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Nov 29 05 12:48p Peter Weiler (925) 938-1610 p.6 2.3 TASK 4— GRAB GROUND WATER SAMPLING Additional ground water quality delineation was not performed following the improved delineation of some of the landfill cells. Therefore,this task will advance borings to collect ten grab ground water samples in specific areas to characterize ground water quality in the vicinity of inadequately characterized landfill cells (Figure 10). The resulting data will be used to (1) augment the current characterization of ground water quality adjacent to the landfill cells, and (2) identify locations of additional monitor wells,if needed. Samples will be collected from borings advanced using hydraulic direct-push equipment. "Upon encountering a water bearing zone, 5 feet of slotted PVC screen will be lowered into the boring to serve as temporary well casing to collect ground water samples. The samples will be collected in laboratory-supplied containers using a bailer or peristaltic pump. The water sample containers will be sealed, labeled, and placed in a cooler containing ice immediately after collection. The label will identify the boring number, depth of the sample interval, date and time of sample collection, and the sampler's initials. The samples will be transported to a state-certified laboratory following standard chain-of-custody protocols. Based on the prior ground water analytical data, the grab ground water samples will be analyzed for: ■ Total petroleum hydrocarbons as motor oil by EPA Method 8015 ■ Volatile organic compounds by EPA Method 8260 • Title 22 metals (dissolved)by EPA Methods in the 6000 series. 2.4 TASK 5 --MONITOR WELL INSTALLATION As discussed above in Task 4, although the Navy has performed extensive ground water monitoring, additional ground water quality delineation has not been performed following the improved delineation of some of the landfill cells. Based on the prior quarterly monitoring events, the monitor wells dotitingradient from Landfill Cells C, D, and E have yielded measurable concentrations of VOCs. Therefore, the eleven proposed monitor wells (and grab ground water samples proposed above) are intended to identify which of the cells are acting as a source area. The resulting data will be used to (1) augment the current characterization of ground water quality adjacent to the landfill cells, and (2) identify locations of additional monitor wells, if needed. The proposed monitor well locations are shown on Figure 10. November 2005 Page 3 Environmental Risk Services Corporation