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• <br />Table 6 provides a comparison of ground water quality to agricultural <br />standards. This Paradox database generated table does not include the <br />units of concentration (mg/l or ug/1) for each parameter. The units used <br />for each parameter are the same as those listed on the standards table <br />(Table 5) and are also the same as those used in the water quality <br />reports. The frequency column on Table 6 indicates the number of <br />exceedences out of the total number of samples (i.e., 1/2 indicates one <br />exceedence out of two samples). Below is a summary of standards that <br />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) 1/3 <br />Manganese (CDPHE, irrigation) 4/8 <br />In addition, a total of six samples from three wells had cadmium values <br />that were less than an elevated detection limit (30 ug/l vs. a normal <br />detection limit of 3 ug/1), which was higher than the CDPHE standard of <br />10 ug/1. Likewise, the same samples had lead values that were less than <br />an elevated detection limit (200 ug/l vs. a normal detection limit of 20 <br />ug/1), which was higher than the CDPHE standard of 100 ug/l. The cause <br />of these elevated detection limits was a decision by the laboratory to <br />dilute the samples prior to analyses in order to reduce the effects of <br />interferences (primarily, high salinity). <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 />5