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<br /> TABLE 1 - CHECKLIST OF REQUIRED IA.
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Valley Wholesale Drug, 1401 W. Fremont St., Stockton, San Joaquin County N
<br /> 1. Distance to production wells for municipal, domestic, agriculture, No municipal supply oi'domestic wells are located
<br /> industry and other uses within 2000 feet of the site; within 2000 feet of the site:
<br /> Y� 2. Site maps, to scale, of area impacted showing locations of former and existing tank Two 1,000-gallon gasoline USTs
<br /> systems, excavation contours and sample locations, boring and monitoring well elevation were removed 6/94.
<br /> contours, gradients,and nearby surface waters, buildings, streets, and subsurface
<br /> utilities,
<br /> 3. Figures depicting lithology(cross section), treatment system diagrams; Site lithology consists of sand,silt and clay.
<br /> The total depth investigated was 42 feet.
<br /> 0 4. Stockpiled soil disposed off-site(quantity); Approximately 128 cu.yds. of excavated loll was disposed offsite at an
<br /> unknown location.
<br /> 0
<br /> Y Ten monitoring wells(MW-1 through MW-10)installed for this investigation,
<br /> 5. Monitoring wells remaining on-site, fate; will be abandoned.
<br /> FY___1 r,. - oate -vid-from_Z#o.9-feet.
<br /> 6�Tabulated-results-of-ati-groundwater:eloations-and-depths-to-watedepth. wr
<br /> Groundwater flow direction was towards the
<br /> northwest.
<br /> 0 7. Tabulated results of all sampling and In 6/94, maximum soil results were: TPHg(4,100 mg/kg), benzene
<br /> lyses. (88 mg/kg), toluene(450 mg/kg), ethylbenzene(150 mg/kg),and xyleneswa
<br /> l
<br /> Y (1,200 mg/kg). Boring soil results in 8/04 were TPHg(558 mg/kg),
<br /> Detection limits for confirmation sampling benzene(0.3 mg/kg), toluene(2.36 mg/kg),Methylbenzene(5.14 mg/kg),
<br /> ❑Lead analyses xylenes(6.3 mg/kg), and MtBE(0.03 mg/kg). Groundwater results in 3/96
<br /> were TPHg(24,000 Ng/L), benzene(4,700 erg/L), toluene(3,400 Ng/L),
<br /> ethylbenzene(1,000 Ng/L),xylenes(1,000 pg/L), and MTBE(270 pg/L).
<br /> In 10/04,groundwater results were TPHg(269 pg/L), benzene(1.21ig/L),
<br /> ethylbenzene(6.2 pg/L),xylenes(2.1 pg/L),'and MtBE(55 pg/L).
<br /> 8. Concentration contours of contaminants found and those remaining in soil r ;
<br /> and groundwater, both on-site and off-site: The extent of contamination is defined by
<br /> ®Y Lateral and Y Vertical extent of soil contamination soil borings and monitoring wells.
<br /> Lateral and ® Vertical extent of groundwater contamination
<br /> 0 9. Zone of influence calculated and assumptions used for subsurface Based on the limited extent of
<br /> remediation system and the zone of capture attained for the soil and confaminatlon,'an engineered remediation
<br /> groundwater remediation system; system was not required at this site.
<br /> 0 10.Reports/information Y] Unauthorized Release Form 28 QMRs(8/95 to 10/04) ;
<br /> i
<br /> Y❑ Boring logs N❑ PAR N❑ FRP Y❑ Other:Receptor Survey, Site Conceptual Model, Closure Report 1
<br /> 11.Best Available Technology(BAT) used or an explanation for not using BAT; Remove USTs,overexcavation and natural
<br /> attenuation.
<br /> ,�J
<br /> 12.Reasons why �,_.No contamination was.found.1n-groundwater.-R9ihor-soil contamination s'
<br /> Y
<br /> una`ttainable using BAT, remains on-site.
<br /> 13.Mass balance calculation of substance The consultant estimates 56 gallons of TPHg and 0.041 gallons of MtB15,
<br /> treated versus that remaining; contamination remain in soil;and 0.1 gallons of TPHg and 0.034 gallons of .
<br /> MtBE remain in groundwater.
<br /> N 14.Assumptions,parameters, calculations and model
<br /> A risk assessment was not
<br /> used in risk assessments, and fate and transport
<br /> required.
<br /> modeling;and
<br /> Y� 15. Rationale why conditions remaining at site will not Soil contamination is limited in extent and based on 28 quarters
<br /> adversely impact water quality, health, or other of groundwater monitoring with declining concentrations,
<br /> beneficial uses. contamination is not continuing to leach into groundwater.
<br /> By: Comments: Two 1,000-gallon gasoline USTs were removed 6/94 from the subject site. ,ln 6/94, maximum soil results
<br /> JL.B were: TPHg(4,100 mg/kg), benzene (88 mg/kg), toluene(450 mg/kg), ethylbenzene (150 mg/kg), and xylenes
<br /> (1,200 mg/kg). Boring soil results in 8/04 were TPHg(558 mg/kg), benzene (0.3 mg/kg), toluene.(2.36 mg/kg),
<br /> Date: ethylbenzene (5.14 mg/kg), xylenes(6.3 mg/kg), and MtBE(0.03 mg/kg). Groundwater results in 3/96 were TPHg
<br /> (24,000 pg/L), benzene(4,700 pg/L), toluene(3,400 pg/L), ethylbenzene(1,000 Ng/L), xylenes(1,000 Ng/L), and MtBE
<br /> 2/23/05 (270 pg/L). In 10/04, groundwater results were TPHg(269 pg/L), benzene (1.2 pg/L), ethylbenzene(6.2 pg/L), xylenes
<br /> (2.1 pg/L), and MtBE(55 pg/L). Based on the limited extent of soil contamination and decreasing contaminant
<br /> concentrations in groundwater, Regional Board staff concur with San Joaquin County's.Closure Recommendations
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