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mss_ C1IAvrER 5 CONCLUSIONS These conclusions have been made after reviewing the data available for ARCO Products Company Station 2093, Tracy, California. Groundwater currently flows in a northerly direrl ydirection cast butpa�st ntitc�i direction events)-a by as much as 90 degrees (ha The groundwater from four of the monitoring wells (ATR 1, ATR 3. ATR 4' and ATRand -5) contained benzene dwaterith the highest sampl s cane ted from the o f sitencentrations nmonitoringg in wel s ATR-4. None of the groan contained detectable concentrations of hydrocarbon constituents. • Based on the results of this and pa3t investigations. the east or south. norotb ezenet, does not exist beyond the site boundary ethylbenzene, toluene, m ATRllna concentrations ATR git can be concluded that the northern groundwater samples from approximately represents the northern boundary of the boundary of the site app to the hydrocarbon-affected groundwater. Permission from the owner of the property is west of the site to install two proposed monitoring wells could ht be ob ori off ced r still pending. Because of this, the western boundary Y groundwater has not been completely defined. • soil samp' collected from the off-site monitoring wells co ntained None of the present in detectable concentrations of hydrocarbon constituents. Hydrocarbons are p the soil the soil surrounding the underground storage tanks (U rei dicated bytThe sample results from boreholes BH-1 and 13x-2 and previousinvestigations. st likely the s. arbon source of the hydrocarbons in thisarea northeast portion of the site(ATR-1 and ATR-7 affected soil has also been identified to drocarbons in the approximately 10 feet below ground surface). The source there rite by northeast portion may be the pump islands. At this time there is no indication of off- site soil contamination. • TCE was detected in one well (ATR-2) in low concentrations.