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Similarly, the CDOH has established a chronic standard of .002 mg/L for unionized sulfide • <br />as hydrogen sulfide (H2S). It should be noted that the water quality analyses in the <br />appendices of this AHR report the sum of ionized and un-ionized sulfide as sulfide. To <br />compare Peabody~s reported sulfide concentrations against the stream standard, it is <br />necessary to convert the reported concentration to un-ionized sulfide as hydrogen sulfide. <br />This is accomplished in two steps. Sulfide values ere converted to sulfide as hydrogen <br />sulfide by multiplying by 1.06. io express the sulfide as hydrogen sulfide values in <br />terms of un-ionized su Lf ide, the procedure on Page 477 of "Standard Methods for the <br />Evaluation of Water and Wastewater" (APRA, 1985) was used. The procedure consists of <br />multiplying the sulfide as hydrogen sulfide values by an un-ionized sulfide correction <br />factor. Since any su Lfides in surface water should be rapidly oxidized to sulfates, it is <br />likely that any sulfides detected in surface water are the result of sulfides existing in <br />the suspended solids, or are the result of interferences with the sulfide analyses. <br />Table 25 (Appendix A) presents the results of comparing surface water quality data from <br />all surface water and NPDES sites within the Fish Creek Basin collected during 1992 <br />against ODOR stream standards established for Segment 138 of the Yampa River. Table 25 <br />indicates that ell sites where water quality was analyzed experienced exceedences. • <br />Parameters that were higher than the standards include sulfates, su Lfides (un-ionized), <br />iron, mercury, lead, zinc, and silver and manganese. It is noteworthy of mentioning that <br />even Site 11, which is upstream of Seneca mine discharges, has exceeds the iron, sulfide <br />and mercury standards. <br />Water discharged from the Seneca II Mine is not used directly for irrigation. Indirectly, <br />although, eater discharged from the mine is significantly diluted by eater from either <br />Fish Creek or the Yampa River before it is diverted and used for irrigation. Due to the <br />relative amount of dilution by additional water from both sources, the ambient water <br />qualities of Fish Creek end the Yampa River are the dominant factors in determining their <br />suitability for irrigation. <br />eater discharged from the Seneca I! Mine (s used for livestock vatering. Table 23 <br />(Appendix A) presents the most stringent livestock standards as compiled from various <br />organizations by the OSRRE (OSMRE, 1989). Surface water quality measured et stream and <br />NPDES sites during the 1992 water year were compared with the livestock standards, and the <br />comparison results are presented in Table 26 (Appendix A). pR was measured at higher • <br /> 26 <br />