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/ • • <br />CC&V believes these ground-water data are appropriate to judge the current quality of <br />ground water in the vicinity of the volcanic diatreme. <br />APPENDIX 11 <br />Dr. Posey states: This appendix presents results of water quality monitoring at CDPHE <br />station number AG-1 (Arequa Gulch No. 1, above Cazlton Mill) for June 4, 1987 to <br />November 9, 1992. AG-1 is a Health Department mandated compliance point. Some of the <br />sampling events exceed water quality standards at that point in Cadmium, Copper, <br />Manganese, Mercury, Silver and Zinc." <br />Station AG-1 is not mandated for anything. It was established voluntarily by CC&V and the <br />data reported to the OMLR. The data have been used in submissions to the CDPHE. Dr. <br />Posey is correct in that the concentrations at AG-1 exceed the concentrations he has <br />determined to be "standazds." First, they are not the correct standards and second, if they <br />were, what would Dr. Posey suggest CC&V is responsible for -treating the ambient and <br />natural stream? We have discussed this in detail in the earlier portions of this response. <br />APPENDIX 12 <br />Dr. Posey summarizes his opinions about the comparisons between humidity cell water <br />quality and water quality at AG-1 in his Table 1. As we have addressed earlier, Dr. Posey <br />has not taken into account ambient-based water-quality standards in his assessment of <br />whether the humidity cell data excced arbitrarily-selected standards (because there are no <br />standards for Arequa Gulch at present). Dr. Posey has imposed a sulfate standard on a <br />stream that is not classified for drinking water (besides, the sulfate standazd is a secondary <br />standard which, therefore, is not to be used for absolute determinations of compliance). He <br />has also imposed an aluminum standazd which is not listed for Cripple Creek (the nearest <br />classified stream). Dr. Posey also concludes that data for lead, mercury, nickel, selenium, <br />and silver aze not reported. Appendix 9 includes all of those data. AccuLabs performs those <br />analyses. <br />The pH of sampled testing fluid from the humidity cells representing rock to be placed in <br />Arequa Gulch are shown in Appendix 12 to be within the range of Arequa Gulch and slightly <br />higher. There is no sulfate standazd for waters that are not supplies of drinking water. <br />Nonetheless, the sulfur concentrations in the humidity cell samples aze lower than in Arequa <br />Gulch. As we have noted, there is no aluminum standard for the streams in the azea. <br />Again, the concentrations in the humidity cell extracts aze almost all lower than the levels <br />found in Arequa Gulch. As Dr. Posey notes, the arsenic values for the humidity cells aze <br />also quite low. Cadmium samples run at sufficiently low detection limits (AccuLabs) are <br />well below the levels in Arequa Gulch. Total chromium concentrations in the cell extracts <br />run at the lower detection limits are also as low as the lowest observed in Arequa Gulch. <br />Copper values determined at the more sensitive limits are at the low end of the <br />concentrations observed in Arequa Gulch. Iron concentrations are within the range of <br />21 <br />