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TAb%.c 1 - CHECKLIST OF REQUIRED brATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Former Shell (Case#2),420 West Kettleman Lane, Lodi, San Joaquin County
<br /> 0 1. Distance to production wells for municipal, domestic, agriculture, A well survey in 1999 shows the nearest municipal
<br /> industry and other uses within 2000 feet of the site; supply well (#12)is approximately 30 feet to the
<br /> southwest and downgradient of the site. No other
<br /> wells were located within 2000 feet of the site.
<br /> 0 2. Site maps, to scale, of area impacted showing locations of former and existing tank One 10,000-gallon gasoline, one
<br /> systems, excavation contours and sample locations, boring and monitoring well elevation 8,000-gallon gasoline,and one
<br /> contours, gradients, and nearby surface waters, buildings, streets, and subsurface utilities, 5,000-gallon gasoline USTs
<br /> were removed in January 1999.
<br /> YD 3. Figures depicting lithology(cross section), treatment system diagrams;
<br /> Site lithology consists of silt, silty sand and
<br /> ETJsand to 100 feet, the total depth investigated.
<br /> 4. Stockpiled soil disposed off-site(quantity);
<br /> Approximately 744 cubic yards of excavated soil was transported to
<br /> Forward Landfill,Manteca.
<br /> Q5. Monitoring wells remaining on-site, fate;
<br /> Three monitoring wells(AW5,ML'416,MW-J)and three soil vapor extraction
<br /> wells(VE-1 through VE-3)have been installed for this investigation. The
<br /> wells will be properly destroyed pending site closure.
<br /> 0 6. Tabulated results of all groundwater elevations and depths to water,
<br /> The depth to water varied from 54 to 60 feet,and
<br /> the groundwater flow direction varies from
<br /> southeast to southwest
<br /> 7.Tabulated results of all sampling and analyses: On 2199,TPHg (9,950 mglkg), benzene(0.962 mg/kg)and MtBE(60.4
<br /> B Detection limits for confirmation sampling mg/kg)were detected in soil. TPHg (110 NgIL), benzene(7.7 pg/L), and
<br /> MtBE(99 pg/L)were detected in groundwater in 2001. On 12102,only
<br /> Lead analyses xylenes(0.64 pgIL)were detected in groundwater.
<br /> 8. Concentration contours of contaminants found and those remaining in soil
<br /> d groundwater, both on- and off-site: The extent of contamination is defined by
<br /> Y Lateral and Y Vertical extent of soil contamination on-site soil borings and monitoring wells.
<br /> Lateral and Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface During a five-day pilot study in 11/01,soil
<br /> remediation system and the zone of capture attained for the soil and vapor extraction removed approximately 2
<br /> groundwater remediation s stem; gallons of TPH-g and 0.75 gallons of MtBE.
<br /> 10.Reports/information Unauthorized Release Form E] QMRs(3/00 to 12/02)
<br /> E Boring logs El SIR 0 FRP (No Further Action Request Report, 12/02)
<br /> 0 11.Best Available Technology(BAT) used or an explanation for not using BAT,• Remove USTs, SVE,and natural attenuation.
<br /> Y❑ 12.Reasons why background was/is Decreasing concentrations have been attained at all monitoring wells. Minor
<br /> unattainable using BAT soil contamination remains on-site.
<br /> ETI 13.Mass balance calculation of substance Mass balance was not calculated. Confirmation soil sampling after soil vapor
<br /> treated versus that remaining; extraction did not detect contaminants in soil.
<br /> Q14.Assumptions,parameters, calculations and model used in risk
<br /> assessments, and fate and transport modeling,and A risk assessment was not required.
<br /> 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. nine sampling events, contamination is not continuing to
<br /> leach to groundwater. Groundwater monitoring shows a
<br /> decreasing trend in concentrations.
<br /> By: Comments: One 5,000-gallon, one 8,000-gallon, and one 10,000-gallon gasoline USTs were removed from the subject
<br /> JLB site in January 1999. Soil contamination was identified at the gasoline USTs area,piping, and dispensers. Multiple
<br /> borings, one groundwater grab sample, and three monitoring wells were completed to delineate and monitor
<br /> Date: contamination at this site. In 11/01, soil vapor extraction removed 2 gallons of TPHg and 0.75 gallons of MtBE before
<br /> concentrations declined sharply after 5 days. Monitoring wells MW-5, MW-6, and MW-8 were sampled from 3/00 to
<br /> 3/20/03 12/02. In 12/02,groundwater contaminant concentrations declined to<50 pg/L for TPHg, <0.5 pg/L for benzene, and
<br /> <0.5 Ng/L for MtBE. Additionally, the City of Lodi samples Public Supply Well#12(Well#12)monthly for contaminants.
<br /> No contaminants have impacted groundwater from Well#12. Based on the minor soil contamination and decreasing
<br /> contaminant concentrations in groundwater, Regional Board staff concur with San Joaquin County's Closure
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