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Parameter # of Sites / # of Excursions <br />Iron, Total Recoverable (TR) 5/5 <br />Two of the five iron exceedances were from NPDES sites 016 and 017. All <br />of the exceedances occurred during snowmelt runoff. They were likely due <br />to high suspended solids (TSS) values normally observed during snowmelt <br />runoff. The TSS values for two NPDES sites were from 19 and 72 mg /1, <br />while the TSS values at the three stream sites were 480 to 790 mg /1. <br />This strict aquatic life standard (1.0 mg/1) was exceeded in over half <br />of the pre- mining stream samples. <br />The sulfide data presented in Appendix E are the total of both the <br />ionized (S ) and un- ionized (HS) forms of hydrogen sulfide. The un- <br />ionized form is the potentially toxic form, and is what the CDPHE water <br />quality standard is based upon. A procedure for calculating the un- <br />ionized form may be found on the website: <br />http: / /www.mullalyengineering.com.au /images /product /fileiProblem of Hydr <br />o en Sulphide in Sewers. df page 5, Table 1. No excursions of the 0.002 <br />mg /l un- ionized sulfide standard occurred this year. <br />The aquatic life ammonia standard is dependent on pH and temperature. <br />The detection limit for ammonia is 0.05 mg /1. All values above detection <br />limit are compared to table standards found on this website, page 87: <br />http: / /www.epa.gov /waterscience /criteria /ammonia /99update.pdf <br />No ammonia excursions occurred this year. <br />The drinking water standard for mercury is 2 ug /1. The aquatic life <br />standard for mercury is 0.01 ug /1, which is set to protect the average <br />human consumer of fish. SCC's lab uses a method with a detection limit <br />of 0.2 ug /1. None of the samples collected this year were above the <br />detection limit. During the last NPDES permit renewal, the CDPHE <br />performed a reasonable potential analysis on SCC's outfalls. It <br />determined that there was no reasonable potential for SCC's outfalls to <br />exceed the mercury limit; therefore, mercury monitoring is no longer <br />required for SCC's outfalls. <br />21 <br />