Laserfiche WebLink
r <br /> ,40 feet near the former UST facility, they are distributed between 10 and 40 feet in VM-2, near the former <br /> dispenser island The implication is that VM-2 is located considerably closer to the leak point than are <br /> any of the other borings <br /> 5.1 Extent of Soil Contamination <br /> The absence of any evidence of soil contamination in HP-2 makes it possible to draw a zero line <br /> between it and VM-1 and VM-2 (Figure 5) Using the data collected fom the SB-series of bonngs <br /> drilled by Hunter & Associates, this line can be extended between SB-2 and SB-3 (Figure 5) The <br /> extent cannot be determined to the east of VM-2 or the west of VM-1 with the present data <br /> 5 2 Extent of Groundwater Contamination <br /> The groundwater data collected in July give a strong. suggestion that two separate plumes of <br /> contaminated groundwater have conringled beneath the site One plume, consisting primanly of <br /> gasoline and its components, appears to be centered east or southeast of VM-1, where TPH-g <br /> concentrations are double those in VM-1 (Figure 6) Assuming that the contaminants have spread in <br /> the direction of groundwater flow, this gasoline plume may be elongated in an east-west direction, as <br /> suggested in Figure 6, although additional monitoring points would be needed to confirm this Except <br /> perhaps for MTBE and xylene, it does not appear that contamination has reached V4-3, which is <br /> presently the most downgradient well <br /> Chlorinated hydrocarbons are present at much higher concentrations in VM-1 than in any of the other <br /> wells, suggesting that a second plume, consisting of one or more solvents, is present to the south or <br /> west of the gasoline plume This plume may be derived from an off-site source Concentrations <br /> decrease markedly from VM-1 to the east, but at Ieast one chlorinated hydrocarbon has reached VM-3 <br /> At this time, however, we do not have sufficient data to map the solvent plume <br /> 5.3 Groundwater Monitoring <br /> A variety of hydrocarbon contaminants have been detected in the groundwater beneath the site Some <br /> of these (i a the halocarbons), pose a serious health risk to people Therefore, we recommend that <br /> groundwater monitoring be continued to determine whether the contaminant plumes are stable or are <br /> migrating The next morutonng event should take place in December, 1996 <br /> 6 <br />