SITE INFORMATION AND CORRESPONDENCE

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-'\BLE 1 -CHECKLIST OF REQUIRED DATA 1 FOR NO FURR ACTION REQUESTS AT UNDERGROUNINK SITES Site Name and location: Former Continental Grain Company, 1805 Harbor St., Stockton, San Joaquin County(Case 390229) UDistance to production wells for municipal, domestic, A 2000 well survey, including a field reconnaissance, ulfure, industry and other uses within•2000 feet of the site. u onrsaml!ngweldata, no!mately wells are threatened due to1, feet to thetased h.this case. Y 2. Site maps, to scale, of area impacted showing locations Contained in several reports on file. of any former and existing tank systems, excavation . contours and sample locations, boring and monitoring well elevation contours, gradients, and nearby surface waters, buildings, streets, and subsurface utilities; Site lithology consists of sand,silt, and clay to total depth of Y 3. Figures depicting lifhology(cross section), treatment 90 feet. system diagrams; Approximately 1,308 tons of contaminated soil N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); excavated during corrective action was transported to Forward Landfill, Manteca. Y 5. Monitoring wells remaining on-site, fate; A reported 11 monitoring wells installed over time. All monitoring wells will be properly abandoned prior to formal closure per County. Depth to groundwater varied from-4 feet to--13 feet below ground YR_ ,6_�Tabulated results of all groundwater ,_._„ _ surface-fts). The groundwater gradientvaried"from-0.003to 0.019 ft/h. elevations and depths to water, . The downgradient groundwater flow direction varied from northeast to southwest. 7. Tabulated results of all sampling All data adequately tabularized in various reports, including closure report. and analyses: FYIDetection limits for confirmation sampling �Y Lead analyses 8. Concentration contours of contaminants found and those remaining in soil.and The extent of the identified groundwater, and both on-site and off-site: contamination shown in applicable reports. 0 Lateral and Y❑Vertical extent of soil contamination FY Lateral and Vertical extent of roundwater contamination 9. Zone of influence calculated and assumptions used for subsurface remediation Over-excavation was the system and the zone of capture attained for the soil and groundwater remediation engineered remediation. system; 10.Reports l information FYI Unauthorized Release Fomn QMRs(from-1998 to 2008) 0 Well and boring logs ❑Y PAR FRP 10 FY Other, Closure Summary Report,2009 Y 11.Best Available Technology(BAT)used or an explanation for not using BAT, Removal of USTs, over-excavation and -natural-atte[ruation.___ ------ - �__ Y 12. Reasons why background wasfis unattainable using BAT; Limited soil and groundwater contamination remain on- site. 7Y 13.Mass balance calculation of substance treated versus that The consultant estimates TPHd in soil as 11,301 pounds prior to remediation;after remediation 0.873 lbs of TPHd remaining; remains in groundwater and 2482 lbs. remains in soil Y 14. Assumptions, parameters, calculations and model used in Due to the distance to the nearest buildings(+200')and risk assessments, and fate and transport modeling; the business(grain elevators), a vapor intrusion survey was not required. Soil was over-excavated to 28'b s. Y 15. Rationale why conditions remaining at site will not adversely Groundwater concentrations continue to decline with impact water quality, health, or other beneficial uses;and many wells already at non-detect. Site no longer poses a threat. Py: JL Comments:Site is located adjacent to a USEPA Superfund Site(McCormick-Baxter), and property use(Port of Stockton grain elevator)is not expected to change from commercial. Due to remedial efforts in the source Date: area, confirmation sampling has shown that this site no longer poses a threat to human health and safety or to 10/22/09 water quality. Regional Board staff concurs with San Joaquin County's recommendation for issuance of a No Further Action letter. i