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87, found on this website: http://nepis.epa.gov/Adobe/PDF/20003O3L.pdf. No sites exceeded <br />the ammonia standard in the past five years. <br />The drinking water standard for mercury is 2 ug/1. The aquatic life standard for mercury is 0.01 <br />ug/1 which is set to protect the average human consumer of fish. PSCM's lab uses a method with <br />a detection limit of 0.2 ug/1. None of the stream samples collected in the past five years were <br />above the drinking water standard. During a previous NPDES permit renewal, the CDPHE <br />performed a reasonable potential analysis on Outfalls 002 (NPDES2) and 004 (NPDES4), and <br />determined that there was no reasonable potential for these outfalls to exceed the mercury limit; <br />therefore, mercury monitoring is no longer required at these outfalls. <br />Table 11 provides a statistical summary of the water quality for the years 2011 to 2015 for Spoil <br />Springs 1, 2, , 10 and 10A (SSSPGI, etc.). Spoil Springs 1 and 2 flow into the NPDES 004 Pond, <br />and Spoil Springs 10 and 10A flow into the NPDES 002 Pond. Table 11A provides water quality <br />data for SSSPGIOA collected in 2010, since no samples were collected at this site from 2011 <br />through 2015. Table 12 provides a comparison of those data with the CWQCC surface water <br />agricultural standards (Reg. 31) presented in Table 13. Water quality data collected at Spoil <br />Springs 1, 2, , 10 and 10A were compared to the agricultural standards because the post -mining <br />land uses of the reclaimed parcel in this Phase III bond release application as designated in the <br />Seneca II and PSCM Mines' Permit Application Package for the State Mining Permit are livestock <br />grazing and wildlife habitat. Table 12 is of the same format previously discussed for Table 10. <br />Four of the CWQCC surface water agricultural use standards were exceeded. The manganese <br />standard, 0.2 mg/1, was exceeded at Spoil Springs 2, 10 and 10A. However, as indicated in the <br />recently revised CWQCC Regulation 31, the standard of 0.2 mg/1 applies to plants grown in <br />acidic (<6.0 pH) soils. In alkaline soils, as are found in the PSCM region, a more appropriate <br />(EPA, 1976) standard would be 10 mg/1. The maximum dissolved (D) manganese values for <br />Spoil Springs 2, and 10 were less than 1.0 mg/1. Spoil Springs 2, 10 and 10A all showed <br />potentially dissolved (PD) manganese values greater than 1.0 mg/L. The maximum D <br />manganese value was also exceeded in 2014 at Spoil Springs 2 and 10. PD manganese values <br />observed at these sites in 2013 were all less than 10 mg/1. <br />31 <br />