ARCHIVED REPORTS_WELL ABANDONMENT, SOIL AND GROUNDWATER INVESTIGATION REPORT 2009

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Appendix B:Previous Environmental Activities 1 proceed with the destruction of MW-5 without additional sampling and analysis because continued access to the well for this purpose was denied by the property owner, and because the well was unaffected by crude oil from the former OVP or TAOC pipelines.13 SAIC ANNUAL 2009 GROUNDWATER MONITORING AND SAMPLING 14 Annual groundwater monitoring and sampling was performed on February 11, 2009. The oleophilic sock in well MW-1 was replaced because it exhibited separate-phase oil (SPO) staining. Staining was not observed on the oleophilic sock in MW-2, and therefore the sock did not require replacement. SPO has been observed in MW-1 and MW-2 since 1999, with a total of ' 0.5 gallon removed from these wells as of the 2009 sampling event. The groundwater sample from MW-3 had detections of TPHd and chrysene above ESLs or WQOs. A duplicate sample from MW-3 also reported concentrations of benzo(a)anthracene, chrysene, and pyrene above ESLs or WQOs. SAIC's annual 2009 groundwater monitoring and sampling report recommended the following: • Discontinue monitoring and oleophilic sock replacement in wells MW-1 and MW-2, which over 10 years have yielded only minor amounts of SPO in proportion to the cost of SPO recovery efforts. • Discontinue sampling of MW-3. This well is not a perimeter well, and provides no additional information regarding water quality. MW-3 has indicated no significant changes in petroleum-hydrocarbon concentrations since 2005. • Properly destroy wells MW-1 through MW-3. 1 SAIC 2009 RWQCB SPLIT GROUNDWATER SAMPLING EVENT Prior to issuing approval to destroy wells MW-1 through MW-3, the RWQCB requested an additional event where split samples would be collected and submitted to an independent ' laboratory. On July 15, 2009, SAIC and RWQCB staff collected split groundwater samples from MW-3. Concentrations of TPHd were reported at 63 µg/L and no compounds were reported above the respective screening levels in the SAIC sample. The RWQCB sample indicated a TPHd concentration of less than 100 µg/L, which was similar to SAIC's result. No COPCs were detected in the RWQCB sample. A copy of the laboratory analytical report for the sample submitted by SAIC is included in Appendix E.2. Nearby Properties Crop Production Services Inc. (CPS; formerly Western Farm Service) is located at the northwest 1 corner of the intersection of Highway 33 and Welty Road. CPS has stored and distributed bulk liquid and dry fertilizers on its facility since 1969. Records indicate this site contained USTs: a 10,000-gallon diesel UST, and 5,000- and 10,000-gallon gasoline USTs. The USTs were removed in 1987, and their approximate locations are shown on Figure 2 of the main report. 1 Wells were installed at the CPS facility to monitor concentrations s of agricultural chemicals in ' 13.RWQCB,2007. Review of Second Quarter 2007 Groundwater Monitoring and Sampling ing Report— S- Can Welty Road Property,Vernalis,San Joaquin County. August 16. 14.SAIC,2009. Annual 2009 Groundwater Monitoring and Sampling Report, US Can–Welty Road,35275 Welty Road, Vernalis, California. April. B-6 From Science to Solutions