Laserfiche WebLink
r"e <br /> fes= <br /> 1 <br /> r �-r <br /> Perimeter and downgradient of the former gasoline/diesel tack pit(TPI). Soil contamination in <br /> these areas extends vertically to the shallow water table. Vertical rrigration of conn.aminants <br /> appears to have been fairly rapid with Iittle lateral spreading (Figure 5). <br /> f ' <br /> t <br /> .5.2 Groundwater impact <br /> The lateral extent of <br /> groundwater contamination has been defined in most sectors of the site. <br /> Analysis of groundwater samples collected from the monitoring wells,and soil samples collected <br /> from the capillary fringe in the borings and wells, has provided constraints on the limits of <br /> contamination in the following areas: the product line area; the waste oil pit area; and the <br /> western, southern and eastern sides of the gasoline/diesei tank pit ( P1) These appear to <br /> comprise three discrete areas of groundwater contamination <br /> •_ (Figure 5). The downgradient limit <br /> of affected grou:-ldwater emanating from the tank 1pit has not been defined. <br /> bJ <br /> The validity of utilizing, soil samples collected from the capillary fringe as indicators of <br /> g, underlying groundwater contamination is supported by the analytical results of samples collected <br /> from the monitoring wells. Soil samples collected from monitoring wells MWl and MW2 were <br /> found to be significantly impacted, as was groundwater. The soil sample collected from MW3 <br /> contained no detectably contaminants and the groundwater in this well was clean. The lateral <br /> distance of the wells from the source of the leaks (especially MWl) confirm that <br /> the soil <br /> 1r <br /> contamination detected therein is truly,due to capillary phenomena and not simply a result of <br /> Previous vertr�? <br /> P transport. The reasonable inference from the data is that,at this site, capillary <br /> fringe soils serve as reliable indicators of groundwater impact. <br /> The lack of appreciable downgradieiii migration of contaminated groundwater may be due to the <br /> 69 recent vintage of the Ieak combined with the low r-elocity silt/clay aquifer. <br /> lag <br /> f - <br /> 00 <br /> R-012792.LF <br /> i 7 <br /> \r1 <br />