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<br /> TABW 1 - CHECKLIST OF REQUIRED STA :
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Stockton Gateway Project, 325 South EI Dorado Avenue,Stockton,San Joaquin County,,
<br /> A receptor survey was not completed. County states
<br /> i. Distance to production wells for municipal, domestic, agriculture, that no wells are located within 2,006 feet of the site.
<br /> industry and other uses within 2000 feet of the site;
<br /> 2. Site maps, to scale, of area impacted showing locations of former and existing tank systems, Site maps provided.
<br /> excavation contours and sample locations, boring and monitoring well elevation contours,
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities;
<br /> Boring logs show predominantly clay and sandy
<br /> f: 3. Figures depicting lithology(cross section), treatment system diagrams; clay.
<br /> i
<br /> 4 N 4. Stockpiled soil remaining ori-site or off-site disposal(quantity);
<br /> Excavated soil will be spread out on-site.
<br />�f - :Monitoring_wells were notinstalled-- '
<br /> ,'Mbnrtoring welts remaFnrng orr-siteyfa`te;
<br /> FN 6. Tabulated results of all groundwater elevations and depths to water; Depth to water varies from 15 to 25 feet bgs,as
<br /> measured in 4 geoprobe:soil borings.
<br /> 7. Tabulated results of all sampling and analyses: March 2000 maximum groundwater results in ug/!show TPHg at 4,800,
<br /> benzene at 7, toluene at 4, ethyl benzene at 23, xylenes at 99, antl MtBE
<br /> ©Detection limits for confirmation sampling at< 10 by 8020: MtBE and other oxygenates were not identified.lin soil
<br /> . Lead analyses by 8260B. Maximum lead from tank pit soil samples show 11 mg/kg.
<br /> '8. Concentration contours of contaminants found and those remaining in soil Lateral and vertical extent of contamination
<br />�+ FKJ and groundwater., and both on-site and off-site: is defined.,
<br /> E. © Lateral and 0 Vertical extent of soil contamination
<br /> aLateral and Vertical extent of groundwater contamination
<br /> EVI
<br /> 9. Zone of influence calculated and assumptions used for subsurface A remediation system was nonoperated at
<br /> remediation system and the zone of capture attained for the soil and this site,
<br /> groundwater remediation system;
<br /> -Q 10.Reports l informationUnauthorized Release Form F1 QMRs
<br /> Boring logs FNI PARFNT-] FRP � Other(Limited Soil and Groundwater./m., April 2000)
<br /> 11.Best Available Technology(BAT) used or anexplanationfor not using BAT, Remove US Ts, natural attenuation.
<br /> �_...� �_-_��„�,.—.�r...r,.�-_� .��., ,. _.�.. :..-y,.�. ".iM"--_ ";."ter�.. - v - -- ... - ._ .?�.c.a,. y,r �'.'•-. -. s� .vim'-..`�",c`_�•,"�r.,,,..rte,
<br /> Y012.Reasons why background wasps
<br /> TPH and BTEX constituents remain in site soil and groundwater._.
<br /> i unattainable using BAT,• 9
<br /> 13.Mass balance calculation of substance
<br /> treated versus that remaining; Amass balance was not presented.
<br /> it
<br /> 14.Assumptions,parameters, calculations and model used in risk
<br /> assessments, and fate and transport modeling; A risk assessment was not completed.
<br /> FT15. Rationale why conditions remaining at site will not adversely Remaining contamination is limited in area.
<br /> i impact water quality, health, or other beneficial uses;and Contamination will naturally attenuate. ;
<br /> By: Comments: Two US Ts were removed from the site in October 1999, and soil contamination was identified below one of
<br /> the USTs. Five geoprobe borings were completed in March 2000, and TPHg and total xylenes were identified in soil and
<br /> groundwater below the former tank pit. (The deepest soil sample was non detect for all constituents.) TPHg and BTEX
<br /> constituents were also identified in the water sample collected at the former tank pit. AIII four of the other soil boring
<br /> Date: samples were non detect for all constituents,and the water sample from a second boring was also non detect. Fuel
<br /> oxygenates were not identified at this site. Based on the limited extent of site contamination, and the absence of fuel
<br /> f oxygenates, Board staff concurs with San Joaquin County's closure recommendation.
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