NC0020648_Toxicity report_20210222

DocuSign Envelope ID: DC4DA33E-74BB-4657-98E2-5215DD1 F81 C6
Division of Water Resources
February 22, 2021
MEMORANDUM
To: David May
Water Quality Regional Operations, WaRO
DS
Through: Cindy A. Moor
Supervisor, Aquatic ^xicology Branch (ATB)
From: Lorimar S. Henning (�
Environmental Specialist II Aquatic Toxicology Branch (ATB)
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Subject: Whole effluent toxicity test results
Washington WWTP
NPDES Permit # NC0020648/001
Beaufort County
The aquatic toxicity test using flow -proportional composite samples of effluent discharged from
the Washington WWTP has been completed. Washington WWTP has a permitted effluent
discharge of 3.6 million gallons per day (MGD) entering Tar River. Whole effluent samples were
collected on February 2 by Palki Desai for use in an acute Pimephales promelas pass -fail toxicity
test. The test using these samples resulted in a pass. Toxicity test information follows.
Test Type Acute 24-hour Pimephales promelas pass -fail
Test Concentration 90%
Test Result Pass
Control Survival 100%
Test Treatment Survival 100%
Sample pH 7.39 SU
Sample Conductivity 518 micromhos/cm
Sample Total Residual Chlorine 0.07 mg/L
Test results for the above sample indicate that the effluent would not be predicted to have water
quality impacts on receiving water. These samples were split and tested by Environmental
Testing Solutions, Inc. (ETS). The acute Pimephales promelas pass/fail test run by ETS resulted in
a pass Please contact us if you have any questions or if further effluent toxicity monitoring is desired.
We may be reached at [phone].
Basin: Tar -Pamlico
cc: Robbie Bullock (WaRO)