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ZL <br /> Chevron U.S.A. - Page 5 <br /> � <br /> . i <br /> Ground water monitoring wells would be developed by means of pumping. Sampling of the <br /> monitoring wells would be accomplished by means of a teflon bailer. Well development water <br /> would be retained in drums at the subject property pending proper disposal by Chevron after <br /> results of chemical analysis were complete. Auger cuttings from the drilling operation <br /> will be placed on plastic on-site, and covered by plastic sheeting. Those auger cuttings <br /> which do not exhibit obvious presence contamination by field screening with a portable <br /> photoionization detector will be segregated into a "clean" pile for future composite <br /> sampling. Composite sampling and chemical analysis will dictate the proper disposition of <br /> those contaminated soils by Chevron. <br /> Each well head would be surveyed to establish the surface elevation to a common ' <br /> benchmark. The survey would be utilized in helping to determine accurate ground water <br /> surface elevations, and possible future ground water gradient assessments. <br /> u TASK III: Laboratory-Analysis <br /> Soil and ground water samples would be maintained and transported under chain of <br /> custody protocol to a State-approved laboratory for chemical analysis. Soil samples would <br /> be analyzed to detect the presence and concentration of benzene, toluene, xylenes, <br /> . ethylbenzene and total petroleum hydrocarbons. Ground water samples would be analyzed by <br /> \EPA Method 503.1 to detect the presence and concentration of benzene, toluene, xylenes, <br /> TPH, an total lead, Detection limits for the 503.1 analyses are 0.5 parts per billion. <br /> 3 <br /> TASK IV: Report of Findinits <br /> A report would be prepared at the completion of the field, chemical and office <br /> analysis portions of the investigation. The report would detail the funding of the <br /> -- investigation, and would address the components of the criteria established by the RWQCB <br /> for a problem assessment investigation report. Additionally, recommendation would be made <br /> regarding any additional investigation felt necessary to adequately define the extent of <br /> noted contamination at the subject property, if contamination conditions are noted. <br /> PROJECT SCHEDULE <br /> Dames & Moore is prepared to begin this study upon receipt of approval of the proposed <br /> workplan from the San Joaquin Local Health District. It is estimated that the proposed <br /> - scope of services will require approximately six weeks to complete. This schedule is <br /> partially dependent on the time necessary for regulatory agency review, permitting, <br /> scheduling of drilling equipment and time required for specific chemical analysis. We will <br /> arrange our visit to the site for the field portion of the investigation through your <br /> office. <br /> -000- <br />