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<br /> TABLE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: San Joaquin Electric Inc.,535 North Union Street,Stockton,San Joaquin County
<br /> Y 1 1. Distance to production wells for municipal, domestic, agriculture, industry Groundwater was not impacted. Five water
<br /> and other uses within 2000 feet of the site; supply wells are over 2,400 feet north of the site.
<br /> Two wells can't be located and three are not '
<br /> used. .Water is provided by the City of Stockton.
<br /> Y 2. Site maps, to scale, of area impacted showing locations of former and existing tank systems, in 1987,one 550-gallon gasoline
<br /> excavation co.0ntours and sample locations, boring and monitoring well elevation Contours, tank was removed from the site.
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities; The tank was installed in a
<br /> bunker with three concrete
<br /> walls and a concrete floor. The t
<br /> fourth wall was made of dirt.
<br /> i
<br /> Y 3. Figures depicting litholo
<br /> gy(cross section), treatment system diagrams;
<br /> N- 4..Stockpiled.sail rem.aining_.on-site_nr_off-site-disposal-(quantity); None recorded.,.,,�,,-
<br /> .� _
<br /> NA No monitoring wells were installed at the site.
<br /> 5. Monitoring wells remaining on-site, fate; v
<br /> NA Groundwater was not encountered during the site
<br /> 6. Tabulated results of all groundwater elevations and depths to water,' investigation but is estimated at 45 feet bgs.
<br /> TPHg at 30 mg/kg,motor oil at 2,700 mglkg, benzene at 5.0 mg/kg,and xylene at
<br /> krulated results of a!!sampling and analyses: 8.0 mg/kg were detected in soil during tank removal. In January 2000, one soiletection limits for confirmation sampling boring was advanced in the vicinity of the tank removal sample to 30 feet bgs.
<br /> Lead analyses Soil samples from the boring were non-detect for analyzed constituents
<br /> including oxygenates.
<br /> 8. Concentration contours of contaminants found and those remaining in soil
<br /> d groundwater, and bat -site and off-site:
<br /> LJ Lateral and Vertical extent of soil contamination
<br /> F71 Lateral and NA Vertical extent of groundwater contamination ;
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<br /> 9. Zone of influence calculated and assumptions used for subsurface No remediation system was installed. w
<br /> remediation system and the zone of capture attained for the soil and
<br /> groundwater remediation system;
<br /> 0 10.Reports/information Y� Unauthorized Release Form FN_A_j QMRs(Dates)
<br /> LJ Well and boring logs_„E]PAR _ N❑ FRP E._. ,Other_(report name)31 Jan 99, Prelim. Invest. Report
<br /> 0 11.Best Available Technology(BAT) used or an explanation for not using BAT,- The tank was removed from the site.
<br /> 12.Reasons why background wasrs unattainable using BAT, Minor contamination possibly remains in site soil.
<br /> F1 13.Mass balance calculation of substance treated versus that remaining; None submitted.
<br /> 14-Assumptions,parameters, calculations and model used in risk
<br /> assessments, and fate and transport modeling;
<br /> 15.Rationale why conditions remaining at site wilt not adversely Investigations show that contaminants did not migrate vertically
<br /> impact water quality, health, or other beneficial uses;and in soil,suggesting that groundwater was not impacted.
<br /> 0 15.WET or TCLP results
<br /> $y; Comments:During tank removal in 1987,elevated levels of hydrocarbons were detected in soil samples from the sidewall of the
<br /> tank vault. In January 2000, one soil boring was installed within five feet of the sidewall samples. Soil samples from the boring
<br /> Dat : were analyzed for gasoline, diesel, motor-oil,BTEX, and fuel oxygenates, which all were non-detect. Groundwater was not
<br /> encountered during the boring installation. The site is north of the Stockton Redevelopment Center(Center). A map of the area
<br /> /l C� shows four supply wells on the Center's property,and one well northeast of the property. Two of the wells identified as Wells i
<br /> and 4 were not found during San Joaquin County site investigation, and according to the County, Wells 1A, 3, and Tank 3 are no f
<br /> longer used. Based on the absence of contaminants in sail below 15 feet and the probability that groundwater was not impacted,
<br /> staff concurs with San Joaquin County closure recommendation.
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