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„ Part) r <br />Page lh of 20 <br />Permit No. CO-0041467 <br />B. MONITORING REQUIREMENTS <br />2. Whole Effluent Toxicity Testine Requirements -Chronic WET Testine-Outfall(sl: 004A <br />(a) Testine and Reoortine Requirements <br />Tests shall be done at the treauencv listed in Part I.B.1 Test results shall be reported along <br />with the Discharge Monitoring Report (DMR) submitted for the reporting period during which the <br />sample was taken. (i.e., WET testing results for the first calemiaz quarter ending March 31 shall <br />be reported with the DMR due April 28.) The results shall be submitted on the Chronic Tonicity <br />Test report form, available from the Division. Copies of these reports are to be submitted to both <br />the Division and EPA along with the DMR. <br />The permittee shall conduct each chronic WET test in general :tccordance witlt methods described <br />Short Term Methods for Estimative the Chronic Toxiciri of Effluents and Receivine Waters to <br />Freshwater Organisms, EPA/600/4-89/001 or the most current edition, except as modified by the <br />most current Division guidance document entitled Guidelines for Conducting Whole Effluent <br />Toziciri Tests. The permittce shall conduct such tests using Ceriodaphnia dubia and fathead <br />minnows. <br />(b) Failure of Test and Division Notification (Prior to Effective Date of Limitation) <br />Prior to the effective date of the limitation, a chronic WET test is failed whenever 1) there is a <br />statistically significant difference in lethality between the control and any effluent concentration <br />less than or equal to the instream waste concentration ("IWC") and, 2) the ICu, which represents <br />an estimate of the effluent concentration at which 25% of the test organisms demonstrate <br />inhibition as reflected by lethality, is at any effluent concentration less than or equal to the IWC. <br />The season IWC's for this permit have been determined to be: Oct-May 24.5% Jtta-Jul <br />9.54% Aug-Sep 22.1%. The permittee must provide wriar:n notification of the failure of a <br />WET test to the Division, along with a statement as to whether a Preliminary Toxicity <br />Investigation ("PTI")/Toxicity Identification Evaluation ("TIE") or accelerated testing is being <br />performed (see Part I.A.4.(d)). Notification must be received by the Division within 21 <br />calendar days of the demonstration of chronic WET in the rroutine required test. <br />"Demonstration" for the purposes of Parts I.A.4(b),(c),(d) and (f) means no later than the last day <br />of the laboratory test. <br />(c) Automatic Compliance Schedule Upon Failure of Test <br />If a routine chronic WET test is failed, regardless of whether the limit is in effect, the following <br />automatic compliance schedule shall apply. As part of this the petmittce shall either: <br />(i) proceed to conduct the PTI/TIE investigation as described in Part I.A.4.e, or <br />(ii) conduct accelerated testing using the single species found to be more sensitive. <br />amended 04/27/92 effective 06/01/92 <br />amended effective <br />