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suspected that the high fluoride values are related to this type of . <br />water chemistry (Hem, 1989, pg. 121). All wells exist within the Seneca <br />II permit boundary. <br />In the case of iron, the one Wadge Underburden well (7) exhibiting high <br />levels may have higher than usual concentrations of iron pyrite in the <br />rock. The high levels of iron displayed in the three alluvial wells <br />(32, 33 and 6) may be the result of organic matter and plant debris <br />present in the alluvium (Hem, 1989, pg. 77). All these wells have <br />historically exhibited high iron values and all exist within, or <br />upstream of, the Seneca II permit boundary. <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) Manganese exceedances have occurred <br />at all alluvial wells, including the one Grassy Creek alluvial well <br />upstream of Seneca II (Well 71). It should be noted that, while the <br />CDPHE historically used 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 Seneca II region), a more appropriate standard would be 10 <br />mg/1 (EPA, 1976). This year, none of the Seneca II alluvial wells <br />displayed a value higher than 6.05 mg/1, and no spoil wells displayed a <br />value higher than 4.99 mg/1. <br />Finally, water quality analyses performed on samples obtained at the <br />Seneca II shop well (STCS) for this year were compared against both <br />human health (mandatory) and secondary (i.e., recommended but not <br />mandatory) drinking water standards developed for ground water by the <br />CDPHE. No human health standards were exceeded. The CDPHE secondary <br />standard for sulfate, 250 mg/1, was exceeded twice with values of 340 <br />and 550 mg/1. Well STCS has historically exhibited sulfate <br />concentrations higher than the secondary drinking water standard for • <br />this parameter. However, bottled water is consumed at Seneca II. <br />8 <br />