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intermittently since April 1995, and is below the National Primary Drinking Water Standard (5 <br /> ug/L). The second quarter 2009 concentration of tetrachloroethene at AMW-14 (6.9 ug/L) is <br /> comparable to concentrations observed at that well intermittently since March 1996, and slightly <br /> exceeds the National Primary Drinking Water Standard (5 ug/L). The second quarter 2009 <br /> concentration of trichloroethene at AMW-13 (0.78 ug/L) is comparable to concentrations <br /> observed at that well intermittently since March 1994, and is below the National Primary <br /> Drinking Water Standard(5 ug/L). <br /> Historical data from the detection monitoring wells were analyzed for temporal trend using Sen's <br /> Slope trend analysis. Graphs of the Sen's Slope analyses for detection monitoring wells are <br /> included in Appendix E. The following inorganic constituents exhibited an increasing trend <br /> according to the Sen's Slope analysis: barium at AMW-6 and AMW-14, bicarbonate at AMW-2, <br /> AMW-6, AMW-7, and AMW-13, calcium at AMW-7 and AMW-14, chloride at AMW-6 and <br /> AMW-7, magnesium at AMW-7 and AMW-14, nitrate at AMW-2, AMW-6, and AMW-7, <br /> potassium at AMW-14, sodium at AMW-14, field specific conductance at AMW-2 and AMW-7, <br /> strontium at AMW-6 and AMW-14, sulfate at AMW-7, and TDS at AMW-7. There were no <br /> constituents that exhibited a statistically significant increasing trend during the second quarter <br /> 2009 and also exceeded a concentration limit. <br /> Sen's Slope analysis identified decreasing trends in the following inorganic parameters: arsenic at <br /> AMW-2, calcium at AMW-12, chloride at AMW-12, magnesium at AMW-12, nitrate at AMW- <br /> 13,potassium at AMW-12, strontium at AMW-12, and field turbidity at AMW-2 and AMW-14. <br /> None of the organic constituents that were detected in detection monitoring wells during the <br /> second quarter 2009 monitoring event exhibited a significant increasing trend according to the <br /> Sen's Slope analysis. One organic constituent detected in a detection monitoring well during the <br /> second quarter 2009 exhibited a significant decreasing trend: trichloroethene at AMW-14. <br /> 2.2 Corrective Action Monitoring <br /> Groundwater samples were collected by ATC Associates, Inc. from the corrective action <br /> monitoring wells (AMW-1, AMW-4, AMW-5R, AMW-10, AMW-11, AMW-18, and AMW-19) <br /> during the second quarter 2009 monitoring event. Corrective action monitoring well AMW-5R is <br /> a replacement for corrective action monitoring well AMW-5. The field results provided by ATC <br /> Associates, Inc. and laboratory results provided by BC Laboratories, Inc. for the second quarter <br /> 2009 corrective action sampling are summarized on Table 2.3. <br /> VOCs have been consistently detected in samples from corrective action monitoring wells AMW- <br /> 1, AMW-4, AMW-10, and AMW-1 L AMW-5/5R, AMW-18, and AMW-19 have previously <br /> exhibited sporadic VOC detections. <br /> The historical groundwater data for the corrective action monitoring wells are presented in <br /> Appendix F. The data are graphed on time series concentration plots, included in Appendix G. <br /> For VOCs, only those VOCs that exhibited detections for the second quarter 2009 monitoring <br /> event were plotted. <br /> Historical data from the corrective action monitoring wells from March 1994 to the present were <br /> analyzed for temporal trend using Sen's Slope trend analysis. Graphs of the Sen's Slope analyses <br /> for corrective action monitoring wells are included in Appendix G. Table 2.4 summarizes the <br /> results of the corrective action monitoring well trend analysis. The following inorganic <br /> constituents exhibited an increasing trend according to the Sen's Slope analysis: barium at AMW- <br /> 3 <br />