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~G~ <br />Narrative and Discussion <br />PERMIT AND SAMPLE INFORMATION <br />NPDES permit #: <br />Type of sample: <br />Date and time of sample: <br />Date and time of test start: <br />Dilution water. <br />Receiving temperature: <br />TEST ORGANISMS <br />Fathead minnow <br />Daphnia Magna <br />CO-0000213 <br />Effluent Composite <br />3/28/2006 1017 <br />3/29/2006 1100 <br />Reconstituted Laboratory Water <br />4°C <br />• PROCEDURE <br />Age: 7 days <br />Age: <24 hrs <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 discharge permit (CO-0000213), an acute WET test is failed whenever <br />the LCD, which represents an estimate of the effluent concentration which is lethal to 50% of the <br />test organisms in the time period prescribed by the test, is found to be less than or equal to 100% <br />effluent. <br />By this definition, the results of this bioassay indicate that effluent from outfall 007 is acutely toxic <br />to fathead minnow but not to Daphnia Magna survival. Therefore, outfall 007 may be not in <br />compliance with the acute WET portion of its Colorado State Discharge Permit for the first quarter <br />of 2006. <br />• DATE OF REPORT <br />April 4, 2006 <br />Report prepared by: Regina Mahan <br />Biomo itoring Technician Date <br />SGS North America Inc. I Minerals Services Division <br />4665 Paris Street, Suite B- <br />Report reviewed by: Tony Stoyko <br />i~-~~~ ~~a.o6 <br />Bio oniton Supervisor Date <br />CO 80239 t (3031373-4772 f (3031373-4791 www.s <br />e sn ~ Member of Ne SGS Grouo <br />