NC0079057_Toxicity test results_20220607

DocuSign Envelope ID: OCCEDD94-FB7F-4190-868E-931 E780DC3D4
Division of Water Resources
June 7, 2022
MEMORANDUM
To: David May
Water Quality Regional Operations, WaRO
ADS
Through: Cindy A. Moore
Supervisor, Aquatic
From: Lorimar S. Henning
icology Branch (ATB)
btk
Environmental Specialist II, Aquatic Toxicology Branch (ATB)
Subject: Whole effluent toxicity test results
Manteo WWTP
NPDES Permit # NC0079057/001
Dare County
The aquatic toxicity test using a constant time/constant volume composite sample of effluent
discharged from the Manteo WWTP has been completed. Manteo WWTP has a permitted
effluent discharge of 0.6 million gallons per day (MGD) entering Shallowbag Bay. Whole effluent
samples were collected on May 24 by the facility representative, Josh O'Brien 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 97.5%
Test Treatment Survival 100%
Sample pH 7.78 SU
Sample Conductivity 853 micromhos/cm
Sample Total Residual Chlorine <0.2 mg/L
Test results for the above sample indicate that the effluent would not be predicted to have water
quality impacts on receiving water. Please contact us if you have any questions or if further effluent
toxicity monitoring is desired. We may be reached at [e-mail] or
[e-mail].
Basin: Pasquotank
cc: Robbie Bullock (WaRO)