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comparison of those standards to water quality data collected this year <br />from NPDES and stream sites in those basins. Standards that were <br />exceeded are: <br />s <br />0 WSD5, and WSH7 and Spoil Springs 2, 3 and 4. The TDS trend is decreasing <br />Parameter # of Sites / # of Excursions <br />Iron, Total Rec. 6/8 <br />Nitrite 1/2 <br />Sulfide 3/3 <br />Only two of the eight iron exceedances were from NPDES sites. They were <br />likely due to high suspended solids values normally observed during <br />snowmelt runoff. This strict aquatic life standard (1.0 mg/1) was <br />exceeded in over half of the premining stream samples. <br />Three samples experienced exceedances of the sulfide standard (0.002 <br />mg/l un-ionized) this year. Only one of these exceedances was from a <br />NPDES site. Most exceedances were associated with high suspended solids. <br />The analytical method available to SCC detects both dissolved sulfides <br />and acid-soluble metallic sulfides present in suspended matter. It is <br />suspected that a large portion of the sulfides detected is of the latter <br />type, which would bias the un-ionized results high. Any dissolved <br />sulfides present in surface water should eventually oxidize to sulfates. <br />No exceedances occurred at NPDES sites. <br />NPDES 005 exceeded the nitrite standard, 0.05 ug/l, twice with values of <br />0.06 and 0.11 ug/1. Nitrites are unstable in aerated water and will <br />oxidize into nitrates (Hem, 1989). <br />NPDES Effluent Criteria (Permit No. CO-0000221). No excursions of NPDES <br />effluent criteria occurred this year. <br />Surface Water Summary. Flow values from NPDES ponds were above average <br />this year at all ponds. TDS values at NPDES sites 006 and 017 are <br />increasing, as are TDS values at downstream surface water sites WSHF1, <br />at NPDES sites 009, 015 and 016 and Spoil Springs 1. The TDS trend is <br />21