ARCHIVED REPORTS_2009_14 - Laserfiche WebLink

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VOCs have been consistently detected in samples from corrective action monitoring wells AMW- 1, AMW-4, AMW-10, and AMW-11. AMW-5/5R, AMW-18, AMW-19, and AMW-19BR have previously exhibited sporadic VOC detections. Historical data from the corrective action monitoring wells from March 1994 to the present were analyzed for temporal trends using Sen's Slope trend analysis. Graphs and summary tables of the Sen's Slope analyses for corrective action monitoring wells are presented 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, AMW-5R, and AMW-1913R, bicarbonate at AMW-1, AMW-5R, and AMW-18, chloride at AMW-5R, nitrate at AMW-4 and AMW-5R, pH at AMW-5R and AMW-19BR, sodium at AMW-5R, field specific conductance at AMW-1 and AMW-5R, strontium at AMW- 18, sulfate at AMW-4, AMW-5R and AMW-10, TDS at AMW-5R, and field turbidity at AMW- 5R, AMW-10, and AMW-19. Carbonate at AMW-5R exhibited an apparent increasing trend according to the Sen's Slope analysis, but this trend is due to a historical increase in the laboratory PQL. The third quarter 2009 concentration of barium at AMW-1 (0.34 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 2009 concentration of barium at AMW-5R (0.32 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 2009 concentration of barium at AMW-19BR (0.24 mg/L) is comparable to concentrations observed at that well for the past three monitoring events, and is well below the National Primary Drinking Water Standard(2 mg/L). The third quarter 2009 concentration of bicarbonate at AMW-1 (690 mg/L) is comparable to concentrations observed at that well intermittently since November 2003. The third quarter 2009 concentration of bicarbonate at AMW-5R (460 mg/L) is comparable to concentrations observed at that well consistently for the past eight monitoring events. The third quarter 2009 concentration of bicarbonate at AMW-18 (340 mg/L) is comparable to concentrations observed at that well consistently since November 2004. The third quarter 2009 concentration of chloride at AMW-5R (I 10 mg/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 2009 concentration of nitrate at AMW-4 (1.3 mg/L) is comparable to concentrations observed at AMW-4 intermittently since March 1996, and is below the National Primary Drinking Water Standard (10 mg/L). The third quarter 2009 concentration of nitrate at AMW-5R (29 mg/L) is comparable to concentrations observed at AM -5R during the past eight monitoring events, and exceeds the National Primary Drinking Water Standard(10 mg/L). The third quarter 2009 field pH value at AMW-5R (7.3 s.u.) is comparable to values previously observed at AMW-5, and is within the National Secondary Drinking Water Standard range (6.5 - 8.5 s.u.). The third quarter 2009 field pH value at AMW-19BR (7.09 s.u.) is comparable to values observed at that well during the past five monitoring events, and is the lowest pH value observed since February 2008. The third quarter 2009 field pH value at AMW-19BR is within the National Secondary Drinking Water Standard range (6.5 - 8.5 s.u.). The third quarter 2009 concentration of sodium at AMW-5R(74mg/L) is comparable to concentrations observed at that well during the past eight monitoring events. The third quarter 2009 field specific conductance value at AMW-1 (1,310 umhos/cm) is comparable to values observed at that well intermittently since November 2004. The third quarter 2009 field specific conductance value at AMW-5R 4