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0 W * GIpLES ENGINEERING ( )SSOCIATES. INC. Limited Phase II ESA 239 West 11`h Street Tracy, California Giles Project No. 2E-1108004 Page 3 No obvious signs of a release (odors or staining) were noted within the soil borings completed in conjunction with the Limited Phase II ESA. However, low level organic vapors were detected the soil sample collected from soil boring B-3 (4 to 6 feet bgs) during field screening. Field screening results (PID readings) are included on the soil boring logs, included in Attachment C. No VOCs or TPHs were detected above the laboratory method detection limits. The soil laboratory analytical report and chain -0f -custody documentation are included in Attachment D. Groundwater Analytical Results Temporary well screens were placed in the open boreholes of soil borings GP -1, GP -3, and GP -4 to facilitate groundwater collection. Groundwater was observed within the temporary wells at twelve to fourteen feet bgs. Groundwater samples were collected from each temporary well and submitted to AccuTest for VOCs analysis. Select VOCs were detected at concentrations below respective regional screening levels, Maximum Contaminant Levels (MCLs) in the groundwater samples collected from GP -1, GP -3, and GP -4. The groundwater results are summarized in Table 1 and the laboratory analytical report and chain -of -custody documentation are included in Attachment E. Conclusions Based on the groundwater results from samples collected from temporary wells GP -1, GP -3, and GP -4 in conjunction with Giles Limited Phase II ESA, it is our opinion that a low level VOC (dichlorodifluoromethane) impacts present exists within the groundwater may have been associated with the prior use(s) of the site as a automobile sales and service facility (1920s to 1950s), and a grocery store (1960s to the 1990s). Dichlorodifluoromethane is a coolant gas (R-22) and was commonly used in refrigeration units (automobile air conditioning or food chillers). Toluene was detected in groundwater samples collected from GP -3 and maybe associated with automobile refueling. The chloroform detected in groundwater samples collected from GP -3 maybe considered a laboratory artifact; chloroform is a common laboratory extraction solvent. The dichlorodifluoromethane in groundwater samples collected from GP -1, GP -3, and GP -4, toluene in samples from GP -3, and chloroform in samples from GP -3 were reported between the laboratory method detection limit (MDL) and reporting limits. Therefore, the reported values can not be reproduced. In addition, the detected VOCs were reported at levels well below applicable regulatory standards. No soil impact was detected in soil samples submitted from GP1 through GP -5 at the water table ' interface. Therefore, no correlation can be made for potential source areas associated with the detected groundwater impacts. ' Recommendations Based on the results of the Limited Phase II ESA, it is apparent that a low level VOC impacted groundwater condition exists at the Site and is associated with a historic on or off -Site release. The t groundwater VOC levels detected are well below applicable regulatory standards. Considering the aforementioned, there is no evidence that a new release or spill has occurred on the Site, and it is Giles opinion that no further environmental investigation is warranted. However, as a condition of the well and boring permit application, one copy of the Limited Phase 11 ESA will be sent to the San