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Due to the lack of consistent types of analyses for trace elements and the variability of • <br />lower limits of analytical detection among particular types of analytes, some comparisons <br />were indeterminable or suspect. Often, a sample analyte concentration is lower than the ' <br />analytical limit of detection. Al:.o, the Lowe s~t limit of detection may be higher than the <br />water quality standard in some in::ta nces. If either of the above instances occurs when <br />the program is making the comparison, the ground water site with the questionable data is ' <br />marked with an asterisk (*) in the appendices. Ground water sites marked by an asterisk <br />are not considered as sites that helve analyte concentrations which exceed a water quality <br />standard, but are deemed suspect instead. <br />Domestic Drinking Water Suitability. A summary of the analytes which exceed the domestic <br />drinking water quality standards by aquifer unit is presented in Table 7-20. Of the four <br />standards, domestic water quality c:ri to ria are the most stringent, and, as expected, the <br />greatest number of excursions occur when Seneca II-W ground water quality is compared with <br />domestic standards. All wells in all aquifers have samples that exceed TDS standards. <br />All wells completed in the Wadge Overburden, Wadge Coal, and Wolf Creek Coal have samples <br />that exceed NH3 standards. Samples from both wells monitoring the Watering Trough Cu lch <br />alluvium have exceeded the standards for Pb and Fe. All four wells completed in the • <br />Hubberson Gulch alluvium have had S04 exceedences. <br />' Maximum contaminant levels (MCLs) for certain inorganic chemicals, as described in 40 CFR <br />141.11, were exceeded at sites completed in all the aquifers. Levels of Cd, Cr, Pb, N03, <br />and Se exceeded the MCLs for these parameters. Secondary maximum contaminant levels <br />(SMCLs), as described min 40 CFR 143.3, also were exceeded in all the aquifer units. <br />Levels of Fe, Mn, N03, pH, 504, Zn, and TDS exceeded the SMCLS for these parameters. <br />Based on the number of MCL and SMCL exceedences, Seneca II-W ground .water is mostly <br />unsuitable for domestic use. Ground water from wells at Seneca II-W would require <br />treatment and consistent monitoring according to the regulations prescribed for public <br />water supplies before the water could be used for domestic drinking water purposes. <br />Aquatic Life Water Suitability. Information presented in Table 7-20 summarizes the <br />parameters which exceed the standards for aquatic life water quality by aquifer unit at <br />the Seneca II-W complex. Aquatic life water suitability is based to a large extent on the <br />condition of hardness. In short, the higher the value of hardness, the higher the value <br />of the water quality sta ndard for aquatic life and vice versa for lower values of hardness • <br />(see Appendix 7-5). All wells completed in the Wadge Overburden and the Wadge Coat have <br />58 <br />