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TABLE 1 -CHECKLIST OF REQUIRE' IATA
<br /> FOR.,,,,,, FURTHER ACTION REQUESTS AT UNDEh„-...OUND TANK SITES
<br /> Site Name and Location: U-Haul Facility No. 710050, 2701 N. Wilson Way, Stockton, San Joaquin County
<br /> 1. Distance to production wells for municipal, domestic, Two domestic supply wells are located 400 and 450 feet south of
<br /> the Site,and residential neighborhoods most likely supplied by
<br /> Y agriculture, industry and other uses within 2000 feet of the site; domestic wells are located 300 feet east of the Site. These wells
<br /> are located up or cross-gradient to the plume form this Site and
<br /> are therefore not at risk.
<br /> 2. Site maps, to scale, of area impacted showing locations of former In 7/90,one 6,000-gallon, 8,000-gallon,and a 10,000-
<br /> Y and existingtanks stems, excavation contours and sample locations, gallon gasoline and one fig waste oil US Ts were
<br /> Y P removed.Site maps and figures showing former tank
<br /> borings and monitoring wells elevation contours, gradients, and nearby locations, excavations,buildings,and residual pollutants
<br /> surface waters. buildings, streets, and subsurface utilities; were submitted in various reports.
<br /> 3. Figures depicting lithology(cross Cross sections figures are available in various reports. Subsurface soil consists of silty
<br /> Y sand,silt,sand, clayey sand and clay.In addition,on the eastern portions of the Site,
<br /> section), treatment system diagrams; more clayey soils predominate. Total depth investigated was 150 ft. bgs.
<br /> 4. Stockpiled soil remaining on-site or Soil from excavation and site activities was transported to TPS Technologies in
<br /> Y Adelanto, Republic Services Vasco Road Landfill in Livermore,and/or HKM
<br /> off-site disposal(quantity); Environmental Services in La Grange, CA for disposal.
<br /> Y 5. Monitoring wells remaining on-site, fate; All monitoring wells will be properly destroyed once Site closure is determined.
<br /> Y Depth to groundwater has varied from 40'bgs to 65'bgs. Groundwater flow direction
<br /> 6. Tabulated results of all groundwater varies from N-NW-SW.
<br /> elevations and depths to water,
<br /> Y 7. Tabulated results of all sampling and analyses: All data adequately tabularized in various reports.
<br /> Detection limits for confirmation sampling
<br /> Lead analyses
<br /> Y 8. Concentration contours of contaminants found and those remaining in soil The remaining impacted groundwater plume is
<br /> and groundwater, and both on-site and off-site: estimated to extend to 125 ft. bgs. The horizontal
<br /> extent is not clearly defined due to three of the
<br /> EY Lateral and BVertical extent of soil contamination furthest down-gradient wells being impacted by the
<br /> N Lateral and Y Vertical extent of groundwater contamination plume from an adjacent Site,Harry's Auto.
<br /> N 9. Zone of influence calculated and assumptions used for subsurface Vapor extraction wells were designed and
<br /> constructed to capture approx.30-40 feet of radial
<br /> remediation system and the zone of capture attained for the soil and
<br /> influence.
<br /> groundwater remediation system:
<br /> Y 10.Reports/information FY Unauthorized Release Form ❑Y QMRs
<br /> ❑Y Well and boring logs ❑N PAR ❑N FRP [Y Other Notice of Termination of Vapor Extraction
<br /> Activities and Site Status Report, 3/12 Closure Request, 6112
<br /> Y 11.Best Available Technology(BAT) used or an Vapor Extraction and Air Sparge technologies were implemented as BAT
<br /> explanation for not using BAT,'
<br /> Y background warms unattainable SVE and AS systems were shut down after reaching asymptotic recovery rated.
<br /> 12.Reasons why 9 The remaining plume does not appear to be migrating and the residual
<br /> using BAT: concentrations of petroleum impacts do not pose a threat to human or
<br /> environmental health.
<br /> V 13 Mass balance calculation of substance Approximately 31,950 lbs. of TPH-G was removed and/or destroyed by the SVE
<br /> and AS systems. Remaining masses of TPH-G, TPH-D,benzene, and 1,2DCA are
<br /> treated versus that remaining; a roximatel 0.19 lbs., 2.41 lbs., 0.03 lbs.,and 0.38 lbs.,respectively.
<br /> 14.Assumptions, parameters, calculations and model used The remaining soil vapor and groundwater concentrations meet LTCP
<br /> Y P P standards and can therefore be assumed to not pose a significant risk
<br /> in risk assessments, and fate and transport modeling; to human or environmental health through indoor or outdoor vapor
<br /> ex osure, or throw h direct contact.
<br /> 15.Rationale why Conditions remaining at site will not The impacted groundwater plume has generally exhibited stable or
<br /> Y Y g decreasing trends over the last 10 sampling periods,and does not
<br /> adversely impact water quality, health, or other beneficial pose a threat to human or environmental health according to Cardno
<br /> uses: and ATC consultants.
<br /> N 16.WET or TCL
<br /> results NA
<br /> By. Comments: The Site is currently in use as a U-Haul Moving and Storage truck rental facility.It is in a largely commercial
<br /> area and there are no plans in the foreseeable future for the land use to change. In 1990, ETC removed the UST systems
<br /> CLC and took soil samples from the excavated tank pit.Analytical results confirmed that a release had occurred,and
<br /> groundwater monitoring was initiated in 1992. SVE and AS remediation ran from October 2007-December 2009,and then
<br /> again from September 2010-February 2012.AS was operated until November 2012. The plume from this Site appears to be
<br /> stable and decreasing, off-site wells may be impacted by a release from Harry's Auto. While there is no estimate as to when
<br /> Date: the Site will meet background, the residual impacts from the Site do not threaten nearby domestic wells. The case meets
<br /> the criteria of the State Water Board's Low Threat Closure Policy and therefore should not pose a threat to human health or
<br /> 7121/2014 the environment.
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