ARCHIVED REPORTS_2008_14 - Laserfiche WebLink

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For VOCs,only those VOCs that exhibited detections for the third quarter 2008 monitoring event were plotted. Historical data from the corrective action monitoring wells from March 1994 to the present were analyzed for temporal trend using Sen's Slope trend analysis. Graphs of the Sen's Slope analyses for corrective action monitoring wells are included in Appendix G. Table 2.4 summarizes the results of the corrective action monitoring well trend analysis. The following inorganic constituents exhibited an increasing trend according to the Sen's Slope analysis: barium at AMW- 1 and AMW-5R, bicarbonate at AMW-1, AMW-5R, and AMW-18, chloride at AMW-5R, nitrate at AMW-4 and AMW-5R, sodium at AMW-5R, field specific conductance at AMW-1 and AMW-5R, sulfate at AMW-5R and AMW-10, TDS at AMW-5R, and field turbidity at AMW-10 and AMW-19. The third quarter 2008 concentration of barium at AMW-1 (0.39 mg/L) is comparable to concentrations observed at that well intermittently since May 2004, and is well below the National Primary Drinking Water Standard (2 mg/L). The third quarter 2008 concentration of barium at AMW-5R (0.33 mg/L) is comparable to concentrations observed at that well since August 2003,and is well below the National Primary Drinking Water Standard(2 mg/L). The third quarter 2008 concentration of bicarbonate at AMW-1 (850 mg/L) is comparable to concentrations observed at that well intermittently since February 2004. The third quarter 2008 concentration of bicarbonate at AMW-5R (5 10 mg/L) is comparable to concentrations observed at that well consistently for the past four monitoring events. The third quarter 2008 concentration of bicarbonate at AMW-18 (350 mg/L) is comparable to concentrations observed at that well consistently since February 2005. The third quarter 2008 concentration of chloride at AMW-5R (110mg/L) is comparable to concentrations previously observed at AMW-5, and is below the National Secondary Drinking Water Standard (250 mg/L). The third quarter 2008 concentration of nitrate at AMW-5R (28 mg/L) is comparable to concentrations observed at AMW-5R during the past four monitoring events, and is above the National Primary Drinking Water Standard (10 mg/L). The third quarter 2008 concentration of sodium at AMW-5R (74 mg/L) is comparable to concentrations observed at that well during the past four monitoring events. The third quarter 2008 field specific conductance value at AMW-1 (1,310 umhos/cm) is comparable to values observed at that well consistently since February 2006. The third quarter 2008 field specific conductance value at AMW-5R (1,370 umhos/cm) is comparable to values observed at AMW-5 intermittently since November 2003. The third quarter 2008 concentration of sulfate at AMW-5R (65 mg/L) is comparable to concentrations observed at that well (or AMW-5)consistently since July 2001, and is well below the National Secondary Drinking Water Standard (250 mg/L). The third quarter 2008 concentration of sulfate at AMW-10 (77 mg/L) is comparable to concentrations observed at that well since November 2006, and is well below the National Secondary Drinking Water Standard (250 mg/L). The third quarter 2008 concentration of TDS at AMW-5R(870 mg/L)is comparable to concentrations observed at that well during the past four monitoring events. The third quarter 2008 field turbidity value at AMW-10 (3 NTUs) is comparable to or lower than field turbidity values observed at that well since May 1995. The third quarter 2008 field turbidity value at AMW-19 (>999 NTUs) is consistent with the field turbidity observed at that well during the past seven monitoring events. 4