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Information to Support Denison BLM Environmental Assessment Remand <br />Denison Sunday Mines Group <br />would cause a significant impact to overall populations and community of the <br />referenced species. " <br />Comment: Denison may not presume that no migration will be required if it can <br />be demonstrated that no Threatened or endangered species, or their habitat, are <br />not present. Nor can Denison presume that an impact that may affect some <br />individuals but does not affect the overall population is not of concern. BLM <br />typically requires that any impacts, whether significant or not, be mitigated <br />whenever reasonable. <br />Denison must provide additional information to demonstrate how the potential <br />exceedance of cadmium will be addressed to protect wildlife, livestock, and <br />human health. As an example, Denison has not provided enough information for <br />the BLM to be able to determine what the total area of high cadmium levels is, <br />and how this area compares to the total area offorage. Nor has Denison <br />considered how impacts would be limited to mule deer. As an example, does are <br />known to have smaller ranges relative to bucks. Reclaimed mine sites are often <br />heavily grazed, due to the high quality of vegetation on the sites. Cadmium may <br />be accumulated in the body. Would there be any potential affects if a hunter <br />were to shoot an individual deer with relatively high cadmium? <br />Discussion 'As discussed in the EPP (Attachment B, Table 4 -1), detected cadmium <br />concentrations in development rock range from non - detect to 27.8 <br />milligrams per kilogram (mg /kg) compared to the BLM wildlife risk <br />management criterion (RMC) of 3 mg /kg (BLM 2004, Table 4). <br />Development rock samples from the St. Jude and West Sunday mine rock <br />piles do not indicate exceedances of the BLM wildlife RMC. At the Topaz <br />mine rock pile, only one of the three samples collected slightly exceeded <br />the cadmium RMC (cadmium concentrations of 0.6, 0.7, and 4.6 mg/ kg <br />were detected). However, at the Sunday mine rock pile, elevated <br />cadmium concentrations were detected; 4.1 and 18.5 mg /kg. For the <br />Topaz and Sunday mine rock piles, the elevated concentrations of <br />cadmium in development rock are approximately 1.4 to 9.3 times the <br />BLM wildlife RMC. As discussed in the BLM guidance (BLM 2004, p.11), <br />exceedances of 1 -10 times the criteria should be interpreted as moderate <br />risks that may be addressed by management and or institutional controls. <br />Regarding impacts to mule deer, as described in the BLM guidance <br />(BLM 2004, p. 8), the wildlife RMC were developed based on "careful <br />consideration of regional scientific literature, and on the basis of field <br />observations, several wildlife receptors have been selected to represent a <br />range of the types, sizes, and habitats of birds and mammals <br />representative of temperate BLM lands. The selected wildlife receptors <br />are the deer mouse, mountain cottontail, bighorn sheep, white- tailed <br />deer, mule deer, cattle, elk, mallard, Canada goose, and trumpeter swan." <br />Regarding potential impacts to the ecosystem including exposure to <br />humans via wildlife consumption, the BLM guidance (BLM 2004, p. 11) <br />indicates that "various approaches have been suggested for selecting a <br />Final Sunday Mines BLM Remand Letter.doc 14 <br />