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Average neonates per adult were affected in all test concentrations with no <br /> reproduction in the Bromide levels of 1000, 100, 10, and 1 ppm. An average of <br /> only 0.7 neonates per adult was obtained in the 0.1 ppm concentration. Average <br /> neonates per control adult were 18.6. There was a statistically significant difference <br /> In the number of births between the control and those animals exposed to every <br /> test concentration. <br /> Fathead Minnow Test Results <br /> Test results for the fathead minnows are summarized in Table 2. Survival <br /> was good with 85% survival in the 1000 ppm Bromide concentration and ranging <br /> from 90-100% in the remaining test concentrations. Control survival was 100%. <br /> Average weights of the fish after seven days ranged from 0.51 mg per <br /> individual in the 100 ppm test concentration to 0.57 mg in the 10 and 1000 ppm <br /> concentrations. Average weight in the controls was 0.50 mg. No statistically <br /> significant differences were noted between the control fish weights and those of the <br /> exposed animals. <br /> DISCUSSION <br /> A chronic effect was found in reproduction in the ceriodaph test. This was <br /> similar to the raw effluent where only 40% of the animals survived the test. The <br /> NaBr seemed to help in reducing toxicity as all but the lowest exposure treatment <br /> resulted in improved survival. However, reproduction was affected in all of the NaBr <br /> treated samples, possibly as a result of high TDS (total dissolved solids) levels <br /> and/or contaminant levels in the effluent. It would appear, however, that the NaBr <br /> does not produce a toxic response even at high concentrations. Nevertheless, the <br /> role of the TDS contributed by the NaBr would need to be determined in a dilution <br /> series exposure before a definitive safe exposure level could be suggested. A <br /> concentration of 100 ppm bromide did not appear to greatly affect TDS levels <br /> compared to raw effluent concentrations. <br /> No effect on survival or growth was seen in the fathead minnow test. <br /> REFERENCES <br /> APHA/AWWA/WPCF. 1985. Standard methods for the examination of water and <br /> wastewater. 16th Edition. American Public Health Association. 1268 pp. <br /> Hach Chemical Company. 1978. DR-EU2,3 and 4 methods manual. Hach <br /> Chemical Company, Loveland, Colorado. <br /> Weber, C.I. et al. 1989. Short-term methods for estimating the chronic toxicity of <br /> effluents and receiving waters to freshwater organisms. Second Edition. <br /> EPA/600/4-89/001. 249 pp. <br />