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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 />CO-0000213 <br />EfFluent Composite <br />04/30/07 0910 <br />Date and time of test start: <br />Dilution water: <br />Receiving temperature(s): <br />05/01 /071100 <br />Reconstituted Laboratory Water <br />6.4° C <br />• TEST ORGANISMS <br />Fathead minnow <br />Ceriodaphnia dubia <br />Age: <24 hrs <br />Age: <24 hrs <br />• PROCEDURE <br />Chronic bioassays as outlined in the most recent protocols specified by the Water Quality Control <br />Division of the Colorado Department of Health (1998). <br />• DISCUSSION <br />According to the Western Fuels New Horizon Mine discharge permit (CO-0000213), a chronic <br />WET test is failed whenever there is a statistically significant difference inlethality between the <br />control and any effluent concentration less than or equal to the Instream Waste Concentration. <br />The IWC for this permit has been determined to be 100%. <br />By this definition, the test results indicate that the effluent was not chronically toxic tc <br />fathead minnow or to Ceriodaphnia dubia survival. Therefore, outfall 007 is in compliance <br />with the chronic WET portion of its Colorado State Discharge Permit for the second <br />quarter of 2007. <br />• DATE OF REPORT <br />June 5, 2007 <br />Report reviewed by: Ken Holliday <br />' monitoring Supervy~ r D t~ <br />4 <br />