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Soil Sampling Report - Chevron Service Station #9-3232, Stockton, CA
<br />April 28, 1999
<br />Waste Oil UST Removal and Soil Sampling
<br />On March 11, 1999, one 1,000 -gallon single -walled fiberglass waste oil UST was uncovered and
<br />removed by Wendt. Upon removal, the UST was visually inspected for evidence of failure. Holes
<br />were not observed in the UST. The UST was removed from the site and disposed of by Ecology
<br />Control Industries (ECI) of Richmond, California.
<br />Two soil samples, labeled TK4-N and TK4-S, were collected from beneath the north and south ends of
<br />the former waste oil UST at depths of approximately 10 feet bgs. Soil discoloration was observed
<br />beneath the north end of the waste oil UST between depths of approximately 10 and 16 feet bgs.
<br />Discolored soil was excavated and stockpiled separately on-site for further sampling and disposal. One
<br />additional soil sample, labeled TK4-N(17), was collected from beneath sample TK4-N at a depth of
<br />approximately 17 feet bgs. Soil sample locations are shown on the attached Figure 2.
<br />These soil samples were analyzed for TPHg, BTEX, MtBE, Total Petroleum Hydrocarbons as diesel
<br />(TPHd), Total Recoverable Petroleum Oil (O&G), Halogenated Volatile Organic Compounds
<br />(HVOCs), polychlorinated biphenyls (PCBs), and the metals cadmium, chromium, lead, nickel, and
<br />zinc. Sample TK4-N contained TPHg (reported by the laboratory as gasoline and unidentified
<br />hydrocarbons C6 -C12) at a concentration of 2 ppm, xylenes at 0.014 ppm, TPHd (reported by the
<br />laboratory as unidentified hydrocarbons >C12) at 810 ppm, and O&G at 2,700 ppm. However, after
<br />additional excavation in the vicinity of sample TK4-N, the additional sample TK4-N(17) collected from
<br />beneath sample TK4-N at a depth of approximately 17 feet bgs, and sample TK4-S contained no
<br />detectable concentrations of TPHg, BTEX, MtBE, TPHd, HVOCs, and PCBs. O&G was detected in
<br />samples TK4-N(17) and TK4-S at concentrations of 79 and 110 ppm, respectively.
<br />Product Line and Dispenser Removal and Soil Sampling
<br />On March 11, 1999, the product dispensers and 2 -inch diameter double-wall fiberglass product lines
<br />were removed. Per the direction of Mr. Kith of the SJCEHD, GR personnel collected four soil
<br />samples, labeled D1, D2, D3, and D4, from beneath the product dispensers at depths ranging between
<br />3.75 and 4.0 feet bgs. In addition, seven soil samples, labeled P1 through P7, were collected from
<br />beneath the product piping at depths ranging between 3.75 and 4.5 feet bgs. Soil in the vicinity of
<br />product piping and dispensers consisted of silt and clayey silt. Soil sample locations are shown on the
<br />attached Figure 2.
<br />These soil samples were analyzed for TPHg, BTEX, MtBE, and oxygenated compounds by EPA
<br />Method 8260. Soil samples collected from beneath the product piping and dispensers did not contain
<br />any detectable concentrations of TPHg, BTEX, MtBE, or oxygenate compounds, except for 0.0051
<br />ppm of toluene detected in sample P4, 0.0093 ppm and 0.0069 ppm of xylenes detected in samples P1
<br />and P6, respectively.
<br />346463.03
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