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<br />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 />• TEST ORGANISMS <br />Fathead minnow <br />Ceriodaphnia dubia <br />Date and Time of brood isolation: <br />• PROCEDURE <br /> <br />CO-0000213 <br />Effluent Grab <br />09/23/09 09:45 <br />09/24/09 12:30 <br />Reconstituted Laboratory Water <br />3.0 °C <br />Age: 14 days <br />Age: 0-4 hrs <br />8:30 <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 results 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 third quarter of 2009. <br />• DATE OF REPORT <br />October 27, 2009 <br />Report prepared by: Stephanie Green Hawkins <br />Supervisor Bioassay Laboratory <br />Date <br />4