Laserfiche WebLink
Mountain Coal Company SeaCrest Number. 399033 <br />A total of twenty organisms at each concentration was used for the acute tests. Daphnia <br />magna were exposed in 30 ml plastic disposable beakers. Twenty ml of the effluent mixture <br />was added to each beaker. Fathead minnows were exposed in 260 ml plastic cups containing <br />200 ml of medium. Exposure medium was replaced after each 24 hour period and organisms <br />surviving at each concentration were counted and recorded. Routine measurements were <br />made of temperature, pH, and dissolved oxygen in each concentration. <br />Acute tests were performed according to the procedures outlined in Weber (1993). <br />Daphnia magna tests were conducted over 48 hours with fathead minnows being exposed for <br />96 hours. The tests were run with exposure concentrations of 100%, 75%, 50%, 25%, and <br />12.5% effluent. Water used for the control and as the dilution water was laboratory <br />reconstituted freshwater. <br />Data Analysis <br />Data from the tests were analyzed on a Computer Source 386 personal computer. <br />Where applicable, LC50's were calculated using EPA's TOXDAT Multi-Method Program <br />according to the binomial, probit, or moving average methods. Statistically significant <br />differences between control and exposed organisms were determined using the TOXSTAT <br />software developed at the University of Wyoming. <br />RESULTS <br />The results of the tests are summarized in Appendix 2. No mortality was seen in the <br />Daphnia magna test where survival was 100% in every effluent concentration. Survival was <br />also 100% in the control. <br />The fathead minnow test showed no toxicity, with 100% survival in every effluent <br />concentration. Control survival was 100%. <br />DISCUSSION <br />The 013 discharge site passed the whole effluent toxicity test guidelines for both test <br />species. <br />The SeaCrest Group 3 <br />