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i Both borings were advanced to a depth of 53 feet using a truck- mounted 8-inch hollow-stem auger rig. The CME-75 drill rig and two- man crew were supplied by West Hazmat Drilling Corporation. 3.2 Soil Sampling ' Discrete soil samples were collected at five-foot intervals ahead of the drill bit using a split-tube sampler loaded with three pre- cleaned 2 by 6-inch brass tubes. The sampler was driven into the soil with a 140-1b hammer, and the number of blows required to advance the sampler in six-inch increments was recorded on the boring log. To avoid cross contamination, the sampling equipment ' was washed in a tri-sodium phosphate (TSP) solution and rinsed twice with water prior to each sampling run. For each sample, both ends of the lead tube were covered with aluminum foil, capped and sealed with tape. The samples were labeled, logged on a chain of custody form, and stored on ice pending transmission to Alpha Analytical Laboratories in Ukiah. Two soil samples from each boring were analyzed for total petroleum hydrocarbons (TPH as gasoline and diesel) and purgeable aromatics (BTE&X) in accordance with EPA methods 8015 modified and 8020, respectively. 3. 3 Logging Auger returns and soil from the middle brass tube were monitored for the presence of organic vapors using a photo-ionization detector (PID: Thermo Environmental 580A, 10. 0 eV, calibrated to isobutylene) . The soil was then described in accordance with the Unified Soil Classification System. Boring logs are included in Appendix C. 3.4 Monitoring Well Completion ' The borings were completed as groundwater monitoring wells by the installation of 0. 020 screen PVC liner from 33 to 53 feet. No. 3 monterey sand was used from 31 feet to total depth. Bentonite pellets were used from 29 to 31 feet and the well was backfilled to the surface with Portland Cement. 3.5 Monitoring Well Purge Procedures The third monitoring event was conducted on June 21, 1993 . A Solinist water level meter was used to measure the depth to groundwater in the five monitoring wells. After water levels were measured, a three-stage submersible pump was used to purge approximately 9 to 12 gallons of water from monitoring wells MW-1 to MW-4 . Because of muddy conditions, a PVC bailer was used to hand purge approximately 7 gallons of water from monitoring well MW-5. Temperature, pH and conductivity were measured at one-gallon 3