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1 March 16, 1988 F' . Roberts Oil Company Page 2 are located outside the northeast portion of the fenced perimeter, adjacent to Victor Road. Initial site investigation work in April 1985 consisted of drilling and sampling a single borehole located in the southeast corner of the transfer block. Analytical results of the samples collected indicated that total hydrocarbons and toluene were detected in the underlying soil profile. The borehole was completed as a ground water quality monitoring well. Floating product was observed in a ground water quality sample collected from the well by bailing. Further site assessment work was undertaken by Roberts Oil Company in the summer of 1985, and was conducted by J.H. Kleinfelder & Associates. The work performed by Kleinfelder was in accordance with a workplan developed in concert with Roberts Oil Company, the State of California Central Valley Regional Water Quality Control Board, and The San Joaquin County Health Department. The purpose of the assessment was to conduct a soil and ground water quality contamination investigation, with the objective of determining areas onsite where hydrocarbons may be present. The work consisted of drilling and sampling nine boreholes to various depths around the above ground storage tank farm, and between the transfer block and the loading area. Two of the boreholes were drilled at an angle to obtain soil samples from beneath the above ground storage tank farm. Thirty eight soil samples were collected from the nine boreholes at varying depths, and were qualitatively screened for the presence of hydrocarbons utilizing a Photovac photoionization detector (PID). The results of the PID analysis indicated that total volatile hydrocarbons were present in detectable concentrations in four boreholes; one angle borehole located south of the above ground storage tank (B-8), and three vertical boreholes located between the transfer block and the loading area (B-2, B-4, B-6). Higher PID values were detected in the three vertical boreholes, between 6.5 and 21.5 feet below ground surface. Based on the results of the PID screening, eleven soil samples were submitted for chemical analyses, which included volatile aromatic compounds, total hydrocarbons, and total lead. All analyses were conducted utilizing USEPA analytical methods. The analytical results basically confirm ed the PID screening effort, with higher analytical concentrations mirroring