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• Parameter # of Wells / # of excursions Iron (CDOH, irrigation) 1/2 Manganese (CDOH, irrigation) 3/4 In addition, one sample had a cadmium value that was less than an elevated detection limit (20 ug/1 vs. a normal detection limit of 3 ug/1), which was higher than the CDOH standard of 10 ug/1. Likewise, the same sample had a lead value that was less than an elevated detection limit (200 ug/1 vs. a normal detection limit of 20 ug/1), which was higher than the CDOH standard of 100 ug/l. The cause of these elevated detection limits was a decision by the laboratory to dilute the samples prior to analyses in order to reduce the effects of interferences (primarily, high salinity). Elevated levels of iron may be attributed to natural (i.e., not mining related) conditions, since elevated levels for this parameter are not found in the adjacent Seneca II spoil wells. The high levels of iron • displayed in the one alluvial well (YGAL15) may be the result of organic matter and plant debris present in the alluvium (Hem, 1989, pg. 77). This well displayed high levels of iron prior to mining. High manganese values may, in part, be due to recharge from the spoil aquifer, although high values are often common, especially in alluvial material (Hem, 1989, pgs. 86-89). The wells displaying high manganese values this year also did so prior to mining. It should be noted that, while the CDOH uses a standard of 0.2 mg/1, the EPA states that Lhis standard is used to protect crops grown in soils with a pH value lower than 6.0. In soils with a higher pH (as are found in the Yoast region), a more appropriate standard would be 10 mg/1 (EPA, 1976). This year, no well displayed a value higher than 1.20 mg/1. Ground Water Summary TDS trends are decreasing at three wells, stable at five wells, and • increasing at seven wells. CDOH agricultural ground water standards for iron and manganese were exceeded at certain monitoring wells. In the 7