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<br /> - ABLE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Shockley'Trucking,850 Milgeo Rd., Ripon, San Joaquin County(RB#390833)
<br /> Y 1 1. Distance to production wells for municipal, A 2011 sensitive receptor survey reported 5 domestic, 2 municipal and
<br /> one irrigation water supply wells within 2,000'of the Site. The nearest
<br /> domestic, agriculture, industry and other uses wells are 400'to the west-northwest(domestic)-and 1,300'to the east
<br /> within 2000 feet of the site. (municipal). The wells are not threatened by the release.
<br /> Y 2. Site maps, to scale, of area impacted showing locations of any former and I In 4194, one 10,000-gall6n and one 2,300-gallon
<br /> existing tank systems, excavation contours and sample locations, boring diesel, three 500-gallon gasoline, and one
<br /> and monitoring well elevation contours, gradients, and nearby surface 550-gallon waste oil USTs were removed.
<br /> waters, buildings, streets, and subsurface utilities;
<br /> Y 3. Figures depicting lithology(cross section), treatment Site lithology consists of clay, silt, and sand to 51', the total depth
<br /> system diagrams; investigated.
<br /> Y 4, Stockpiled soil remaining on-site or off-site disposal The excavated soil was reused as backfill in the excavation, and
<br /> (quantity); clean soil was used to cap the three separate excavations.
<br /> 7y 5. Monitoring wells Ten (10)monitoring wells(MW-1 through MW-4 and MW-6 through MW-11)and six(6)remediation
<br /> remaining on-site, fate; wells(OSP1A through OSP3A and OSP1B through OSP3B)will be properly destroyed prior to
<br /> closure. MW-5 was destro ed in 2008.
<br /> 6. Tabulated results of all groundwater Depth to,groundwater varied from 16'bgs to 31'bgs.'Groundwater flow
<br /> -elevations-and-depths lo-water,-- direction varied from northwest to southeast Groundwater gradient varied
<br /> from 0.0006 to O.O0�Uff
<br /> 7. Tabulated results of all sampling All data adequately tabularized in various reports.
<br /> and analyses:
<br /> Detection limits for confirmation
<br /> sampling
<br /> Lead analyses
<br /> 8. Concentration contours of contaminants found and those remaining in The extent of the identified contamination is
<br /> soil and groundwater, and both on-site and off-site: described in the available reports.
<br /> Y❑Lateral and M Vertical extent of soil contamination
<br /> Lateral and MVertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface Free product removal(FP), soil vapor
<br /> remediation system and the zone of capture attained for the soil and extraction(SVE), and ozone sparging(OS)
<br /> groundwater remediation system; were the engineered remediation.
<br /> 10.Reports/information E Unauthorized Release Form ❑Y QMRs (49)6-96 to 7-12
<br /> ❑y Well and boring logs �y PAR FRP ❑y Other Closure Report, 2-13
<br /> YJ 11.Best Available Technology(BAT) used or an explanation USTs removal, FP, OS, and natural attenuation.
<br /> for not using BAT;
<br /> Y12. Reasons why background wasrs Residual soil and groundwater contamination remains.
<br /> attainable using BAT;
<br /> - y "13,Mass'balance calculation-ofsubstance-"---FP.removed approximately_1,1,25-gal.-,TPH_from-groundwater.An SVE_pilot...
<br /> treated versus that remaining, study removed 2.3 gat of TPH from soil.Approximately 3,653 gal of TPN
<br /> remain in soil and 11.6 gal. of TPN remain in groundwater.
<br /> Y 14. Assumptions,parameters, calculations The regulatory agency did not require a soil vapor survey. A HHRA did
<br /> and model used in risk assessments, and fate not show a risk from soil. Soil passed the Region 2 ESLs above 15'bgs.
<br /> and transport modeling; Soil met SWRCB low risk closure policy for commercial use. Consultant
<br /> states TPH does not pose a significant risk.
<br /> _71 15. Rationale why conditions remaining at site Soil and groundwater contamination reportedly are limited in extent.Land
<br /> will not adversely impact water quality, health, use(commercial)is not expected to change in the foreseeable future.
<br /> or other beneficial uses;and Consultant estimated WQGs will be reached by 2023. Groundwater plume
<br /> is stable.
<br /> By: JLB �� Comments:In 4194, one 10,000-gallon and one 2,300-gallon diesel, three 500-gallon gasoline, and one
<br /> 550-gallon waste oil USTs were removed at the subject site. Residual soil and groundwater contamination
<br /> F,41
<br /> remains. Based upon the limited extent of contamination reported in soil and groundwater,a stable plume,
<br /> 33 no foreseeable changes in future land use(commercial), and minimal risks from groundwater and soil,
<br /> Regional Board staff concur with San Joaquin County's Closure Recommendation.
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