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I ~ a decision by the laboratory to dilute the samples prior to analyses in <br />order to reduce the effects of interferences (primarily, high salinity). <br />elevated levels of iron and fluoride may be attributed to natural (i.e., <br />not mining related) conditions, since elevated levels for those <br />parameters are not found in Seneca II spoil wells. In the case of <br />fluoride, the three wells (8P1, 11 and 191 that have elevated levels <br />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). 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 71) 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 />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. The <br />CDOH has recently revised their surface water agricultural standard to <br />reflect this pH qualifier. In soils with a higher pH (as are found in <br />the Seneca II region), a more appropriate standard would be 10 mg/1 <br />(EPA, 1976). This year, none of the Seneca II alluvial wells displayed <br />a value higher than 5,31 mg/1, and no spoil wells displayed a value <br />higher than 2.49 mg/1. <br />9 <br />