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KLEINFELDER 5 CONCLUSIONS AND RECOMMENDATIONS Kleinfelder was requested by San Joaquin County to assess two underground storage tank sites at the San Joaquin General Hospital One of the tanks (T1) was in use at the time of the request, but had failed a recent tank test, while the other tank (T2) had not been used in many years, and was scheduled for closure to allow for construction Because the tanks had been installed in the 1940's and accurate drawings of the tank locations were not ' available, and the prevalence of utility lines in the general vicinity of the tanks, a geophysical survey was conducted on September 19, 1991, to assess the locations of the tanks and the utility lines During the performance of the geophysical survey, a third tank (T3)was found adjacent to tank 72 ' On October 31, 1991, two soil borings were dulled at opposite ends of tank Tl. Qualitative organic vapor readings indicated the possibility of shallow contamination on the east side of T1 or its associated service lines Three samples were analyzed from the east side of T1, and two additional samples were analyzed from the west side, to quantitatively assess the i potential contaminant concentrations Per San Joaquin County's Public Health Department, Environmental Health Division's direction, the samples were analyzed for extractable TPH, purgeable TPH, BTEX, EDB, and total lead Of the above analytes, only lead was detected above the laboratory reporting limit for the samples submitted from the ' borings drilled adjacent to tank T1 Based on the analytical data for the samples submitted from the tank Tl borings, Kleinfelder recommends no further assessment of the soil in the vicinity of tank T1 Also on October 31, 1991, one angle soil boring was drilled beneath tank T2 and one angle boring was drilled beneath tank T3 Due to the limited access, the borings were drilled from the east side of the tanks and angled such that they passed approximately 3 feet ' beneath the east end of the tanks and approximately 15 feet beneath the west (fill) end of the tanks Two samples were analyzed from each of the borings The samples were ' analyzed for the same petroleum hydrocarbon constituents as the tank T1 samples Sample 61099, collected from beneath the west end of tank T2 in boring B-2, and sample 61096, collected from beneath the west end of tank T3 in boring B-1, contained reportable iconcentrations of petroleum hydrocarbons and lead The samples collected from beneath the east ends of the tanks were reported to contain lead above the laboratory reporting limit, but petroleum hydrocarbon concentrations were below laboratory reporting limits FR21-91-29 Page 9 of 11 ' Copyright 1991 Kleinfelder,Inc