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No sites exceeded the sulfide standard (0.002 mg /1) this year. The <br />sulfide values provided in Table 13 differ from the values reported in <br />Appendix D. The sulfide data presented in Appendix D are the total of <br />both the ionized (S) and un- ionized (H.S) forms of hydrogen sulfide. <br />The un- ionized form is the potentially toxic form, and is what the CDPHE <br />water quality standard is based upon. A procedure for calculating the <br />un- ionized form may be found on the website: <br />http:// www. mullalyengineering .com.au /images/product /file /Problem of_Hydr <br />open Sulphide in Sewers.pdf page 5, Table 1. The results of those <br />calculations are presented in Table 13 of this AHR. The analytical <br />method detects both dissolved sulfides and acid - soluble metallic <br />sulfides present in suspended matter. It is suspected that a large <br />portion of the sulfides detected is of the latter type, which would bias <br />the un- ionized results high. Any dissolved sulfides present in surface <br />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 />http : / /www.epa.gov /waterscience /criteria /ammonia /99update.pdf <br />NPDES Effluent Criteria (Permit No. CO- 0000221) . No excursions of NPDES <br />effluent criteria occurred this year. For NPDES8, the two excursions of <br />the selenium stream standard noted above were not NPDES permit limit <br />excursions. The permit limit for this outfall for selenium is to <br />"Report" only. This outfall has a NPDES Compliance Schedule to meet the <br />selenium limit by December 31, 2015. SCC is currently investigating <br />means of selenium control. SCC is also performing an aquatic life survey <br />in this drainage, and is also investigating the possibility of a site - <br />specific standard. <br />Surface Water Summary. 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 />12 <br />