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<br />'YABLE 1'- CHECKLIST OF REQUIRED DATA U
<br />FOR. i NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br />Site Name and Location:
<br />Earthgrains Baking Companies, Inc., 2651 S. Airport Way, Stockton, San Joaquin County
<br />(RB #390065) _
<br />Y
<br />1. Distance to production wells for municipal, domestic, -
<br />A 2008 sensitive receptor survey reported two domestic
<br />agriculture, industry and other uses within 2000 feet of the site.
<br />wells (200'south and 600, south) and one irrigation well
<br />(370'south) within 2,000' of the site. The wells are not
<br />Y
<br />2. Site maps, to scale, of area impacted showing locations of
<br />threatened by the USTs release.
<br />In 4-87, two 6,000 -gallon gasoline USTs were removed. In
<br />any fanner and existing tank systems, excavation contours and
<br />9-89, two 12,000 -gallon diesel USTs and associated
<br />sample locations, boring and monitoring well elevation
<br />piping and dispensers were removed. In 2-96, one 1,000.
<br />contours, gradients, and nearby surface waters, buildings,
<br />gallon diesel UST was removed.
<br />streets, and subsurface utilities,
<br />Y
<br />3. Figures depicting lithology (cross section), treatment system
<br />Site lithology consists of clay, silt, sand, and gravel to
<br />diagrams; -
<br />104', the total depth investigated.
<br />Y
<br />4. Stockpiled soil remaining on-site or off-site disposal (quantity);
<br />The location of the 450 y excavated soil disposed
<br />offsite was not discussed in the available reports.
<br />Y
<br />5. Monitoring wells remaining on-site, fate;
<br />Thirteen (13) monitoring wells (MW -1 through MW -13) two piezometers (PZ -1
<br />and PZ -2) and eight remediation wells (SP -1 through SP -6, SP -A, and VW -1)
<br />:will be properly destroyed.
<br />6. Tabulated results of all groundwater,
<br />Depth to groundwater varied from 36' bgs to 56' bgs. Groundwater flow
<br />elevations and depths to water,
<br />direction was predominantly towards the east. Groundwater gradient
<br />varied from 0.001 Wft to 0.003 ft/ft.
<br />7. Tabulated results of all sampling
<br />All data adequately tabularized in various reports, including closure report.
<br />and analyses:
<br />Y❑ Detection limits for confirmation
<br />sampling
<br />QN Lead analyses
<br />_
<br />onc
<br />B,Centration�contours of contaminants found and those remaining in soil and
<br />The extent of the identified
<br />groundwater, and both
<br />--contaminationa esscritie—U-0 e- -
<br />Y] Lateral and l Vertical extent of soil contamination
<br />available reports.
<br />FT Lateral and Vertical extent of groundwater contamination.
<br />9. Zone of influence calculated and assumptions used for subsurface remediation
<br />SVE/AS was the engineered remediation.
<br />system and the zone of capture attained for the soil and groundwater remediation
<br />system;
<br />10. Reports/ information FY -1 Unauthorised Release Form FE QMRs (56) 8-93 to 4-10
<br />❑Y Well and boring logs. PAR FRP FY Other. Closure Reports (11-09 8 6-11))
<br />Y
<br />11. Best Available Technology (BAT) used or an explanation for not using
<br />USTs removal, over -excavation, SVE(AS and
<br />I
<br />BAT;
<br />natural attenuation.
<br />I,
<br />12. Reasons why background washs unattainable
<br />Residual soil and groundwater contamination remains on-site.
<br />BAT,'
<br />Y
<br />13. Mass balance calculation of substance treated
<br />Consultant estimated residual soil mass as 8,580 lbs of TPHg; and
<br />versus that remaining; _
<br />1096 lbs TPHg remained in groundwater.
<br />7Y
<br />14. Assumptions, parameters, calculations and
<br />Soil concentrations did exceed Region 2 Environmental Screening
<br />model used in risk assessments, and fate and
<br />Levels (ESLs) for commercial use at depths of 15' bgs or more, below
<br />transport modeling; -
<br />typical direct contact depth. A soil vapor survey was not required.
<br />`
<br />Fate and transport modeling shows no impacts to nearby sensitive
<br />-
<br />receptors. Consultant states site does not re resent a significant risk.
<br />Y
<br />15. Rationale why conditions remaining at site. will
<br />Soil and groundwater contamination reportedly are limited in extent.
<br />not adversely impact water quality, health, or other
<br />Land use (commercial) is not expected to change in the foreseeable
<br />beneficial uses; and
<br />future. TPH is estimated to reach WQGs in 2043.
<br />By:
<br />JLB
<br />Comments In 4-87, two 6,000 -gallon gasoline USTs were removed; in 9-89, two 12,000 -gallon diesel USTs and
<br />associated piping and dispensers were removed; in 2-96;.one 1,000 -gallon diesel UST was removed.at the
<br />Date:
<br />-subject site.: Minor residual soil and groundwater contamination remains on-site. Based upon the limited
<br />12/19nj/2011
<br />extent of contamination reported in soil and groundwater, a stable groundwater plume with declining
<br />concentrations, no foreseeable changes in future land use (commercial), and minimal risks from soil, soil
<br />va or and aroundwater, Regional Board staff concur with San Joa uin CountClosure Recommendation.
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