NC0020354_Effluent Toxicity Testing_19990826

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
Kerr T. Stevens, Director
KEN CORNATZER
PITTSBORO, TOWN-WWTP
P.O. BOX 759
PITTSBORO, NC 27312
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NC ENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
August 26, 1999
SUBJECT: Revised Whole Effluent Toxicity Enforcement Policy
Effluent Toxicity Testing
NPDES Permit No. NCO020354
CHATHAM County
KEN CORNATZER:
Based on recent discussions with EPA Region IV, the Division of Water Quality (DWQ) is further
modifying its Whole Effluent Toxicity (WET) Enforcement Policy. The primary difference will be
separation of DWQ's application of civil penalties from compliance determinations. Any WET test result
that does not achieve compliance with the NPDES permit limit will be considered a violation of the
permit and the permittee will be sent, at minimum, a Notice of Violation. The Division's new Whole
Effluent Toxicity Enforcement Policy will apply to whole effluent toxicity monitoring initiated on
or after September 1, 1999.
Draft NPDES permits sent to public notice after 7/1/99 will contain chronic toxicity test condition
language which specifies follow-up multiple concentration toxicity testing upon any single quarterly test
failure. The first test of the quarter (three-month monitoring period defined by the permit) may be
conducted either as either a pass/fail test or as a multiple concentration (ChV) test. If the pass/fail test
fails or if the chronic value is lower than the permit limit, then a NOV is issued and at least two multiple
concentration tests (one per month) are required over the following two months. NOVs will be generated
for each failure to meet the permit limit. As many analyses as can be completed during the quarter will be
accepted.
Permittees with NPDES permits which contain "old" chronic toxicity pass/fail testing language will have
the OPTION to respond to any single quarterly toxicity test failure with follow-up multiple concentration
toxicity testing or single concentration toxicity testing. The enclosed toxicity test condition language will
be incorporated in the NPDES permit upon permit renewal and/or permit modification. Initiation of
multiple concentration toxicity testing after any single quarterly failure will influence the Division's
enforcement response. Permittees will be issued a NOV for any test result that does not achieve
compliance with the permit limit. A civil penalty will be assessed for each quarter of toxicity
noncompliance based on the arithmetic average of ChVs submitted for the remaining two months of the
quarter.
Mailing Address:
1621 Mad Service Center
Raleigh, NC 27699-1621
Telephone [phone]
Fax [phone]
State Courier #52-01-00
Location:
4401 Reedy Creek Road
Raleigh, NC 27699-1621
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Important WET Enforcement Policy items are:
I. CHRONIC TOXICITY TESTING
• The first test of the quarter can be conducted as either a pass/fail test or a
chronic value (ChV) test.
• If the pass/fail test fails or if the ChV is lower than the limit, then a NOV is
issued and at least two ChV tests (one per month) will be conducted over the
following two months. As many analyses as can be completed will be
accepted.
• A NOV will be issued for any test result failing to meet the permit limit.
• Any civil penalty assessed will be based on performance over a quarter.
• NPDES Permits containing chronic toxicity pass/fail testing will be modified
upon permit renewal to include the new permit language.
H. ACUTE TOXICITY TESTING
• A NOV will be issued for each acute limit violation.
• A civil penalty will be assessed for any two consecutive acute limit
violations.
Note that no changes have occurred in DWQ's enforcement responses to acute limit noncompliances
since the May 13'' mailing.
Choosing to respond to a chronic "fail" result with a pass/fail test instead of conducting multiple
concentration toxicity testing during the second and third months of the calendar quarter will
result in enforcement for single concentration test results which do not meet chronic toxicity
permit limitations.
As in the past, if you are unable to consistently comply with your toxicity permit limitation, you may
notify your respective Regional Office to discuss the possibility of entering into a Special Order by
Consent (SOC). The SOC provides conditional compliance for permit parameters that the facility can not
consistently comply with and may be issued in situations where facility operation and maintenance are
not in question. If a SOC is signed by the permittee/DWQ and contains toxicity as a noncompliant
parameter, you will be required to: conduct a Toxicity Reduction Evaluation (TRE), submit quarterly
TRE progress reports, and reduce/eliminate effluent toxicants to acceptable levels.
Additional explanation of key WET enforcement initiatives can be located on the Division's Aquatic
Toxicology Unit web page at http://esb.ehnr.state.nc.us/ATU.html.
If you have any questions, please contact me or Mr. Kevin Bowden at [phone].
Sincerely,
Matt Matthews, Supervisor
Aquatic Toxicology Unit
cc: Regional Office Supervisor, RRO
Facility Files
Central Files
Enclosure 66 0 1 d3S

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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 H 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 II 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 II 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 TGP313 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: North Carolina Division of Water Quality
Environmental Sciences Branch
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.

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