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E TABLE 1 - CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS-AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Reich's Grocery, 7505 Linne Road, Tracy, an Joaquin County
<br /> Four water supply wells were identified within 700 feet
<br /> ED1. Distance to production wells for municipal, domestic, agriculture, of the site. Sampling results of the three downgradient
<br /> industry and other uses within 2000 feet of the site; wells were non-defect.
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<br /> Two 1,500-gallon gasoline
<br /> 2. Site maps, to scale, of area impacted showing locations of former and existing tank systems, US Ts were removed in 9/93.
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<br /> excavation contours and sample locations, boring and monitoring well elevation contours, Site maps are available in
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities; the various reports.
<br /> 3. Figures depicting lithology(cross section), treatment system diagrams; Site lithology consists of clay with sand andgravel to 25 feet, sand and gravel to 40 feet, and
<br /> interbedded sand, silt, and clay to 100 feet
<br /> 4. Stockpiled sot!disposed off-site (quantity); The disposition of excavated soils was not presented. The soil was
<br /> 3 likely returned to the tank pit excavation.
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<br /> t 5. Monitoring wells remaining on-site, fate; Six monitoring wells were installed for this investigation. The wells will be
<br /> F properly destroyed pending site closure.
<br /> The depth to water varied from 42 to 50 feet, and
<br /> g. Tabulated results of all groundwater elevations and depths to water; the groundwater flow direction is to the northwest.
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<br /> 7. Tabulated results of all sampling and analyses: The maximum soil concentrations show TPHg at 48,300 mg/kg, and
<br /> MtBE at 180 mg/kg. MtBE has been identified in groundwater at a
<br /> Detection limits for confirmation sampling maximum of 1,800 jug/l. Current monitoring shows the MtBE site
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<br /> Lead analyses maximum is 41 ug/l. Lead was identified of a maximum of 270 mglkg in
<br /> l�1 soil at six feet below the former dispenser.
<br /> a. Concentration contours of contaminants found and those remaining in soil The extent of contamination is defined by
<br /> and groundwater, both on-site and off-site: on-site soil borings and monitoring wells.
<br /> Lateral and MY Vertical extent of soil contamination
<br /> Lateral and M Vertical extent of groundwater contamination
<br /> { FT� g, Zone of influence calculated and assumptions used for subsurface A SVE pilot test completed in October 1995
<br /> ! remediation system and the zone of capture attained for the soil and identified a soil vapor ROI at 15 feet. The
<br /> groundwater remediation system; SVE system operated for approximately six
<br /> months and removed 433 gallons of TPHg.
<br /> 10.Reports/information -1 Unauthorized Release Farm QMRs(3/94 to 5/02)
<br /> EJ Boring logs a PAR FRA (CAP, 12/95 & Closure Summary Report, 9/02)
<br /> 11,Best Available Technology(BAT) used or an explanation for not using BAT, Remove USTs, SVE to reduce soil
<br /> contamination, and natural attenuation.
<br /> 0 12.Reasons why background was/is Shallow soil contamination remains on-site at the former UST areas, and MtBE
<br /> unattainable using BAT; contamination remains in groundwater downgradient of the former UST areas.
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<br /> 13.Mass balance calculation of substance The consultant estimates that 430 gallons of TPHg was removed in six months
<br /> treated versus that remaining; of SVE, and confirmation borings show a 46 to 95 percent reduction in mass.
<br /> M Consultant states that less than one pound of MISE remains in groundwater.
<br /> Results of fate and transport modeling predicted that
<br /> 14. Assumptions,parameters, calculations and model used in risk BTEX constituents would not impact groundwater at this
<br /> assessments, and fate and transport modeling; site. MtBE and lead calculations were not required.
<br /> 1 15. Rationale why conditions remaining at site will not adversely Groundwater monitoring and sampling documents
<br /> impact water quality, health, or other beneficial uses;and decreasing trends of MTBE. Groundwater will reach
<br /> Water Quali Objectives within a reasonable time.
<br /> By: Comments: Reich's Grocery Store is located in a rural part of San Joaquin County south of Tracy. Two 1,500-gallon gasoline
<br /> MH USTs were removed from the site in September 1993, and fuel service is no longer available. Soil contamination was identified
<br /> following UST removal, and a SVE system was operated at the site for approximately six months. The SVE system reportedly
<br /> removed 430 gallons of TPHg from site soils. Confirmation soil borings were completed in February 1999, and MtBE was
<br /> Date: identified in groundwater in the former tank pit area. Six monitoring wells were installed from August 1999 to June 2001, and
<br /> these wells have been monitored from four to eleven quarters. Decreasing trends of MtBE are shown in monitoring wells MW--1
<br /> 11/12/02 and MW-3, and the current sampling results(June 2002) show MtBE at 0.73 and 41 pgfl, respectively. All other constituents are
<br /> non-detect. Three domestic wells were identified at 135 to 415 feet downgradient of the former UST site, and one school well was
<br /> identified at approximately 700 feet upgradient. All three domestic wells were sampled and found to be non-detect. The nearest
<br /> downgradient well at 135 feet northwest was destroyed in late 2000. The site is covered with asphalt and concrete, which should
<br /> limit leaching of contaminants to groundwater. Based on the decreasing trends of MtSE in groundwater and the delineation of the
<br /> groundwater plume, Board staff concur with San Joaquin County's closure recommendation.
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