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TECHNICAL APPROACH SUMMARY The objectives of the proposed site investigation are to evaluate the vertical extent of impacted jest P P 9 soil beneath the north end of the middle former UST and to determine if groundwater has been impacted by gasoline hydrocarbons To achieve these project objectives, one sod boring will be drilled for sod and groundwater-grab sampling and analysis and the on-site water supply well will be re-sampled for laboratory analysis A permit will be obtained from PHSIEHD and a project report will be prepared to document the results of the investigation The single sod boring will be drilled with hollow-stem augers to a depth of approximately five feet below the first encountered groundwater-bearing zone (i e , total depth of approximately 90 feet) Sod samples will be collected at five-foot intervals, logged and screened with a PID Based on the PID measurements, up to six soil samples will be submitted for laboratory analysis Prior to sod sample submission to the laboratory, PHSIEHD will be consulted To collect asam roundwater- rab le, a two-inch diameter PVC temporary well will be g 9 P constructed and installed in the borehole The temporary well will consist of 10 feet of 0 020- inch well screen spanning approximately five feet above and five feet below the static groundwater level Blank PVC casing will thread into the top of the well screen and extend to the surface Neither a sand pack nor a well seal will be installed in the temporary well Prior to groundwater-grab sampling, the temporary well will be purged and allowed to adequately recharge The groundwater-grab sample will be collected with the disposal bailer and submitted to the laboratory for analysis Once the sod and groundwater-grab sampling is completed, the temporary well will be removed and the soil boring will be abandoned with 20 1 cement bentonite grout, installed to the bottom of the borehole using a tremae pipe Waste soil generated during the drilling of the soil boring will be stockpiled at the site using a base and cover of plastic sheeting Proper disposition of the waste sod will be based on the results of the soil sample analyses Equipment rinsate water and purged groundwater will be stored on-site in 55-gallon drums pending waste profiling and proper disposition To confirm that the on-site water supply well has not been impacted by gasoline hydrocarbons, groundwater from the well will be re-sampled for laboratory analysis The selected soil samples, groundwater-grab sample and on-site water well sample will all be analyzed for TPH-as-gasoline, BTEX, MTBE, DIPE, ETBE, TAME and TBA by EPA Method 8260 The sod samples will also be analyzed for total lead by EPA Method 6010 To document the results of the investigation, a report will be prepared by a California Registered Geologist and submitted to PHSIEHD, USTCF and RWQCB Given standard turnaround for regulatory review and approval of this work plan and bid solicitation and USTCF cost pre-approval, the planning and permitting task could begin by August 1999 If the drilling is completed during September 1999, the laboratory analyses and project report could be completed by the end of October 1999 3