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Mr Martin Hams March 22, 2000 Page 4 of S summarized in Table 2 Laboratory reports and chain of custody documentation are included in Attachment B 4.3 Groundwater Analytical Results The grab groundwater sample collected from boring SBI contained elevated levels of gasoline constituents Most notably, TPHg was detected at 8,000 parts per billion (ppb), benzene was detected at 13 ppb, and lead was detected at 810 ppb The lead result is in excess of the primary drinking water Maximum Contaminant Level (MCL) of 15 ppb established by the U S Environmental Protection Agency This elevated level is due to the fact that the water sample was unfiltered and contained a significant amount of silt from the zone of soil contamination The sample was subsequently filtered and analyzed for dissolved lead on January 10, 2000 using EPA method 6010/200 7 No dissolved lead was detected in the sample (<5 0 ppb) A copy of the laboratory report is included in Attachment B No gasoline oxygenate additives were detected in the sample, although the detection limits were elevated by one order of magnitude due to dilution factors The groundwater sample collected from boring SB2 was not analyzed 5.0 SUMMARY AND CONCLUSIONS 5.1 Summary J I • Lithology beneath the site consists of interbedded layers of well graded sand, clayey sand, silt, and clay to at least 26 feet bgs, the maximum depth explored • Soil samples collected from a depth of 9-11 feet bgs in each of the three borings advanced at the site were discolored and had moderate to strong hydrocarbon odors • Soil samples collected from the three borings at depths of 4-6 and 14-16 feet bgs had slight hydrocarbons odors and some discoloration, except in boring SB3, where only the sample from 4-6 feet bgs showed evidence of contamination • Gasoline hydrocarbon constituents were detected only the samples collected at 10 feet bgs from each boring No soil contamination was detected in any soil samples collected at depths greater than 11 feet bgs • Groundwater was encountered at a depth of approximately 9 5 feet bgs in each boring • The groundwater sample collected from boring SBI contained elevated levels of gasoline constituents, including benzene, ethylbenzene, xylenes, and lead However, no dissolved lead was detected in the groundwater sample • No MTBE or other gasoline oxygenate additives were detected in the water sample 5.2 Conclusions • Shallow soil in the immediately vicinity of the former UST has been impacted by a release of gasoline • Soil contamination attenuates rapidly with depth and does not appear to extend deeper than datalgroundmltu$boyVeport suhsuuaum.doe