ARCHIVED REPORTS_2010_13 - 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. Wells 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 Mann-Kendall / 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 Mann-Kendall/ 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-5R, field pH at AMW-5R, sodium at AMW-5R, field specific conductance at AMW-1 and AMW-5R, strontium at AMW- 18, sulfate at 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 Mann-Kendall/Sen's Slope analysis,but this trend is due to a historical increase in the laboratory RL. The first quarter 2010 concentration of barium at AMW-1 (0.48 mg/L) is comparable to historical concentrations observed at that well, and is well below the National Primary Drinking Water Standard (2 mg/L). The first quarter 2010 concentration of barium at AMW-5R (0.28 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 first quarter 2010 concentration of bicarbonate at AMW-1 (960 mg/L) is comparable to historical concentrations observed at that well. The first quarter 2010 concentration of bicarbonate at AMW-5R (380 mg/L) is comparable to concentrations observed at that well since August 2007. The first quarter 2010 concentration of bicarbonate at AMW-18 (350 mg/L) is comparable to concentrations observed at that well since November 2004. The first quarter 2010 concentration of chloride at AMW-5R (88 mg/L) is comparable to concentrations previously observed at AMW-5, and is below the National Secondary Drinking Water Standard(250 mg/L). The first quarter 2010 concentration of nitrate at AMW-5R (15 mg/L) is comparable to concentrations observed at that well since August 2007, and exceeds the National Primary Drinking Water Standard(10 mg/L). The first quarter 2010 field pH value at AMW-5R (7.57 s.u.) is comparable to historical values observed at that well, and is within the National Secondary Drinking Water Standard range of 6.5 - 8.5. The first quarter 2010 concentration of sodium at AMW-5R (64 mg/L) is comparable to concentrations observed at that well since August 2007. The first quarter 2010 field specific conductance value at AMW-1 (2,180 umhos/cm) is higher than historical values observed at that well. The first quarter 2010 field specific conductance value at AMW-5R (1,071 umhos/cm) is comparable to historical values observed at that well. The first quarter 2010 concentration of strontium at AMW-18 (0.94 mg/L) is comparable to concentrations observed at that well since August 2004. The first quarter 2010 concentration of sulfate at AMW-5R (61 mg/L) is comparable to concentrations observed at that well (or AMW-5) since May 2000, and is well below the National Secondary Drinking Water Standard (250 mg/L). The first quarter 2010 concentration of sulfate at AMW-10 (44 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 first quarter 2010 concentration of TDS at AMW-5R (700 mg/L) is comparable to historical concentrations observed at that well. The first quarter 2010 field turbidity value at AMW-5R(43 4