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TAB 1 - CHECKLIST OF REQUIRED SOTA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Corral Hollow Trucking Terminal,30600 Corral Hollow Road,Tracy,San Joaquin County
<br /> Y 1.Distance to production wells for municipal,domestic,agriculture, As shown In GeoTracker,the closest municipal well/s
<br /> industry and other uses within 2000 feet of the site, about 3,600 feet northeast of the site. An on-site
<br /> domestic well is within 100 feet of the UST area.
<br /> 0 2. Site maps,to scale,of area impacted showing locations of former and existing tank systems, Ten USTs were removed In
<br /> excavation contours and sample locations,boring and monitoring well elevation contours, March 1998. Site maps are
<br /> gradients,and nearby surface waters,buildings,streets,and subsurface utilities, provided in various reports.
<br /> Y❑ 3.Figures depicting lithology(cross section),treatment system diagrams; The general soll litho/ogy consists of sand
<br /> and gravel Intervals,and gravelly clayey silt to
<br /> 45 feet,the total depth Investigated.
<br /> Na 4. Stockpiled soil disposed off-site(quantity); Excavated soils were stockpiled and sampled,and later spread out on
<br /> the site to aerate. The excavation was backfilled with native materials.
<br /> 5.Monitoring we/is remaining on-site, fate; Groundwater was not encountered during assessment and soil excavation
<br /> activities,and monitoring wells were not installed.
<br /> 0 6. Tabulated results of all groundwater elevations and depths to water, Groundwater was not encountered at 45 feet,the
<br /> total depth Investigated.
<br /> 7.Tabulated results of all sampling and analyses: Following excavation activities,the maximum concentrations In soil
<br /> ©Detection limits for confirmation sampling (in mg/kg)show TPHg at 3.0,benzene at 0.04, toluene at 0.15,ethyl
<br /> benzene at 0.05,xylenes at 0.03,and MtBE at 0.18. TPHd was not
<br /> F1Lead analyses detected In post excavation samples. Total lead was Identified at 6 to
<br /> 13 mg/kg during tank removal activities in March 1998.
<br /> y 8. Concentration contours of contaminants found and those remaining in soil
<br /> 0
<br /> and groundwater,and both on-site and off-site: Sol/contamination was removed during
<br /> Lateral and 0 Vertical extent of soil contamination overexcavation activities. Groundwater
<br /> was not encountered.
<br /> ElLateral and F1 Vertical extent of groundwater contamination
<br /> 9.Zone of influence calculated and assumptions used for subsurface Based on the soil excavation activities
<br /> remediation system and the zone of capture attained for the soil and completed,additional site remediation was
<br /> groundwater remediation system, not required.
<br /> Y❑ 10.Reports/information El Unauthorized Release Form N❑ QMRs
<br /> Boring logs 0 PAR FRP Soil Excavation Report,January 1999
<br /> Q11.Best Available Technology(BAT)used or an explanation for not using BAT,• The USTs and contaminated soils were
<br /> removed.
<br /> Minor soil contamination remains in the former tank pit area. The
<br /> 12.Reasons why background wasrs contamination Is limited In extent,and does not present a signillowd that to
<br /> unattainable using BAT,•
<br /> water quality.
<br /> 13.Mass balance calculation of substance Based on the excavation of contaminated soils,a mass balance was not
<br /> treated versus that remaining, . required.
<br /> 14.Assumptions,parameters,calculations and model used in risk Based on the excavation of contaminated soils,a risk
<br /> assessments,and fate and transport modeling; assessment was not required.
<br /> 15.Rationale why conditions remaining at site will not adversely Contaminated soils were excavated and aerated on-site,
<br /> impact water quality,health,or other beneficial uses,and and only minor soil contamination remains in the former
<br /> tank pit area. The contamination will naturally degrade.
<br /> By: Comments: The site is a former truck stop. Two 12,000-galion gasoline,and eight 12,000-gallon diesel USTs were
<br /> MH removed in Manch 1998,and TPHd, TPHg,BTEX,and MtBE constituents were identified in soil to 13 feet. Impacted soils
<br /> were excavated in November 1998 to a total depth of 45 feet. Approximately 4,000 cubic yards of soil was aerated on-
<br /> Date: site. Confirmation soil samples were collected,and only minor soil contamination remains in the former tank pit area.
<br /> 2/4/02 The depth to groundwater is estimated at greater than 60 feet. An on-site domestic well,approximately 100 feet south of
<br /> the former tank pit area was sounded and sampled on 28 December 2000. The depth to water was measured at 190 feet,
<br /> and the pump was set at 300 feet. The domestic well water sample analyzed by 3510 and 8260B methods only showed
<br /> motor oil at 1.3 mg4. This detection is believed to be from the pump removal activities. Based on investigation and
<br /> remedial activities completed to date, Board staff concur with San Joaquin County's closure recommendation.
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