SITE INFORMATION AND CORRESPONDENCE

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San Joaquin County DIRECTOR PQuiN Donna Heran, REHS �O._ `.• .CD Environmental Health Department ASSISTANT DIRECTOR 600 East Main Street Laurie Cotulla, REHS U): Stockton , California 95202-3029 PROGRAM COORDINATORS Carl Borgman, REHS C �- P Mike Huggins, REHS, RDI q 6 F O R �� Website: www.S/govorg1ehd Margaret Lagorio, REHS Phone : (209) 468-3420 RobertMcClellon, REHS Fax: (209) 464-0138 Jeff Carruesco, REHS, RDI Kasey Foley, REHS March 18, 2008 Mr. David Atwater Van De Pol Enterprises, Incorporated 3147 South El Dorado Street Stockton, California 95201 Subject: Pacific Pride — South El Dorado Street 3147 South El Dorado Street Stockton, CA 95206 The San Joaquin County Environmental Health Department (EHD) has reviewed Site Conceptual Model (SCM) dated May 10, 2007, and analytical results for groundwater samples collected during the first three quarters of 2007, submitted by Advanced GeoEnvironmental, Inc. (AGE) on your behalf for the above-referenced site. Based on the results presented in the SCM, AGE has determined the following: • The vadose zone petroleum-hydrocarbon-impacted soil is defined laterally toward the north, northeast, south, southeast, and west of the former underground storage tank (UST) area. • The vadose zone petroleum-hydrocarbon-impacted soil is "generally" defined vertically at the site to approximately 45 feet below surface grade (bsg) . • Approximately 20,043 pounds of gasoline, or 3 ,206 gallons of gasoline remain at the site. • The dissolved petroleum hydrocarbon plume is defined laterally toward the north, northwest, west, southwest, and southeast. • The dissolved petroleum hydrocarbon plume is "marginally" defined toward the south(east) by monitoring well MW-9, and northeast by MW-10. • The dissolved petroleum hydrocarbon plume is "moderately" defined, noting that low concentrations of contaminants of concern (COC) have been detected in groundwater collected from cone penetration test (CPT) boring P-7 at 94 to 97 feet bsg, and monitoring wells MW-8 at 120 to 125 feet bsg, and MW- 1 OD at 120 to 125 feet bsg. The EHD concurs with the findings presented by AGE, and based on "non-detect' results for soil samples collected from monitoring wells MW- 1 at 55 and 60 feet bsg, MW-8 at 80, 90, 105, and 125 feet bsg, and MW-5 at 100 feet bsg, the EHD believes the vertical extent of contamination in soil is defined in the source area. Additional investigation is needed to define the dissolved petroleum-hydrocarbon plume south- southeast of the former USTs, near MW-9 in the shallow zone. Gasoline constituents continue to be detected intermittently in groundwater collected quarterly from MW-9 at depths as great as 100 feet bsg, and 1 ,2-dichloroethane ( 1 ,2-DCA) has been detected in groundwater collected from MW-10 at