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1 - CHECKLIST OF REQUIRED!TAB
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Jackpot Food Mart, 94000 E. Hwy 88; San Joaquin County (Lustis#390693)
<br /> Y 1. Distance to production wells for municipal, domestic, agriculture, industry A well survey in 2005 showed one irrigation
<br /> and other uses within 2000 feet of the site; well 1,900 feet south (downgradient) of the
<br /> site and two municipal wells(900 ft
<br /> r' northeast, upgradient 8 1,500 ft southwest,
<br /> downgradient) of the site.
<br /> Y 2. Site maps, to scale, of area impacted showing locations of any former and existing tank systems, One 6,000-gallon UST;
<br /> excavation contours and sample locations, boring and monitoring wei!elevation contours, one 8,000-gallon UST;
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities; and one 12,000-gallon
<br /> `I UST removed in 9191.
<br /> y: Site lithology consists of clay,silt and
<br /> Y 3. Figures depicting lithology(cross section), treatment system diagrams; sand to 100 feet, the Iotal depth
<br /> invest! ated.
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); Excavated soil(150 yd) used to backfill tank pit.
<br /> :YD 5. Monitoring wells remaining on-site, fate; Ten monitoring wells remaining:on-site will be properly abandoned.
<br /> - fi- Tabulated results of all groundwater elevations and depths to water, Depth.to groundwater,varied from 65 to 85 feet
<br /> below ground surface(bgs). The groundwater
<br /> gradient was 0.03ft/ft..varying from south to
<br /> Depth
<br /> 7. Tabulated results W all sampling and analyses: In 9191,maximum soil concentrations were: TPHg;8,900 mg/kg,
<br /> benzene;8.9 mg/kg, toluene;270 mg/kg, ethylbenzene; 100 mg/kg,
<br /> Detection limits,for confirmation sampling xylenes; 730 mg/kg. in 11104, maximum soil concentrations were:
<br /> FY—]Lead analyses;, TPHg, 1,300 mg/kg;and Xylenes,4.6 mg/kg. Maximum groundwater
<br /> concentrations in 4/98(besides free product in 2100) were; TPHg,
<br /> 60,400,ug/L, benzene, 2,200 pg& toluene,:12,500,ug/L;ethylbenzene,
<br /> 2,200 lig/L;xylenes, 10,300,ug/L, and MTBE in 8198, 41.2 irg/L. In 8105,
<br /> maximum groundwater concentrations were: TPHg, 1201rg/L;
<br /> benzene, 2.5 ug/L;eth lbenzene, 1.3 ug/L;and xylenes, 1.3 u /L.
<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: " defined by soil borings and
<br /> i monitoring wells.
<br /> Y❑ Lateral and Vertical extent of soil contamination
<br /> © Lateral and © Vertical extent of groundwater contamination
<br /> .Zone of influence calculated and assumptions used for subsurface remediation system Remove USTs and free product,
<br /> and the zone of capture attained for the soil and groundwater remediation system; overexcavation, SVE/AS, and
<br /> natural attenuation.
<br /> f' 10.Reports 1 information Unauthorized.Rolease Fora ❑Y QMRs(40 from 1994—2005)
<br /> ' ❑Y 'We11 br7d bo
<br /> ririg logs 0`'PAR FkP Other;Closure SummaryRepdrf
<br />?
<br /> Yj 11.Best Available Technology(BAT) used or an explanation for not using BAT; Removal of LISTS, free product removal,
<br /> air sparging,soil vapor extraction and
<br /> natural attenuation.
<br /> Y 12.Reasons why background wasrs unattainable using BAT Limited, minimal soil and groundwater contamination
<br /> remain on-site.
<br /> Y1 13.Mass balance calculation of substance treated versus that remaining; Approximately 38,894.2 lbs TPHg removed.
<br /> 35.14 lbs of TPHg remains in groundwater. An
<br /> estimated 937.7 lbs of TPHg remains in the soil.
<br /> Y 14. Assumptions, parameters, calculations and model used in TPHg exceeds ESLs(Tier 1) for soil. Current residual
<br /> risk assessments, and fate and transport modeling; concentrations are below Tier 2 Site-specific target
<br /> levels. Water Quality Goals may be reached in 5 years.
<br /> Y 15. Rationale why conditions remaining at site will not adversely Soil contamination is limited in extent. Results of 40
<br /> impact water quality, health, or other beneficial uses,and quarters of groundwater monitoring show a decreasing
<br /> trend in concentrations.
<br /> By: JLB/BK Comments: Three gasoline USTs(One 6,000-gallon;one 8,000-gallon;and one 12,000-gallon) removed in 1991.
<br /> Free product removal, soil vapor extraction, air sparging and natural attenuation were`the active remedial actions.
<br /> Date: 317106 Based upon 40 quarters of declining concentrations, and the limited:
<br /> extent of contamination present in soil and
<br /> groundwater, Regional Board staff concur with San Joaquin County's Closure Recommendation.
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