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11113. The lack of detectable fuel contamination in MW2 suggests <br /> that fuel constituents are not dispersing broadly from MW3 and <br /> that there is no offsite movement of contaminated groundwater <br /> from the localized concentration around MW3. <br /> Hydrocarbon sources have been eliminated with the removal of the <br /> underground storage tanks, piping, and associated dispensing <br /> equipment. On thebasis of this study and. previous investiga- e <br /> tions, highly contaminated soils that would function as an active <br /> source:'are not. <br /> present on. the site. The lithologies and. strati <br /> i graphy encountered and site setting indicate that the <br /> w g potential <br /> for hydrocarbon leaching from soils to <br /> {-- groundwater by recharge or <br /> direct infiltration .is low. <br /> Lj <br /> The areal .extentof <br /> groundwater contamination has diminished <br /> �.., <br /> since: .1..986` and at. present: is confined:to .the: site in the -area of <br /> MW3. Monitoring of the area indicates that There a <br /> pparently has <br /> been no local or <br /> proximate water use that would increase the risk of <br /> drawing groundwater Offsite, and the. low <br /> Probability of offsite <br /> migration represents a' limitec_ risk to .1 human receptors. <br /> The low <br /> Probability of offs3to migration is based, 'on a, low iS /S- <br /> hydraulic. conductivity of the aquifer. : Hydraulic conductivities <br /> appear to be on 'theorder of 70-6 m/s or: .less based on f <br /> approximations from purging records. Nor "<?oes it appear that, <br /> wel_1 <br /> performance can be improvedby deepening the wells or by i <br /> fi other techniques: The lour yield of the aquifer limits the <br /> s <br /> availabilit <br /> y ,of water for pumping. For this reason, and because <br /> . . the levels of "contamination are. very low and the contamination <br /> "' has not a s <br /> ppeared:ao be-migrating. based on::the...l.ast two years of <br /> i <br /> f monitoring, no further action is: recommerded 'at -this site. exce t <br /> € t to contnue ;to monitor .the condition of groundwater on a <br /> quarterly .basis for,,. year.' s' <br /> e25/7.1050/8-89/tkt 18 <br /> J <br /> r <br />