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ug/L). The first quarter 2006 cis-1,2-dichloroethene concentration at AMW-13 is well below the National Primary Drinking Water Standard (70 ug/L). The first quarter 2006 concentration of dichlorodifluoromethane at AMW-13 (2.8 ug/L) is comparable to concentrations observed at that well intermittently since September 1996. The first quarter 2006 concentration of tetrachlorothene at AMW-13 (43 ug/L) is the highest concentration observed at that well since March 1994. The first quarter 2006 concentration of trichloroethene at AMW-13 (15 ug/L) is the highest concentration observed at that well since March 1994. The first quarter 2006 concentration of trichlorofluoromethane at AMW-13 (1.0 ug/L) is comparable to concentrations observed at that well intermittently since January 2002. The first quarter 2006 concentration of 1,1-dichloroethane at AMW-14(0.66 ug/L) is comparable to concentrations observed at that well intermittently since December 1996. The first quarter 2006 concentration of dichlorodifluoromethane at AMW-14 (1.6 ug/L) is comparable to concentrations observed at that well intermittently since May 1996. The first quarter 2006 concentration of tetrachlorothene at AMW-13(41 ug/L)is comparable to concentrations observed at that well intermittently since September 1996. The first quarter 2006 concentration of trichloroethene at AMW-14 (4.3 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 trend using Sen's Slope trend analysis. Graphs of the Sen's Slope analyses for detection monitoring wells are included in Appendix E. The following inorganic constituents exhibited an increasing trend according to the Sen's Slope analysis: barium at AMW-7 and AMW-12, bicarbonate at AMW-6, AMW-7, AMW-12, and AMW-13, chloride at AMW-6 and AMW-7, hexavalent chromium at AMW-12, magnesium at AMW-2, nitrate at AMW-2, AMW-6, and AMW-7, sodium at AMW- 14, field specific conductance at AMW-2 and AMW-7, strontium at AMW-14, and total dissolved solids (TDS) at AMW-7. Of the constituents that exhibited a statistically significant increasing trend during the first quarter 2006,only barium at AMW-12 exceeded its concentration limit. The first quarter 2006 barium concentration at AMW-12 (0.26 mg/L) is well below the National Primary Drinking Water Standard (2 mg/L). Note that while detection monitoring well AMW-6 exhibited an increasing trend for nitrate and well AMW-7 exhibited increasing trends for nitrate and field specific conductance, background well AMW-2 also exhibited increasing trends for nitrate and field specific conductance during the first quarter 2006 monitoring event. Sen's Slope analysis identified decreasing trends in the following inorganic parameters: arsenic at AMW-6 and AMW-7, chloride at AMW-12 and AMW-14, nitrate at AMW-13, field specific conductance at AMW-14, sulfate at AMW-6, AMW-13, and AMW-14, total dissolved solids (TDS)at AMW-14, and field turbidity at AMW-2. Of the organic parameters that were detected in detection monitoring wells during the first quarter 2006 monitoring event, cis-1,2-dichloroethene,tetrachloroethene and trichloroethene at AMW-13 exhibited an increasing trend according to the Sen's Slope analysis. The first quarter 2006 concentration of cis-1,2-dichloroethene at AMW-13 (2.3 ug/L) is the second-highest concentration observed at that well since April 1995, the highest occurring in February 2005 (3.2 ug/L). The first quarter 2006 cis-1,2-dichloroethene concentration at AMW-13 (2.3 ug/L) is well below the National Primary Drinking Water Standard (70 ug/L). Tetrachloroethene and trichloroethene at AMW-14 exhibited a statistically significant decreasing trend according to the Sen's Slope analysis. 3