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.9 Chevron U.S.A. - Page 5 Ground water monitoring wells would be developed by means of pumping. Sampling of the monitoring wells would be accomplished by means of a teflon bailer. Well development water would be retained in drums at the subject property pending proper disposal by Chevron after results of chemical analysis were complete. Auger cuttings from the drilling operation will be placed on plastic on-site, and covered by plastic sheeting. Those auger cuttings which do not exhibit obvious presence contamination by field screening with a portable photoionization detector will be segregated into a "clean" pile for future composite sampling. Composite sampling and chemical analysis will dictate the proper disposition of those contaminated soils by Chevron. Each well head would be surveyed to establish the surface elevation to a common benchmark. The survey would be utilized in helping to determine accurate ground water surface elevations, and possible future ground water gradient assessments. TASK III: Laboratory Analysis Soil and ground water samples would be maintained and transported under chain of custody protocol to a State-approved laboratory for chemical analysis. Soil samples would be analyzed to detect the presence and concentration of benzene, toluene, xylenes, ethylbenzene and total petroleum hydrocarbons. {around water samples would be analyzed by EPA Method 503.1 to detect the presence and concentration of benzene, toluene, xylenes, TP—H, an total lead. Detection limits for the 503.1 analyses are 0.5 parts per billion.. TASK N• Report of Findings A report would be prepared at the completion of the field, chemical and office analysis portions of the investigation. The report would detail the finding of the investigation, and would address the components of the criteria established by the RWQCB for a problem assessment investigation report. Additionally, recommendation would be made regarding any additional investigation felt necessary to adequately define the extent of noted contamination at the subject property, if contamination conditions are noted. PROJECT SCHEDULE Dames & Moore is prepared to begin this study upon receipt of approval of the proposed workplan from the San Joaquin Local Health District. It is estimated that the proposed scope of services will require approximately six weeks to complete. This schedule is partially dependent on the time necessary for regulatory agency review, permitting, scheduling of drilling equipment and time required for specific chemical analysis. We will arrange our visit to the site for the field portion of the investigation through your office. L -000-