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<br />• Part <br />Page le of 19 <br />Permit No. CO-0042562 <br />B. MONITORING REQUIREMENTS <br />4. Chronic WET Testing - Outfalls 001 and 002 (continued) <br />(a) Testinf and Reporting Repuirements cont'd <br />The permittee shall conduct each chronic WET test in general accordance <br />with methods described Short Term Methods for Estimating the Chronic <br />Toxicity of Effluents and Receiving Waters to Freshwater Organisms, <br />EPA/600/4-89/001 or the most current edition, except as modified by the <br />most current Division guidance document entitled Guidelines for Conductine <br />Whole Effluent Toxicity Tests. The permittee shall conduct such tests <br />using Ceriodaphnia dubia and fathead minnows. <br />(b) Failure of Test and Division Notification [Prior to Effective Date of <br />Limitation) <br />Prior to the effective date of Che limitation, a chronic WET test is failed <br />whenever 1) there is a statistically significant difference in lethality <br />between the control and any effluent concentration less than or equal to <br />the instream waste concentration ("IWC") and, 2) the IC25, which represents <br />an estimate of the effluent concentration at which 25X of the test <br />organisms demonstrate inhibition as reflected by lethality, is at any <br />effluent concentration less than or equal to the IWC. The IWC for this <br />permit has been determined to be 37X for outfall 001, and 46.9X for outfall <br />002. The permittee must provide written notification of the failure of a <br />WET test to the Division, along with a statement as to whether a <br />Preliminary Toxicity Investigation ("PTI")/Toxicity Identification <br />Evaluation ("TIE") or accelerated testing is being performed (see Part <br />I.B.4.(d)). Notification must be received by the Division within 21 <br />calendar days of the demonstration of chronic WET in the routine required <br />test. "Demonstration" for the purposes of Parts I.B.4(b),(c),(d) and (f) <br />means no later than the last day of the laboratory test. <br />(c) Failure of Test and Division Notification (Beginnine on Effective Date of <br />Limitation) <br />Beginning on the effective date of the limitation, a chronic WET test is <br />failed whenever there is a statistically significant difference in <br />lethality between the control and any effluent concentration less than or <br />equal to the instream waste concentration ("IWC"). The IWC for this permit <br />has been determined to be 37X for outfall 001, and 46:9X for outfall 002. <br />The permittee must provide written notification of the failure of a WET <br />test to the Division, along with a statement as to whether a Preliminary <br />Toxicity Investigation ("PTI")/Toxicity Identification Evaluation ("TIE") <br />or accelerated testing is being performed. Notification must be received <br />by the Division within 21 calendar days of the demonstration of chronic WET <br />in the routine required test. "Demonstration" for the purposes of Parts <br />I.B.4(b),(c),(d), (e) and (g) means no later than the last day of the <br />laboratory test. <br />amended effective <br />