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TAaxeE 1 - CHECKLIST OF REQUIRED woATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: I Jimco Truck Plaza, 1022 Frontage rd., Ripon, San Joaquin County (Case#390718)
<br /> y 1. Distance to production wells for municipal, domestic, agriculture, A 2003 sensitive receptor survey identified
<br /> industry and other uses within 2000 feet of the site. three domestic and one municipal supply
<br /> wells within 2,000'of the Site. The nearest
<br /> (Site Truck Wash) well is within the USTs
<br /> plume(non-detect). None of the wells are
<br /> threatened by the release.
<br /> Y Site maps, to scale, of area impacted showing locations of any former One 7,500-gallon gasoline, one 10,000-gallon
<br /> and existing tank systems, excavation contours and sample locations, gasoline, and one 12,000-gallon diesel USTs
<br /> boring and monitoring well elevation contours, gradients, and nearby were removed 9/98. A waste oil UST was
<br /> surface waters, buildings, streets, and subsurface utilities; removed 5/04.
<br /> Site lithology consists of clay, silt,and sand
<br /> Y 3. Figures depicting lithology(cross section), treatment system diagrams; S 104 feet, the total depth investigated.
<br /> Approximately 1,180 tons of soil was transported to
<br /> Y 4. Stockpiled soil remaining on-site or off site disposal(quantity). Forward Landfill in Manteca.
<br /> :Y] 5. Monitoring wells remaining on-site, fate; Twenty monitoring wells(MW-1 through MW-20)and two remediation
<br /> wells EW-1 and AS-1 were properly abandoned 7/27112.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 15 to 27 feet below ground surface
<br /> elevations and depths to water, (bgs). The groundwater gradient varied from 0.0001 to 0.001 ft/ft. The
<br /> downgradient direction varied in all directions, and most recently to the
<br /> southeast.
<br /> 7. Tabulated results of all sampling and All data adequately tabularized in various reports.
<br /> analyses:
<br /> Detection limits for confirmation sampling
<br /> 0 Lead analyses
<br /> 8. Concentration contours of contaminants found and those remaining in soil and The extent of contamination is
<br /> groundwater, and both on-site and off-site: adequately defined by soil borings
<br /> and monitoring wells.
<br /> Lateral and ❑Y Vertical extent of soil contamination
<br /> © Lateral and © Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation system Approved active remediation was
<br /> and the zone of capture attained for the soil and groundwater remediation system; soil over-excavation.
<br /> 10.Reports/information EY Unauthorized Release Form QY QMRs 38, from 8/99 to 8/11)
<br /> F7 Well and boring logs Ey PAR FRP Other, Closure Report 12/11
<br /> _YJ 11.Best Available Technology(BAT)used or an explanation for not using BAT USTs removal, over-excavation, and
<br /> natural attenuation.
<br /> Y 12.Reasons why background wasps unattainable using BAT; Residual soil and groundwater contamination remain.
<br /> Y] 13.Mass balance calculation of substance treated versus Consultant estimates 34,463.5 lbs. of TPH remains onsite in
<br /> that remaining; soil, and<1 gallon TPH remains in groundwater.
<br /> N 14. Assumptions, parameters, calculations and model used in A risk assessment was not required as soil
<br /> risk assessments, and fate and transport modeling; contamination is not leaching sufficiently to threaten
<br /> the Site truck wash well, over-excavation(16'bgs)limits
<br /> threats from direct contact, and the Site is over 100'
<br /> from the buildings (except open bay truck wash).
<br /> _71 15. Rationale why conditions remaining at site will not adversely Soil and groundwater contamination are limited in
<br /> impact water quality, health, or other beneficial uses;and extent. WQGs will be met by 2023.
<br /> By: JLB Comments: One 7,500-gallon gasoline, one 10,000-gallon gasoline, and one 12,000-gallon diesel USTs were
<br /> removed 9198, and a waste oil UST was removed 5/04.at the subject site. Based upon evidence of a stable
<br /> Date: plume with declining concentrations,no threat to supply wells, limited risk of vapor intrusion or direct
<br /> 9/5/2012 contact exposure, and limited extent of contamination present in soil and groundwater, Regional Board staff
<br /> recommends closure for the site.
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