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FOR CHEVRON INTERNAL USE ONLY <br /> Executive Summary <br /> Former Lyoth Loading Station <br /> Tracy, California <br /> Eight exploratory borings were drilled at the former Lyoth Loading Station t 4v <br /> to assess the impact of site activities on soil and ground water. Two of the <br /> borings were completed as ground-water monitoring wells on the <br /> presumed downgradient edge of the site. Work was performed according <br /> to the Subsurface Investigation Plan prepared by Chevron and as directed <br /> by Chevron personnel. <br /> Soil and ground-water samples were analyzed for total petroleum <br /> hydrocarbons (TPH) as diesel and benzene, toluene, ethylbenzene, and <br /> xylenes (BTEX). The soil sample from the bottom of each boring and the <br /> sample with the highest concentration of volatile vapors, as detected by a <br /> field photoionization detector (PID), were selected for chemical analysis. <br /> The soil sample with the highest concentration of TPH as diesel (MW-2 at <br /> 15 feet) and a surface sample of petroleum-like material (B-2 at 0 feet) <br /> were analyzed for volatile organic compounds using the toxicity. <br /> characteristics leaching procedure (TCLP). Soil samples from boring B-6 <br /> were also analyzed for semi-volatile organic compounds. <br /> Elevated concentrations of TPH as diesel were detected in borings B-3, B- <br /> 6, and MW-2. MW-2 is the only location where TPH as diesel was <br /> detected at the bottom of the boring. Benzene and ethylbenzene were not <br /> detected in any of the soil samples, with low concentrations of toluene and <br /> xylenes in three of the samples. Ground water is also impacted at MW-2 <br /> as evidenced by approximately 2 inches of floating product. Analysis of <br /> ground-water samples from MW-1 did not detect TPH as diesel or BTEX. <br /> Soil samples analyzed from borings B-2 and B-5 exhibited elevated PID <br /> readings, but TPH as diesel and BTEX were not detected. Soil samples <br /> from borings B-2 and B-5 , excluding those previously analyzed, may be <br /> impacted as evidenced by the presence of petroleum odors. <br /> A soil sample was collected at the discharge point for the current owner's <br /> steam cleaner. This equipment is used to clean equipment and parts used <br /> in an on-site maintenance shop. Analyses of the sample did not detect the <br /> presence of TPH as diesel or BTEX. <br /> PJ A65-04.01 <br /> ES - 1 March 6, 1991 <br />