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I feet No TPH or BTE&X contamination were detected in any of the soil samples that were analyzed One halogenated hydrocarbon, bromomethane,was detected in soil sample MW4- 45 at 0 43 µg/g (ppm) No other halogenated organics were detected in any of the samples analyzed I In October of 1993 groundwater depth at the site was approximately 86 feet and groundwater flow was to the north Groundwater in the down-gradient well (MW-3) and cross-gradient well (MW-4) contained benzene (0 4 ppb and 4 1 ppb, respectively) No other petroleum hydrocarbons were detected in these wells However, TPH as gasoline, benzene, and toluene were detected in the up-gradient well (MW-2) GeoAudit inferred that the groundwater flow direction may have vaned in the past, and recommended further monitoring and assessment of the extent of the hydrocarbon plume The monitoring wells were again sampled on January 4, 1994 Benzene was detected in samples from MW-2, MW-3 and MW-4, TPH as gasoline was detected in MW-3 (see Table 3) One or more chlorinated hydrocarbons were also detected in each well 3.0 PROCEDURES t31 Remediation Well Installation On April 4, 1994, remediation well VW-1 was installed at the site The well was installed near the center of the former UST (see Figure 2) The well was drilled using a CME-75 truck mounted, hollow-stem auger drill ng The drill ng and two-man crew were supplied by West Hazmat Drilling Corporation of Rancho Cordova, California The well was drilled to a total depth of 80 feet and sampled continuously from 25 feet to total depth Soil samples were collected using a split spoon sampler loaded with pre-cleaned 2 by 6-inch brass sleeves After collection, the ends of the lead sleeve were covered with aluminum sheets, capped, sealed with tape and placed in a chilled container remaining Samples in the tubes were extruded and screened using a photo-ionization P g detector (PID) The samples were then described in accordance with the Unified Soil Classification System The Boring Log for VW-1 is included in Appendix B Remediation well VW-1 was completed using 4-inch diameter, 0 020 slotted PVC screen from 22 to 72 feet The boring was backfilled with bentonite from 72 to 80 feet The filter pack (#3 Lonestar Sand) was installed from 20 to 72 feet, bentonite was used from 17 to 20 feet, and the boring was backfilled to the surface with Portland cement 3.2 Monitoring Well Sampling On April 6, 1994, groundwater monitoring procedures were conducted at the site The depth C�.akyc.l Akk S.,l.. 4 M-d—Propene.QW4 9U 133