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Ms. Diane Hinson %two, 2 %two' May 19, 1993 approximately 40 feet from the former wastewater tank. The remaining borings were located approximately 20 feet from the preceding boring as shown in Figure 1. The depth of the wastewater line was measured at both ends and was found to range between approximately ten feet below ground surface (bgs) at the west end and approximately four feet bgs at the east end. The borings were drilled using a hand auger to a depth of approximately one to two feet below the wastewater line until native soil was encountered. Soil samples from the native soil were then collected in 2-inch by 6-inch clean brass sleeves driven into the soil using a drive sampler. After removing the brass sleeve from the drive sampler, the ends of the brass sleeves were immediately covered with aluminum foil,capped with plastic end caps and secured with tape. Soil samples were placed in ziploc bags, stored in an ice chest and logged on a Chain-of-Custody form. Sampling equipment was decontaminated by triple rinsing in a non-phosphate detergent followed by a clean water rinse and a final rinse in deionized water. Soil samples were transported (under WEST), Chain-of-Custody procedures to Western Environmental Services and Technology ) a California-certified laboratory in Davis,California. The soil samples were analyzed for total extractable petroleum hydrocarbons (TPH) by Modified EPA Method 8015. Results for 15 of the 18 soil samples collected were reported to contain TPH below detection limits of 10 mg/kg. Two samples were reported to contain detectable levels of TPH as diesel;BH-2 at 12 mg/kg and BH-16 at 110 mg/kg. Three samples were reported to contain detectable levels of TPH quantified as motor oil; BH-2 at 13 mg/kg, BH-15 at 38 mg/kg, and BH-16 at 210 mg/kg, respectively. The TPH quantified as motor oil probably represents lubricating oil. Tabulated analytical results for TPH as diesel and TPH as motor oil are included in Table 1, and copies of the laboratory reports are attached. Based on the results of the soil sampling,the soils beneath the wastewater line have not been significantly impacted by petroleum hydrocarbons. Therefore, abandonment of the wastewater line in place by grouting with neat cement grout is recommended. Following grouting of the wastewater line, the riser pipes at each end of the line would be removed below grade. Abandonment of the wastewater line will then complete tank removal activities at the site. If you have any questions or comments, please do not hesitate to call. Sincerely, effrey Hess Project Manager Attachments cc: Mick Hardin Tim Lassen ENVIRONMENTAL SOLUTIONS