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e�u,M �, d �". %M t�WnAr9R . Working to Restore Nature I 28, 1992, approximately 5 gallons of gasoline were released from a fractured product line between the dispenser islands and the underground tank cavity Results of the initial assessment of the release were reported 1n our second quarter 1992 status report and addendum work plan (RESNA, August 11, 1992, Report 31009-6). Dissolved gasoline hydrocarbons were detected in water samples collected from the three wells Purgeable halocarbons were not detected, except for 1,2-dlchloroethane which was detected In monitoring well MW-2. Fecal and total coliform bacteria were not detected in the sample collected from well MW-3. t In January 1993, RESNA observed drilling of seven soil borings and the installation of two groundwater monitoring wells and four vapor extraction wells Results of this assessment were reported 1n our first quarter 1993 status report (RESNA, June 9, 1993, Report 31009- 7) Analytical data indicated that hydrocarbons present in soil below 26 feet and 1n groundwater were probably from an offsite source Therefore, ARCO requested that an 1 investigation of soil and groundwater be performed offsite and upgradlent of the ARCO station to evaluate whether hydrocarbons were present upgradlent of the site In October 1993, RESNA observed drilling of two soil borings and the installation of two groundwater monitoring wells (MW-6 and MW-7). Results of this assessment were reported in our fourth quarter 1993 status report (RESNA, February 15, 1994, Report 31009-9) Analytical data indicated that residual and dissolved hydrocarbons are present in wells MW- 6 and MW-7 GROUNDWATER MONITORING: FIRST QUARTER 1994 Groundwater Technology, Inc (GTI) of Concord, California, was contracted by ARCO to conduct the field work at the site, GTI 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 evaluate the direction and gradient of groundwater flow beneath the site. The locations of the monitoring wells are shown on Plate 2 On March 22 and 23, 1994, a technician from GTI measured depths to water and collected groundwater samples from the wells for subjective and laboratory analyses The technician noted no floating product or sheen in the seven wells (Table 1) 1 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 1, were used to evaluate the potentlometrlc surface beneath the site Based on the potentlometnc data collected at and near the site, the general direction of 0418cear/31009-1I 2