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A s ,
<br /> .T E 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> ,J�ite Name and Location: Swift Roofing, 1930 W. Fremont St;, Stockton, San.Joaquin County(RB#391178)
<br /> Y 1. Distance to production wells for municipal, domestic, A sensitive receptor survey In 2007 identified one
<br /> agriculture, industry and other uses within 2000 feet of the site, municipal supply well(1,100'north)and one domestic
<br /> well 1,200'sou.theast within 2,000'of the Site.
<br /> Y 2. Site maps, to scale, of area impacted showing locations-of One 1,000-gallon unleaded gasoline UST was reported
<br /> any former and existing tank systems, excavation contours and removed 6/90. Confirmation soil sample data was not
<br /> sample locations, boring and monitoring well elevation available. During a Phase 2 investigation(7/07), one soil
<br /> contours, gradients, and nearby surface waters, buildings, boring was advanced at the'Site in the former UST area.
<br /> streets, and subsurface utilities;
<br /> Y1 3. Figures depicting lithology(crass section), treatment system Site lithology consists of clay,silt and sand to 50', the
<br /> diagrams; total depth investigated.
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); The reports do not discuss soil excavation or disposal.
<br /> ,r
<br /> Y 5. Monitoring wells remaining on-site, fate; Three monitoring wells(MW-1 through MW-3),installed 2/08, will be properly
<br /> abandoned.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 4'to W kgs. Groundwater flow
<br /> elevations and depths to water; direction was towards the north at a gradient that varied from 0.004 ft/ft
<br /> 7. Tabulated results of all sampling In 7/07 the soil boring maximum concentrations were TPHg, 560 mg/kg;benzene,
<br /> and analyses: 0.03 mg/kg;toluene, 0.5 mg/kg;ethylbenzene, 8.8 mg/kg;and xylenes,43 mg/kg. F
<br /> In 2/08,soil borings results were ND. On 7/07, maximum grab groundwater results
<br /> Detection limits for confirmation were TPHg, 2,200 ug/L;benzene, 3 ug/L;toluene, 9.3 ug/L;ethylbenzene, 240 ug/L;
<br /> sampling. and xylenes, 710 ug/!,. In 11/08;all groundwater monitoring results were ND.
<br /> ❑N Lead analyses
<br /> Lyj 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 described in the
<br /> reports.
<br /> LLJ Lateral and Y❑Vertical extent of soil contamination
<br /> Lateral and Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation An engineered remediation was not
<br /> system and the zone of capture attained for the soil and groundwater remediation required by the lead agency.
<br /> astern"
<br /> 10.Reports/information FY Unauthorized Release Form �Y QMRs 4 from 2/08 to 11/08
<br /> I
<br /> RY Well and boring logs PAR ❑N FRP ❑Y Other Case Closure Summary Report(3/09)
<br /> Y11.Best Available Technology(BAT) used or an explanation for not using UST removal and natural attenuation.
<br /> BAT;
<br /> 12. Reasons why background wasrs unattainable Minor residual soil contamination remains on-site.
<br /> Y
<br /> BAT,- r
<br /> 737V1ass men lc-c laWCO o7s bstarrce treated Remaining TPEig_mass was estirrrated_ by_the consultant in 2009'as
<br /> versus that remaining,:. 83.13 lbs in sail.
<br /> Y 14. Assumptions, parameters, calculations and Soil sample results show applicable Region 2 ESLs were not
<br /> model used in risk assessments, and fate and exceeded. The site is a business in a commercial area of Stockton
<br /> transport modeling;
<br /> Y 15. Rationale why conditions remaining at site will Soil contamination reportedly is limited in extent. Land use
<br /> not adversely impact water quality, health, or other (commercial)is not expected to change in the foreseeable future.
<br /> beneficial uses;and
<br /> y
<br /> : JLB Comments:One 1,000-gallon unleaded gasoline'UST was reported removed 6190. Confirmation soil sample
<br /> data was not available. During a Phase 2 investigation (7/07)one soil boring was advanced at the Site in the
<br /> Date: former UST area. In 7/07 the soil boring maximum concentrations were TPHg, 560 mg/kg;benzene,
<br /> 514/12009 0.03 mg/kg;toluene, 0.5 mg/kg;ethylbenzene, 8.8 mg/kg;and xylenes, 43 mg/kg. Soil borings results for
<br /> 2/08 were ND. On 7/07,maximum grab groundwater results were TPHg, 2,200 ug/L;benzene, 3 ug/L;toluene,
<br /> 9.3 ug/L;ethylbenzene, 240 ug/L;and xylenes, 710 ug/L. In 11/08,all groundwater monitoring results were
<br /> ND. Minor residual soil contamination remains on-site. Based upon 4 quarters'of groundwater monitoring,
<br /> the limited extent of contamination reported in soil and groundwater, no foreseeable changes in land use,
<br /> and no applicable ESLs exceeded, Regional Board staff concur with San Joaquin County's Closure 99
<br />
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