NC0020354_Test Results_19990813

Division of Water (duality
August 13, 1999
MEMORANDUM
To: Ken Schuster
Through: Matt Matthews ('+`'J`
From: Sandy Mort 01%
Subject: Whole effluent toxicity test results
Pittsboro WWTP
NPDES Permit # NC0020354/001
Chatham County
The aquatic toxicity test using 24-hour composite samples of effluent discharged from Pittsboro
WWTP has been completed. Pittsboro WWTP has an effluent discharge permitted at 0.25 million
gallons per day (MGD) entering Robertson Creek (7Q10 of 0.00 CFS). Whole effluent samples were
collected on August 3 and 6 by Kirk Stafford for use in a chronic Ceriodaphnia dubia pass/fail
toxicity test. The test using these samples resulted in a pass. Toxicity test information follows.
Test Type
Test Concentrations
Test Result
Control Survival
Control Mean Reproduction
Test Treatment Survival
Treatment Mean Reproduction
First Sample pH
First Sample Conductivity
First Sample Total Residual Chlorine
Second Sample pH
Second Sample Conductivity
Second Sample Total Residual Chlorine
3 -Brood Ceriodaphnia dubia pass/fail
90% sample
Pass
100%
24.8 neonates
91.7%
24.2 neonates
6.96 SU
574 micromhos/cm
<0.1 mg/1
7.10 SU
554 micromhos/cm
<0.1 mg/1
Test results for these samples indicate that the effluent would not be predicted to have water quality
impacts on receiving water. Please contact us if further effluent toxicity monitoring is desired. We
may be reached at [phone].
Basin: CPF04
cc: Central Files
Environmental Sciences Branch Water Quality Section

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AUG 11 99