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<br />occurring during the irrigation season. WR-1 shows a fairly constant <br />concentration of Ca while a lowering of Na appears to be offset by an increase <br />of Mg. This may be a reflection of the leachability of these cations to <br />seasonal fluctuations in the spoils waters. <br />Nitrite/nitrate (NOZ/NO3) concentrations were low in all the alluvial wells <br />throughout the report period, with one exception occurring in TR-4 in May 1984 <br />(Figure 20). This one exception may be associated with the rapid snowmelt <br />which occurred at that time, however, a relationship of this nature cannot be <br />established. WR-1 does show a decrease in NOZ/NO3 over time which is probably <br />related to the flushing of the readily available portions these anions in the <br />spoils. It would not be unexpected if the concentrations of NOZ/NO3 continued <br />to decrease to the levels found in the other wells. Bicarbonate (HCO3) and <br />sulfate (SOy) concentrations exhibit the general trend established by the TDS <br />concentrations (Figure 21), as expected. <br />Dissolved iron (Fe) remained at low levels in all of the wells throughout <br />• the report period, except at TR-2 (Figure 22). The concentrations found in <br />TR-2 appear to be related to the irrigation season with Fe concentrations <br />being diluted by the addition of irrigation waters. Total iron (Figure 22) <br />does not appear to exhibit any detectable trend. In the baseline study it was <br />noted that due to the method by which total iron is measured, all iron <br />complexed or attached to sediment particles is measured as total iron. Upon <br />additional investigation, it was concluded that the concentration of total <br />iron measured in the wells is primarily related to the amount of sediment <br />entrained during sampling. <br />The other detectable trace elements: phosphorus (P), manganese (Mn), and <br />zinc (Zn) remained at consistently low concentrations in all the wells, except <br />for TR-2, during the report period with few exceptions (Figures 23 and 24). <br />The cause of the fluctuations exhibited in the trace element concentrations, <br />particularly Mn (Figure 23), in TR-2 is unknown. <br />Arsenic (AS), selenium (Se) and mercury (Hg) have remained below detection <br />limits for the previous two years with few concentrations being detected <br />previously (Figures 29 and 25) and, therefore, require no additional <br />• <br />