2012-06-08_PERMIT FILE - C2009087A (2)

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PART I Page No. 6 Permit No.: CO0048275 a. Chronic WET Testing and Reporting Requirements Tests shall be done at the frequency listed in Part I.B.I.c. Test results shall be reported along with the Discharge Monitoring Report (DMR) submitted for the reporting period during which the sample was taken. (i.e., WET testing results for the first calendar quarter ending March 31 shall be reported with the DMR due April 28.) The results shall be submitted on the Chronic Toxicity Test report form, available from the Division. Copies of these reports are to be submitted to the Division along with the DMR. The permittee shall conduct each chronic WET test in general accordance with methods described in Short Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms Fourth Edition, October 2002, EPA 821 -R -02 -013 or the most current edition. The permittee shall conduct such tests using Ceriodaphnia dubia and fathead minnows. b. Failure of Test and Division Notification A chronic WET test is failed whenever 1) there is a statistically significant difference in lethality between the control and any effluent concentration less than the instream waste concentration ( "I WC ") and, 2) the IC25, which represents an estimate of the effluent concentration at which 25% of the test organisms demonstrate inhibition as reflected by lethality, is at any effluent concentration less than the I WC. The IWC for this permithas been determined to be 100 %. The permittee must provide written notification of the failure of a WET test to the Division, along with a statement as to whether a Preliminary Toxicity Investigation (" PTI ")/Toxicity Identification Evaluation ( "TIE ") or accelerated testing is being performed. Notification must be received by the Division within 21 calendar days of the demonstration of chronic WET in the routine required test. "Demonstration" for the purposes of Part I.A.4.b, c, d and f. means no later than the last day of the laboratory test. C. Automatic Compliance Schedule Upon Failure of Test If a routine chronic WET test is failed, the following automatic compliance schedule shall apply. As part of this, the permittee shall either: L Proceed to conduct the PTI/TIE investigation as described in Part I.AAA., or ii. Conduct accelerated testing using the single species found to be more sensitive. If accelerated testing is being performed, the permittee shall provide written notification of the results within 14 calendar days of completion of the "Pattern of Toxicity "P'No Toxicity" demonstration. Testing will be at least once every two weeks for up to five tests until; 1) two consecutive tests fail or three of five tests fail, in which case a pattern of toxicity has been demonstrated or 2) two consecutive tests pass or three of five tests pass, in which case no pattern of toxicity has been found. If no pattern of toxicity is found the toxicity episode is considered to be ended and routine testing is to resume. if a pattern of toxicity is found, a PTI/TIE investigation is to be performed. If a pattern of toxicity is not demonstrated but a significant level of erratic toxicity is found, the Division may require an increased frequency of routine monitoring cr some other modified approach. d. PTI/TIE The results of the PTUTIE investigation are to be received by the Division within 120 days of the demonstration of chronic WET in the routine test, as defined above, or if accelerated testing is performed the date the pattern of toxicity is demonstrated. A status report is to be provided to the Division at the 30 60 and 90 day points of the PTUTIE investigation. The Division may extend the time frame for investigation where reasonable justification exists. A request for an extension must be made in writing and received prior to the 120 day deadline. Such request must include a justification and supporting data for such an extension. The permittee may use the time for investigation to conduct a PTI or movedirectly into the TIE. A PTI consists of a brief search for possible sources of WET, which might reveal causes of such toxicity and appropriate corrective actions more simply and cost effectively than a formal TIE. If the PTI allows resolution of the WEr incident, the TIE need not necessarily be conducted. If, however, WET is not identified or resolved during the PTI, the TIE must be conducted within the allowed 120 day time frame.