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FOR NO FURTHER ACTION REQUESTS AT UNDIERGROUN
<br /> ND TANK SITES
<br /> Site Name and Location: Country Club Food and Fuel, 1856 Country Club Blvd., Stockton, San Joaquin County
<br /> (RB#391048)
<br /> Y 1. Distance to production wells for municipal, domestic, A sensitive receptor survey In 2000 identified no
<br /> agriculture, industry and other uses within 2000 feet of the site. municipal supply and no domestic/agricultural wells
<br /> within 2,000'of the site.
<br /> Ir 2. Site maps, to scale, of area impacted showing locations of Two 10,000-gallon gasoline and one 10,000-gallon diesel
<br /> any former and existing tank systems, excavation contours and USTs and associated piping were removed 3/99 from the
<br /> sample locations, boring and monitoring well elevation site. MTBE was also detected in soil confirmation
<br /> contours, gradients, and nearby surface waters, buildings, samples. 1,2-DCA and EDB were also detected in grab
<br /> streets, and subsurface utilities; groundwater samples from the tank pit
<br /> Y 3. Figures depicting lithology(cross section), treatment system Site lithology consists of clay,silt,and sand to 57, the
<br /> diagrams; total depth investigated.
<br /> Y 4. Stockpiled soil remaining on-site or off-site disposal(quantity); Approximately 370 yd of soil over-excavated during the
<br /> USTs removal was trans orted to BFI Livermore.
<br /> Y 5. Monitoring wells remaining on-site, fate; Five monitoring wells(MW-1 through MW-5) will be properly abandoned.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 7'to 13'bgs. Groundwater flow
<br /> elevations and depths to water,- direction, varied from north to northwest. Groundwater gradient varied
<br /> from 0.001 to 0.002 Wft.
<br /> 7. Tabulated results of all sampling Maximum stockpile soil concentrations on 3/99 were TPHd, 300 mg/kg;toluene,
<br /> and analyses: 0.073 mg/kg;ethylbenzene, 0.068 mg/kg;and xylenes, 0.29 mg/kg; while MTBE,
<br /> Y 0.54 mg/L was also detected in confirmation soil samples. In 7/00 and 5/05,soil
<br /> ❑ Detection limits for confirmation boring results were ND. In 3/99, grab groundwater concentrations were TPHg,
<br /> sampling 5,900 ug/L;benzene, 140 ug/L;toluene, 380 ug/L;ethylbenzene, 30 ug/L;xylenes,
<br /> 670 ug/L;MTBE, 40,000 ug/L; 1,2-DCA, 301 ug/L;and EDB, 6,701 ug/L. In 9/08,all
<br /> ❑Y Lead analyses groundwater monitoring results were ND.
<br /> 8. Concentration contours of contaminants found and those remaining in soil and The extent of the identified
<br /> groundwater, and both on-site and off-site: contamination is described in the
<br /> reports.
<br /> Lateral and Vertical extent of soil contamination
<br /> FY
<br /> Lateral and Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation An engineered remediation was not
<br /> system and the zone of capture attained for the soil and groundwater remediation required by the lead agency.
<br /> system;
<br /> 10.Reports/information ❑Y Unauthorized Release Form ❑Y QMRS 33 from 7/00 to 9/08
<br /> 0 Well and boring logs ❑Y PAR a FRP FY1 Other Soil Vapor Intrusion Rpt. (11/08), NFAR Rpt. (4/09)
<br /> Y 11.Best Available Technology(BAT)used or an explanation for not using USTs removal, over-excavation of
<br /> BAT; I contaminated soil, and natural attenuation.
<br /> 12. Reasons why background warms unattainable Minor residual soil contamination remains on-site.
<br /> �,
<br /> BAT,
<br /> Y 13.Mass balance calculation of substance treated The consultant estimated remaining soil contaminant mass as MTBE,
<br /> versus that remaining; 0.05 pounds.
<br /> 7714. Assumptions, parameters, calculations and Region 2 ESLs were not exceeded for vapor intrusion or residual soil
<br /> model used in risk assessments, and fate and contamination. The site is located in a mixed residential/commercial
<br /> transport modeling; area of Stockton.
<br /> Y 15. Rationale why conditions remaining at site will Soil contamination reportedly is limited in extent. Land use
<br /> not adversely impact water quality, health, or other (commercial)is not expected to change in the foreseeable future.
<br /> beneficial uses; and
<br /> By: JLB t} Comments: Two 10,000-gallon gasoline and one 10,000-gallon diesel USTs,associated piping,and 370 y of
<br /> soil were removed 3/99 from the subject site. MTBE was also detected in soil confirmation samples.
<br /> Date: 1,2-DCA and EDB were also detected in grab groundwater samples from the tank pit. Based upon
<br /> 6!4/2009 33 quarters of groundwater monitoring showing a stable plume with declining concentrations to ND, the
<br /> limited extent of contamination remaining in soil, no foreseeable changes in land use(commercial), and no
<br /> Region 2 ESLs exceeded for soil vapor or residual soil contamination, Regional Board staff concur with San
<br /> Joaquin Countv's Closure Recommendation.
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