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SOIL VAPOR EXTRACTION PILOT STUDY REPORT San Joaquin County Montgomery Ward Auto Service Center Public Health Services Department 5400 Pacffic Avenue Stockton CA Site Code 2163 ' collected for laboratory analysis The Photo-iomzation Detector (PID) reading and laboratory analysis will serve as the baseline soil vapor concentrations Thereafter, ' PID readings were recorded at the adjacent wells and probes at approximately 30- minute intervals until two consecutive readings showed that steady state conditions had been reached At that time (at 1700 hrs), a second soil vapor sample (VEW-1AO1700) was collected for laboratory analysis Vacuum and vapor concentration measurements were also recorded at each soil probe and at the other extraction well (VEW-1B) ■ The second test scenario was identical to the first test except VEW-1B was used as the extraction well ■ The third test scenario involved both extraction wells VEW-1A and VEW-1B were ' both connected to the vapor extraction system The parameters specified earlier were recorded in 30 minutes intervals until steady state was reached for both wells together The field measurement are included in Appendix K and the laboratory analyses of vapor concentrations are included in Appendix L 7.3 Air Sparging Pilot Field Tests, To test effectiveness of air sparging, EAI conducted an air sparging test using the following criteria ■ Extraction using both VEW-1A and VEW-1B (lower screened interval was blocked off using a packer during this test), ■ Injection through VEW-1B using the injection system (through lower screened interval), ■ Injection pressure of 30 psi, and ■ Injection rate of 5 cfm During the air sparging test, EAI field personnel recorded the following parameters ■ Vacuum at all soil probes, ■ Concentration (using PID) of vapors at all soil probes and wells, N Concentration (by laboratory analysis) of vapors at VEW-1A & VEW-1B, ■ Dissolved oxygen in adjacent wells using field instrument, I ■ Dissolved oxygen in adjacent wells using laboratory analysis, ■ Biological parameters in adjacent wells using laboratory analysis, and 0 Vapor concentration, flow rates and oxygen at inlet to VES unit The field measurement are included in Appendix K and the laboratory analyses of vapor concentrations are included in Appendix L 1 7.4 LaboratoEy Analyses Of Vapor Sam les 1 The: vapor samples collected from the wells and the soil vapor probes were sent to a certified laboratory for analysis by EPA Method TO-14 Results reported by this analysis includes TPH-G and BTEX and are summarized in Table I I for soil vapor probes and in Table 12 for VES wells Laboratory Reports are included in Appendix L Project No 1232 - 9 - ENVIRONMENTAL AUDIT, INC