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' Soil Sampling Report ARCO Facility No. 5569 Stockton,California Page 2 On October 29, 2001, Delta returned to the site to collect soil samples from beneath three 12,000-gallon USTs removed from the site. Samples were collected under the direction of Environmental Health Specialist Michelle Stemi-le. Nine soil samples (3 beneath each UST [Tl, T2, and T3]) were collected from beneath the former USTs at an average depth of approximately 15 feet below ground surface (Figure 1). Following collection of the samples, the ends of each brass tube were covered using Teflon sheets and plastic caps, and the samples were placed in an ice-chilled cooler. Each sample was sealed, labeled with the ARCO station number, sample name, collection date and collection time. To avoid cross contamination between samples, all sampling equipment was washed with an aqueous solution of AlconoxTm detergent, rinsed with potable water, and rinsed again with distilled water. Four samples (SP-1 through SP-4) were collected from the soil and pea gravel stockpile generated by the construction contractor. The samples were composited by the laboratory into one sample. The results of this composite sample were used to confirm that this material (primarily pea gravel) was acceptable by San Joaquin County PHS as backfill material for the UST pit. All soil samples were relinquished to Sequoia Analytical Inc. (Sequoia), a California Department of Health Services (CADHS) certified laboratory, for chemical analysis. Delta and Sequoia adhered to strict chain-of-custody procedures from the time of sample collection to the time of sample analysis. Soil samples were analyzed for total petroleum hydrocarbons as gasoline (TPHG), benzene, toluene, ethylbenzene, and xylenes (BTEX), and methyl tertiary butyl ether (MTBE) using USEPA Method 8015/8020 DHS/LUFT, and for MTBE, tertiary amyl methyl ether (TAME), di-isopropyl ether (RIPE), ethyl tertiary butyl ether (ETBE), and tertiary butyl alcohol (TBA) using USEPA Method 8260B. The waste composite sample (SP-1,2,3,4) was analyzed for TPHG, BTEX, and MTBE using USEPA Method 8015/8020 DHS/LUFT, and for total lead using USEPA Method 6010A. Laboratory analytical results are presented in Table 1 and certified analytical reports with chain-of-custody documentation are presented in Appendix A. All soil samples were reported below method reporting limits with the exception of T-1-2 which contained only total xylenes at 0.036 mg/kg. If you have any questions concerning this report,please contact me at (530) 676-6000. Sincerely, �DELTA ENVIRONMENTAL CONSULT ,IN Kiran Nagaraju ay . J son, R.G. Staff Engineer Pr je anager P:WRCO15569VLeportsARCO partial demo soil sampling.doe