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<br /> TABW 1 - CHECKLIST OF REQUIRED( TA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Bogetti Orchard Service,2393 East Highway 132,Vernalis,San Joaquin County
<br /> 1. Distance to production wells for municipal, domestic, agriculture, Three domestic wells are located within 2500 feet(one
<br /> industry and other uses within 2000 feet of the site; is onsite and 150 feet) of the site.
<br /> 'Y� . Site maps, to scale, of area impacted showing locations of former and existing tank One 5,000-gallon and one
<br /> 2
<br /> systems, excavation contours and sample locations, boring and monitoring well elevation 10,000-gallon gasoline, and one
<br /> contours, gradients, and nearby surface waters, buildings, streets, and subsurface utilities; 5,000-gallon diesel USTs were
<br /> removed in 2/99.
<br /> 0 3. Figures depicting lithology(cross section), treatment system diagrams; Site lithology consists of clay, silt, and sand.
<br /> The total depth investigated was 45 feet.
<br /> 0 4. Stockpiled soil disposed off-site(quantity); Amount of soil excavated and fate of stockpile soil was not documented.
<br /> 0 5. Monitoring wells remaining on-site, fate; Five monitoring wells(MW-1 to MW-5)were installed for this investigation.
<br /> The five wells will be properly abandoned.
<br /> Y
<br /> 6.yTabulated-results of.all groundwater elevations and depths to waterThe depth to water varied from 9 to 13 feet. The, groundwaterflow-direction is-towards-the------ x —
<br /> northeast
<br /> Y 7. Tabulated results of all sampling and analyses.- In 2/99,soil analyses reported TPHg(4 mg/kg),benzene(0.007 mg/kg)
<br /> and MtBE(0.32 mg/kg). In 7/02,additional soil analyses reported
<br /> 0 Detection limits for confirmation sampling TPHg(4 mg/kg), TPHd(4 mg/kg), benzene(0.012 mg/kg)and
<br /> ©Lead analyses MtBE(2.7)mg/kg). Grab groundwater sample results in 2/99 were
<br /> 37,000 Ng/L for TPHg and 3,200 fig/L for MtBE. In 4/03,groundwater
<br /> results from monitoring wells were 0.56 pg/L(benzene)and 10 pg/L
<br /> (MtBE). Grab groundwater sampling of the three domestic wells did
<br /> not detect contaminants.
<br /> FY 1 8. 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 Vertical extent of soil contamination
<br /> Lateral and Vertical extent of groundwater contamination
<br /> 0Based on the limited extent of soil
<br /> 9. Zone of influence calculated and assumptions used for subsurface
<br /> remediation system and the zone of capture attained for the soil and contamination,an engineered remediation
<br /> groundwater remediation system; system was not required at this site.
<br /> Q 10.Reports/information Y❑ Unauthorized Release Form seven QMRs(2/00 to 4/03)
<br /> fl Boring logs Y❑ PAR El FRP 0 Other
<br /> 11.Best Available Technology(BAT) used or an explanation for not using BA T, Remove USTs,and natural attenuation.
<br /> 0 12.Reasons why background was/is
<br />. unattainable using SAT Decreasing concentrations have been attained at all monitoring wells. Minor
<br /> - - ==! !W soil contamination remains-on-site.
<br /> 13.Mass balance calculation of substance yv
<br /> treated versus that remaining; The consultant estimated 0.44 pounds of MtBE remain in soil. Minimal
<br /> contamination was detected in groundwater in 2003.
<br /> 14.Assumptions,parameters, calculations and model used in risk
<br /> assessments, and fate and transport modeling;and A risk assessment was not required.
<br /> 0 15. Rationale why conditions remaining of site will not adversely Soil contamination is limited in extent,and based on
<br /> impact water quality, health, or other beneficial uses. seven sampling events, contamination is not continuing
<br /> to leach to groundwater. Groundwater monitoring
<br /> shows a decreasing trend in concentrations.
<br /> By: Comments: One 5,000-gallon and one 10,000-gallon gasoline, and one 5,000-gallon diesel USTs were removed from the
<br /> JLB subject site in 2/99.. Multiple borings and five monitoring wells(MW-1 to MW-5) were completed in 2000 to 2003 to
<br /> delineate and monitor contamination at this site. In 1999, maximum soil concentrations reported were TPHg(4 mg/kg),
<br /> Date: benzene(0.007 mg/kg)and MtBE(0.32 mg/kg). In 2/02, additional soil analyses reported TPHg(4 mg/kg), TPHd
<br /> (4 mg/kg), benzene(0.012 mg/kg)and MTBE(2.7)mg/kg), soil results were essentially unchanged. Grab groundwater
<br /> 10/29/03 sample results in 2/99 were 37,000 pg/L for TPHg and 3,200 pg/L for MtBE. In 4/03 after 7 quarterly events,groundwater
<br /> results from monitoring wells were 0.56 yg/L(benzene)and 10 pg/L (MTBE). Groundwater flow direction is to the
<br /> northeast. Groundwater from three nearby domestic wells tested ND in 10/03. Based on the limited extent of soil
<br /> contamination and decreasing contaminant concentrations in groundwater, Board staff concur with San Joaquin County's
<br /> Closure Recommendation.
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