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S6011017 4 <br />PofenliaiforRocir fo be Toxic Forming <br />EPA 2008) for a commercial/ indi <br />level concentrations: aluminum, <br />iron, lithium, magnesium, molyb <br />strontium, thallium, tin, titanium <br />commercial/ industrial exposure <br />land use of the property (e.g., not <br />provided in this scenario are con <br />human health exposure to metal <br />worker) than what is anticipated <br />to RMCs, EPA RSLs have been di <br />and represent levels that are prot <br />1996). For example, the use of scr <br />>trial exposure scenario were utilized as screening <br />arium, beryllium, boron, calcium, chromium, cobalt, <br />enum, phosphorus, potassium, silicon, sodium, <br />uranium and vanadium. Although the <br />cenario is not the same as the expected post-mining <br />recreation), the exposure concentrations <br />ervative; that is, the scenario provides additional <br />on the site (e.g., hours of exposure per year for a <br />riven the anticipated post-mining land use. Similar <br />veloped using conservative exposure assumptions <br />!ctive of human health for most site conditions (EPA <br />Bening criteria for an industrial land use is very <br />conservative for the Van 4 Mine, ?ecause it assumes exposure for 250 days per year <br />over 25 years. <br />It should be noted that direct c( <br />assessment regarding if develo, <br />risks are regulated by the Mine <br />accordance with the federal Mi <br />other federal laws and <br />regulations. <br />act risks to miners are not evaluated as part of this <br />lent rock is potentially toxic forming because these <br />fety and Health Administration (MSHA) in <br />Safety and Health Act of 1977 as amended, and <br />Denison`s mining operations comply with these <br />4.1.1 Screening-Level Evaluation <br />Total metals data from development rock samples were compared to screening levels <br />to assess potential direct contact t?isks to humans and wildlife. Table 4-1 provides a <br />summary of total metals concerti <br />compared to corresponding BLn <br />screening levels, the only detect( <br />respective screening value is ars <br />level evaluation indicates that do <br />respect to direct contact risks. A <br />arsenic at the Van 4 Mine is pros <br />The total metals data are also cot <br />are species-specific, and this sere <br />deer mouse, cottontail, bighorn !5 <br />sheep. The screening-level evalu. <br />occur at concentrations that are I <br />However, lead concentrations in <br />local areas may be present when <br />levels, potential toxicity to wildli <br />several reasons: <br />¦ The development rock areas w <br />criteria are very small relative <br />receptors of interest, which re( <br />in the Van 4 Mine development rock <br />RMC and EPA PRGs. With respect to human health <br />l metal with a concentration that exceeds its <br />iic. With the exception of arsenic, this screening <br />telopment rock is not a toxic-forming material with <br />iitional information to further assess the presence of <br />below in Section 4.1.2. <br />spared to BLM wildlife RMC values. The BLM RMCs <br />-ning-level evaluation considers RMC values for <br />veep, white-tailed deer, mule deer, elk, cattle, and <br />tion shows that most metals in development rock <br />wer than their respective screening criteria. <br />one sample exceed the screening level. Although <br />lead concentrations exceed the BLM screening <br />e are not discussed further in this document for <br />re lead locally exceeds the wildlife screening <br />home and/or foraging ranges for most ecological <br />.es the potential exposure levels. <br />F-1 <br />LJ <br />0 <br />LJ <br />4-2