20190752 Ver 3_Chemours Stream Flow-through Cell Project NC SHPO Cover Letter 06-02-2020 draft_20200603

Date
Renee Gledhill -Earley
State Historic Preservation Office
4617 Mail Service Center
Raleigh, NC 27699-4617
RE: Section 106 Consultation for the Chemours — Stream Flow -through Cell Project, Chemours
Fayetteville Works, Bladen County, North Carolina
Dear Ms. Gledhill -Earley,
On February 25, 2019, the North Carolina Superior Court for Bladen County entered a Consent
Order (CO) among The Chemours Company FC, LLC (Chemours) and the State of NC and Cape
Fear River Watch to address discharges of perfluoroalkyl and polyfluoroalkyl substances (PFAS)
at the Chemours Fayetteville Works. Among other things, the CO required Chemours to develop
a remedial plan for reducing PFAS loading from Chemours Fayetteville Work Facility to the Cape
Fear River. Chemours is developing four flow -through cell instream treatment facilities to treat
the water prior to discharge into the Cape Fear River. The project area is shown on Figure 1.
A preconstruction notification (PCN) for Nationwide Permit 38 (Cleanup of Hazardous and Toxic
Waste) is being prepared to comply with Section 404/401 of the Clean Water Act. Since a U.S.
Army Corps of Engineers (USACE) permit under Section 404 of the Clean Waters Act will be
obtained, Section 106 consultation is required.
Release of per- and polyfluoroalkyl substances (PFAS) from the Chemours Company FC, LLC
Fayetteville Works Facility to the Cape Fear River are derived from impacted groundwater
discharging to surface water as seeps. Four groundwater seeps, identified as Seeps A, B, C and
D, are located above the Cape Fear River water level on the bluff face from the facility and
discharge into the Cape Fear River. The locations of Seeps A, B, C, and D are shown on Figure 2.
The treatment flow -through cells will involve the installation of an in -stream system to remove
PFAS contaminants from the surface water at the seeps. The in -situ remedial technology involves
the installation of sheet pile walls to guide seep water discharge through a controlled structure for
on -location treatment. Large wire baskets (gabions) filled with a sorbent material will be installed
in the discharge structures such that the water discharging from each seep location will flow
through the sorbent-filled gabions. The PFAS compounds in the seep water will be absorbed by
the sorbent material in the gabions and the treated water, containing much lower concentrations
of PFAS compounds, will flow out the downhill side of the gabions. Influent and effluent samples
will be collected to monitor the PFAS removal efficiency and to determine when the sorbent
material requires replacement. The occasional replacement of gabion baskets will be performed
using a crane to lift the baskets out of the channel and install new baskets containing fresh
sorbent. The seep treatment remedies will be maintained as long as needed to protect human
health and the environment.

Please find attached the North Carolina State Historic Preservation Office Section 106 Project
Review packet for your review and comment. The project area is approximately 55 acres.
Archival research, a walk-through field reconnaissance, and a site files search with your office
was previously conducted. Although no cultural resources investigations have been conducted
on the proposed project area, regional studies indicate that the probability for encountering intact
prehistoric or historic archaeological sites is considered low.
On behalf of USACE, I have determined that this undertaking will have no effect on historic
properties. In accordance with Section 306108 (formerly Section 106) of the National Historic
Preservation Act and its implementing regulations, 36 CFR Part 800, USACE requests the North
Carolina State Historic Preservation Officer's (SHPO) concur with this determination.
Thank you for your assistance in this matter and a prompt reply would be greatly appreciated.
Please provide written comments to USACE within 30 days of receipt of this letter. If no written
response is received within 30 calendar days, it will be assumed that your office concurs with the
USACE's finding of no historic properties affected.
Sincerely,
USACE Signature Block
Attachment- Figure 1 and 2 — Project Maps

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Figure 1. Chemours Flow -through Cells Project Area (USGS Duart Quadrangle, Bladen County, North Carolina).
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Figure 2. Location Map, Seeps A, B, C, and D, Chemours- Stream Flow -through Cell Project