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C J 2016 Corrective Action Evaluation Report - Austin Road Unit Forward Landfill results. The maps in Appendix D utilize a contour interval of 10 µg/L and do not include values less than 1 µg/L. Figure D-1 presents PCE results in ARU groundwater monitoring wells from May 2016. The May 2016 results indicate that PCE concentrations exceed 1 µg/L at CAP monitoring wells AMW-1 and AMW-13; detection monitoring well AMW-6 (previously identified as a CAP monitoring well); domestic supply wells 7898-A and 8106-A; and in EMP/CAP wells AMW-138, AMW-18B, AMW-19, AMW-19BR, AMW-21, AMW-21S, AMW-22, AMW-225, AMW-24R, AMW-26R, AMW- 29, AMW-31, and AMW-31S. The highest concentration of PCE was measured at 20 µg /L in well AMW-19BR. Figure D-2 presents TCE results in ARU groundwater monitoring wells from May 2016. The May 2016 results indicate that TCE concentrations exceed 1 µg/L at CAP monitoring wells AMW-1 and AMW-13; domestic supply well 8106-A; and in EMP/CAP wells AMW-21, AMW-215, AMW- 22, AMW-22S, AMW-26R, and AMW-29. The highest concentration of TCE was measured at 15 µg /L in well AMW-22S. Figure D-3 presents cis-1,2-DCE results in ARU groundwater monitoring wells from May 2016. The May 2016 results are in agreement with the model simulation in the majority of the modeled area with the following exceptions: cis-1,2-DCE concentrations exceed 1 µg/L at CAP monitoring well AMW-1; and EMP/CAP wells AMW-21, AMW-215, and AMW-22. The highest concentration of cis-1,2-DCE was measured at 11 µg /L in well AMW-1. Figure D-4 presents vinyl chloride results in ARU wells from May 2016. Vinyl chloride was not detected above 1 µg/L in ARU wells in May 2016. These results indicate agreement with the EFS model simulation. 1►��Ij Ti I► � P_1:�'1 During the monitoring period, there have been no exceedances of the TVOC mass TL, and TVOC mass did not exhibit four consecutive quarters of increases. However, there were four exceedances of individual well TVOC concentration TLs during the past four quarters: shallow corrective action well AMW-19 in the fourth quarter 2015, first quarter 2016, and second quarter 2016; and deep corrective action well AMW-19BR in the first quarter 2016. For both wells the exceedances were due to increasing concentrations of PCE. Further monitoring is necessary to evaluate the significance of these increasing PCE concentrations in the vicinity of these wells. As summarized in Appendix B, with the exception of wells AMW-13, AMW-19, and AMW-19BR, overall TVOC concentrations have generally decreased following implementation of the corrective action measures. However, the VOC concentrations (cis-1,2-DCE, PCE, and TCE) are still higher than the concentrations predicted in the model simulations presented in the EFS. Historically, EMP/CAP wells AMW-1, AMW-22, and AMW-22S continue to exhibit the highest Project No. 2016.0007 12016 Corrective Action Evaluation Report - Austin Road Unit 6 Forward Landfill