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TAB 1 - CHECKLIST OF REQUIRED PTA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Van Buskirk Golf Course, 1740 Houston Avenue, Stockton, San Joaquin County
<br /> 0 1. Distance to production wells for municipal, domestic, agriculture, A sensitive receptor survey in 1999 reported one
<br /> industry and other uses within 2000 feet of the site; irrigation well 2,100 feet east and no municipal or
<br /> private supply wells within 2000 feet of the site.
<br /> E] 2. Site maps, to scale, of area impacted showing locations of former and existing tank One 550-gallon diesel UST was
<br /> systems, excavation contours and sample locations, boring and monitoring well elevation removed 4/91. One 1,000-gallon
<br /> contours, gradients, and nearby surface waters, buildings, streets, and subsurface utilities, gasoline/diesel UST was
<br /> 0removed 1/94.
<br /> 3. Figures depicting lithology(cross section), treatment system diagrams, Site lithology consists of sand,silt and clay.
<br /> The total depth investigated was 425 feet.
<br /> 4. Stockpiled soil disposed off-site(quantity); approximately 157 cubic yards of soil was excavated,aerated and
<br /> reused onsite.
<br /> Y 5. Monitoring wells remaining on-site, fate; Ten monitoring wells(MW-1 to MW-10), installed for this investigation, will be
<br /> properly abandoned.
<br /> M,6.,Tab_Tabulated results of all The depth to water varied form 7 to 20 feet. The
<br /> _ _ groundwaterelevations and depths to water; p
<br /> groundwater-flow-direction-varied-from-north to:.__. ,
<br /> northeast. Y"
<br /> 71 7. Tabulated results of all'sampling and analyses: Maximum soil boring results in 1995 reported TPHg(3,800 mg/kg),
<br /> Y Detection limits for confirmation sampling
<br /> TPHd(45 m��),benzene� (5.9 mg/kg)toluene(46 mg/kg),
<br /> ethylbenzene 23 m /k and xylenes(150 mg/kg). In.11/00, additional
<br /> Y Lead analyses soil analyses reported MtBE(0.095 mg/kg). Groundwater maximum
<br /> concentrations from 12196 reported TPHg(93 mg/L0, TPHd(32 mg/L),
<br /> benzene(6.5 mg/L), toluene(35 mg/L), ethylbenzene(4.5 mg/L),
<br /> xylenes(25 mg/L)and MtBE(1.1 mg/L). In 12103,groundwater analysis
<br /> reported MtBE(0.080 mg/L).
<br /> 6.-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: soil borings and groundwater monitoring
<br /> Lateral and nY Vertical extent of soil contamination wells.
<br /> Lateral and �y�,J Vertical extent of groundwater contamination
<br /> Q9. Zone of influence calculated and assumptions used for subsurface Based on the limited extent of soil and
<br /> remediation system and the zone of capture attained for the soil and groundwater contamination,an engineered
<br /> groundwater remediation system; remedlation system was not required at 50
<br /> this site.
<br /> 0 10.Reports/information Y❑ Unauthorized Release Form Y❑ QMRs, 6/94 to 6103
<br /> El Boring logs Y❑ PAR El FRP Other Closure Report(10/03)
<br /> EJ11.Best Available Technology(BAT) used or an explanation for not using BAT. Remove UST, overexcavation,and natural
<br /> attenuation.
<br /> 12.Reasons why backgrnund-wasris- =•.o- Mingr soil and.groundwater contamination remains on-site.
<br /> unattainable using BAT,
<br /> 0 13.Mass balance calculation of substance Mass balance was not estimated.
<br /> treated versus that remaining;
<br /> 0 14.Assumptions,parameters, calculations and model used in risk A 2003 fate&transport model showed a maximum 1700'
<br /> assessments, and fate and transport modeling;and travel across the golf course, Water Quality Objectives
<br /> achieved by 2006. No sensitive receptors threatened.
<br /> Y� 15. Rationale why conditions remaining at site will not adversely Soil contamination is limited in extent,and based on
<br /> impact water quality, health, or other beneficial uses. 14 quarterly sampling events, contamination is not
<br /> continuing to leach to groundwater.
<br /> By: Comments: One 550-gallon diesel UST was removed 4/91 and one 1,000-gallon gasoline/diesel UST was removed 1/94
<br /> JLB from the subject site. Multiple borings and ten monitoring wells were completed from 1991 to 2002, to delineate
<br /> contamination at this site. Maximum soil boring results in 1995 reported TPHg(3,800 mg/kg), TPHd(45 mg/kg), benzene
<br /> Date: (5.9 mg/kg), toluene(46 mg/kg), ethylbenzene(23 mg/kg), and xylenes(150 mg/kg). in 11/00, additional soil analyses
<br /> reported MtBE(0.095 mg/kg). Groundwater maximum concentrations from 12196 reported TPHg(93 m9/L0, TPHd(32
<br /> 312104 mg/L), benzene(6.5 m91L), toluene (35 mg)L), ethylbenzene(4.5 mg1L),xylenes(25 mg/L)and MtBE(1.1 mg/L). in
<br /> 12/03, groundwater samples reported only WE(0.080 mg/L). Based on the limited extent of soil and groundwater
<br /> contamination, a fate&transport modeling which show no sensitive receptors threatened, and fourteen quarters of
<br /> groundwater analysis, which show contamination not continuing to leach into groundwater, Board staff concur with San
<br /> Joaquin County's Closure Recommendation.
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