ARCHIVED REPORTS_VAPOR INTRUSION SURVEY - SOIL GAS SAMPLING REPORT

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Former Columbo/Toscana Bakery - 3 - 15 August 2008 ' 1444 S. Lincoln St., Stockton their LOC from the UST CUF Orphan Sites Cleanup Account, and also due to the enforcement schedule under Regional Board Cleanup and Abatement Order R5-2007- 0725, which requires implementation of their Final Remediation Plan by ' 1 February 2009. Please note that site inclusion in the CPA process and participation by all affected sites is voluntary on the part of the responsible parties, and that efforts to recruit applicants for the CPA should not adversely affect the cleanup progress of those ' sites involved in the CPA process. 3) The Report data and several years of quarterly monitoring show high groundwater ' concentrations in your source area. As such, Regional Board staff requires that Sara Lee move forward with the Feasibility Study/Remediation Evaluation (FS/RE), which was initially due 1 February 2008 and the deadline extended at Sara Lee's request to 1 June 2008. No additional extensions to the FS/RE will be granted. The FS/RE is now due 30 November 2008. 4) As an alternative to the FS/RE, Sara Lee may propose a focused remediation based on proven technologies that are being implemented at the Dolly Madison UST site located 75 feet south of your former USTs. A Dolly Madison Pilot Study (PS) for Soil Vapor ' Extraction and Air Sparging (SVE/AS) was very successful in 2008 in soils which do not differ significantly from your site, and a 2008 Feasibility Study (FS) chose SVE/AS as the most technically and economically feasible remediation for soil and groundwater. ' The consultant recently installed the remaining remediation wells in the source area and is working on the final remediation plan, due 1 November 2008. Electronic copies of the PS-SVE/AS and FS reports are available on Geotracker at htti)s:Hoeotracker.waterboards.ca.gov/profile report.asp?global id=T0607700204. If Sara Lee chooses to follow the Dolly Madison approach, then a response letter with a work plan for remediation wells and a new schedule for implementing remediation to ' address the source area at your site is due 30 September 2008. It is Regional Board staff's opinion that this focused approach for remediation in the source area utilizing a proven technology, while not the final remediation plan, will not delay the issuance of the LOC or significantly reduce State funds available, nor will there be a detrimental effect on the cleanup of the commingled plume(s). On the contrary, source removal has proven to be of benefit to many projects by removing soil contaminants that are leaching to groundwater. In turn, the soil remediation results in reduced mass loading ' of groundwater plume(s) that, if addressed later, could migrate farther downgradient and offsite, thus increasing the remediation costs. Air sparging volatilizes constituents into the gas phase in groundwater,,which are then captured by SVE. The operating SVE/AS system can be integrated later into a larger remediation plan. 5) The Report noted the distribution of petroleum hydrocarbons in soil and recommended ' conducting a soil gas survey to evaluate the risk of vapor intrusion to building occupants. A workplan for the soil gas survey and a schedule to implement the work is due 30 September 2008. An example of an approved soil gas survey workplan and a report are available electronically at the website listed in comment#4 above. 6) One stated purpose of the workplan that Regional Board staff approved for the fieldwork conducted for the Reportwas to provide data to focus the installation of