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were exceeded. Given in parenthesis is the source and use of each <br />standard. <br />Parameter # of Wells / # of excursions <br />Fluoride (CDPHE, irrigation) 2/2 <br />Iron (CDPHE, irrigation) 1/2 <br />Manganese (CDPHE, irrigation) 4/5 <br />The high fluoride values at Wells YWC33 and YWCU33 are most likely a <br />natural condition associated with a sodium bicarbonate type water. It is <br />suspected that the high fluoride values are related to this type of <br />water chemistry (Hem, 1989, pg. 121). Several wells at SCC's Seneca II <br />Mine with high fluoride values also exhibit this type water. <br />Elevated levels of iron may be attributed to natural (i.e., not mining <br />related) conditions, since elevated levels for this parameter are not <br />found in the adjacent Seneca II spoil wells. The high levels of iron <br />displayed in the one alluvial well (YGAL15) may be the result of organic <br />matter and plant debris present in the alluvium (Hem, 1989, pg. 77). <br />This well displayed high levels of iron prior to mining. <br />High manganese values may, in part, be due to recharge from the spoil <br />aquifer, although high values are often common, especially in alluvial <br />material (Hem, 1989, pgs. 86-89). The wells displaying high manganese <br />values this year also did so prior to mining. It should be noted that, <br />while the CDPHE uses a standard of 0.2 mg/1, the EPA states that this <br />standard is used to protect crops grown in soils with a pH value lower <br />than 6.0. In January 2008, CDPHE revised their ground water agricultural <br />standard to reflect this pH qualifier. In soils with a higher pH (as are <br />found in the Yoast region), a more appropriate standard would be 10 mg/1 <br />(EPA, 1976). This year, no well displayed a value higher than 1.10 mg/l. <br />Ground Water Summa <br />TDS trends are decreasing at two wells, stable at seven wells, and <br />increasing at eight wells. CDPHE agricultural ground water standards for <br />6 <br />