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TABLI�1 - CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Tracy Cold Storage,24500 South Mac Arthur Drive,Tracy, San Joaquin County
<br /> 0 1. Distance to production wells for municipal, domestic, agriculture, Two water supply wells located on-site. The older
<br /> industry and other uses within 2000 feet of the site; well, designated as the South Well,is located within
<br /> the area of soil contamination.
<br /> ED2. Site maps, to scale, of area impacted showing locations of former and existing tank systems,
<br /> excavation contours and sample locations, boring and monitoring well elevation contours,
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities;
<br /> YF 3. Figures depicting lithology(cross section), treatment system diagrams; Boring logs show predominantly silty clay soils.
<br /> A treatment system was not installed.
<br /> y� 4. Stockpiled soil remaining on-site or off-site disposal(quantity); 1,522 cubic yards of soil was excavated in 7/98, then
<br /> aerated and spread out on-site.
<br /> 5. Monitoring wells remaining on-site, fate; Ten monitoring wells were installed on-site. Five monitoring wells have been
<br /> destroyed due to excavation activities,and the remaining monitoring wells
<br /> will be destroyed pending site closure.
<br /> 6. Tabulated results of all groundwater elevations and depths to water, Depth to water varies from 8 to 12 feet bgs,and
<br /> • flow is to the northwest
<br /> 7.Tabulated results of sampling and analyses: June 1999 monitoring results for MW-1A (former tank area)in pg/1 show
<br /> TPHg at 3,800,BTEX at 150, 5.3, 22,and 18, respectively. MtBE,
<br /> ©Detection limits for confirmation sampling analyzed in 6/96, 10/97,and 12/97, was<1.0 pg/1 for all wells sampled.
<br /> nLead analyses Maximum lead analyzed from site soils is 48 mg/kg.
<br /> ED8. Concentration contours of contaminants found and those remaining in soil Lateral and vertical extent of soil and
<br /> and groundwater, and both on-site and off-site: groundwater contamination defined.
<br /> Lateral and 19 Vertical extent of soil contamination
<br /> Lateral and Vertical extent of groundwater contamination
<br /> 9.Zone of influence calculated and assumptions used for subsurface A remediation system was not installed at
<br /> remediation system and the zone of capture attained for the soil and this site.
<br /> groundwater remediation system;
<br /> y� 10.Reports/information Y❑ Unauthorized Release Form y❑ QMRs(5/95 to 9/99)
<br /> 0 Well and boring logs aPAR Q FRP 0 Other(QMR and Case Closure Request, 9/99)
<br /> 11.Best Available Technology(BAT)used or an explanation for not using BAT, Excavate contaminated soils,applied 510
<br /> pounds of ORC to backfill material.
<br /> 12.Reasons why background waslis Some contaminated soil remains in place. Shallow water levels release
<br /> Y unattainable using BAT, contamination into groundwater.
<br /> •
<br /> 13.Mass balance calculation of substance An estimated 15,000 pounds of contaminated soils were identirred on-site,and
<br /> treated versus that remaining, 11,450 pounds were removed by excavation activities. This represents a 76%
<br /> reduction in mass.
<br /> 14.Assumptions,parameters,calculations and model used in risk A risk assessment was not completed.
<br /> EEassessments, and fate and transport modeling,
<br /> Y 15. Rationale why conditions remaining at site will not adversely QMRs document the reduction of petroleum
<br /> impact water quality, health, or other beneficial uses;and hydrocarbons in on-site monitoring wells.
<br /> By: Comments: One UST was removed in the 1970's, initial soil borings were completed in 8/94, and over excavation of the
<br /> tank pit soils were completed in 7/98. Groundwater contamination has dropped significantly since contaminated soils were
<br /> excavated. Contamination is limited to on-site soil and groundwater. MtBE has not been identified at this site. Two water
<br /> supply wells are located downgradient and within 100 feet of the former UST area. The older well designated as the
<br /> Date: "South Well"is located within the area of soil and groundwater contamination, and does not have well construction
<br /> information available. Sampling results were non detect for both water supply wells sampled in 6/99. Based on the
<br /> existing water supply well located within the soil and groundwater contamination area, San Joaquin County's closure
<br /> °° recommendation is not appropriate at this time.
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