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<br />R. G. OTTO & ASSOCIATES <br /> <br />study. Respective values below the waste rock piles were 3.5 <br />uqm/1 (s.d. =,2.2) and 2.6 ugm/1 (s.d. 1.0), Differences is <br />sampling locations, procedures and, to a lesser degree, in <br />analytical techniques probably account for the differences is <br />magnitudes of the means and variances between programs. However <br />again, the concentrations are well below applicable water quality <br />standards in both cases. <br />Csoss-pile differences is uraaium.conceatrations for both data <br />sets are within the bounds of statistical reliability (the <br />differences are not statistically significant) when considered on <br />as annual basis. The (annual) mean values differ by less than a <br />single standard deviation in each case. However, there is an <br />apparent seasonal variability is the Cotter/USGS data set that is <br />absent (or at least less obvious) is the Radioactive Materials <br />License data set, The •trend' toward slightly increased uranium <br />concentrations below the waste rock pile in the Cotter/USGS data <br />set is most apparent is the data collections for the dry, late <br />summer period (July/1-uqust) when stream flows are relatively low. <br />This is the period when one would least expect impacts of the <br />waste rock piles on stream quality in that these is typically <br />little i! nap surface runoff or infiltration of water into the <br />piles to drive percolation to the ground water. <br />Ia conclusion, the concentrations of all measured pazam,eters are <br />indistinguishable (statistically) above and below the waste rock <br />41 <br />