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have historically displayed high levels. Those wells are also unique in . <br />displaying a sodium bicarbonate type water; with almost no calcium, <br />magnesium, or sulfates; and with relatively high pH values. It is <br />suspected that the high fluoride values are related to this type of <br />water chemistry (Hem, 1989, pg. 121). The excursion at Well 33 (5.3 <br />mg/1) is suspected to be an anomaly. All values prior to May 2005 were <br />less than 0.5 mg/1. The October 2005 value was 0.2 mg/1. All wells <br />exist within the Seneca 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 two alluvial wells (32 <br />and 33) may be the result of organic matter and plant debris present in <br />the alluvium (Hem, 1989, pg. 77). All these wells have historically <br />exhibited high iron values and all exist within the Seneca II permit <br />boundary. <br />High manganese values may, in part, be due to recharge from the spoil • <br />aguif er, 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 />CDOH uses a standard of 0.2 mg/1, the EPA states that this standard is <br />used to protect crops grown in soils with a pH value lower than 6.0. In <br />soils with a higher pH (as are found in the Seneca II region), a more <br />appropriate standard would be 10 mg/1 (EPA, 1976). This year, none of <br />the Seneca II alluvial wells displayed a value higher than 6.03 mg/1, <br />and no spoil wells displayed a value higher than 0.72 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 />CDOH. No human health standards were exceeded. The CDOH secondary <br />standard for sulfate, 250 mg/1, was exceeded twice with values of 420 • <br />and 440 mg/1. Well STCS has historically exhibited sulfate <br />10 <br />