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TABLY1 - CHECKLIST OF REQUIRED DA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Former Mel Bokides Petroleum, 2191 Navy Drive, Stockton,San Joaquin County (Lustis#391045)
<br /> y 1. Distance to production wells for municipal, domestic, agriculture, A well survey in 2000 showed 4 wells;one
<br /> industry and other uses within 2000 feet of the site; crossgradient, 150 feet to the east;and three
<br /> downgradient, 1200 feet northeast, 1700 feet
<br /> northwest, and 1800 feet northwest.
<br /> YJ 2. Site maps, to scale, of area impacted showing locations of any former One 20,000-gallon and two 10,000-gallon diesel
<br /> and existing tank systems, excavation contours and sample locations, USTs, three 20,000 and one 10,000-gallon
<br /> boring and monitoring well elevation contours, gasoline USTs, and one 1,000-gallon waste oil
<br /> gradients, and nearby surface waters, buildings, streets, and UST were removed in 12/98.
<br /> subsurface utilities;
<br /> Y1 3. Figures depicting lithology(cross section), treatment system diagrams; Site lithology consists of clay,silt and
<br /> sand to 65 feet, the total depth
<br /> investigated.
<br /> Y 4. Stockpiled soil remaining on-site or off-site disposal(quantity); Approximately 1,368 tons of over-excavated soil was
<br /> removed from the tank pits down to 9 ft bgs and
<br /> disposed at Forward Landfill in Manteca. j
<br /> _� -- -- �' -5. Moniton..'ngweNsremaining on-site,.fate,-_iMile monitoring wells(MW:.1 through MW-9) remaining on-site will be
<br /> properly abandoned.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 6 to 13 feet below ground surface
<br /> elevations and depths to water; (bgs). 'The groundwater gradient varied from 0,003 to 0.01 ft/ft, and the
<br /> downgradient direction varied in:all directions due to adjacent river
<br /> surface water level influence.
<br /> 7. Tabulated results of all sampling and In 12/98, maximum soil concentrations were: TPHg, 710 mg/kg; TPHd,
<br /> analyses: 2,900 mglkg;benzene,0.32 mg/kg, toluene; 1.3 mg/kg, ethylbenzene;0.58 mg/kg,
<br /> Y xylenes; 1.1 mg/kg, ETBE, 0.15 mg/kg; TBA 0.21 mg/kg and MtBE, 1.2 mg/kg. In
<br /> Detection limits for confirmation 7/00, maximum soil boring concentrations.were: TPHd, 1.2 mg/kg; TBA,
<br /> sampling 0.078 mg/kg, and MtBE, 0.17 mg/kg. Maximum grab groundwater concentrations
<br /> in 12/98 were: TPHg, 77,000Erg/L; TPHd, 70,000,ug/L;benzene, 7,890,rg/L toluene,
<br /> 0 Lead analyses 6,000 pg/L;ethylbenzene, 2,900,ug/L;xylenes, 17,000 Erg/L;ETBE, 180 pg/L,and
<br /> MtBF, 2,100 pg/L. In 6/05, maximum groundwater concentrations were: TPHg,
<br /> 120 /L;and MtBE, 130 /L MW-6).
<br /> 8. Concentration contours of contaminants found and those remaining in soil and The extent of contamination is
<br /> ndwater, and both on-snd off-site: adequately defined by soil borings
<br /> Y Lateral and 1Y I Vertical extent of soil contamination and monitoring wells.
<br /> ©Lateral and ©Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation Remove USTs, overexcavation,
<br /> system and the zone of capture attained for the soil and groundwater remediation and natural attenuation.
<br /> system;
<br /> 10.Reports/information ❑Y Unauthorized Release Form ❑Y QMRs(11 from 2000—2005)
<br /> ""Well and_boring-logs.:, PAR. FNJ.-FRP__ F_Y�_ Other,Closure-Summary_Reports_.
<br /> Y 11.Best Available Technology(BAT) used or an explanation fornot using BAT* Removal of USTs and natural attenuation.
<br /> Y1 12.Reasons why background wasfis unattainable using BAT Limited soil contamination and groundwater pollution
<br /> remains on-site.
<br /> Y1 13.Mass balance calculation of substance treated versus that An engineered remediation was not required. Residual
<br /> contamination was estimated at 2.3 gallons of TPHg in
<br /> remaining; soil and 0.3 lbs of MtBE in-groundwater.
<br /> 7Y 14. Assumptions,parameters, calculations and model used in TPHg and MWE exceeded Water Quality Goals(WQGs).
<br /> risk assessments, and fate and transport modeling; 1
<br /> Y 15. Rationale why conditions remaining at site will not adversely Soil contamination is limited in extent. Results of 11
<br /> impact water quality, health, or other beneficial uses;and quarters of groundwater monitoring show a decreasing
<br /> trend in concentrations."WQGs may be reached in 151
<br /> years,although water quality near ship channel is poor
<br /> due to salinity, -
<br /> By: JLB Comments: One 20,000-gallon and two 10,000-gallon diesel USTs, three 20,000 and one 10,000-gallon gasoline
<br /> USTs, and one 1,000-gallon waste oil UST were removed in 12/98 from subject site. Site is a large fenced
<br /> Date: 3/27106 petroleum transfer facility at Port of Stockton surrounded by auto recyclers and a railroad, so threats from vapor
<br /> intrusion are minimal. Based upon 11 quarters of declining groundwater concentrations, and the limited extent of
<br /> contamination Dresent in soil. Regional Board staff concur with San Joaguin County's Closure Recommendation.
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