SITE INFORMATION AND CORRESPONDENCE

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, , E,1,-_CIHE1ZKUST OF REQUIRED DATA I '6fi&OftUEST3 AT UNDERGRWft TQC S Site Name and Location: Daniels PropertyNellow Cab Co.,2210 Country Club Blvd.,Stockton,San Joaquin County 1.Distance to production wells for municipal,domestic,agriculture,industry Non-operational municipal well 1,500 feet and other uses within 2000 feet of the site; northeast(downgradient)of sits. Non- operational Irrigation well 1,400 feet west. 2. Site maps,to scale,of area impacted showing locations of former and existing tank systems, In July 1992,one 2,000- excavation contours and sample locations,boring and monitoring well elevation contours, gallon gasoline UST was gradients,and nearby surface waters,buildings,streets,and subsurface utilities, removed. In March 1998, three borings were drilled. 3. Figures depicting lithology(cross section),treatment system diagrams, Boring logs depict lithology for P-1 and P-2. Contamination appears to be limited to former UST pit. © 4. Stockpiled soil remaining on-site or off-site disposal(quantity), No overexcavation performed. 5.Monitoring wells a maining on-sits,fate No monitoring wells installed. 6. Tabulated results of all groundwater elevations and depths to water, Groundwater encountered at 12 feet bgs. Flow direction is to the N/NE. 7.Tabulated results of all sampling and analyses: Soil and groundwater samples could be collected from only P-1, HN Detection limits for confirmation sampling located In former UST pit. Maximum concentrations in soil were TPHg(24 ppm)at 12 feet bgs,and ethylbenzene(0.0057 ppm)and Lead analyses xylene(0.0087 ppm)at 15 feet bgs. Soil samples were NO at 20 and 25 feet. Groundwater sample showed TPHg at 1,700 ppb, ethytbenzene at 48 ppb,and xylene at 50 ppb. Benzene and fuel oxygenates were not detected in all samples. 8. Concentration contours of contaminants found and those remaining in soil Vertical extent of soil impact is approx.15 ,agdgroundwater,and bot -site and off-site: feet bgs,as defined by P-1. Limited lateral U Lateral and Vertical extent of soil contamination extent of soil impact inferred by lack of m Lateral andN❑ Vertical extent of groundwater contamination hydrocarbon indicators in P-2,located 15 Ci feet NW of P-1. Unable to define extent of groundwater contamination with only one grab water sample. © 9.Zone of influence calculated and assumptions used for subsurface No remediation system installed. remediation system and the zone of capture attained for the soil and groundwater remediation system; © 10.Reports/information Unauthorized Release Form OMRs(Dates) *W dbon�ig PAR FRP Oiher(report name) 2.Feb.200i)Ctosur Summary rt IT-i CJ © 11.Best Available Technology(BAT)used or an explanation for not using BAT; No remedial actions taken. © 12.Reasons why background wasrs unattainable using BAT; Natural attenuation will achieve water quality objectives with time. © 13.Mass balance calculation of substance treated versus that remaining; Site Investigation suggests contamination is limited to UST pit. 14.Assumptions,parameters,calculations and model used in risk No risk assessment performed. © assessments,and fate and transport modeling; 0 15.Rationale why conditions remaining at site will not adversely Clay and silty soil will retard dissolved hydrocarbons ict water quality,health,or other beneficial uses;and from migrating off-site. Nearest downgradient groundwater receptor is 1,500 feet from site. © 1 ET or TCLP results No WET or TCLP analyses performed. By: Comments:Site can be closed as a low risk groundwater case. Although the extent of hydrocarbon contamination was not defined by the investigation conducted,the County corroborates that the Date: limits can be inferred by the low hydrocarbon concentrations detected at the UST pit and field 5/11/ observations at other boring locations. No benzene or MTBE were detected above the lab limits.