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Mountain Coal Company CO-0038776 SeaCrest Number: 303417 <br />A total of twenty organisms at each concentration were used for the daphnia test. <br />Daphnia magna were exposed in 30 ml plastic disposable beakers. Approximately twenty ml <br />of the effluent mixture was added to each beaker. Exposure medium was replaced after each <br />24 hour period and organisms surviving at each concentration were counted and recorded. <br />Routine measurements were made of temperature, pH, and dissolved oxygen in each <br />concentration. <br />The acute test was started on December 2, 2003 and was pertormed according to the <br />procedures outlined in Weber (1993). The Daphnia magna test was conducted over 48 hours. <br />The test was run with exposure concentrations of 100%, 50%, 25%, 12.5%, and 1.9% effluent. <br />Water used for the control and as the dilution water was moderately-hard laboratory <br />reconstituted freshwater. <br />Data Analysis <br />Data from the tests were analyzed on a PentiumR personal computer. Where applicable, <br />LC50's were calculated using EPA's TOXDATMnlti-Method Program according to the binomial, <br />probit, or moving average methods. <br />RESULTS <br />The results of the Daphnia magna test are summarized in Appendix 2. In the test <br />survival was 80% in the 100% effluent and ranged from 90-100% in fhe remaining effluent <br />concentrations. Survival was 100% in the control. <br />DISCUSSION <br />The 017 discharge site passed the third accelerated test with the Daphnia magna. No <br />significant toxicity was seen and no LC50 concentration was produced. This makes the second <br />accelerated test to pass in a row. Therefore accelerated testing is now completed and the site <br />may return to its normal testing schedule. <br />The SeaCrest Group 3 <br />