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<br />Site-specific water quality data have been collected from the Piceance Site. The results <br />of groundwater sampling of the Upper and Lower Aquifers from American Soda wells <br />are provided in Tables G-1, G-2, and G-3. <br />Water quality data collected during drilling of American Soda water supply well 20-8, <br />solution mining well 20-3, and monitoring well 20-5 (Tables G-1, G-2, and G-3, <br />respectively) indicate TDS levels in the Uinta Formation ranging from 944 to 1,260 mg/1 <br />at depths of 357 to 650 feet (Agapito 1997b, Agapito 1997c, Agapito 1997d). TDS <br />concentrations increase in the Green River Formation (Parachute Creek Member) <br />portion of the Upper Aquifer, with the water sample from 811 feet, immediately above <br />the Mahogany Zone, yielding a TDS concentration of 15,900 mg/1 (Agapito 1997d).' <br />The water sample collected from the lower part of the Lower Aquifer at American Soda <br />test solution mining well 20-3 exhibits a TDS concentration of 26,600 mg/1 at 1,411 feet, <br />immediately above the Dissolution Surface, of 26,600 mg/l (see footnote 1) (Agapito <br />1997d). Conductivity measurements suggest that Lower Aquifer TDS concentrations <br />likely range from approximately 18,300 to as high as 33,000 mg/1 immediately above <br />the Dissolution Surface of the Piceance Site (Agapito 1997a, Agapito 19976, Agapito <br />1997d). <br />The salinity of the Lower Aquifer increases and water quality deteriorates with depth <br />toward the Dissolution Surface (Welder and Saulnier 1978, Daub personal <br />communication 1996). The TDS concentration of the Lower Aquifer is estimated to <br />range to over 60,000 mg/l. The Colorado Department of Public Health and <br />Environment considers water with total dissolved solids in excess of 10,000 parts per <br />million (ppm) (10,000 mg/1) to be nonpotable. The Lower Aquifer does not meet the <br />standard for drinking water because of marginal pH and high concentrations of <br />fluoride, arsenic, cadmium, chloride, iron, mercury, manganese, lead, and selenium. <br />Elevated levels of barium, boron, lithium, copper, chromium, and strontium are also <br />common. The Lower Aquifer does not meet the standards for irrigation water because <br />of marginal pH and excessive molybdenum and fluoride. <br />' It should be noted that all American Soda TDS estimates presented here are considered to be <br />conservative for the following reasons: 1) analytical TDS concentrations are lower than expected based <br />on the generally high degree of correlation of TDS and conductivity in the absence of high levels of <br />organic compounds and 2) analytical TDS concentrations are lower than the sum of all anions and cations <br />analyzed. It is felt that these low TDS values are an artifact of the analytical method (heating and <br />evaporation), which would cause dissociation of the sodium bicazbonate to sodium carbonate, carbon <br />dioxide, and water, with loss of the produced carbon dioxide and water to the atmosphere. Compared to <br />conductivity measurements, analytical TDS concentrations are 15 to 40 percent lower than expected. <br />G-4 <br />