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Selected Trace-Metal Trends <br />Following are summaries of selected trace-element trends portrayed in the time study (5-minute <br />vs. 18-hour) of the Togo mine-waste leachate. <br />Aluminum (AI).-Togo leachate had high concentrations of aluminum. Concentration ranged <br />from 5,890 µg/L in the 5-minute leachate and rose to 5,940 µg/L after 18 hours. <br />Cadmium (Cd).-Low concentrations of cadmium were found with concentrations of 0.21 <br />µg/l, after 5 minutes, rising to 0.26µg/L after 18 hours. <br />Copper (Cu).-Togo leachate copper concentrations ranged from 83.8 µg/L in the 5-minute <br />leachate to 114 µg/L after 18 hours. <br />Iron (Fe).-Togo leachate iron concentrations were the highest of all 13 sites studied. Iron <br />concentration ranged from 22,100 µg/L in the 5-minute leachate and rose to 22,600 gg/L after <br />18 hours. <br />Manganese (Mn).-Somewhat high concentrations of manganese were found in leachate from <br />the Togo mine-waste. Manganese values ranged from 238 µg/L in the 5-minute leachate to <br />284 after 18 hours. <br />Mercury (Hg).-Mercury was not detected in the Togo leachate. <br />Nickel (Ni).-Minor concentrations of nickel were found in the leachate with a minor increase <br />in leachate concentration over time. The 5-minute concentration was 11.7 µg/L, rising to 15.6 <br />gg/L after 18 hours. <br />Lead (Pb).-Leachate lead concentration was minor and decreased over time from 3 µg/L <br />after 5 minutes to 1.2 pg/L after 18 hours. <br />Zinc (Zn).-Moderate concentrations of zinc were found in the Togo leachate and the <br />concentration rose over time. The 5-minute zinc concentration was 99.7 µg/L; this value rose <br />to 112 µg/L after 18 hours. <br />Burke Mine <br />The Burke mine is located in the Snake River watershed below the confluence with Deer Creek. <br />The mine is hosted in the Swandyke hornblende gneiss. <br />Net-Acidity <br />5.0 kg CaCO,/ton. <br />pH Trend <br />There was a slight increase in pH over time in the Burke mine-waste leachate. pH rose from 5.0 <br />after 5 minutes to 5.1 after 18 hours. (+0.1 pH units). This indicates net-acid production in the leachate over <br />time. <br />Specific Conductance Trend <br />The Burke leachate had the second lowest conductance of the 13 sites studied, with measurements <br />of 9.38 µS/cm after 5 minutes, rising to 13.3 pS/cm after 18 hours. <br />Sulfate <br />The sulfate concentration was very low with concentrations of 4 mg/L after 5 minutes and 5 mg/L <br />after 18 hours. <br />H a gem a n_S I R_2508. d o c 18 7/21/2004 2:50 PM