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T�LBLE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Former SP Service Station No. 11193, 3202 W.Hammer Lane, Stockton, Sari Joaquin County
<br /> (RB#390779)
<br /> Y]
<br /> 1. Distance to production wells for municipal, domestic, A 1999 sensitive receptor survey identified one irrigation
<br /> agriculture, industry and other uses within 2000 feet of the site. well 315'to the west and no water.supply wells within the
<br /> search area. The well is not threatened by the release.
<br /> =y2, Site maps, to scale, of area impacted showing locations of In December 1992, a site investigation reported
<br /> any former and existing tank systems, excavation contours and petroleum hydrocarbons in soil and groundwater.
<br /> sample locations, boring and monitoring well elevation In December 1998, two 10,000-gallon gasoline and one
<br /> contours, gradients, and nearby surface waters, buildings, 8,000-gallon gasoline US Ts and associated piping were
<br /> streets;`and subsurface utilities; removed.
<br /> Site lifhology consists of clay,silt;sand, and gravel to
<br /> Y 3. Figures depicting lifhology(cross section), treatment system 1131, the total depth investigated.
<br /> diagrams;
<br /> Approximately 1,083 tons of the"excavated soil was
<br /> Y 4- Stockpiled soil remaining on-site or off-site disposal(quantity); trans orted to Forward Landfill in Manteca.
<br /> Y 5. Monitoring wells remaining on-site, fate; Fourteen monitoring wells(MW-1R, MW-2R, MW-3 through MW-13, and
<br /> VW-1)and ten remediation wells(OS-1 through OS-10)will be properly
<br /> abandoned.
<br /> fi. Tabulated results of all groundwater Depth to groundwater varied from 9'to 21'bgs. Groundwater flow
<br /> direction varied from northeast to southeast, and�groundwater gradient
<br /> televations,and_depths=to_water r -vaned from`O OOi-to D:D5
<br /> 7. Tabulated results of all sampling All data adequately tabularized in various reports, including closure report. i
<br /> and analyses:
<br /> Detection limits for confirmation
<br /> sampling
<br /> Lead analyses
<br /> 8. Concentration contours of contaminants found and those remaining in soil and The extent of the'identified
<br /> groundwater, and both on-site and off-site: contamination is shown in applicable
<br /> i reports..
<br /> Lateral and ��Vertical extent of soil contamination
<br /> Lateral and FY1 Vertical extent of groundwater contamination
<br /> 9. Zone'of influence calculated and assumptions used for subsurface remediation Batch groundwater extraction and ozone
<br /> system and the zone of capture attained for the soil and groundwater remediation, injection were the active remediation.
<br /> system;
<br /> YJ 10.Reports 1 information 0 Unauthorized Release Form, �Y QMRS 63 from 12/92 to 2111
<br /> ❑ Wel
<br /> y Wei 11 and boring logs ❑y PARQy FRP �y Other Closure Report(6111)
<br /> Y 11.Best Available Technology(BAT)used or an explanation for not ,TUSTs removal, over-excavation,batch groundwater
<br /> usin BAT' extraction, ozone injection,and natural attenuation.
<br /> Y 12. Reasons why background wasfrs Minimal residual soil and groundwater,contamination remains on-site.
<br /> tfainable using BAT,
<br /> 13:Mass-bola►ice--calculation-of.substance-treated-. The consultant estimated remaining TPH as 0.44 lbs In soil, and
<br /> Y 2.87 l5s in groundwater.
<br /> versus that remaining,
<br /> Y 14. Assumptions, parameters, calculations and The consultant did not conduct a soil gas survey;however, in soil
<br /> model used in risk assessments, and fate and TPHg at 3'bgs in the dispenser island and benzene at 16'bgs in the
<br /> transport modeling; tank pit exceeded Region.2 commercial ESLs.for direct exposure and
<br /> gross contamination, and direct exposure,of 50'and 25,respectively
<br /> from the station building. Water qua goals will be reached in 2012.
<br /> Y 15. Rationale why conditions remaining at site Soil and groundwater contamination reportedly are limited in extent..
<br /> will not.adversely impact water quality, health, or Land use(commercial)is not expected to change in the foreseeable
<br /> other beneficial uses;and . I future. Vapor intrusion risk has been addressed. Plume is stable.
<br /> By: JLB. Comments:In December 1992,a site investigation reported petroleum hydrocarbons in soil and
<br /> 1 . groundwater.. In December 1998, two 10,000-gallon gasoline and one 8,000-gallon gasoline USTs and
<br /> Date: associated piping were removed from the subject Site. Based upon 63 quarters of groundwater monitoring
<br /> 10/5/2011 :', showing a stable plume with a declining concentration trend, the limited extent of contamination remaining .
<br /> in soil and groundwater, no foreseeable changes in land use,and limited threats from groundwater,soil,and'.!
<br /> soil vapor intrusion,Regional Board staff concur with San Joaquin County s Closure Recommendation.
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