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7 Six heavy metals (barium, chromium, molybdenum, nickel, vanadium and zinc) were detected in groundwater samples collected at the Site. Barium, vanadium and zinc were detected in all groundwater samples. The maximum concentrations for these constituents were 0.114, 0.0149 and 0.0491 milligrams per liter (mg/L), respectively. Chromium was detected in TW-1 through TW-3 at a maximum concentration of 0.00825 mg/L. Molybdenum was only detected in TW-5 at a maximum concentration of 0.009 mg/l. Nickel was detected in TW-2, TW-3 and TW-5 at a maximum concentration of 0.00877 mg/L. Only five VOCs were detected in groundwater at the Site during the RI. All of the VOCs were detected in Monitoring Well TW-5 and include: 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, n-butylbenzene, rrp-xylenes and o-xylenes. Results for these constituents were relatively low with the maximum detection being 38 ug/L (1,2,4-trimethylbenzene). Select analytical data results from groundwater samples collected during the RI investigation are shown in Figure 5. 4.0 DELINEATION AND RECOMMENDATIONS FOR ADDITIONAL SAMPLING Based on the analysis of the results from the July/August 2008 investigation, additional delineation may be necessary in order to achieve a better understanding of distribution of contaminants of concern in soil/soil gas/groundwater. It should be noted that vertical delineation of impacts in soil have been achieved and that further vertical delineation of impacts in soil gas cannot be achieved because groundwater at the Site is located at approximately 8 feet bgs. The following is a description of the proposed additional sampling for the delineation of impacts in soil and soil gas: 4.1 Lateral Delineation—Soil Horizontal delineation for soil has been achieved with the exception of the southwest comer of the Site near Borings TB-24 and E3-1 and in the northeast portion of the Site near Boring B1-1. As previously discussed, results from Borings TB-24 and E3-1 showed elevated concentrations of TPH at depths of up to 10 feet bgs; however, analytical results for samples collected at 15 feet bgs were non-detect for all TPH constituents. In addition, concentrations of TPH were higher in Boring E3-1 than in TB-24. Horizontal delineation of PAH impacts have been achieved across the Site with the exception of impacts identified in Boring Bl-I at the northeast comer of the Site. However,the PAH impacts identified in this boring are shallow (maximum of 3 feet bgs) and the adjacent property has an elevation that is approximately 5 feet below the surface grade at the Site. Further delineation of impacts in Borings E3-1 and B1-1 is recommended. 4.2 Lateral Delineation—Soil Gas Based on the elevated concentrations of the gasoline UST related impacts identified in Soil Gas Boring A3-SGI, adjacent to the PG&E Service Center warehouse, the delineation of lateral impacts in soil gas have not been achieved to the degree necessary for potential future health risk evaluation. Concentrations in this soil gas boring require delineation to determine the lateral extent of VOC impacts in soil.