Laserfiche WebLink
' Sulfolane Remedial <br /> Investigation Work Plan <br /> ARCADIS Former Occidental Chemical Corporation <br /> Lathrop, California <br /> 1. Introduction <br /> ' On behalf of Glenn Springs Holdings, Inc., (GSHI),ARCADIS U.S., Inc.(ARCADIS) <br /> has prepared this Sutfolane Remedial Investigation Work Plan(Work Plan)for the <br /> ' former Occidental Chemical Corporation(OCC)manufacturing facility(Site).The Site <br /> is located at 16777 South Howland Road near the southwest comer of Louise Avenue <br /> and South Howland Road in Lathrop,San Joaquin County, California(Figures 1 <br /> ' and 2). <br /> 1.1 Background <br /> OCC operated an agricultural chemical production facility at the Site from 1964 to <br /> 1975.After production was discontinued,the presence of soil fumigant pesticides <br /> (1,2-dibromo-3-chloropropane[DBCP]and ethylene dibromide[EDB])were identified <br /> as the primary chemicals of concern(COCs)following investigations under the <br /> oversight of the California Regional Water Quality Control Board—Central Valley <br />' Region(RWQCB). Later tetrahydrothiophene(sulfolane)was also identified as a COC. <br /> In 1982, OCC implemented a Groundwater Remedial Program(Remedial Program) <br />' that included the extraction and treatment of affected groundwater and the injection of <br /> treated groundwater. The Remedial Program is operated pursuant to the requirements <br /> of the Stipulation and Judgment Approving Settlement in U.S. et al.vs. Occidental <br /> Petroleum Corporation et al., CIVS-79-989 MLS. OCC has assigned GSHI the <br /> responsibility of managing the Remedial Program at the facility.The Site is currently <br /> owned and operated by J.R. Simplot Co.(Simplot). <br />' In 2006, the RWQCB noted that high sulfolane and fumigant concentrations in <br /> groundwater monitoring well PW18 suggested that a potential residual source area <br />' existed in soil in the vicinity of this well and requested a soil investigation(RWQCB - <br /> 2006).A work plan to investigate vadose zone soil in the vicinity of PW181WS-1 was <br /> submitted on March 29,2007 and approved by the RWQCB on May 16,2008. <br />' Soil samples were collected between June 2008 and September 2008 to determine the <br /> impact in the soil located south of PW18. In total, 107 soil samples were collected from <br /> 31 soil boring locations(CRA 2008). In October 2008,two new extraction wells <br />' (EW-08A and EW-08B)were installed in the vicinity of PW 18 to increase the mass <br /> removal rate in groundwater in this area(CRA 2008). Soil boring and groundwater <br /> extraction well locations are shown on Figure 3 and copies of the analytical data tables <br />' from the investigation are included in Appendix A. <br /> b'"W H-0A Vft%g lt.d= 1 <br />