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Mineral Joe Mine Environmental Protection Plan 15 <br />a factor of 2.5 to 6. The federal standard of 500 mg/L is a secondary water quality standard based on a <br />palatability (taste) of drinking water. SMCLs are non - mandatory, non - enforceable water quality standards <br />that are established only as guidelines to assist public water systems in managing their drinking water for <br />aesthetic considerations, such as taste, color and odor. These contaminants are not considered to present a <br />risk to human health at the SMCL (EPA, 2012). <br />TDS is naturally high in groundwater throughout the Paradox Basin and elsewhere in the arid west. Golder <br />(2009) found that total dissolved solids (TDS) in groundwater at the contact of the Moenkopi /Chinle had <br />TDS concentrations between 590 and 1,030 mg/L, while groundwater near the Hermosa/Chinle contact had <br />higher TDS concentrations (1,140 to 3,040 mg /L). No other groundwater was encountered at the Pinon <br />Ridge site in the Paradox Valley, as the alluvium was dry. Similarly, Weir, et al., (1983) reported that total <br />dissolved solids in the alluvium of the Paradox Basin ranged from 302 to 1,560 mg/L, with an average of <br />770 mg/L. These concentrations naturally exceed SMCLs established for drinking water. <br />5.4.1.7 Vanadium <br />No MCL currently exists for vanadium; however, the Superfund Removal Action Level for vanadium is <br />0.25 mg/L and the Colorado agricultural standard is 0.1 mg/L. SPLP leachates of Mineral Joe waste rock <br />(16 mg/L) and JD -8 Mine ore (14 to 19 mg/L) exceeded the agricultural groundwater quality standard. <br />Vanadium concentrations in groundwater collected from monitoring wells and pumping wells in 2010 from <br />the Pillion Ridge site ranged up to 0.035 mg/L (Energy Fuels, 2011). Elsewhere in Colorado, at the New <br />Rifle Processing Site, the Ground Water Compliance Action Plan set an alternate concentration limit (ACL) <br />of 50 mg/L for vanadium which was determined to be protective at the Colorado River point of compliance <br />(DOE, 2010). <br />5.4.1.8 Uranium <br />Notably, uranium did not exceed drinking water standards in the SPLP leachates from the ore or waste <br />rock. However, uranium is discussed here because uranium has been identified as the potentially toxic <br />material necessitating the EPP. <br />Soils surrounding the Mineral Joe Mine waste rock pile have a high potential for sequestration of <br />radioactive materials according to information developed by the NRCS (2012). Table 8 shows that the <br />Ustic torriothents, Monogram Loam, and other soils on and near the site have very low bioavailability of <br />radioactive constituents and a very high potential for sequestration of radioactive materials. The <br />bioavailability of all soils is rated as 0 due to cation exchange capacity (CEC), pH, or organic sorption <br />(Table 8) while the sequestration potential of all soils is rated as 1.0 due to adsorption by clay. <br />Sequestration potential based on adsorptive capacity due to CaCO3 is rated at 0.82 to 1.0 for all soils except <br />the Monogram Loam, which is rated at 0.50. Sequestration immobilizes or impedes the transport of <br />constituents in the environment. <br />4148B.120927 Whetstone Associates <br />