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3WFH vapor extraction system was constructed at the site and began operating July 23, 1993. Quarterly groundwater monitoring results have shown detectable levels of petroleum hydrocarbons in the monitoring wells in the past but have decreased to nondetectable levels with continued operation of the vapor extraction system (Table 1) ' GROUNDWATER SAMPLING AND GRADIENT EVALUATION Smith Environmental personnel performed the latest quarterly groundwater monitoring of monitoring wells on June 13, 1995. At the direction of SJCPHS in a conversation on July 14, 1994, the number of wells required to be sampled was decreased from six to three, but all six wells were sampled at the direction of Coca-Cola Field work consisted of measuring depth- to-water (DTW) levels in all wells and collecting groundwater samples from all wells and submitting groundwater samples for laboratory analysis. ' Water level measurements were collected from wells MW-1 through MW-6 The depth to water ranged from 59 81 to 60 34 feet below top of well casing elevation Groundwater ' elevations have increased an average of 2 78 feet since March 27, 1995. The water level data were used to develop the groundwater elevation contour map (Figure 2) Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost aquifer beneath the site ' flowed in a northwesterly direction The average hydraulic gradient on June 13, 1995 was calculated to be 0 001 ft/ft or about 5 feet/mile. The data indicates a change in gradient direction which previously has been to the east or northeast This change appears to be due to a slight depression in the water table in the vicinity of well MW-1. A summary of groundwater monitoring data is presented in Table 2 Groundwater elevations are referenced to feet mean sea level ' Groundwater samples were collected from six shallow groundwater monitoring wells, MW-1, MW-2, MW-3, MW-4, MW-5 and MW-6. Prior to collection of groundwater samples a ' minimum of three well casing volumes were purged. The depth-to-water, pH, electrical conductivity, and temperature were measured and allowed to stabilize before groundwater samples were collected. No evidence of measurable floating product or hydrocarbon vapor was noted in the water samples Samples were then collected from each well using disposable bailers Purge water was contained in 55 gallon DOT approved drums. Purge water from this ' event and the previous sampling event did not contain detectable concentrations of petroleum hydrocarbons and was discharged to the ground surface ' The groundwater samples collected from each well were submitted with Chain of Custody Record to Sequoia Analytical Laboratories, a State Certified laboratory (FLAP #1210). Samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), total petroleum ' hydrocarbons as diesel (TPHd), and benzene, toluene, ethylbenzene, and total xylenes (BTEX) utilizing EPA methods 8015/8020 Groundwater well purge and sample logs are provided in Appendix A 540056IQUARTLYI2QTR1995 DOC