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dichlorobenzene, chlorobenzene, cis -1,2 -dichlorobenzene, diisopropyl ether, tetracholorethene, and trichloroethene were detected at AMW-1 above the laboratory RL. Trichloroethene was detected at AMW-10 above the laboratory RL. Dichlorodifluoromethane, tetrachloroethene, and trichloroethene were detected at AMW-19BR above the laboratory RL. 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 Mann -Kendall / Sen's Slope analyses for corrective action monitoring wells are presented in Appendix G. For constituents whose historical data consist primarily of non -detects (carbonate alkalinity, oil and grease, volatile petroleum hydrocarbons, and VOCs), trend evaluation was performed on data from the earliest detection through the present. Wells with no historical detections for a constituent were not evaluated for trends. Table 2.4 summarizes the results of the corrective action monitoring well trend analysis. Mann - Kendall / Sen's Slope analysis identified significant increasing statistical trends in the following inorganic constituents: arsenic at AMW-1; barium at AMW-1 and AMW-19; bicarbonate alkalinity at AMW-5R and AMW-18; chloride at AMW-5R and AMW-19BR; nitrate at AMW- 5R; field pH at AMW-4, AMW-5R, AMW-11, and AMW-19BR; potassium at AMW-5R; sodium at AMW-5R; field specific conductance at AMW-1 and AMW-5R; sulfate at AMW-5R and AMW-10; field temperature at AMW-5R; TDS at AMW-5R; and field turbidity at AMW-5R and AMW-10. Mann -Kendall / Sen's Slope analysis identified significant decreasing statistical trends in the following inorganic constituents: barium at W-10 and -11; bicarbonate alkalinity at AWIL -10; calcium at -4 and -10; chloride at -4, -10, -11, and IrW-18; hexavalent chromium at -19 and -19; magnesium at -4, - 10, and AMW-11; nitrate at AMW-1, AMW-10, W-19, and AMW-19BR; field pH at AMW- l; potassium at AMW-4, AMW-10, AMW-11, and AMW-18; sodium at AMW-10 and AMW-18; field specific conductance at AMW-4, AMW-10, and AMW-11; strontium at AMW-4 and AMW-10; sulfate at -1, AMW-18, AMW-19, and AMW-19BR; field temperature at AMW-11; TDS at AMW-4, AMW-10, AMW-11, and AMW-18; and field turbidity at AMW-4. Mann -Kendall / Sen's Slope analysis identified significant increasing statistical trends in the following VOCs: 1,1-dichloroethane at AMW-1; 1,2 -dichlorobenzene at AMW-1; chlorobenzene at AMW-1; and cis-l,2-dichloroethene at AMW-l. Mann -Kendall / Sen's Slope analysis identified significant decreasing statistical trends in the following VOCs: 1,1-dichloroethane at AMW-19BR; 1,2-dichloroethane at AMW-1; cis-1,2- dichloroethene at AMW-10 and AMW-19BR; tetrachloroethene at AMW-10; and trichloroethene at AMW-10. The fourth quarter 2012 concentration of arsenic at AMW-1 (0.0061 mg/L) is below the National Primary Drinking Water Standard of 0.01 mg/L, and is within the range of concentrations observed at that well since April 1995 (<0.01 to 0.019 mg/L). The increasing trend for dissolved arsenic at AMW-1 is not observed when the data are limited to the period of February 2009 to November 2012, indicating that concentrations have stabilized in the past three years. The fourth quarter 2012 concentration of barium at AMW-1 (0.48 mg/L) is below the National Primary Drinking Water Standard of 2 mg/L. The increasing trend for dissolved barium at AMW-1 is not observed when the data are limited to the period of May 2006 to November 2012, indicating that concentrations have stabilized in the past six years. The fourth quarter 2012