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24 <br />slightly (= 1 µg/g) in soils near the Henderson mill and tailing since the <br />beginning of ore processing. However, this trend is weak, if present at all. <br />Arsenic (AS) levels were found to be highest in the control soil fran Ute <br />Pass in 1976 (Table 5). Arsenic concentrations have apparently decreased at <br />all locations since 1976, or lab extractions were not very efficient. Both <br />selenium (Se) and cyanide (CN) levels were too low to detect at all ;six <br />locations. Fluoride (F) concentrations in soils were not different ;mtonq the <br />six locations, but had increased at several locations between 1976 and 1979, <br />but decreased again in 1985. <br />Large differences existed between tailing and soil for cancentre~tions of <br />Mo, Pb, and F (Table 4). Two of these three constituents, Mo, and F,. might <br />have increased in soil during the early years of mill operation in the area <br />around the Henderson mill (Table 5). Although changes in soil concentrations <br />have not been great, they were nonetheless detected. Some of these <br />differences might, however, be related to differences in laboratory procedures <br />and instrumentation. Or, this may be indicative of fallout of dust from the <br />milling process or blowing of tailing. If these data are indicative of <br />fallout, then lead concentrations in soil should have also increased as lead <br />was high in tailing (Table 3). However, lead concentrations in soils at the <br />six locations did not indicate any significant trend with respect to distance <br />or direction from the mill tailing pond. These data do, however, indicate the <br />necessity of continued monitoring in the future. Other changes related to <br />soil macro- and micro-nutrient status appear to be more related to inherent <br />soil and micro-climatic differences that exist at the various sites. <br />