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ug/L). The third quarter 2009 concentration of tetrachloroethene at AMW-14 (7.5 ug/L) is comparable to concentrations observed at that well intermittently since March 1996, and is greater than the National Primary Drinking Water Standard (5 ug/L). The third quarter 2009 concentration of trichloroethene at AMW-13 (0.64 ug/L) is comparable to concentrations observed at that well intermittently since March 1994, and is below the National Primary Drinking Water Standard (5 ug/L). The third quarter 2009 concentration of trichloroethene at AMW-14 (0.66 ug/L) is comparable to concentrations observed at that well intermittently since March 1996,and is below the National Primary Drinking Water Standard(5 ug/L). Historical data from the detection monitoring wells were analyzed for temporal trends using Sen's Slope trend analysis. Graphs and summary tables of the Sen's Slope analyses for detection monitoring wells are presented in Appendix E. The following inorganic constituents exhibited an increasing trend according to the Sen's Slope analysis: barium at AMW-6 and AMW-14, bicarbonate at AMW-2, AMW-6, AMW-7, and AMW-13, calcium at AMW-7 and AMW-14, chloride at AMW-6 and AMW-7, magnesium at AMW-6, AMW-7, and AMW-14, nitrate at AMW-2, AMW-6, AMW-7, and AMW-14, potassium at AMW-14, sodium at AMW-14, field specific conductance at AMW-2 and AMW-7, strontium at AMW-6 and AMW-14, sulfate at AMW-7, and TDS at AMW-6 and AMW-7. Carbonate at AMW-2 and AMW-12 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. There was only one constituent that exhibited a statistically significant increasing trend during the third quarter 2009 and also exceeded a concentration limit: barium at AMW-14. As described above, the third quarter 2009 barium concentration at AMW-14 (0.24 mg/L) is comparable to concentrations observed at that well consistently since August 2006, and is well below the National Primary Drinking Water Standard(2 mg/L). Sen's Slope analysis identified decreasing trends in the following inorganic parameters: calcium at AMW-12, chloride at AMW-12, magnesium at AMW-12, nitrate at AMW-13, potassium at AMW-12, strontium at AMW-12, and field turbidity at AMW-2.and AMW-14. None of the VOCs that were detected in detection monitoring wells during the third quarter 2009 monitoring event exhibited a significant increasing trend according to the Sen's Slope analysis. Two VOCs that were detected in detection monitoring wells during the third quarter 2009 exhibited a significant decreasing trend: dichlorodifluoromethane and trichloroethene at AMW- 14. 2.2 Corrective Action Monitoring During the third quarter 2009 monitoring event, ATC associates, Inc. collected groundwater samples from corrective action monitoring wells (AMW-1, AMW-4, AMW-5R, AMW-10, AMW-11, AMW-18, AMW-19, and AMW-1913R). Corrective action monitoring well AMW-5R is a replacement for corrective action monitoring well AMW-5. Corrective action monitoring well AMW-19BR is a replacement for corrective action monitoring well AMW-1913. The field results provided by ATC Associates, Inc. and laboratory results provided by BC Laboratories, Inc. for the third quarter 2009 corrective action monitoring event are summarized on Table 2.3. The historical groundwater data for the corrective action monitoring wells are presented in Appendix F. Times series concentration plots of historical groundwater data for the detection monitoring wells are presented in Appendix G. For VOCs, only those compounds that exhibited detections at corrective action monitoring wells during the third quarter 2009 monitoring event were plotted. 3