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ARCO Products Coman py *4we \A 3septemher 16,1999 ARCO Service Station#0434 SOl West Kettl an Lan CA as nondetect in all of the product line and dispenser samples collected. MtBE was reported in three samples at a maximum concentration of 0.560 mg/kg by EPA Method 8260 (PL2@4'). Dispenser and product lines analytical data is presented in Table 1 and soil sample locations are shown on Figure 2. Over-excavation and Soil Sampling - UST Excavation For installation of the new USTs, soil was removed from the old UST excavation to a total depth of 18 feet bgs (approximately 200 cubic yards). On July 21,1999, six soil samples were collected at a depth of 18 feet bgs in the areas of previous samples T- 1N@13', T-1C@14', T-1S@14', T-2N@14', T-2C@14', and T-2S@14'. A deeper sample beneath the location of T-3S@13.5' could not be collected due to the proximity of underground utilities. All six over-excavation samples were reported as nondetect for TPH-g and BTEX. Trace MtBE was detected in one sample (T-2C@18') at a concentration of 0.191 mg/kg. Over-excavation activities were observed and approved by Ms. Margaret Lagorio of the San Joaquin County Environmental Health Department. UST soil analytical data are presented in Table 1. Field and laboratory procedures are presented as Attachment A. Certified analytical reports and chain-of-custody documentation are presented as Attachment B. Stockpiled Soil Approximately 1,070 tons of soil was generated during the removal of the USTs, product lines, and dispensers. Eight composite (four sleeves to one sample) samples were collected from the stockpiled soil for characterization prior to disposal. Stockpiled soil was disposed of at Forward Landfill in Manteca, CA. Stockpiled soil analytical data is presented in Table 2. Field and laboratory procedures are presented as Attachment A. Certified analytical reports and chain-of-custody documentation are presented as Attachment B. Soil disposal certificates are included as Attachment C. SUMMARY OF FINDINGS • After over-excavation, TPH-g and BTEX compounds were reported as nondetectable in six soil samples collected beneath the USTs. MtBE was detected in one of six samples (T-2C@18') at a concentration of 0.191 mg/kg. • Over-excavation was not performed in the area of UST sample T-3S@13.5. TPH-g and MtBE were reported at 5.15 mg/kg and 0.141 mg/kg, respectively in this sample. • TPH-g was reported in two of the nineteen samples collected beneath the product lines and fuel dispensers at a maximum concentration of 10.3 mg/kg (PLl@5.5'). Benzene was reported as nondetect in all of the samples collected. Trace MtBE was reported in three of the 077.41741.500/P11LL.DOC