NC0030210_correspondence_19990805

Division of Water Quality
August 5, 1999
MEMORANDUM
TO: Dave Goodrich
THROUGH: Matt Matthews i"'14'_
FROM: Kristie Robeson Y9
SUBJECT: NPDES Permit Modifications
Revised Chronic Toxicity Language
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Due to recent discussions with EPA Region IV, the Division is further modifying its
Whole Effluent Toxicity Enforcement Policy. Therefore, the -chronic toxicity language to be
used in permits will once again change. Listed below are the nine facilities that currently have
a Phase II chronic toxicity testing requirement in their NPDES permits. Our office previously
sent you a memo dated 5/10/99 requesting modification of these nine permits to include the
new chronic toxicity language. However, through discussions with EPA, our office was told
that they would not approve permits which contained that toxicity language. The chronic
language has since been revised and approved by EPA Region IV. Our office now
recommends modifying the permits for the nine facilities listed below to include the revised
permit language for chronic toxicity testing.
CMUD-McAlpine WWTP
NPDES Permit No. NCO024970
Mecklenburg County
CMUD-Mallard Creek WWTP
NPDES Permit No. NC00302W
Mecklenburg County
CMUD-McDowell Creek WWTP
NPDES Permit No. NC0036277
Mecklenburg County
Concord Rocky River WWTP
NPDES Permit No. NCO036269
Cabarrus County
Delta Mills
NPDES Permit No. NC0006190
Catawba County
Duke Power -Lincoln Turbine
NPDES Permit No. NCO080781
Lincoln County

Takeda Chemical Products
NPDES Permit No. NC0059234
New Hanover County
Winston-Salem Archie Elledge WWTP
NPDES Permit No. NC0037834
Forsyth County
Winston -Salem -Lower Muddy Creek WWTP
NPDES Permit No. NC0050342
Forsyth County
Please find attached the appropriate chronic toxicity test condition language to be
used in these nine permit modifications. You should also note that this language contains our
new mailing address, which should be used in future toxicity permit language. Should you
have any questions, please feel free to contact me or Matt Matthews at 733-2136.
Attachment
cc: Rex Gleason-MRO
Rick Shiver-WIRO
Larry Coble-WSRO
Colleen Sullins
Shannon Langley -Point Source Compliance/Enforcement Unit

CHRONIC TOXICITY PERMIT LIMIT (QRTRLY)
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant mortality to
Ceriodaphnia dubia at an effluent concentration of _%.
The permit holder shall perform at a minimum, quarterly monitoring using test procedures outlined in the "North Carolina
Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised February 1998, or subsequent versions or "North Carolina
Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -February 1998) or subsequent versions. The tests
will be performed during the months of . Effluent sampling for this testing shall be performed at the
NPDES permitted final effluent discharge below all treatment processes.
If the test procedure performed as the first test of any single quarter results in a failure or ChV below the permit limit, then
multiple -concentration testing shall be performed at a minimum, in each of the two following months as described in
"North Carolina Phase H Chronic Whole Effluent Toxicity Test Procedure" (Revised -February 1998) or subsequent
versions.
The chronic value for multiple concentration tests will be determined using the geometric mean of the highest
concentration having no detectable impairment of reproduction or survival and the lowest concentration that does have a
detectable impairment of reproduction or survival. The definition of "detectable impairment," collection methods,
exposure regimes, and further statistical methods are specified in the "North Carolina Phase Il Chronic Whole Effluent
Toxicity Test Procedure" (Revised -February 1998) or subsequent versions.
All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge Monitoring
Form (MR-1) for the months in which tests were performed, using the parameter code TGP3B for the pass/fail results and
THP3B for the Chronic Value. Additionally, DWQ Form AT-3 (original) is to be sent to the following address:
Attention: Environmental Sciences Branch
North Carolina Division of
Water Quality
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Branch no later than 30 days after
the end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/physical measurements and all
concentration/response data, and be certified by laboratory supervisor and ORC or approved designate signature. Total
residual chlorine of the effluent toxicity sample must be measured and reported if chlorine is employed for disinfection of
the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required, the
permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating the facility
name, permit number, pipe number, county, and the month/year of the report with the notation of "No Flow" in the
comment area of the form. The report shall be submitted to the Environmental Sciences Branch at the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring will be required
during the following month.
Should any test data from this monitoring requirement or tests performed by the North Carolina Division of Water Quality
indicate potential impacts to the receiving stream, this permit may be re -opened and modified to include alternate
monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control organism survival,
minimum control organism reproduction, and appropriate environmental controls, shall constitute an invalid test and will
require immediate follow-up testing to be completed no later than the last day of the month following the month of the
initial monitoring.
QCL Version 5199