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Mr. James Barton,PG 24 April 2014 Page 5 Soil behavior type (SBT) will be interpreted using relationships between these parameters. Pore pressure dissipation tests will be conducted to estimate the elevation of the water table; results, along with SBT logs from each location, will be evaluated and used to select the groundwater sampling depth interval(s) at each location. Groundwater Sampling Three groundwater samples will be collected from distinct borings at each of the four locations shown in Figure 2 and analyzed for VOCs by EPA Method 8260 and for TPHd by EPA Method 8015. Groundwater samples will first be collected from the B-Zone at each location for expedited analysis; samples of first water and the A-Zone sand will be collected subsequently. Samples will be collected by. advancing hollow CPT rods equipped with a disposable tip and filter screen to the desired sample depth interval and then retracting the rods approximately 2 to 4 feet to expose the screen and collect using a stainless steel bailer. All sampling equipment will be decontaminated before sampling at each location. Groundwater samples will be collected into laboratory-supplied sample containers and labeled with project identification, sample location, analytical parameters, time and date of sampling, and sample preservative, if any. Groundwater samples will be stored in an ice-cooled chest, maintained at approximately 4°C, for transport under standard chain-of-custody procedures to a California-certified analytical laboratory. Each groundwater sample will be analyzed for VOCs, including toluene, by EPA Method 8260 and for TPHd by EPA Method 801.5. B-Zone samples will be analyzed with a 24-hour turnaround time (TAT) in order to assess whetheradditional sampling is necessary in deeper water bearing zones for vertical delineation of toluene. Task 2: Installation of Offsite Groundwater Monitoring Wells Task 2 consists of the installation of a three-well cluster of two-inch diameter monitoring wells to (1) monitor the potential transport of toluene from the Dopaco area, and (2) further delineate the vertical and horizontal extent of toluene in groundwater. The three wells will be named DMW-6WT, DMW-6A, and DMW-6B, for wells screened across the water table, the A-zone sand, and the B-zone sand, respectively. Based on available data, DMW-6WT will be screened from approximately 10 to 25 ft bgs, DMW-6A will be screened from approximately 30 to 40 ft bgs, and DMW-6B will be screened from approximately 60 to 70 ft bgs. Well screen intervals may be revised based on conditions observed in the field and the RWQCB will be consulted prior to well installation. Offsite Characterization Workplan engineers I scientists I innovators I