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1.3 Current Investigation Objectives and Modifications <br /> The current investigation objectives described in this groundwater site assessment and <br /> monitoring well installation workplan are: <br /> 1. Assess the horizontal extent of petroleum hydrocarbon contaminated groundwater <br /> adjacent to the Parmar Texaco site. This effort will include installation of three deep <br /> soil borings (-60 feet bgs) converted to 2" diameter groundwater monitoring wells (PT- <br /> MW 10, 11 and 12) located offsite and semi-annual groundwater sampling and <br /> monitoring (Figure 20). <br /> 2. Advance three soil borings near the former UST pit(PT-SB 16-1 to 16-4) (Figure 23). <br /> Former proposed soil boring PT-SB 16-3 has been removed from the program. These <br /> three soil borings will be drilled and sampled to assess the vertical and horizontal extent <br /> of the petroleum hydrocarbon compounds in soil at the initial petroleum hydrocarbon <br /> release site and to collect confirmation soil samples to evaluate remedial effectiveness. <br /> These borings are shown on Figure 23. <br /> Two additional soil borings will be drilled: a single soil boring (PT-SB 16-5) will be <br /> drilled and sampled adjacent to the location of the former 550-gallon waste oil tank to <br /> complete an evaluation of the site in terms of the SWRCB Low Threat Closure Plan <br /> (LTCP) (Figure 23). Another soil boring (PT-SB 16-6) will be advanced midway <br /> between PT-MW6 and PT-SVE1 to assess soil conditions upgradient of PT-MW9. <br /> Soil samples collected from these borings at 5 and 10 feet bgs will also assist in <br /> evaluation of the site in terms of the SWRCB Low Threat Closure Plan (LTCP). These <br /> soil boring locations are shown on Figure 23. <br /> 3. A deep,Geoprobe soil boring will be advanced immediately adjacent to groundwater <br /> monitoring well PT-MW 12 on the City of Lodi Grape Bowl lands. This Geoprobe <br /> boring will allow the collection of a groundwater grab sample from the deep <br /> groundwater zone between 70 and 80 feet bgs. <br /> 4. Assess the site for potential vapor intrusion hazard by evaluating contaminant <br /> concentration and distribution in shallow soil samples and groundwater samples and <br /> compare results with the criteria for the Low Threat Closure Policy regarding vapor <br /> intrusion evaluation. Should soil gas samples be deemed necessary by RWQCB staff to <br /> evaluate further a modified workplan will be submitted for review and approval. <br /> 5. Update the existing Sensitive Receptor Survey that is over ten years old. <br /> 6. Prepare a report of findings for the soil boring, groundwater monitoring well and soil <br /> gas well installations. <br /> Parmar\Site Assessment workplan\02152018.wpd 9 <br />