Laserfiche WebLink
Former Chevron Station #9-8632 - 4 - 19 March 2019 <br />575 W. Grant Line Rd <br />Tracy, San Joaquin County <br />General Criteria - This Site meets the eight General Criteria for closure as outlined in the <br />LTCP. The Site is located within the service area of the City of Tracy public water system. <br />Media Specific Criteria - This Site meets the three Media-Specific Criteria as outlined in the <br />following items 1 through 3 for case closure under the LTCP. <br />1. Groundwater — Chevron concludes and Water Board staff concurs that petroleum <br />hydrocarbon concentrations in groundwater are stable and declining in the monitoring <br />wells at the Site. The extent of petroleum hydrocarbons in groundwater is defined <br />laterally and vertically by downgradient on-site monitoring wells. The maximum extent of <br />hydrocarbon impact to groundwater is less than 100 feet from the source area (former <br />USTs). The Site's residual petroleum plume in groundwater is defined and meets all <br />three (a through c) conditions outlined in Groundwater-Specific Scenario 1 of the LTCP. <br />Petroleum Vapor Intrusion to Indoor Air — Site conditions meet the criteria outlined in <br />Petroleum Vapor Intrusion to Indoor Air Scenario 3A of the LTCP. <br />3. Direct Contact and Outdoor Air Exposure Criteria - No analyzed petroleum <br />constituents remain in shallow soil above the commercial/industrial land use screening <br />levels outlined in Table 1 of the LTCP. <br />CONCLUSIONS <br />A release of petroleum fuel occurred from the Site's USTs. Chevron conducted limited <br />excavation removing approximately 500 pounds of petroleum hydrocarbons. Site investigation <br />data indicate that remaining petroleum hydrocarbons in groundwater are defined, stable, and <br />expected to attenuate below established water quality objectives within a reasonable time <br />frame. Therefore, the remaining petroleum constituents are unlikely to pose a threat to human <br />health or further impacts to waters of the state as they attenuate. Consequently, they do not <br />justify the cost of any additional active remediation or monitoring, and Central Valley Water <br />Board staff concurs with GHD's recommendation for Site closure.