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PARTI <br />Page No. 6 <br />Permit No.: CO-0000]32 <br />methods described in Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and <br />Marine Organisms, EPA/600/4-90/027 or the most current edition, except as modified by the most current Division <br />guidance document entitled Guidelines jor Conducting Whole E}gluent Toxicity Tests. <br />b. Failure of Test and Division Notification <br />An acute WET test is failed whenever the LCD, which represents an estimate of the effluent concentration which is lethal <br />to 50% of the test organism in the time period prescribed by the test, is found to be less than or equal to 100% effluent. <br />The permittee must provide written notification of the failure of a WET test to the Division, along with a statement as to <br />whether the Preliminary Toxicity Incident ("PTI")/toxicity Identification Evaluation ("TIE") investigation or accelerated <br />testing is being performed (see next section). Notification must be received by the Division within 14 calendar days <br />of the demonstration of acute WET in the routine required test. "Demonstration" for the purposes of subparts b., c., <br />d. and f. means no later than the last day of the laboratory test. <br />c. Automatic Compliance Schedule Upon Failure of Test <br />If a routine acute WET test is failed, the following automtic compliance schedule shall apply. As part of this the <br />petmittee shall either: <br />i. proceed to conduct the PTI/I'IE investigation as described in subpart d., or <br />ii. conduct accelerated testing using the single species found to be more sensitive. <br />If accelerated testing is being performed, the permittee shall provide written notification of the results within 14 <br />calendar days of completion of the "Pattern of Toricity"/"No Toricity" demonstratiop. Testing will be at least - <br />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 <br />pattem of toxicity has been demonstrated or, 2) two consecutive tests pass or three of five tests.pass, in which case no <br />pattem of toxicity has been found. 'If no pattem of toxicity is found the toxicity episode is considered to be ended and <br />routine testing is to resume. If a pattem of toxicity is found, a PTI/ITE investigation is to be performed. If a pattem of <br />toxicity is not demonstrated but a significant level of erratic toxicity is found, the Division may require an increased <br />frequency of routine monitoring or some other modified approach. <br />d. PTI/1'IE <br />PTI/TIE investleatton. The Division may extend the time frame for investigation where reasonable justification exists. <br />A request for an extension nnrst be made in writing and received prior to the 120 day deadline. Such request must <br />include a justification and supporting data for such an extension. <br />The permittee my use the time for investigation to conduct a PTI or move directly into the TIE. A PTI consists of a <br />brief seazch for possible sources of WET, which might reveal causes of such toxicity and appropriate corrective actions <br />more simply and cost effectively than a formal TIE. If the PTI allows resolution of the WET incident, the TIE need not <br />necessarily be conducted. If, however, WET is not identified or resolved during the PTI, the TIE must be conducted <br />within the allowed 120 daytime frame. <br />Any permittee that is required to conduct a PTI/TIE investigation shat] do so in conformance with procedures identified <br />in the following documents, or as subsequently updated: 1) Methods for Aquatic Toxicity Identification Evaluations. <br />Phase I Toxicity Characterization Procedures, EPA/600/6-91/003 Feb. 91 and 2) Methods for Aquatic Toxicity <br />Identification Evaluations, Phase II Toxiciri Identification Procedures EPA/600/3-88/035 Feb. 1989. <br />A third docunent in this series is Methods for Aquatic Toxicity Identification Evaluations, Phase III Toxicity <br />Confirmation Procedures, EPA/600/3-88/036 Feb. 1989. As indicated by the title, this procedure is intended to confimt <br />that the suspected toxicant is truly the toxicant. This investigation is optional. <br />Within 90 days of the detemtination of the toxicant or no later than 210 days after demonstration of toxicity, whichever is <br />sooner, a control program is to be developed and received by the Division. The program shall set down a method and <br />procedure for elimination of the toxicity to acceptable levels. <br />Reviscd 03/22/04 <br />