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Countryside Market, Stockton - 2 - 12 December 2023 2. Additional surrounding domestic wells DW10755, DW10757, DW10856, and DW10922 have not been sampled since 2012 or 2015. At those times, these wells were unimpacted by the Site release. In order to confirm that these wells remain unimpacted, the JET agreed that all four of these wells should be sampled the once more. 3. Based on the data in RMD's 20 October 2023 Quarterly Treatment System O&M Report (3Q23 O&M Report), soil vapor extraction (SVE) system mass removal rate during 3rd quarter 2023 was approximately 15 pounds of petroleum per day. During the meeting, RMD stated that they began work to optimize the SVE system by decreasing dilution and increasing extraction flow rate, and that the removal rate increased to approximately 35 pounds per day. The JET agreed that continued SVE system optimization efforts are needed to increase mass removal rate as much as possible. 4. Based on data in the 3Q23 O&M Report, air-sparge (AS) system flow rates during 3rd quarter 2023 averaged 2.1 standard cubic feet per minute (scfm) at an average pressure of 6.6 pounds per square inch (psi). The JET agreed that the AS system should be optimized to increase the sparge flow rate. Operation of the three AS wells upgradient of source area (AS-1 through AS-3) should be discontinued to allow for greater system sparge capacity in the remaining AS wells. 5. The JET agreed that you will continue quarterly operation and maintenance (O&M) of the SVE/AS remediation systems and submit quarterly reports by the first day of the second month following the end of each calendar quarter (i.e. 1 May, 1 August, 1 November, 1 February). Where semi-annual groundwater monitoring and quarterly O&M are performed in the same quarter, the associated reports may be combined. 6. Groundwater levels at the Site have dropped significantly since Site monitoring wells were installed. Other than well OBS-1, all Site monitoring wells have frequently been dry or contained insufficient water for sampling. MW-1 through MW-7 have contained sufficient water for sampling during only one or two semi- annual events since 2015. As such, the JET agreed that three additional deeper monitoring wells are needed in the vicinity of existing wells MW-1, MW-6, and MW-7. You will need to submit a work plan and assessment report for this work. 7. A 30-foot bio-attenuation zone exists beneath the Site. However, cumulative total petroleum hydrocarbons (TPH) concentrations in soil within the bio- attenuation zone exceed 100 milligrams per kilogram (mg/kg). The soil sample collected from 20 feet bgs in the OBS-1 borehole contained 140 mg/kg TPH as gasoline (TPHg). As such, Site conditions do not meet Low Threat UST Case Closure Policy (LTCP) Petroleum Vapor Intrusion to Indoor Air criteria for future development. Therefore, the JET agreed that three soil gas wells are needed to assess hydrocarbon concentration in soil gas beneath the Site to evaluate the