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PARTI Permit No. CO-()032638 Page No. 5 A. DEFIMTION OF EFFLUENT LIMITATIONS 3. Whole Effluent Toxicity Testine Requirements (Acute) Outfalls 004 and 007 (June-Febrnarv Onlv) (continued) b. Failure of Test and Division Notification An acute WET test is failed whenever the LCSO, which represents an estimate of the effluent concentration which is lethal to 50% of the test organisms in the time period prescribed by the test, is found to be less than or equal to 100% efFluent. The permittee must 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 by the Division within 14 calendar days of the demonstration of acute WET in the routine required test. "Demonstration" for [he purposes of Parts I.A.3.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 acute WET test is failed, [he following automatic compliance schedule shall apply. As part of this the permittee shall either: i) Proceed to conduct [he PTI/TIE investigation as described in Part I.A.3.d., 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"/"No Toxicity" demonstration. Testing will be a[ 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. [f a pattern of toxicity is found, aPTI/TIE investigation is to be perfotmed. 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 or some other modified approach. d. PTI/TIE 30, 6U and YU day points of the I'I'I/TIE 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 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 time frame. Any permittee that is required to conduct aPTI/TIE investigation shall do so in conformance with procedures identified in the following documents, or as subsequently updated: 1) Methods for Auuatic Toxicitv Identification Evaluations. Phase 1 Toxicitv Characterization Procedures, EPA/60016-91!003 Feb. 9l and 2) EP Feb. 1989. A third document in this series is Methods for Aquatic Toxicitv Identification Evaluations. Phase III Toxicitv Confirmation Procedures, EPA/600/3-88/036 Feb. 1989. As indicated by the title, this procedure is intended to confirm that the suspected toxicant is truly the toxicant. This investigation is optional. See Parl I.C. for Definitions.