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TAB 1 - CHECKLIST OF REQUIRED TA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> [Sii:te:N�ame �Locat�ion: Gilliand Property,',3776 Grant Line Road,Tracy, San Joaquin County
<br /> 1. Distance to production wells for municipal, domestic, agriculture, Groundwater contamination was not identified,and a
<br /> industry and other uses within 2000 feet of;the site; well receptor survey was not required As shown in
<br /> j Geo Tracker,no wells are within 2,000 feet of the site.
<br /> 2. Site maps, to scale, of area impacted showing locations of former and existing tank systems, Three gasoline USTs were
<br /> excavation contours and sample locations,'boring and monitoring well elevation contours, removed in 4/90. Maps are
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities, provided in the Summary
<br /> Report.
<br /> ED 3. Figures depicting fithology(cross section), treatment system diagrams; Lithology consists of sand and clay to 9 feet,
<br /> and silt and clay to 16 feet, the total depth:',
<br /> investigated.
<br /> 4. Stockpiled soil disposed off-site(quantity); The disposition of excavated soil.was not presented. The soils were
<br /> likely returned to the tank pit excavations.
<br /> 5. Monitoring wells remaining on-site, fate; Groundwater contamination was not identified,and monitoring wells were not r
<br /> installed.
<br /> 6. Tabulated results of all groundwater elevations and depths to water; First groundwater was encountered at 11 feet. The
<br /> estimated flow direction is to the north. i
<br /> 7. Tabulated results of all sampling and analyses: The maximum concentrations from tank pit soil samples show TPHg at
<br /> Detection limits far confirmation sampling 560 mg/kg and total BTEC at 2.55 mg/kg. Soil and groundwater !
<br /> samples analyzed from soil borings were non-detect for all
<br /> 0 Lead analyses constituents including MtBE at acceptable detection limits. Lead was
<br /> identified at 9 to 11 mg/kg in soil.
<br /> 8. Concentration contours of contaminants found and those remaining in soil Soil samples collected at 10 to 15 feet
<br /> and groundwater, both on-site and off-site: using push probe methods were non
<br /> Many❑ detect for all constituents. Groundwater
<br /> Lateral d Vertical extent of soil contamination
<br /> Lateral and ❑ Vertical extent of groundwater contamination grab samples collected at each soil boring
<br /> were also non-defect fora!!constituents.
<br /> 0 N 9. Zone of influence calculated and assump'ti'ons used for subsurface
<br /> remediation system and the zone of capture attained for the soil and Based on the limited soil contamination,
<br /> groundwater remediation system; site remediation was not required.
<br /> YD 10.Reports 1 information Yl Unauthorized Release Foran N� QMRs.
<br /> El Boring logs ❑ PAR H❑ FRP ] Summary Report of.Subsurface Investigation, 1/02
<br /> 11.Best Available Technology(BAT) used or an explanation for not using BAT; t The US Ts were removed.
<br /> y --?2
<br /> 2.-Reasons yr"y=babkr curd svaw�s�- - Soil and groundwater,in-the-.vicinity of the.former USTs_is_not.imnacted_by
<br /> unattainable using BAT, petroleum hydrocarbons: Ary`remaimng contamination does not present a
<br /> significant threat to water quality.
<br /> 13.Mass balance calculation of substance
<br /> treated versus that remaining; Based on the limited soil contamination,a mass balance was not required.
<br /> 14.Assumptions, parameters, calculations and model used in risk Based,on the limited soil contamination,a risk
<br /> assessments, and fate and transport modeling; assessment was not required.
<br /> 0 Y 15. Rationale why conditions remaining at site will not adversely Contaminants in soil are limited to the tank pit area,and
<br /> impact water quality, health, or other beneficial uses. will naturally degrade. Groundwater was not impacted.
<br /> dt
<br /> By: Comments: The site is an agricultural, commercial, and residential property. One 2000-gallon and two 3000-gallon
<br /> MH gasoline USTs were removed from the site in April 1990. Low-level soil contamination was identified during the tank
<br /> removal activities, and three push probe soil borings were completed in January 2002 to define the extent of .
<br /> contamination. Soil and groundwater samples collected in January2002 were analyzed for TPHg, BTEX, lead, and fuel
<br /> Date: oxygenates including MTBE,and lead was the only constituent identified. Lead concentrations ranged from 9 to 11 mg/kg
<br /> 3/8/42 in the soil samples, and was less than 51rg4 in the groundwater grab samples. Based on the investigation completed to
<br /> date, Board staff concur with San Joaquin County's closure recommendation.
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