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• vicinity of the proposed operation, precipitation flushing or gravel washing is not likely to cause measurable increases in metals concentrations. Radon. U~ and Plutonium. Radon and U'}' are part of the uranium decay series and are found in very low levels in most rocks. Plutonium, practically speaking, occurs only as a by-product of uranium enrichment. Plutonium probably could not be measured in these rocks. C. Concentrations of the above toxins and carcinogens will increase when t{~e alkrvial gn•ounrdwater aquifer is disturbed. Lowering the tivater table will concentrate dissolved solids. Mechanical cn~shing and washing will increase TDS and TSS. TDS will increase at least 3 times over ambient concentrations. RESPONSE. Disaggregation of unsaturated alluvium due to mining may increase dissolved solids concentrations in the short term where previously unexposed salts are exposed to water and then flushed out. Lowering the water table locally will produce more unsaturated gravel and thus more water in the unsaturated zone for evaporation. Mechanical crushing and washing will increase TDS to the extent the newly exposed mineral surfaces are stored on site and allowed to weather. Mechanical crushing and washing will increase TSS. At nearby pits, TDS and TSS are monitored under the NPDES program, even though standards are not developed for these parameters. Settling ponds are established in the proposed mining plan to contain solids. D. The operation qualifies as a DMO owing to potential adverse effects to gro:nndwater or surface water. RESPONSE. There is nothing about the composition of the aggregate that would justify designating this operation for more rigorous monitoring or installation of Environmental Protection Facilities (EPF's). Acid ortoxic-forming materials are not part of the make of the gravel at this deposit. E. The operation: tivill have tonic forming substances on site, some of which will be nnan- rnade. No shndies regarding presence of acid or toxic forming s:~bstances. RESPONSE. Naturally occumng materials, such as sulfide minerals, are not present in the gravel in sufficient quantity to justify this objection or to justify studies regarding the presence of acid ortoxic-forming substances. Mineralized rock on site is rare. Man-made substances other than fuels and lubricants are not proposed for storage or use on site.