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Wright performed a soil and groundwater investigation in the vicinity of the former tanks and in the assumed downgradient direction (see Wright report dated April 21, 2000). That study revealed low concentrations of apparently degraded petroleum contaminants near the former tank pits, however, an elevated dissolved contaminant concentration was observed at exploratory boring B-3. After a review of this report, the PHS EHD has required installation of at least one groundwater monitoring well at the B-3 Iocation. Scope of Work PHS EHD File Review PHS EHD has recommended reviewing site files for two locations just north of Tracy Auto Stereo; 2421 Holly Street and 15 Grantline Road. These sites are contaminated and a review of these files would be beneficial to the work, especially given the difficult location of the well in the busy lanes, and complex subsurface utility maze of Grantline Road. Since only one monitoring well would be installed, it would be of use for the sites to share groundwater measurement data and tie the new well casing elevation to the existing site surveys. In this way, Wright could use depth to groundwater information at the other sites, and provide groundwater contour flow information tied to other existing well arrays. Wright will schedule a file review for these two sites with Ms. Carol Dissa of PHS EHD (ph. 209/468-3420) to perform the review. Exploratory Drilling and Sampling One exploratory boring will be drilled at the site (see Figure 1). The boring will be positioned at the Boring B-3 location, and adjusted as required given utility proximity. Drilling and well installation permits will be secured from the PHS EHD, and all utilities will be cleared prior to doing the field work. The boring will be advanced to define the uppermost water bearing strata, and will be advanced to the contact of the underlying confining strata immediately below this uppermost water bearing strata. The borehole will be drilled with truck mounted hollowstem auger drilling equipment. All drilling equipment and sampling tools will be cleaned prior to arriving, and before leaving the site. The augers will be advanced to the desired sampling depth interval, and a drive .split spoon sampler will be driven ahead of the drill bit. The sampler will then be retrieved and dissembled, and the soil filled brass liners, if retained for chemical analysis, will be sealed with TeflonO paper and plastic endcaps, labeled, logged onto chain-of-custody forms and place in a chilled ice chest. The borehole will be logged using the Unified Soil Classification System under the supervision of a registered geologist. Additional lithologic information will be collected to describe the subsurface geology. Additional soil samples may be collected at minimum five-foot intervals, at intervals of obvious contamination and at stratigraphic features of interest. Upon completion of the borehole drilling and information collection, one monitoring well will be installed in the borehole. Monitoring_Well Installation One monitoring well will be installed for long term plume monitoring. The well will be cased with Sch. 40 PVC casing, threaded together; glues will not be used. The slotted interval will be a 0.020 inch slot and the annular space around the slots will be backfilled with a 2/12 size sand. Previous experience has shown this to be a reliable well design in fine grained and stratified depositional environments. Final well design will be modified to the site specific conditions encountered in the borehole during drilling. Once the aquifer strata has been defined, the casing will be lowered to the bottom Page 2