SITE INFORMATION AND CORRESPONDENCE

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Dolly Madison/Langendorf Fakery - 2 - 29 April 2011• 1426 S. Lincoln St. -J Stockton, San Joaquin County Between February 1997 and July 2008, nineteen groundwater monitoring wells (MW-1 through MW-19) were installed onsite. Groundwater monitoring continued until 14 October 2010, when maximum concentrations were TPHg, 840 ug/L, toluene, 4.8 ug/L; ethylbenzene, 7.9 ug/L and xylenes, 96 ug/L. The final MTBE, 90 ug/L and TBA, 130 ug/L are the result of the commingled sites (four adjacent USTs releases from 1444 S. Lincoln St and 440/441/508 W. Charter Way) plume diving and advancing below the Site plume. See Figure 2 for all sampling and monitoring well locations. Feasibility testing included soil vapor extraction (SVE) with air �;parging (AS). An SVE/AS treatment system with six SVE wells (VW-1 through VW-6) and 4 AS wells (AS-1 through AS-4) operated periodically from September 2009 through December 2010. Five soil gas monitoring wells (SGW-1 through SGW-5) were installed in December 2007. Risk Assessment A soil gas survey conducted in January 2008 passed the San Francisco Bay Regional Water Quality Control Board Environmental Screening Levels (ESLs) for commercial property, and a TIER 2 Human Health Risk Assessment determined that residual petroleum hydrocarbons in site soils and groundwater did not pose a threat to human health or the environment. Residual soil contamination failed the ESLs for gross contamination and direct exposure with TPHg (230 me/kg) and direct exposure with benzene (0.32 mg/kg), TPHg sampled at 10' bgs and benzene at 30' bgs, which is below typical construction worker exposure depth. However, soil contamination is no longer leaching into groundwater at a rate faster than natural attenuation can remove TPHg and MTBE. Residual petroleum hydrocarbons in site soils pose a minimal threat to human health or the environment. Land use (commercial) is not expected to change in the fcreseeable future. Sensitive Receptor Survey A 1997 and a 2000 sensitive receptor survey identified no supply wells located within 2000' of the site. No wells are threatened by the petroleum hydrocarbons release at this site. Site Geology and Hydrogeology Site lithology consists of clay, silt, sand, and gravel to 120' below ground surface (' bgs), the maximum extent of investigations. Between 1997 and 2010, depth to water varied from 17' bgs to 25' bgs. Groundwater flow direction varied from southeast to northeast, and the gradiem varied from 0.001 ft/ft/to 0.004 ft/ft. Residual Mass Calculation The corsultant estimates initial mass of TPHg in soil as 1,122 pounds. SVE/AS removed 1,086 Its of TPHg from soil. Groundwater will reach Water Quality Goals (WQGs) in 2011.