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' Project No 034-97252 Page No 7 10.0 DISCUSSION OF FINDINGS Based on the depth of fill materials encountered in Boring P2 (nine feet) it appears that flus boring is within the former UST pit area The highest concentrations of petroleum hydrocarbons detected during ' our investigation were in samples obtained from depths of 10 feet to 20 feet in this boring (140 to 260 mg/kg TPH-G) Below a depth of 20 feet in P2, the samples revealed very low and decreasing ' concentrations of TPH-G and BTEX The deepest sample from this boring (40 feet) contained ethyl benzene and total xylenes at concentrations slightly above detection limits, however, and benzene, ' toluene, and TPH-G in this sample were below detection limits The data from the Boring P2 samples establish vertical attenuation of contaminants to non-detectible or near-non-detectible concentrations 1}(v d ' Borings B1, Pl, P3, and P4 were located within approximately 25 feet laterally of the former UST pit The shallow soul samples from Borings B1 and P1 (to a depth of approximately 15 feet) did not contain ' detectible concentrations of TPH-G or BTEX, however, deeper samples from these borings revealed very low concentrations of TPH-G and BTEX The analytical data from the Boring P3 soil samples also exhibit a trend of increasing TPH-G and BTEX concentrations with depth, however, the concentrations of petroleum hydrocarbons detected within the Boring P3 samples also are very low (less than 35 mg/kg TPH- G) The soil samples from Boring P4 did not contain detectible concentrations of TPH-G and BTEX The analytical data from the Boring B1, P1, P3, and P4 soil samples generally establish significant lateral Ajb attenuation of contaminants The samples obtained from Boring B1 were also tested for total lead The analytical results indicate that the concentrations of lead measured in these samples are within the range of naturally occuring lead in soils in the region 11.0 CONCLUSIONS Based on the results of our investigation, it appears the former UST was located in the vicinity of Boring P2, and that relatively low, residual concentrations of petroluem hydrocarbons are present in soils in this area The analytical data establish both horizontal and vertical attenuation of the contaminants, with highest concentrations of TPH-G and BTEX being present in soils from a depth of 10 to 20 feet in Boring P2 The actual depth to groundwater at the site is unknown Regional groundwater depth information l suggests that groundwater would be present at an approximate depth of 40 feet on the site, however KRAZAN&ASSOCIATES,INC Offices Serving the Western United States '497252 REP I