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Mountain Coal CO-0038776 SCG Project Number: 304146 <br />Ammonia was measured by a Thermo Orion ion-selective electrode according to the procedures <br />in APHA/AWWA/WEFZ. <br />The acute test(s) were started on June 16, 2004. The test(s) were performed according to <br />the procedures outlined in EPA-821-R-02-0123, and the Colorado Dept. of Public Health and <br />Evironment°. The Daphnia magna test(s) were conducted over a 48-hour period. Exposure <br />concentrations include 0%(control), 1.9%, 12.5%, 25%, 50%, and 100% effluent mixtures. <br />Moderately hard laboratory reconstituted water was used as the dilution water and control for the <br />test(s). Reconstituted water is prepared by adding sodium bicazbonate, calcium sulfate, <br />magnesium sulfate and potassium chloride to deionized water. <br />A total of 20 organisms at each concentration were used for the Daphnia magna test(s). <br />Daphnia magna were exposed in 30m1 plastic disposable beakers, each of which contained 15m1 <br />of the effluent mixture. <br />Exposure medium in each chamber was replaced every 24-hours and organisms surviving <br />at each concentration were counted and recorded. Routine measurements were made of <br />temperature, pH and dissolved oxygen in each concentration, before and after the water change. <br />Test Procedures for Diluted Acute Tests <br />Three additional acute tests were performed to re-confirm the potential for TDS as a <br />source of toxicity in the effluent. These tests were designed to indicate the presence of other <br />contaminants that could be present. <br />The tests were accomplished by making three reconstituted test solutions. Aliquots of the <br />original effluent were diluted to stocks of 12.5%, 25% and 50%. Each of these stock solutions <br />was the returned to its original state by bringing the alkalinity back to that of the original <br />effluent. Laboratory grade NaHCO; (sodium bicazbonate) was added in order to raise the <br />alkalinity. These reconstituted samples were then run in toxicity tests at concentrations of 1.9%, <br />12.5%, 25%, 50% and 100%. This has the effect of maintaining a constant alkalinity while <br />diluting other contaminants that could be present in the original effluent. )n essence, if sirnilaz <br />toxicity is observed in all of the tests, then the alkalinity can be recognized as the cause of the <br />problem. If the toxicity decreases with the increasing dilution of the reconstituted samples, then <br />it can be assumed that some other toxicant is present. <br />Data Analysis <br />Data from the test(s) were analyzed on a Pentium®personal computer. Where applicable, <br />LC50's were calculated using EPA's TOXDATE Multi-Method Program according to the <br />binomial, probit or moving average methods. <br />RESULTS <br />Original Sample <br />An LC50 of 86.6% was measured in this test (See Table 1). Survival was 40% in the <br />100% effluent and ranged from 80-100% in the remaining effluent concentrations. Survival was <br />100% in the control. The results of all tests can be found in Appendix 2 of this report. <br />The SeaCrest Group, LLC 6 <br />