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LTE COMMENCIAl TESTING & ENGINEEPING CO. <br />DISCUSSION cont. <br />increased as the pH was increased. Cations, such as Na+, Ca++ Mg++ and K+, aze alkaline <br />earth elements and easily form metal oxides; that when added to water form metal <br />hydroxides. Based on the results of the total metal scan by ICP, concentrations of Na`, Ca", <br />Mg++, and K+ dominated the cationic constituents in solution. <br />Some other observations: <br />^ While adjusting the pH to 3.0, bubbles occurred near the surface of the effluent...an <br />indication of something volatizing. As the pH 3.0 adjustment/aeration test completely <br />removed the toxicity and the pH ]0 adjustment/filtration test significantly reduced the <br />toxicity, it is a fair assumption that the chemical species that volatized could have been the <br />toxicant. <br />• There is strong evidence that indicates that the toxicity is pH dependent. In the <br />characterization tests that exhibited significant toxicity the pH was 9.3-9.5. In the <br />characterization tests that exhibited moderate or reduced toxicity the pH was 9.0-9.3. In the <br />characterization tests that exhibited removed toxicity the pH was below 9.1. In particular, <br />the pH 3.0 adjustment/aeration 100% effluent had a pH of 7.6. <br />^ Metals that typically cause toxicity towards Daphnia magna, such as zinc, nickel and <br />cadmium had low concentrations. These did not appear to be the toxicants. <br />Furthermore, an ion balance program was utilized to see how the charge balance differed. The <br />analysis of the test solution indicated a % difference of -18.34. Usually a % difference that <br />exceeds f 5,0 is considered an unbalanced charge and could indicate a potential problem. This <br />seems to be the case with eflluent from Mountain Coal Company. Please refer to Appendix D <br />for complete analysis. <br />In summation, it appears that cationic metal and/or cationic surfactants are the source of toxicity <br />in Mountain Coal Company's effluent. However, TDS cannot be ruled out either, as the major <br />constituents of TDS (sodium, calcium, etc) are present in lazge concentrations and the TDS <br />concentration is 2900 mg/L. The exact cause of toxicity could not be achieved in this limited <br />testing. Further analysis may be necessary. <br />8 <br />