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• Division of Wildlife Issues and Responses <br />for June 5, 1997 Letter <br />(continued) <br />the DOW concern is valid and will make every effort to analyze water sampling data to <br />determine whether metal concentrations are increasing due to mining activities through <br />review of the annual hydrology report required to be submitted. Currently, there is no <br />evidence which indicates that mining will cause concentrations of cadmium, copper, and <br />zinc to increase beyond applicable standazds. This issue is therefore adequately addressed. <br />No response is necessary for this comment. <br />Detection Limits <br />The DOW expressed the concern that the method used to analyze various constituents be <br />changed to allow detection of small concentrations of the constituent. This is apparently <br />necessary due to very low levels of some metals being toxic to fish and aquatic life. <br />However, as hardness and alkalinity go up, the toxicity is reduced. For example, for <br />copper, fresh water organisms should not be affected at 4-day average concentrations of <br />• 6.5, 12, and 21 ug/I at a hardness of 50, 100 and 200 mg/1 respectively (EPA 1986). The <br />baseline surface water hardness in Lorencito Canyon is nearly 200 mg/]. This <br />phenomenon is also recognized for cadmium. However, the Division concurs that <br />detection limits should be at the lowest possible levels given equipment and analysis <br />limitations in today's labs. The applicant should investigate and address this issue of lower <br />detection limits. <br />e o e <br />The March 17, 1997, letter from John Woodling to Kent Gorham identified concerns with <br />analytical detection limits for cadmium, copper, zinc, selenium, silver and nitrite as follows in <br />Table 1. It does appear that ICPMS provides better detection limits, however, those detection <br />limits do not seem justified given EPA's Lowest Observed Effect Level (LOEL) for freshwater <br />aquatic organisms. LCC notes that the coal regulations reference the analytical methodologies <br />associated with the Clean Water Act (40 CFR 136), and ICPMS is currently not an approved <br />method under those regulations. However, it has been approved for use under SDWA and RCRA <br />(Scott Habermehl, ACZ, Personal Communication). LCC will perform one analysis on each of <br />these parameters and defers to CDMG as to the methodology of choice. <br /> <br />6 <br />