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BLE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Former Shell Station, 9313 E. Charter Way Stockton, San Joaquin County(RB#391067)
<br /> Y 1. Distance to production-wells for municipal, domestic, A 1199.9 sensitive receptor survey identified two water
<br /> agriculture, industry and other uses within 2000 feet of the site. s pply wells within the search area, one 650'to the north
<br /> a d one 1,885'to the southeast of the Site.
<br /> Y1 2. Site maps, to scale, of area impacted showing locations of Ir April 1999, two 10,000-4allon gasoline and one
<br /> any former and existing tank systems, excavation contours and 8,000-gallon gasoline USTs were removed.
<br /> sample locations, boring and monitoring well elevation
<br /> contours, gradients, and nearby surface waters, buildings,
<br /> streets, and subsurface utilities;
<br /> =Y3. Figures depicting lithology(cross section), treatment system S'te lithology consists of clay,silt,sand, and gravel to
<br /> diagrams; 100', the total depth investigated.
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); The fate of the excavated soil is not discussed in the
<br /> available reports.
<br /> YJ 5. Monitoring wells remaining on-site, fate; INine monitoring we (MW-1 through MW-9) will be properly abandoned.
<br /> 6. Tabulated results of all groundwater Depth to ground vater varied from 35'to 45'bgs. Groundwater flow
<br /> elevations and depths to water, direction varied rom northeast to southeast, and groundwater gradient
<br /> varied from 0.00 to 0.006 ft/ft.
<br /> 7. Tabulated results of all sampling All data adequately tabula ized in various reports, including closure report.
<br /> -and-analyses.--
<br /> El
<br /> nd-analyses:El Detection limits for confirmation
<br /> sampling
<br /> Lead analyses
<br /> yJ $. Concentration contours of contaminants found and those remaining in soil and The extent of the ide»tified
<br /> groundwater, and both on-site and off-site:. contamination shown in applicable
<br /> reports.
<br /> 0 Lateral and Y❑Vertical extent of soil contamination
<br /> nY Lateral and FyJ Vertical extent of groundwaterconta nination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation Groundwater pump and treatment(2006-
<br /> system and the zone of capture attained for the soil and groundwatet remediation 2009)was the active remediation.
<br /> s stem;
<br /> 10.Reports/information [A Unauthorized Release Form ❑Y QMRs 29 from 1/03 to 11109
<br /> ❑Y Well and boring logs IS] PAR FRP FYI Other Closure Report(7110)
<br /> Y 11.Best Available Technology(BAT) used or an explanation for not USTs removal, over-excavation, groundwater pump
<br /> usin BAT, and treatment and natural attenuation.
<br /> Y12. Reasons why background walls Minimal residual soil and groundwater contamination remains on-site.
<br /> attainable using BAT
<br /> Y 13.Mass balance calculation of substance treated The consultant estimated remaining TPH as 376 lbs in soil,and 7 tbs. in
<br /> versus that remaining; groundwater.
<br /> 714. Assumptions, parameters, calculations and The consultantdid not conduct a soil gas survey;however, TPHg,
<br /> 4- odel-used-in-risk-assessments;-anr-fate-z ,ethylbenzene,- ndxydenes aLl_QS 21::5'-,_and.21..5'bgs-and-at_ov.er_7.0--
<br /> transport modeling; from a plannea future station building, exceeded Region 2 commercial
<br /> ESLs for direci exposure and gross contamination in soil at depths
<br /> - below normal v iorker contact.,Water quality goals will be reached in
<br /> 20 years.
<br /> Y 1 15. Rationale why conditions remaining at site Soil and group Iwater contamination reportedly are limited in extent.
<br /> will not adversely impact water quality, health, or Land use(corn ercial)is not expected to change in the foreseeable
<br /> other beneficial uses;and future. Vapor itrusion risk has been addressed. Plume is stable.
<br /> By JL Comments:In April 1999, two 10,000-gallon gasolin and one 8,000-gallon gasoline USTs were removed from
<br /> the subject Site.Based upon 29 quarters of groundi rater monitoring showing a stable plume with a slowly
<br /> Date: declining concentration trend, the limited extent of contamination remaining in soil and groundwater,no
<br /> 3/23/2011 foreseeable changes in land use, and limited threat from groundwater,soil, and soil vapor intrusion,
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