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. NO FURTHER ACTION REQUEST COLBERG BOAT WORKS JUNE 2002 SITE CHARACTERIZATION Distribution of Petroleum Constituents and Oxygenates in Soil Analytical data collected from soil samples during investigation of the subject site are contained in Tables 2, 3 and 4. The lateral extent of petroleum hydrocarbon impacted soil is shown on Figure 7 Petroleum hydrocarbon concentrations were detected in single samples in four different boreholes, so there was no vertical extent of impact to illustrate In the April 1999 report titled Mass Balance for Remaining TPH G the estunated amount of TPH G remaining in soil was 171 kg(3 77 pounds). MTBE was detected in only one sample from SB-21 at 20 feet bgs, at a reported concentration of 0 030 mg/kg Soil borings SB-25 through SB-30 were installed on January 28,2002 to investigate the area east of MW-3 and soil boring SB-21 as requested by the County None of the petroleum hydrocarbon constituents were detected in soil as shown in Table 2 The analytical reports are contained m Appendix F Distribution of Petroleum Constituents and Oxygenates in Groundwater Groundwater analytical data for the subject site are contained in Tables 5 and 6 The estimated lateral extent of TPH G,benzene, and MTBE based on data collected on September 29, 1999 are shown.on Figures 8, 9, and 10, respectively. This data was used in the report titled Estimated Mass of Petroleum Hydrocarbon Constituents Remaining in Groundwater, dated February 8, 2000 The entena used for calculation and the estimated remaining mass of TPH G, benzene and MTBE are shown in Tables 7, 8,and 9,respectively The data indicates that 0 238 lbs of TPH-G, 0 060 lbs of benzene,and 0 149 lbs of MTBE remain m the groundwater at the subject site. On January 28, 2002 groundwater was sampled in soil borings SB-25 through SB-30 in the area east of MW-3 and soil boring SB-21 The analytical data is shown in Table 5 and on Figures 8, 9, and 10, but not included in the September 29, 1999 contour intervals due to the differences in the dates of sample collection The analytical reports are contained in Appendix F In the January 28, 2002 samples TPH G was reported at 56 micrograms per liter(µg/1) in SB-25, and at 68 µg11 in SB-26,both slightly above the reporting limit of 50 µg/1 TPH G was not detected in the other soil borings Benzene was reported at 12 µg/1 in SB-26 slightly above the reporting limit of 0.50 µg/1 and not detected in the other soil borings MTBE was reported at 0 72 gg/l in SB-26, and at 0.18 µg/1 in SB-28, both slightly above the reporting lint of 0 5 µg11 MTBE was not reported in the other soil borings. These concentrations are below both primary and secondary state of California MCLs for MTBE • 5