NC0024406_Correspondence_20240927

DUKE Charlotte,
Church Street
Charll otte,NC 28202
4
E N E RGY® 336-669 2994 6t
September 27, 2024
North Carolina Department of Environmental Quality
Division of Water Resources
Aquatic Toxicology Branch
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Attn: Cindy Moore, Branch Supervisor(submitted electronically)
Re: Toxicity Test Results for Outfall 006
Duke Energy-Belews Creek
NPDES Permit No. NC0024406
Belews Creek Steam Station
3195 Pine Hall Road
Stokes County, Belews Creek, North Carolina 27009
Dear Ms. Moore:
On September 4, 2024, Duke Energy was notified of a failed toxicity test conducted by the Division of
Water Resources' Aquatic Toxicity Laboratory. A grab sample from the effluent force main was collected
on August 20 and 22, 2024 by Mr. Mike Mickey of the NCDEQ Water Quality Regional Operations
Section (WSRO). The failed test result was due to a statistically significant difference between
reproduction in the effluent sample versus reproduction in the control.
Duke Energy requested a meeting with the Aquatic Toxicity Branch (ATB)to discuss the test results and
determine if any follow up actions would be required. The meeting was held September 6, 2024 and the
following is a summary of the topics discussed:
• The sampling that was performed by the NCDEQ WSRO on August 20 and 22, 2024 and the
subsequent toxicity test failure is not in any way a compliance sampling event. No violations or
enforcement will follow.
• A note from the sampling event by Mr. Mike Mickey stated that the "spigot was turned on to grab
a sample." It was discussed that due to the batch operation of the system, this is a normal
procedure and the system was allowed to stabilize prior to samples being collected.
• The presence of chlorine in the first sample (0.13 mg/L)was also discussed. Since chlorine is
used early in the process of the system, it is nearly impossible to record any amount of residual
chlorine in the effluent. Other Duke Energy sites have seen interference from manganese that
has created a false positive. Running an interference test could have determined if the chlorine
test result was accurate.
• Duke Energy requested and received the full lab reports to review.
• An explanation on the statistical program used by the ATB to determine if the reproduction
between the sample vs. control was given by Ms. Moore. It was stated that we did not have any
mortality of the Ceriodaphnia but the reproduction of neonates compared to the control sample
was statistically a "significant difference"which resulted in the failure.
• If Duke Energy prefers, a re-sample can be requested with the NCDEQ WSRO.
It should be noted that the toxicity test history for the site shows there has not been a failed test in 20+
years of sampling. In addition, the most recent NPDES compliance toxicity test conducted for sampling
that occurred on August 5 and 8, 2024 resulted in a PASS.

I can be reached at Melon ie.Martin(a�Duke-Energy.com or(336) 669-2994 if you have any questions or
concerns.
Respectfully submitted,
�W^U�L - *��j
Melonie Martin
Environmental Services
Attachments: Meeting Attendance Report
Cc(via email): Madison Myers—NCDEQ ATB
Molly Nicholson—NCDEQ ATB
Travis Thornton—Duke Energy
Freddie Wilson—Duke Energy
Brenda Johnson—Duke Energy

Meetingtitle Duke Energy Belews Creek Toxicity
Start time 9/06/24,8:57:50 AM
End time 9/06/24,9:45:06 AM
Meeting duration 47m 15s
Participants
Name Email
Martin, Melonie [e-mail] Duke Energy Site Env. Professional
Thornton,Travis [e-mail] Duke Energy Site System Owner
Johnson, Brenda [e-mail] Duke Energy Site Env. Field Support
Wilson, Freddie [e-mail] Duke Energy Site Operations Manager
Moore,Cindy [e-mail] NCDEQ ATB ATB Branch Supervisor
Myers, Madison [e-mail] NCDEQ ATB ATB Lab Cert&QA/QC Spec.
Nicholson, Molly [e-mail] NCDEQ ATB Comp.&Customer Service Spec.