NC0003760_Permit (Modification)_20211021

4DUPONT►
October 5, 2021
Mr. Robert Bullock
Division of Water Resources
Washington Regional Office
943 Washington Square Mall
Washington, NC 27889
Re: DuPont Kinston Plant — NPDES Permit No. NC00037E0
Outfall Sampling Notification
Dear Mr. Bullock,
DuPont Kinston Plant
4693 Hwy.11 North
Grifton, NC 28530
RECEIVED/NCDENR/DWR
OCT 21 2021
Water Quality
Regional Operations Section
Washington Regional Office
Thank you for being on the call on Wednesday, September 15th to discuss the proposed modifications to
the DuPont Kinston Site's NPDES permit. In preparation work for the NPDES permit renewal, DuPont
Kinston became aware that total cadmium has been inadvertently measured to a Practical Quantitation
Level (PQL) of 1.0 µg/L versus the required 0.5 µg/L at Outfalls 002 and 003. These outfalls are not
subject to an effluent limit for cadmium, and cadmium has been consistently non -detect at Outfalls 002
and 003. Moving forward, DuPont Kinston will ensure all pollutants are measured to the required PQL.
As a part of the NPDES permit renewal, the Kinston Site is making a request to move the monitoring
point for Outfall 002 back to the previously permitted iodation. The currently permitted monitoring point
for Outfali 002 is in a canal that also collects surface runoff from the adjoining farmland. The canal
continues to experience washout. A painted cinder block retaining wall from the adjoining farmland has
collapsed into the canal at the currently permitted Outfall 002. Repairs and stabilization will be extensive,
and DuPont believes that a U.S. Army Corps of Engineers Jurisdictional Determination will be required.
In addition, 401/404 permitting may be required depending on 1:he determination.
During the compliance inspection in October of 2020, DuPont Kinston's Operator in Responsible Charge
(ORC) indicated that the monitoring location designated in the current permit for Outfall 002 has
extensive washout to the point that the physical conditions are :hazardous to personnel at this location.
Based on discussions during the compliance inspection, it was the ORC's understanding that the grab
samples could be collected at the previously permitted monitoring location until repairs and stabilization
are complete or the permitted monitoring point for Outfall 002 is relocated. The previously permitted
monitoring location is safe and easily accessible.
While we are waiting on approval of the new permit, the Kinston Site will resume collecting 002 samples
at the permitted location; however, samples will have to be taken slightly upstream to avoid the washout
and physical hazards. Attachment 1 shows the former Outfall 002 location, the current Outfali 002
location, and the upstream sampling location. Attachment 2 shows the revised outfall designations
submitted in the NPDES permit renewal application on October 1, 2021.
If there any questions, please feel free to contact me at [phone].
Sincerely,
Shelby Arellano
Environmental Engineer
DuPont Kinston Plant
DuPont Industrial Biosciences USA LLC

ATTACHMENT 1

DuPont Kinston - Current Outfall Designations
4
II
UNIFl KINSTON LLC
KINSTON, NORTH CAROUNA
OUTFALL LOCATION MAP
caesmawmm • uwo•m
pnangal {burs

ATTACHMENT 2

DuPont Kinston NPDES Permit Renewal - Revised Outfall Designations
Key:
X NPDES Stormwater Outfall
X NPDES Wastewater Outfall
X Outfall with No Exposure to Industrial Activity
Central Accumulation Area
Satellite Accumulation Area
* Essential Materials Loading and Unloading
+ Structural BMP
Outfall 002 - Containment Basin
Outfall 004 - Grassed Swale
Outfall 006 - Diversion Structure
Outfall 007 - Settling Basin
Drainage Areas:
Outfall 004 Drainage Area = 31.96 acres, Impervious = 12.52 acres
Outfall 007 Drainage Arca = 10.15 acres, Impervious = 7.60 acres
..C\)7.-
:....." ',.-.,,,,,-,,,,,,,..14-,N /
-- --_---0-,fi-17-c(i,1(\ iliri
/i,/ �—�r Ohl !I .1�—'<ll
JJ
&Track .4
S
l
oad
ing
Basin])
•
‘--4.�
;k.ssr Outfal1012 �l
pulfaR 011\rchdia
! 00
1
L out/Baai
it n': :
001 Monitoring
I Hr [<
��)r 1�1•
1 1JI
V outfa11006
(( t