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Mr. Maurice Benson November 12, 2008 Page 2 stakeholders presenting results from CPT fieldwork proposed in the work plan. Handouts indicate that fieldwork began on September 24, 2008 and continued through September 30, 2008 totaling five locations with 21 discrete sampling intervals being completed at that point. In the future, DESJC should provide the regulatory agencies with ample time for review of fieldwork proposals along with submission and response to comments prior to commencement of fieldwork. 2. Page 3-1, Table 3-1, section 1, Problems to be Solved; The third bullet states the investigation will provide a "better definition of the extent of the VOCs to define the plumes in order to assess the operation of the groundwater remedy." Reviewing figure 1-1 the proposed CPT locations focus sampling efforts in the areas south of Schulte Road and do not propose any fieldwork to the north/northeast of the former Rose residence, east of Banta Road where both historical and more recent analytical data show concentrations over the TCE Maximum Contaminant Level (MCL) of 5.0 pg/L. Figures 4 & 5 from Appendix A of the report identify 1994 TCE concentrations above the MCL in areas north of Schulte Road, east of Banta Road at CPT023 and CPT022 locations. Additionally, CPT work completed in 2001 along Banta Road indicates that TCE exists in groundwater above MCL at locations CP0392 and CP0394, yet no additional CPT samples are proposed to delineate the plume extending to the north/northeast. Historical and current data indicate that the TCE plume originating around the extraction well (EW) network at EW024B and EW025B has migrated underneath the farmers' land to the north/northeast, and has traveled over 1200 feet, verified by historical and current detections of TCE above the MCL at long-term monitoring (LM) wells LM157A and LM158B. TCE concentrations over the MCL at both LM157A, the ACL Compliance Well, and LM158B, the Guard Well, indicate that the actual TCE toe-of-plume is further down-gradient, past the last DDJC-Tracy monitoring well cluster. DESJC should focus fieldwork efforts to adequately delineate the TCE plume east of Banta Road both vertically and horizontally. The fieldwork effort should originate around the EW024B/EW025B network and continue to the north/northeast, terminating somewhere down-gradient past LM157A/LM158B until the TCE MCL in groundwater has been adequately defined to the MCL. The fieldwork efforts should fill in the data gaps presented by both historical data (CPT023/ CPT022), and 2001 analytical data from CPT0392 and CPT0394 locations. The associated fieldwork data should also be used to demonstrate that the natural attenuation processes are occurring for TCE plume, east of