ARCHIVED REPORTS_PHASE I ENVIRONMENTAL SITE ASSESSMENT AND LIMITED SUBSURFACE INVESTIGATION

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y Winston#209 Manteca,CA August 8,2002 r cohesive soils and allowed to sit in a warm location for a minimum often minutes prior to screening. Following headspace development, the PID sampling probe was inserted through a small opening in the sample bag and the highest meter response was recorded on the geologic boring log. 9.3.3 Sampling Location Selection The general intent of the investigation was to collect soil and groundwater samples to identify the potential presence of impacted media. Soil sample depth intervals selected for laboratory analysis were based upon the highest field screening results;or in the absence of ` significant organic vapors,the soil sample was collected from the interval directly above the groundwater saturated zone or from the terminus of the soil boring. 9.3.4 Laboratory Analysis The soil samples selected for laboratory analysis were containerized in laboratory supplied sample containers. The soil samples were labeled, stored on ice and transported under appropriate chain-of-custody procedures to Test America of Nashville, Tennessee. The collected soil samples from each hydraulic lift GeoProbe boring locations were analyzed r for the presence of TPH diesel range organics(DRO)and TPH oil range organics (ORO) by EPA Method 8015. The collected soil sample from the OWS GeoProbe boring location was analyzed for the presence of TPH DRO/ORO by EPA Method 8015 and volatile organic compounds (VOCs), including fuel oxygenates by EPA Method 8260B. 9.4 PHASE II RESULTS 9.4.1 Geology/Hydrogeology ` In general, subsurface geology consisted of sand and gravel from beneath the concrete baserock/asphalt to approximately 2 feet bgs, underlain by brown to dark grayish brown sand and silty sand from 2 to 12 feet bgs(total depth). Field boring logs are included in Appendix E. Groundwater was not encountered during drilling activities. The boring location is presented on Figure 2. r 9.4.2 Field Screening Results Continuous soil samples were collected and field screened for the presence of organic vapors using a PID equipped with a 10.2 eV lamp source. PID readings above background are as follows: Field Screening Results Date TimeSample Result '"` '�`�� "' Depth-= - "" (hours) (ppm) (feet) -- 7/15/02 1515 209HL-2 1 2 9.4.3 Laboratory Results No constituents were detected above the method detection limit for the soil samples submitted to the analytical laboratory for analysis of TPH DRO/ORO,VOCs including fuel oxygenates. Refer to Appendix D for a complete analytical report. Analytical results were compared to California regulatory criteria,where appropriate. No regulatory action levels currently exist for TPH concentrations in soils. Accordingly,to assess the potential impact 0042 gy store 209 phase 2 reviewedl SECOR International Incorporated 14