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<br /> 71
<br /> "BLE 1 -CHECKLIST OF REQUIRED DATA�.d
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUNDTANK SITES
<br /> Site Name and Location: Central California Traction Company, 1645 Cherokee Road(AKA Lane), Stockton,
<br /> San Joaquin County(RB#390790)
<br /> Y 1. Distance to production wells for municipal,domestic, A July 2010 sensitive receptor survey Ident/fled five
<br /> agriculture, industry and other uses within 2000 feet of the site. water supply wells between 1,000'and 2,000'of the Site.
<br /> 2. Site maps, to scale, of area impacted showing locations of any in January 1999, one 6,000-gallon gasoline and one
<br /> former and existing tank systems, excavation contours and 1,000-gallon diesel USTs were removed.
<br /> sample locations, boring and monitoring well elevation contours,
<br /> gradients, and nearby surface waters, buildings, streets, and
<br /> subsurface utilities;
<br /> Y 3. Figures depicting lithology(cross section), treatment system Site lithology consists of clay,silt, sand, and gravel to
<br /> diagrams; 85', the total depth Investigated.
<br /> y 4. Stockpiled soil remaining on-site or off-site disposal(quantity); Approximately 10,404 tons of over-excavated soil was
<br /> transported to Forward Landflll In Manteca.
<br /> 5. Monitoring wells remaining on-sife, fate Three monitoring wells(MW-5 through MW-7)will be properly abandoned.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 43'to 55'bgs. Groundwater flow
<br /> elevations and depths to water,• direction varied from northwest to east. Groundwater gradient varied
<br /> from 0.001 to 0.007 Aft
<br /> ---- abulawedr la -
<br /> and analyses:
<br /> Detection limits for confirmation
<br /> sampling
<br /> QN Lead analyses
<br /> LyJ 8. Concentration contours of contaminants found and those remaining in soil and The extent of the Identifled
<br /> groundwater,and both on-site and off-site: contamination shown In applicable
<br /> reports.
<br /> 0 Lateral and ©Vertical extent of soil contamination
<br /> Lateral and M Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation Soil over-excavation was the approved
<br /> system and the zone of capture attained for the soil and groundwater remediation engineered remediation.
<br /> system"
<br /> 10.Reports/information Y Unauthorized Release Form Y QMRs 11 from 9/00 to 7/10
<br /> PAR �y FRP ❑y Other closure report(11-10)
<br /> Qy Well and boring logs E
<br /> Y 11.Best Available Technology(BAT)used or an explanation for not USTs removal, over-excavation,soil vapor extraction,
<br /> using BAT,• dual phase extraction, and natural attenuation.
<br /> 12. Reasons why background was/is Minor residual soil and groundwater contamination remains on-site.
<br /> y ttainab/e using BAT,•
<br /> 13.Mass balance calculation of substance treated Over-excavation removed approximately 14,797 lbs of TPHd from soil.
<br /> 13 Ms Ihat lanceMmaical; Approximately 1.45 lbs of TPH-d remain In soil and 0.57 gals of TPHd
<br /> _ __Y ___ rofiialninWtundwater. --
<br /> Y 14. Assumptions,parameters, calculations and TPHd will reach WQGs in 1 year. A J&E model predicts soil vapor will
<br /> model used in risk assessments, and fate and not pose a risk from vapor Intrusion.A R/SC4 risk assessment
<br /> transport modeling; modeling of sol/did not exceed 1X10E6 for cancer risk or 1 for non-
<br /> cancer risk for gross contamination or direct exposure.
<br /> 15. Rationale why conditions remaining at site Soil and groundwater contamination reportedly Is limited in extent and
<br /> will not adversely impact water quality, health, or present below 65'bgs.Land use(commercial)Is not expected to
<br /> other beneficial uses,and change In the fnreseeab/e future. Vapor Intrusion risk has been
<br /> addressed. Water quality goals will be reached In approximately 1 year.
<br /> By: JL5 Comments:In January 1999,one 6,000-gallon gasoline and one 1,000-gallon diesel USTs were removed from
<br /> the subject Site.Based upon 11 quarters of groundwater monitoring showing a stable plume with declining
<br /> E11/t2
<br /> concentrations, WQGs reached In approximately 1 year, the limited extent of contamination remaining in soil
<br /> /2010 and groundwater,no foreseeable changes in land use, and limited threats from groundwater, soil, and soil
<br /> gas,Regional Board staff concur with San Joaquin County's Closure Recommendation.
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