SITE INFORMATION AND CORRESPONDENCE

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Former TAOC Pump station - 2 - 2 March 2004 990 Beechnut Tracy, San Joaquin Co. The majority of the samples were analyzed for TPH as oil and grease (TPH-og) and BTEX compounds. TPH-og detected in 19 samples, ranged from ND in several samples at various depths to a high of 8,450 mg/kg at 15 feet (P-19). Subsequent sampling and analysis reported TPH as crude oil values ranging from ND in several samples to a high of 54,000 mg/kg at 5.5 feet in GMX-09. Benzene was ND and toluene, ethylbenzene and xylene concentrations from 0.06 to 0.28 mg/kg were reported. Ten soil samples from nine borings were tested for PAHs (polyaromatic hydrocarbons). Various PAHs were detected at concentrations from ranging from ND to 53 mg/kg phenanthrene, 5.8 mg/kg benzo(a) pyrene, and 3.1 mg/kg benzo(b) fluoranthene, among others in GMX-09 at 5.5 feet. Hydrocarbon fingerprinting results indicated that the TPH product at GMX-09 is degraded Bunker fuel. Results from the northern portion of the property appear to represent a combination of petroleum mixtures, including Bunker fuel and biodegraded crude oil. Soil Stockpile The stockpile is approximately six feet high and approximately 100 feet by 300 feet in size. Drilling and/or sampling of the stockpile appears to have been conducted in the past, unfortunately the analytical information from this work has been lost. Groundwater No groundwater monitoring wells have been constructed on this site. Based on information from the adjacent site, depth to water is approximately nine to 14 feet with a north - northwest gradient. Analytical results for grab groundwater collected in May 2001 indicate that groundwater in the southern and central portion of the site ranged from ND to 89 pg/L TPH-d. A TPH-d concentration of 1,700 pg/L was reported for a sample obtained from GMX-01, in the northern portion of the site. Benzene was ND in all grab groundwater samples. With the exception of some samples reporting results at or slightly above the minimum laboratory detection limits, toluene, ethylbenzene, and xylene, were ND. PAH compounds were ND with the exception of naphthalene at 0.3 pg/L reported in one sample. CURRENT INVESTIGATION In September and October 2003, Geomatrix conducted a soil and groundwater investigation and advanced borings to collect soil and groundwater samples for analysis. According to the 13 January 2004 Soil Investigation Report referenced above, the purpose of the investigation was to: a) assess the vertical extent of TPH in soil; b) assess groundwater downgradient of the site; c) collect additional PAH and BTEX data for use in a screening level human health risk assessment (HRA); d) evaluate mounded soil; and e) assess extent of PAHs in shallow impacted soil near previous boring GMX-09. Consistent with previous investigations, depth to groundwater at the site is approximately 12 to 14-feet and the gradient is generally north-northwest.