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for any surface water site observed this year was 1.46 mg/1. Premining <br />manganese values often exceeded the 0.2 mg/1 standard. <br />Table 11 shows the CDOH receiving stream standards for Dry Creek (Yampa <br />Segment 13d) and Sage Creek (Yampa Segment 13e). Sage Creek was <br />resegmented by the CDOH in 2003. These standards were based on the <br />presence of fish in the lower portions of the creeks. However, the upper <br />portions that Seneca II-W discharges into have no fish present. All <br />standards for 13d and 13e are the same except for selenium (see Table <br />11) Table 12 provides a comparison of those standards to water quality <br />data collected this year from NPDES and stream sites in those basins. <br />Standards that were exceeded (excluding ammonia and sulfide) are: <br />Parameter <br />Chromium (acute/chronic) <br />Copper (chronic) <br />Iron <br />Lead (chronic) <br />Nitrite <br /># of Sites / # of Excursions <br />1/1 <br />1/1 <br />5/8 <br />1/1 <br />3/5 <br />The chromium, copper and lead excursions are from the same sample <br />collected at WSH7 in April, and are probably due to high suspended <br />solids (892 mg/1). Only three of the eight iron exceedences were from <br />NPDES sites. They are probably due to suspended solids. This strict <br />aquatic life standard (1.0 mg/1) was exceed in over half of the <br />premining stream samples. Nitrites are unstable in aerated water (Hem, <br />1989), and will oxidize to nitrates. <br />Ammonia values require extra calculations to determine exceedences. The <br />standard is 0.06 mg/1 un-ionized NH3, while the method detects both un- <br />ionized NH3 and ionized NH4. The following table calculates the actual <br />un-ionized NH3 concentration of the exceedences reported on Table 12. <br />Ammonia values were calculated from the Internet site <br />http://aquanic.org/images/tools/ammonia.htm. <br />22 <br /> <br />• <br />• <br />