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<br /> TABLE 1 - CHECKLIST OF REQUIRED DATA
<br /> 1 FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> IM �
<br /> Site Name and Location: Stagg High School, 1621 Brookside Road, Stockton, SanPPJoaquin County
<br /> 1. Distance to production wells for municipal, domestic, agriculture, As shown in Geotracker, the nearest water supply well
<br /> industry and other uses within 2000 feet of the site; is approximately 600 feet to the south and upgradient
<br /> of the site.
<br /> ❑ b i� Two USTs(ane 500-gallon
<br /> 2.
<br /> Y Site maps, to scale, of area impacted showing locations of former and existing tank systems, asollne and one 10,000- '
<br /> excavation contours and sample locations, boring and monitoring well elevation contours, g
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities; p. gallon diesel) were removed
<br /> in December 1990.
<br /> 3. Figures depicting litholo cross section treatments tem diagrams, Site lithology consists of silt and clay to 30 feet,
<br /> Y g P g gY( )� ys „ r
<br /> the total depth investigated. -
<br /> 4. Stockpiled soil disposed off-site(quantify); Excavated soil was returned to the tank pit excavation.
<br /> EW]
<br /> i5. Monitoring wells remaining on-site, fate; Five monitoring wells have been installed for this investigation. The wells
<br /> will be properly destroyed pending site closure. ;
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<br /> �Y The depth to water varied from 8 to 40 feet, and the 6. Tabulated results of afi groundwater elevations and depths to water; ,
<br /> groundwater flow direction is to the northeast.
<br /> �y 7. Tabulated results of all sampling and analyses: Groundwater monitoring results for all monitoring wells have been
<br /> non-detect for all constituents analyzed(TPHg, BTEX, and fuel
<br /> MDetection limits for confirmation sampling oxygenates and additive's)from 2/01 to 3/02. Lead was identified at a
<br /> Lead analyses maximum of 15 mg/kg in a monitoring well soil sample. i
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<br /> 8. Concentration contours of contaminants found and those remaining in soil The extent of contamination is defined by
<br /> 0 and groundwater, both on-site and off-site: i on-site soil borings and monitoring wells.
<br /> Y� Lateral and Vertical extent of soil contamination
<br /> r' Lateral and Vertical extent of groundwater contamination i
<br /> 9. Zone of influence calculated and assumptions used for subsurface Based on the limited extent of soil
<br /> El remediation system and the zone of capture attained for the soil and contamination, an engineered remediation
<br /> groundwater remediation system; system was not warranted at this site.
<br /> 10.Reports/information Ifl Unauthorized Release Form [TJ QMRs(21991 to 3/02)
<br /> 171 Boring logs N❑ PAR N❑ FRP (Supplemental Subsurface investigation Report, 7/01)
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<br /> 11.Best Available Technology(BAT) used or an explanation for not using BAT,-, Remove USTs, natural attenuation:
<br /> Background groundwater concentrations have been-attained at all monitoring
<br /> 12.Reasons why backgrour,,d waslis .-- - 3 .-,r - *.--
<br /> unattainable using BAT wells. Minor soil contamination'remairi on-site at the former gasoline UST
<br /> area.
<br /> 13.Mass balance calculation of substance
<br /> The consultant estimates that 103 pounds(16 gallons)of TPHg remains in,
<br /> � ��
<br /> treated versus that remaining; shallow soils in the area of the farmer gasoline UST.
<br /> f. 14.Assumptions, parameters, calculations and model used in risk A risk assessment was not required. t
<br /> assessments, and fate and transport modeling;and ,j ,
<br /> 15. Rationale why conditions remaining at site will not adversely Sol/contamination is limited in extent, and based on the
<br /> f impact water quality, health, or other beneficial uses. last four sampling events, soil contamination is not
<br /> leaching to groundwater. i
<br /> By: Comments: Two USTs(one 500-gallon gasoline and one 10,000-gallon diesel)were removed from the subject'site in
<br /> MH December 1990. No contamination was identified at the diesel UST location, a,nd the County did not require any
<br /> j additional work in this area. Soil contamination was identified at the gasoline UST location, and multiple boring's and five
<br />[ Date: monitoring wells were completed to delineate and monitor contamination at this�sife. Monitoring well MW-1 was installed
<br /> in the former gasoline tank pit, and it has been sampled from 2/99 to 3/02. TPHg, BTEX, and MfBE(maximum at
<br /> 11/27/02 12.5 pg/1) was identified in MW-1;however,groundwater from this well and monitoring wells MW-2 through MW-5 have
<br /> f been non-detect for all constituents for the last four sampling events. Based on the limited extent of soil contamination
<br />[ and no contaminants in groundwater, Board staff concur with San Joaquin Couity's Closure Recommendation.
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