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analytical method detects both dissolved sulfides and acid - soluble <br />metallic sulfides present in suspended matter. It is suspected that a <br />large portion of the sulfides detected is of the latter type, which <br />would bias the un- ionized results high. Any dissolved sulfides present <br />in surface water should eventually oxidize to sulfates. <br />No sites exceeded the ammonia standard this year. The aquatic life <br />ammonia standard is dependent on pH and temperature. The detection limit <br />for ammonia is 0.05 mg /l. All values above detection limit are compared <br />to table standards, page 87, found on this website: <br />htt2://www.epa.gov/waterscience/criteria/ammonia/99update.pdf <br />NPDES Effluent Criteria (Permit No. CO- 0000221). No excursions of NPDES <br />effluent limits occurred this year. The excursions of the selenium <br />standard noted above at NPDES8 in April, May and June were not NPDES <br />permit limit excursions. The permit limit for this outfall for selenium <br />is to "Report" only. This outfall has a NPDES Compliance Schedule to <br />meet the selenium limit by December 31, 2015. SCC is currently <br />investigating means of selenium control. SCC is also performing an <br />aquatic life survey in this drainage, and is also investigating the <br />possibility of a site- specific standard. <br />Surface Water Summar . Water discharged from the Seneca II Mine is not <br />used directly for irrigation. Indirectly, although, water discharged <br />from the mine is significantly diluted by water from Fish Creek before <br />it is diverted and used for irrigation. Due to the relative amount of <br />dilution by additional water from both sources, the ambient water <br />quality of Fish Creek is the dominant factor in determining their <br />suitability for irrigation. Water discharged from the Seneca II Mine is, <br />however, used for livestock watering. <br />TDS values at NPDES8 are stabilizing. Spoil Spring 9 also exhibits a <br />stable TDS trend. NPDES discharges are normally suitable for livestock <br />and irrigation, but occasionally exceed selenium water quality standards <br />for aquatic life. <br />12 <br />