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PART 1 Page 10 Permit No. CO-0038776 R. It10N1TORRVG REQUIREl1fEN'FS 3. Acute WET Testine - Outfalls 002, 004 and 011 (continued) The peratit[ee shell conduct an acute 48-hour WET lest using Ceriodaphnia sp., and an acute 96-hour WET test using fathead minnows. Acute tests will be replacement static tests of a single effluent grab sample. The permittee shall conduct each acute WET Itst in general accordance with methods described in Methods for Measurinc the Acute Toxicity of Effluents and Receivine Waters to Freshwater and Marine Organisms, EPAl600/4~90/027 or the most current edition, except az modified by the most current Division guidance document entitled Guidelines for Conducline Whole Effluent Toxicity Tests. (b) Failure of Test end Division Notification An acute WET test is failed whenever the LCSa, which represents en estimate of the effluent concentration which is lethal to 5096 of the test organisms in the time period prescribed by the test, is (pond to be less than or equal to 10090 effluent. The permittee atust provide written notification of the failure of a WET test to the Division, along with a statement as to whether the Preliminary Toxicity Incident ("PTI")/Toxicity identification Evaluation ("TIE") investigation or accelerated testing is being performed (see next section). Notification must be received h}~ the Division within 14 calendar days of the demonstration of acute WET in the routine required test. "Demonstration" for the purposes of Parts 1. B.4(b),(c),(d)snd (f) means no later than the last day of the laboratory test. (c) Automatic Compliance Schedule Uoon Failure of Test If a routine acute WET test is failed, the following automatic compliance schedule shall apply. As part of this the permittee shall either: (i) proceed to conduct the ]'TIITIE investigation as described in Pan I.B.4.(d), or ii) conduct accelerated testing using the single species found to be more sensitive. If accelereled testing is being pert'ot~tted, the permittee shall provide written noliRartion of the results within 14 calendar days nl' completion of [he "Pattern of Toxicity"/"No Toxicity" demonstration. Testing will ha 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 pattem of toxicity has been demonstrated or, 2) two consecutive tests pass or three of five tests pass, in which case no pattem of toxicity hes been found. If no pattem of toxicity is found the toxicity episode is considered to be ended and routine testing it; to resume. If a pattern of toxicity is found, a PTl/TIE investigation is to be performed. If a pattem of toxicity is not demonstrated but a significant level of erratic toxicity is found, the Division rosy require an increased frequency of routine monitoring or some other modified approach. (d) PTI/TIE The results of the PI'1/TiE invtstieation are to he received by the Division within 120 days of [he demonstration of acute VtBT in the routine test. as defined shove. nr if accelerated testine is performed, Ihu date the pattern of toxicity is demonstrated. A status report is to he provided to the Division at the 30. 60 and 90 day points nl' the PTI/TIE investigation. The Division may extend the lime framt for investieatitm .vllere 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 move directly 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 WET 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 lime frame. INI)III' A/Y/93