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Mountain Coal Company CO-0038776 SeaCrest Number: 303411 <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 mI <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 November 21, 2003 and was performed 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 85% in the 100% effluent and 100% in the remaining effluent concentrations. <br />Survival was 100% in the control. <br />DISCUSSION <br />The 017 discharge site passed the second accelerated test for the Daphnia magna. No <br />significant toxicity was seen and no LC50 concentration was produced. <br />REFERENCES <br />Weber, C.I. et. al. 1993. Methods for Measuring the Acute Toxicity of Effluents and Receiving <br />Waters to Freshwater and Marine Organisms (fourth edition). Environmental Protection Agency <br />Report No. EPA/600/4-90/027F. 293 pp. <br />APHA/AWWANVEF. 1998. Standard Methods for the Examination of Water and Wastewater. <br />20th Edition. American Public Health Association. <br />Loveland, Colorado. 1260 pp. <br />Group 3 <br />