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Workrng to Restore Nature 1993 On September 7, 1993, our geologist collected soil samples (one composite of four samples) from the stockpiled soil for analyses to evaluate disposal options. At ARCO's request, on November 11. 1993, drill cuttings were transported by Dillard Trucking of Byron, California, to the BFT landfill in Pleasanton, California, for disposal Laboratory Methods and Results Select soil samples from the borings and the samples from the stockpile were analyzed for total purgeable hydrocarbons (equivalent to total petroleum hydrocarbons as gasoline [TPHg]) with benzene, toluene, ethylbenzene, and total xylene isomers (BTEX) distinction using Environmental Protection Agency (EPA) Methods 5030/8015/8020 One soil sample collected from boring B-20 was analyzed for halogenated volatile organic compounds (HVOCs) using EPA Method 8010 Samples were analyzed at Sequoia Analytical in Sacramento,California(California Department of Health Services Hazardous Waste Testing Laboratory Certification 1624) Copies of the Chain of Custody Records and laboratory analysis reports are attached Results of analyses indicated gasoline hydrocarbons were detected in soil samples from borings B-20 and B-21 at concentrations from 180 parts per million (ppm) to 1,3- 00"m; the highest concentration was detected in soil from boring B-20 at a depth of 20 5 feet Benzene concentrations ranged from below laboratory detection limits to 1, 2 pPm HVOCs were not detected Results of analyses are shown in Table 1 GROUNDWATER MONITORING• FOURTH QUARTER 1993 EMCON Associates of Sacramento, California, was contracted by ARCO to conduct the field work at the site; EMCON subsequently forwarded their field notes and the laboratory reports to RESNA Field work included measuring depths to water and collecting groundwater samples for subjective and laboratory analyses RESNA used these data to I evaluate the direction and gradient of groundwater flow beneath the site The locations of the monitoring wells are shown on Plate 2 On October 28, 1993, a technician from EMCON measured depths to water and collected groundwater samples from the wells for subjective and laboratory analyses. The technician I noted no floating product or sheen in the five wells (Table 2) The wellhead elevations of the monitoring wells at the site were previously surveyed by Tom O Morrow Inc The surveyed elevations and the depth-to-groundwater measurements, summarized in Table 2, were used to evaluate the potentlometric surface beneath the site 1 1130cear/31009.9 3