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'. 05 June 2001' . AGE-NC Project No. 95-0106 quarters of 1999, the first quarter of 2000 and the second quarter.of 2001. Additionally, - ' TPH-g was detected in MW-7 for the first time since monitoring began in 1998. • .• Analytical data from monitoring well' MW-2 limits the:horizontal; extent of dissolved: hydrocarbons southward of the site. Analytical data from well MW-3 and MW-6 limits the ; extent of dissolved hydrocarbons northeastward of the site. Analytical-data from monitoring well MW-5 limits the,extent of dissolved' hydrocarbons'north-westward of the site. The ' extent of dissolved hydrocarbons to.the east is not well defined at this time; it appears,that. •' the plume of contaminated ground water may have shifted to the east. • As can be seen on Table' 2, TPH-g concentrations were generally higher in ground water samples collected from the offsite well MW-4 than in the ori-site well, MW-1,however,. benzene concentrations have generally been higher in samples from MW-1. Continued detection of TPH-g and BTEX in ground water samples collected from the off-site well MW4,.and the recent detection of TPH-g in MW-7,indicates that.the plume of impacted' ground water has migrated off-site towards the north and east, however, the general lack of detection of hydrocarbons in the MW-6,MW-5 and MW-3 wells shows that the plume isnot wide=spread and has not migrated.northeast of MW-4 or northwest of the former UST pit. � . • The.extent of the plume around MW-4 is constrained by data from MW-6,toward the north- ' northeast, and MW-5 toward,the southwest relative to MW-4. The northwesternand southeastern extent of the plume from MW-4 is not well,con' thrained. The results of this and previous monitoring events and previous soil investigations leads AGE to conclude that: • The hydrocarbons encountered in ground water samples,from MW-1 and MW-4,represent' ' a northward extension of.the..hydrocarbon-impacted ground water that had already reached ' its current extent at the tithe the monitoring well'system was installed beginning in 1996.The . hydrocarbons encountered iri•ground water samptes'from MW-7 may.represent a recent, eastward extension of the hydrocarbon-impacted ground water. The variation of liydrocarbon coriceriirations in.sainples collected from MW-1'and MW-4 ' maybe due to its closer proximity to'impacted soil left in place near the former UST site: 6.0. RECOMMENDATIONS± ' AGE'recommends continued ;quarterly _montoring:of.the rrionitoring .well network: The next monitoring event should be scheduled for August 2001..The workplan addendum recently approved J Advanced GieoEnvlronmental,Inc.