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Narrative and Discussion. <br />PERMIT AND SAMPLE INFORMATION <br />NPDES permit #: <br />Type of sample: <br />Date and time of sample(s): <br />Date and time of test start: <br />Dilution water: <br />Receiving temperature(s): <br />CO-0000213 <br />Effluent Grab <br />06/24/08 09:00 <br />06/25/08 12:30 <br />Reconstituted Laboratory Water <br />15.9 °C <br />• TEST ORGANISMS <br />Fathead minnow <br />Cerodaphnia dubia <br />Age: <14 days <br />Age: <24 hrs <br />• PROCEDURE <br />Acute, 48 and 96-hour bioassays as outlined in the most recent protocols specified by the Water <br />Quality Control Division of the Colorado Department of Health (1998). <br />• DISCUSSION <br />According to the Western Fuels - Colorado discharge permit (CO-0000213), an acute WET test is <br />failed whenever the LC50, which represents an estimate of the effluent concentration which is <br />lethal to 50% of the test organisms in the time period prescribed by the test, is found to be less <br />than or equal to 100% effluent. <br />By this definition, the resu'Its of this bioassay indicate that effluent from outfall 011 is not <br />acutely toxic to fathead minnow or Ceriodaphnia dubia survival. Therefore, outfall 011 is <br />in compliance with the acute WET portion of its Colorado State Industrial General Minimal <br />Discharge Permit for the second quarter of 2008. <br />• DATE OF REPORT <br />July 1, 2008 <br />Report prepared by: Stephanie Green <br />Supervisor Bioassay Laboratory <br />Report approved by: Ken Holliday <br />Co dinator, Aquatic Toxic y <br />4