willis Creek, Seeps, Old Outfall 002) and
discharges into them as seeps.
Black Creek Aquifer: The BCA is comprised of fine to medium grained sands. The BCA
directly adjacent to the Cape Fear River. The BCA is interpreted to be the only transmissive
groundwater zone at Site in direct contact with the Cape Fear River. Groundwater in the BCA
flows from west to east towards the Cape Fear River.
TR0795 10 June 2021

Ueosyntec
consultants
GareoYnrec C;omadtatusatNt:.P.C.
NCLtxnce Nutt ehe®tint 295
0 1,000 2 000 3,000 4 000 5,000 6,000 7,000 8,0O0
South North
Seep B
9° Old Otll(all __ Crossing Intake Access Seep to r.o a 90
Channel ,� Seep A Road 'M s Creek"
Road to Crossing v ,�,�, w��
p
80
Ill
Ci
INI
I<11� �W2 � ial ° f -rs,. tli9 80 N
ll
�1
k �. BI ' �i . I1` $ F y I1
I.ll�di 'If I . in, a, ilia ,: i■ .,..., t
= III1 Fri ,ii poit,i �i a 11 i ! ' III , , , , ` 'a • 2
m 50 ^ ti \ t _, Y/t � — rh _'1--- 50
a a' r-- 1.:11k
I� � a I III ■ � l '.! ii,, .� I ' I � _ it !
1 ii
1-t', idi , fr, ,
s �! 1I
"41111IT •k‘• '-.. 1 :1111
I sriEl 1 ---mg.
''s 's 1 1 ,,) il
I 11 —11,1 iii.,...,,,,,,,,,
; 0 i ;,.., _ s i s t II t;•
-20
1 u ILIL) 2,00C 3 000 4 000 ,00O Ei,O0O 7000 fl 000
e
Distance Along Baseline(feet)
Legend ew«.
sane weaaed�,t u uses ta.F�asiwy ❑ Interpreted Geology Water Levels - .°B"
p<`etm Hiatt Resolution Cross Section with Interpreted Geology
seryasv 1, soma,awwrer a..,...mo Eo ... g.—
®uses Ken uses voo�N ®ups isPithy Ej°ewea crap erg c.e�.gwe. iocmm��,nrtea m., r Chem..Fayenewk wonrs north Camino
of 1 empk Cieek rv�naa+spor,svrn ttaee«a.�wp�psgm��a.t
@ wl^�.',$W 01ypep W0t-9r eC t6 PootYF+' Sand
❑Steno!Pouter +y �:. = upp..cop.Foot rRfa6ariaa�Wpold Geolaarvca
e II :v i.r53 " NW®Brie wTh SiftE. mrraT We�meesme■ re CI'Bt.*creek,Conrenrp one 11 Upper Cage Fear Coming UM GeO8rsyn w. + ,:"tvrw�.�,—,oay.a: Figure
[MI u, eaee att , uses crater sa d III uses ssalei
Bork Creek Cmfinsg Ust UPer Cape Fear BUM- BZi 31e 0 B27 consultants
1 0.0 1......-igt p. r iii —Zone Interspersed Znre d4�erspesetl Fwt 4
u9C' Oral il".tCS $ia
�sa' , ''/
Coarse Sedm>enK Coarser Se3rcnrs nuaau r-G2t wrlta H.Sa RatNyt May M21
Figure 4: High Resolution Cross Section with Interpreted Geology
TR0795 11 June 2021

Geosyntec°
consults
GrwwytMex: onu,lion.of NC,P.C.
4.2 Extracted Groundwater Flow Estimate
To model groundwater remedy scenarios in support of preparing a groundwater remedy design,
a three-dimensional (3D) transient-state finite element numerical groundwater flow model was
constructed in FEFLOW version 7.2 (DHI-WASY). The model domain covers an area
approximately 72,690,473 square ft (2.61 square miles) and models the hydrogeology of the
Site. The model varies in thickness from about 170 feet near the plant to 55 feet at the base of
the bluff adjacent to the Cape Fear River. The North Carolina Department of Public Safety
Light Detection and Ranging (LiDAR) elevation model was used to present ground surface
topography (NC DPS, 2015), while topography of the underlying model geology layers were
based on lithostratigraphic data obtained from Site monitoring wells, soil borings, hydraulic
profiling tool, and cone penetration tests contained in the three-dimensional visualization
model, EVSTM.
The model was calibrated to groundwater conditions and measurements observed from 2018
to 2020 using data from 139 Site wells: 60 wells in the Perched Zone, 32 wells in the Surficial
Aquifer, and 47 wells in the BCA. Results indicate that the model simulation compares
reasonably well with the observations from monitoring wells (Figure 5). This outcome
provided validation of the groundwater model's ability to simulate the field conditions.
The groundwater model was used to simulate remedy scenarios to identify which combination
and positioning of extraction wells and barrier wall would meet the CO Addendum paragraph
3(b) objective of intercepting groundwater flowing from under the facility towards the Cape
Fear River.The results of the remedy modeling indicates objectives can be met with extraction
wells in the BCA spaced at approximately 200 feet intervals with pumping rates varying
between 5 to 30 gallons per minute (gpm) per well with targeted extraction of the Surficial
Aquifer in specific locations. The progression of the design process presently indicates
approximately 60 groundwater extraction wells along the length of the remedy. These flow
simulations indicate extraction flow rates of 150 and 800 gpm from the Surficial and Black
Creek aquifers respectively.
4.3 Captured Seep Water Flow Estimate
The remedy is required to capture and treat the baseflow volume of seeps daylighting
upgradient of the remedy and stormwater flows from rain events of 0.5 inches or less. The
captured seep base flow rates were estimated using measured data from flumes and the
stormwater flows estimated using a hydrological model created using U.S. Environmental
Protection Agency's (EPA) Storm Water Management Model (SWMM).
The flumes installed in Seep A and B at locations A-4 and B-2 were used to estimate dry
weather baseflow rates (Figure 6). These two locations are both considerably downgradient of
the capture locations and therefore provide a high-end estimate of expected flow rates as more
seepage derived flow reaches these locations than at the capture location. Based on over 270
TR0795 12 June 2021

Geosyntec°
days of observation for each flume, the 95th percentile instantaneous dry weather flow readings
for Seep A was 31 gpm and Seep B was 130 gpm.
Stormwater flows from the seeps were estimated assuming 24-hour equalization storage for
pulses of volume from storm events up to 0.5 inches. The modeled volume of rainfall from
both seeps combined was estimated to be between 110,000 and 156,000 gallons. Equalized
over 24 hours, this results in a high end estimate of 108 gpm of flow.
4.4 Combined Flow Estimate
The present best estimate of flow to the GWTS was estimated from expected groundwater and
seep flows. Total expected groundwater flow was estimated via the results of the modeling
simulations and the seep flow was estimated via flume measurements that have been ongoing
since 2019. The estimated hydraulic loading in gpm from extracted groundwater and seeps for
the post-remedy construction condition is shown in Table 1.
Table 1: Hydraulic Loading of Representative Groundwater and Seep Sources
Source Approximate Flow Rate
0
Seeps Baseflow 161 gpm
*
Seeps Stormflow 108 gpm
°
Groundwater from Surficial Aquifer 150 gpm
Groundwater from Black Creek Aquifer 800 gpm
Total Flow 1,219 gpm
* Seeps stormflow represents maximum increase over baseflow averaged over 24-hour period.
0 Seeps baseflow and Shallow Groundwater may include some double counting.Seeps baseflow represents the 95th
percentile instantaneous flow from each of Seeps A and B at location representative of the remedy capture location.
TR0795 13 June 2021

Geosyntec
consultants
Gemynlec Conwitatxaaf Nt:,P.C.
NC 1Aceute No.:4-' 11aad C4PS
CBI
111, =, �
--
1
6
�3. li
' {II
,-* 9 4 � a ivy
as _' } .a_ ,, '.• 'E
_
. :> YN
y
zan I uqa .ea?
Lege./
ly
amyl Eau:potentas e'en NAVD 88,
Cw Buy Flow Model Simulated Equipotentials
a11�R Cmetlnt Head}?Boundary!}1'a°S CReekl
Chemars fayegevl?e works.Noah CsNra
�Tmwme,,t Head Baer Boundary,C�a Fear
Recarge Area
modead u-r G osyntec° r-���.o.W. �.a
NO*6 urxtsutranu ,�. �., ._.m
Ui sa.m ef11.8l .GeoEy.earaux G¢agcrdm CNE`.]A I D8
ara IS'^.AeCIGR10.IGN.a'd eN GIS:be cmttaemi.
Raleep March 2021
Figure 5: Numerical Modeling Simulated Groundwater Levels
TR0795 14 June2021

Ueosyntec°
consultants
Gttsyewec COniuttoottM NC.P.C..
NC i i Yates No.:G.,?B11n sod r'-293
fl
e .e h Legend
r Nt l - Seep A Upstream Capture
" r1 t `;R I Point
t t - Seep B Upstream Capture
ea' *Ia {t _. Point
Seep A-4 Flume Location
N Seep 8-2 Flume Location
l
t ... . Planned Groundwater Remedy
I
Route
% ...,'- Seep
w — . 'm t Estimated Watershed
- , Seep A-Modeled Catchment
"� k .. Seep B-Modeled Catchment
t, Seep A-Additional Catchment
✓ ' Measured by Flume
v - ,./ j,, // ,f /`0 �
// , ` , - Seep B-Additional Catchment
.>7,/,' ' Measured by Flume
r 1 Seep catchment areas were estimated using
geospabal methods and toots,and
r based on tidal-data collected for Chemours.
1 2.Seep locations identified veually as reported in
Geosyntec,2t119.Seeps and
s,. Creeks Investigation Report.Chemours
"' r ' Fayetteville Works.26 August 2019.
111 »3 3.Basemap source:Esri,DigitalGlobe,GeoEye.
' tt .,,, : Earthstar Geographies,
<
t CNES/Airbus DS,USDA,USGS,AeroGRID.IGN,
,,, _ a t and the GIS User Community.
I
500 250 0 500 Feet
r
3
I i
a
Seep Drainage Areas
e`,. Chemours Fayetteville Works,North Carolina
J
GCOSyrlteCD +......'M..a sir;
ccm*u1 t
Raleigh March 2021
Figure 6: Seep Flume and Proposed Capture Locations
TR0795 15 June 2021

Geasyntec°
consultants
4.5 Pumping and Conveyance Design
Groundwater modeling remedy development presently indicates approximately of 50 Black
Creek Aquifer and 10 Surficial Aquifer extraction wells will be required to intercept
groundwater. The combined maximum total flow rate produced from these wells is expected
to be 950 gpm.
Each well pump is expected to extract approximately 5 to 30 gpm and will be sized to have
additional flow capacity for contingency. The extraction wells will be of high-density
polyethylene (HDPE) construction below finished grade, whereas the wellhead will be of
polyvinyl chloride construction.
Each wellhead will then tee into their corresponding conveyance line (i.e., North or South
Force mains), constructed of HDPE. Approximately two thirds of the required extraction wells
will convey groundwater through the North Force main while the remaining third is conveyed
via the South Force main. The conveyance lines will be sized to accommodate the total
collected flow of the extraction with added contingency to allow for increased extraction rates
if required. Extracted groundwater will be conveyed to a surge tank prior to being treated by
the GWTS.
The seep flow will be impounded at or near seep capture locations (impoundment storage) to
provide equalization storage during rainfall events and remove readily settlable/suspended
solids prior to being conveyed to a break tank and treated by the GWTS.
The total maximum dry weather flow to the GWTS, after the groundwater remedy is fully
operational, including seep flow, is estimated to be 1,111 gpm. Total flow over a 24-hour
period with up to 0.5 inches of rainfall is estimated to average 1,219 gpm. The design flow rate
for the GWTS was selected to be 1,500 gpm to allow for increased groundwater extraction
from the extraction wells and potential changes in post-installation flow behavior from the
seeps.
At the break tank, the influents from the extracted groundwater and the seeps will be combined.
The effluent of the equalization tank will then be drawn on demand by the GWTS. The
impoundment storage will be dredged periodically, and solids characterized and disposed of at
an appropriately designated facility.
5. STEP 3 ALTERNATIVES
Following consultation with the NCDEQ, only the alternative cases below were considered in
the Steps 3 and 4 assessment.
TR0795 16 June 2021

Geosyntec°
constdtants
5.1 Technologically Feasible Discharge Alternatives
5.1.1 Connection to Existing Public Treatment Plant
Conveying the effluent from the new treatment system for the groundwater and seeps flow to a
local Publicly Owned Treatment Works (POTW) has been evaluated. The nearest POTW to
the site is Fayetteville Public Works Commission (PWC) Rockfish Creek Water Reclamation
Facility (WRF) located approximately nine miles north of the Chemours site. The nearest
public sewer connection to this facility is approximately six miles north of the Chemours site.
The Fayetteville PWC has indicated that they will not accept the treated water. A letter
reflecting this is attached as Appendix A. The PWC Rockfish Creek WRF uses biological
treatment technology (i.e. for the treatment of domestic sewage) and does not provide treatment
for residual PFAS compounds in their influent. The extracted groundwater and captured seeps
will be treated for 99% removal of PFAS indicator compounds, and this process will also
remove other residual organic compounds in the water such that there will be minimal residual
oxygen demand in the treated effluent. Thus, the PWC cannot provide any additional effective
treatment for the treated groundwater and seeps, and such inflow would only serve to dilute the
plant load, add hydraulic loading, and result in increased operational costs and possible
performance issues for no net environmental benefit.
Additionally, the City of Fayetteville's Sewer Use Ordinance precludes the discharge of surface
water into the city's sewer system. As such there are no local public sewer connections
available to receive the treated groundwater and seeps flow, and hence discharging the water to
a POTW is not a feasible option
5.1.2 Wastewater Reuse
Reusing the treated effluent from the new groundwater and seep flow treatment system within
the manufacturing process or as non-contact cooling water was evaluated in lieu of discharging
the treated effluent from the GWTS back into the Cape Fear River. Direct discharge was
determined to be the preferred option to wastewater reuse. First, the GWTS must operate year-
round. Groundwater is continually recharged and flowing and the seeps are perennial surface
water flows. Both these flows are primary pathways of PFAS to the Cape Fear River and per
the CO Addendum must be intercepted, treated, and then per GWTS requirements, discharged.
Meanwhile the facility does not operate continuously, and ceases manufacturing activities for
one month per year. During this time each year, and other periodic shutdowns, the GWTS
operation would be unable to discharge treated water and would consequently be limited in its
ability to accept and treat water needing treatment.
Additionally, reusing treated water at the facility would not have a beneficial impact on the
river.The volume of treated water would comprise approximately 14%of the Site's daily water
TR0795 17 June 2021

Geosyntec
r natwtsli<1rri;
use,thus offsetting only a small fraction of the water withdrawn from the river.Treated effluent
water reuse would also not change the water balance or the PFAS loading to the Cape Fear
River.
5.1.3 Direct Discharge
This section discusses the direct discharge of treated groundwater and seep water into the
receiving body (Cape Fear River), and the treatment process of the proposed treatment system
supported by a conceptual PFD. A detailed account of each unit operation shown in the PFD
can be found in the attached Engineering Report (Geosyntec, 2021c). The Engineering Report
also contains the data considered in the engineering design.
Based on turnkey vendor proposals currently under consideration, the GWTS is assumed to be
comprised of the following series of treatment units:
1. Metals oxidation;
2. Ultrafiltration (UF) or similar solids separation technology;
3. Granular Activated Carbon (GAC) adsorption;
4. Solids Handling & Dewatering; and
5. Ancillary processes for backwashing and residuals handling.
The influent oxidation system will be designed to help ensure complete oxidation of reduced
iron species (or other dissolved metals), by means of pH adjustment and possible addition of
inorganic coagulant and/or flocculant. Following oxidation, flow will proceed to the solids
separation unit in which particle sizes above an appropriate control threshold will be removed.
The filtrate will then be pumped to the GAC adsorption process, which will remove the PFAS
and other contaminants from the water. The GAC effluent will undergo further pH adjustment
back to near-neutral conditions and then be discharged to the Cape Fear River via the pipe that
conveys existing flows from Outfall 002 to the river.
The solids separation unit reject, solids separation unit cleaning, and GAC backwash water will
collect in one or more thickener tanks. The thickened solids will be dewatered using a filter
press or centrifuge. Sludge cake will be transferred into hoppers that will be trucked off-site for
disposal, at a permitted waste disposal facility. The dewatering filtrate will be returned to the
head of the plant and blended with the influent downstream of the oxidation tanks. A backwash
water tank will store a limited volume of treated water to supply GAC backwash, polymer
dilution, and other process water requirements. A GAC backwash waste tank will collect
backwash water and bleed it back into the treatment process downstream of the oxidation tanks.
Paragraph 2(c)(i) and paragraph 3(b)(ii) of the Addendum to the CO establish treatment
standards for the GWTS, as measured by the concentrations of indicator parameters of HFPO-
DA, PMPA, and PFMOAA. The long-term seep remediation objective at paragraph 2c(i)
requires a 99% reduction in annual mass loading of PFAS for the treated seep water. The
objective for the groundwater treatment in paragraph 3(b)(ii) is to provide a minimum PFAS
TR0795 18 June 2021

Geosyntec v
consultants
t:mx otecComillfoltseiN SEC.
NC umot.: 4.;tan°o dC-av-
removal efficiency of 99% of treated groundwater. Based on vendor experience, Chemours'
experience at Outfall 003, and outcomes of past treatability pilot studies, it is anticipated that
these treatment requirements will be met. In addition, Chemours is currently performing
treatability studies based on anticipated wastewater characterizations of the groundwater and
seeps.
A conceptual PFD of the GWTS and the associated sludge handling system is shown in Figure
7.
TR0795 19 June 2021

Geosyntec Q
consultants
Geenynrru€41nulianoof NC.,@C.
Nclitp pNimc s40044di=-2aa
H2SO4 12'diameter vessels
pH to3_5
UF
--
Vessel r. GAO r GAC GAG
I I
Frac tank —' Frac tank
Feed l UF To Outfall
• -` ho.
L. Frac tank
--op' Vessel
UFH. GAG --► GAG --i► GAG I. 4r Frac tank r
Vessel GIP
Frac tank
mm
--- . GAG --o. GAC I—►h CAC
Caustic T
UF S8S To GAC BrW.
Caustic —b. Vessel PH to 6 9 Rinse,Sluice
Chlorine
Coagulant
UF
Vessel
Frac tank 4
4 GAC
Backwash
iv i Out
Anionic '* Frac tank
polymer ----- --- 4—
OF Reject
Cone Cone i
Decant Bottom Bottom
-* Tank Tani( Decant
Sludge
Filtrate GAC System
Anionic polymer . I
Solids handling
Filter Solids
IPrecs Solids roll-off Pre-and post-treatment
Cationic polymer
Figure 7: Conceptual Process Flow Diagram of Primary Treatment Process and Solids Recovery Process
TR0795 20 June 2021

Geosyntec c'
consultants
6. STEP 4 ECONOMICS
6.1 Economic Feasibility of Alternatives
A 20-year Present Value of Costs Analysis (PVCA) has been performed for the Direct
Discharge option which has been evaluated to be the preferred option. A PVCA was also
performed for the wastewater reuse option. Use of an existing POTW was determined to
be technically unfeasible and therefore is not included in the economic evaluation.
A preliminary design was prepared for the Direct Discharge option along with the associated
costs.The estimate uses standard factors for cost estimation,and as such is a Rough Order
of Magnitude estimate. For the PVCA costs, future expenditures have been converted to
a present value cost at the beginning of the 20-year planning period. Based on EPA
guidance, a discount rate of 3.5% for a 20-year period has been used in the analysis.
The PVCA includes all costs associated with construction, startup and annual operation
and maintenance costs. Costs also include, but are not limited to, the following:
• Capital costs
• Equipment costs
• Labor costs
• Installation costs
• Design costs
• Operations and maintenance costs
• Laboratory costs
• Waste disposal costs
• Labor costs
• Utility costs
Cost information is preliminary and has been generated from the following sources:
• Non-binding vendor quotes
• Publicly available land costs
• Previous project experience and bids
• Cost estimation manuals (e.g. Means Construction Index) and standard factors
TR0795 21 June 2021

Geosyntec°
cCmsi Uants
f4M)1 caasialAomsvfNC,BC.
timssrNa.:C: i7oeadCA
Because of the turnkey nature of the proposed commercial treatment system, many of
these cost elements are captured within a few broader cost categories described below.
For example, the majority of facility operating costs are captured in a monthly operating
contract fee.
6.1.1 PVCA Calculation Method
The following standard formula per the guidance document for computing the Present
Value has been utilized:
PV = Co + L Ct
(1 + r)t
t=i
Where:
PV = Present Value of costs
Co= costs incurred in the present year
Ct= costs incurred in year t
t = time period after the present year, where t = 0
n = ending year of the life of the facility
r = current EPA discount rate
6.1.2 PVCA Summary
A summary cost table presenting the present worth for the treatment alternatives
considered at a design flow of 1,500 gpm, are presented as Table 2. Detailed cost
estimates are provided in Appendix B.
TR0795 22 June 2021

Geosyntec°
consultants
GeooyftWxCossidOuttiatit:..i..
NC Liceme Nw:C iluandC
Table 2: Present Value Cost Analysis Summary Table
Scenario Treatment Option Total Capital Total Annual Present Value
Cost (Co) O&M Cost (C)
1 Direct Discharge-only $8,500,000 $4,200,000 $68,200,000
Treatment System
2 Treated Effluent Reuse $9,900,000 $4,200,000 $69,600,000
7. CONCLUSION AND PATH FORWARD
In summary, the groundwater and seep flow associated with the newly proposed
groundwater remedy will be collected and treated (by physical/chemical precipitation,
filtration and carbon adsorption). The preferred alternative is to discharge the treated
groundwater and seep water into the existing pipe which also conveys the effluent from
Outfall 002. It is therefore anticipated that the environmental impacts associated with the
current groundwater onsite will be significantly diminished and the treated water will
exhibit a significant reduction in PFAS target compounds, total suspended solids, and
dissolved metals. This will reduce the impact of these pollutants in the Cape Fear River.
Onsite water reuse would limit the operation of the GWTS when the Site is not
discharging and provides no additional benefit to the river.
Since the treated effluent presents a substantially reduced environmental impact to the
Cape Fear River relative to pre-remedy conditions (i.e. prior to construction of the
groundwater extraction network and supporting barrier wall), Chemours considers this
option to be the most feasible and environmentally beneficial to address the requirements
outlined in the Addendum to the CO. This evaluation is further supported by current
treatment successes at the existing Outfall 003 treatment facility, and the additional
technical details regarding treatment presented in the Engineering Report.
Approval of this EAA and subsequent permit authorization is respectfully requested as
expeditiously as possible so that Chemours can meet the requirements of the Consent
Order and Addendum.
TR0795 23 June 2021

Geosyntec°
consultants
tleusZ,"' C.mzc,tkatix nt,Y.P
I..ii'cllw'~? C,-3100 and t:-l:if
8. REFERENCES
Geosyntec, 2019a. Cape Fear River PFAS Mass Loading Model Assessment and
Paragraph 11.1 Characterization of PFAS at Intakes. Chemours Fayetteville
Works. August 2019.
Geosyntec, 2019b. Corrective Action Plan, Chemours Fayetteville Works. December
2019.
Geosyntec, 2021a. Cape Fear River PFAS Mass Loading Assessment — Fourth Quarter
2020 Report. Chemours Fayetteville Works. March 2021.
Geosyntec, 2021b. Pre-Design Investigation Summary, Chemours Fayetteville Works.
March 2021.
Geosyntec, 2021c. Engineering Report — Treatment of Groundwater and Upgradient
Seeps Water. June 2021.
North Carolina Department of Public Safety (NC DPS), 2015. North Carolina's Spatial
Data Download. https://sdd.nc.gov/
TR0795 24 June 2021

Geosyntec°'
consultants
Neo4ymr4 Comoinaotsoi NC.FL
NC Lk•trro NC:C-3606*nd C."415
APPENDIX A - PWC REFUSAL TO
ACCEPT TREATED WASTEWATER
TR0795 June 2021

101/1
DARSWEIL L.ROGERS,COMMISSIONER • 1 FAYETTEVILLE PUBLIC WORKS COMMISSION
WADE R.FOWLER,JR.,COMMISSIONER Jf IP' S 955 OLD WILMINGTON RD
EVELYN O.SHAW,COMMISSIONER vvv[� V lll���WW P.O.BOX 1089
D.RALPH HUFF,III,COMMISSIONER H t1 OWN UTILITY FAYETTEVILLE,NORTH CAROLINA 28302-1089
DAVID W.TREGO,CEO/GENERAL MANAGER TELEPHONE[phone]
W W W.FAYPWC.COM
September 11, 2019
Parsons
4701 Hcdgcmore Drive
Charlotte,NC 28209
Attention: Michael Robinson, P.E.
RE: Sewer/POTW Connection Near Chemours,
Dear Mr. Robinson:
This is in response to your inquiry to this office regarding the above referenced subject.
More specifically, you mentioned that Chemours is required to treat PFAS impacted water from
a surface water body on-site. The water is groundwater that is daylighting into a ditch and
ultimately flowing to the Cape Fear River. In order to obtain an NPDES permit, it is necessary
to get a letter from the local POTW indicating that they will or will not accept it. It is further
understood that Chemours is required to remove 99%of two specific constituents (I-IFPO-DA
and PFMOAA). As such the water would have a maximum of 50 parts per trillion of HFPO-DA
and around 800 ppt of PFMOAA (along with lower levels of other PFAS constituents).
Currently, PWC owns and operates a water reclamation facility, Rockfish Creek WRF,
approximately 9 miles to the north of the Chemours site at the intersection of Highway 87 and
Old Wilmington Road. The nearest collection lines that discharge to this facility are located
approximately 6 miles north of the Chemours site. In addition, this facility is not designed to
treat wastewater containing HFPO-DA, PFMOAA or other PFAS and PWC will not be able to
accept this wastewater.
If there arc questions or if additional information is needed,please let me.
Si lcerely,
' geke/
i oseph E. Glass, PE
Manager, Water Resources Engineering
BUILDING COMMUNITY CONNECTIONS SINCE 1905
AN EQUAL EMPLOYMENT OPPORTUNITY EMPLOYER

Geosyntec
consultant 4
+nrsytrra CoembenMxufNe.P.C.
c:{MISO 5 :CA:++*Mi*sh ZZ5
APPENDIX B - COST ESTIMATES
TR0795 June 2021

Cost Estimate for Direct Discharge
Chemours Fayetteville Works,North Carolina
Basis of Cost Estimate(Scope and Assumptions):
Direct Discharge of treated effluent to existing Outfall 002.
Estimate is based on currently available budgetary quotations for turnkey treatment system.
Costs associated with collection and conveyance have been excluded since they are the same for all cases.
Construction cost factors are representative and considered sufficient for the Rough-Order-of-Magnitude nature of the estimate.
Item Qty Unit Unit Cost Total Notes
Capital and Construction Costs
GW EWs and Conveyance System — -- same for all scenarios
Turnkey Treatment System(Pretreatment,GAC,Solids Handling) Process Package $ 3,500,000 $ 3,500,000 Suez
Land Costs -- $ - $ -
Raw Capital Costs $ 3,500,000
Installation Cost(Construction,Site Preparation,Civil,Structural) 50% of Raw Capital Costs $ 1,750,000
of Sum of Raw Capital
30% Costs and incl these costs are captured in
Ancillary Cost(1&C Piping-Mechanical&Electrical) Installation Cost the turnkey price above
Sum of Raw Capital Costs, $ 5,250,000
Installation Cost
Total Capital&Construction Cost and Ancillary Cost
Total Capital&Construction Cost(Including Equipment Protection) $ 5,250,000
Professional Services Costs
Total Capital&
Engineering and Project Management 12% of Construction Cost $ 700,000
Sum of Total
Capital&
Construction Cost,
Engineering/PM&
Construction Management,Project Management,General Conditions 8% of Contingency Costs $ 700,000
Professional Services Subtotal $ 1,400,000
Sum of Total
Capital&
Construction Cost
and
Engineering/PM
Contingency 30% of cost $ 1,800,000
Co,Capital Cost $ 8,500,000
+50% $ 12,800,000
-30% $ 6,000,000
Annual Operations&Maintenance Costs
Electricity $ 150,000 $ 150,000 from turnkey demand est
GAC Usage&Replacement $ 800,000 $ 800,000 prelim vendor est
Solids Disposal $ 16,500 $ 16,500
Sampling&Analytical $ 55,000 $ 55,000
System Operations,Maintenance,Equipment Rental,Consumables $ 2,280,000 $ 2,280,000 turnkey monthly O&M
Variable Cost of Treatment(vendor) $ 883,000 $ 883,000 turnkey flow-based fee
Annual O&M Subtotal $ 4,200,000
C,Annual Cost $ 4,200,000
+50% $ 6,300,000
-30% $ 2,940,000
n,Years 20
r,Discount Rate 3.5%
Present Worth Formula
PW Factor for n Years 14.2124
Total:Present Worth Value of Capital&Annual O&M Costs over 20 Years $ 68,200,000
+50% $ 102,300,000
-30% $ 47,800,000
Rough Order of Magnitude(ROM)preliminary estimate(-30%to+50%).Not for budgetary purposes and is only meant to be used for
interalternative comparison.The estimates have been prepared for guidance in project evaluation and implementation from the information
available at the time of the estimate.The final costs of the project will depend on final approved design,actual labor and material costs
(including but not limited to availability of land),and competitive variable factors.General conditions are subject to change which may lead to
a change in the estimate.Costs have been rounded up.Cost information is preliminary and has been generated from the following sources:
Non-binding vendor quotes(Sales tax may vary);Publicly available costs;Previous project experience and bids;Cost estimation manuals(e.g.
Means Construction Index)and standard factors
Page 1 of 1 June 2021

Cost Estimate for Treatment and Reuse
Chemours Fayetteville Works,North Carolina
Basis of Cost Estimate(Scope and Assumptions):
Reuse of treated effluent at Facility,using base treatment plant cost and assumed allowance for reuse infrastructure.
Estimate is based on currently available budgetary quotations for turnkey treatment system.
Costs associated with collection and conveyance have been excluded since they are the same for all cases.
Construction cost factors are representative and considered sufficient for the Rough-Order-of-Magnitude nature of the estimate.
Item Qty Unit Unit Cost Total Notes
Capital and Construction Costs
GW EWs and Conveyance System — -- same for all scenarios
Turnkey Treatment System(Pretreatment,GAC,Solids Handling) Process Package $ 3,500,000 $ 3,500,000 Suez
Allowance for treated water transfer(pumps,piping,tankage,trenching) -- $ - $ 500,000
Raw Capital Costs $ 4,000,000
Installation Cost(Construction,Site Preparation,Civil,Structural) 50% of Raw Capital Costs $ 2,000,000
of Sum of Raw Capital
30% Costs and $ 150,000 Applied to piping allowance
Installation Cost only. Balance of costs
Ancillary Cost(1&C,Piping-Mechanical&Electrical) included in turnkey costs.
Sum of Raw Capital Costs, $ 6,150,000
Installation Cost
Total Capital&Construction Cost and Anciliary Cost
Total Capital&Construction Cost(Including Equipment Protection) $ 6,150,000
Professional Services Costs
Total Capital&
Engineering and Project Management 12% of Construction Cost $ 800,000
Sum of Total
Capital&
Construction Cost,
Engineering/PM&
Construction Management,Project Management,General Conditions 8% of Contingency Costs $ 800,000
Professional Services Subtotal $ 1,600,000
Sum of Total
Capital&
Construction Cost
and
Engineering/PM
Contingency 30% of cost $ 2,100,000
CO3Capital Cost $ 9,900,000
+50% $ 14,900,000
-30% $ 7,000,000
Annual Operations&Maintenance Costs
Electricity $ 150,000 $ 150,000 from turnkey demand est
GAC Usage&Replacement $ 800,000 $ 800,000 prelim vendor est
Solids Disposal $ 16,500 $ 16,500
Sampling&Analytical $ 55,000 $ 55,000
System Operations,Maintenance,Equipment Rental,Consumables $ 2,280,000 $ 2,280,000 turnkey monthly O&M
Variable Cost of Treatment(vendor) $ 883,000 $ 883,000 turnkey flow-based fee
Annual O&M Subtotal $ 4,200,000
C,Annual Cost $ 4,200,000
+50% $ 6,300,000
-30% $ 2,940,000
n,Years 20
r,Discount Rate 3.5%
Present Worth Formula
PW Factor for n Years 14.2124
Total:Present Worth Value of Capital&Annual O&M Costs over 20 Years $ 69,600,000
+50% $ 104,400,000
-30% $ 48,800,000
Rough Order of Magnitude(ROM)preliminary estimate(-30%to+50%).Not for budgetary purposes and is only meant to be used for
interalternative comparison.The estimates have been prepared for guidance in project evaluation and implementation from the information
available at the time of the estimate.The final costs of the project will depend on final approved design,actual labor and material costs
(including but not limited to availability of land),and competitive variable factors.General conditions are subject to change which may lead to
a change in the estimate.Costs have been rounded up.Cost information is preliminary and has been generated from the following sources:
Non-binding vendor quotes(Sales tax may vary);Publicly available costs;Previous project experience and bids;Cost estimation manuals(e.g.
Means Construction Index)and standard factors
Page 1 of 1 June 2021