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3.0 WORK PLAN, GROUNDWATER EXTRACTION rGroundwater in five of the monitoring wells continues to contain concentrations of MTBE Concentrations of MTBE in the wells nearest the former UST source area (VW-2, MW-2 and MW- 3) have declined significantly, However, as shown on the Charts of MTBE in Groundwater (Appendix B), the historical MTBE concentrations in the wells downgradient of the source area (MW-5, MW-6 and MW-7)exhibit an increasing trend Given the increasing MTBE concentration trend in the downgradient wells, EHD and RWQCB have declined requests to consider the case for regulatory closure EHD and RWQCB indicated that they would reconsider case closure once the MTBE concentration trend could project the natural attenuation of MTBE to below water quality goals As such, the objective of this proposed scope of work is to establish a declining MTBE concentration trend in the downgradient wells, so that the case can be re-considered for regulatory closure To achieve this objective Ramage Environmental proposes to extract groundwater from the downgradient wells (MW-5 and MW-7) on a twice-monthly basis for at least six months Twice-monthly, groundwater will be extracted for approximately four hours from MW-5, and for approximately four hours from MW-7 Groundwater will be extracted using a 3,500-gallon capacity vacuum truck capable of generating a vacuum of between 25 and 29 inches of mercury, and a one- inch diameter, semi-rigged, clear, PVC, downhole stinger Based on the historical groundwater analytical results, the vacuum truck will be used to transport the extracted groundwater as non- hazardous waste to a licensed facility for recycling 1 During the initial groundwater event, the drawdown and sustainable extraction rates will be measured in MW-5 and MW-7, and changes in depth-to-groundwater will be monitored in the surrounding monitoring wells These groundwater yield and radius of influence data maybe used to modify future groundwater extraction efforts immediately following the extraction of groundwater from MW-5 and MW-7, groundwater samples will be collected with a bailer to evaluate the hydrocarbon mass removal The groundwater samples will be transported in an iced cooler with chain-of-custody documentation to a state of California certified hazardous waste testing laboratory, and will be analyzed for TPH-as-gasoline and BTEX by EPA Method 8020/8015M or 8260B, and for MTBE, DIPS, ETBE, TAME, TBA and 1,2-DCA by EPA Method 82606 The results of the monthly groundwater extraction will be documented in subsequent quarterly groundwater monitoring reports �� 7