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1 <br /> Boring M. (Boring # 6 was terminated at a depth of 35 feet without <br /> obtaining a clean bottom•of-the-hole sample in order to avoid possible <br /> contamination of groundwater which at that time was believed to be <br /> between 35 and 40 feet below the ground surface.) fn samples where <br /> oil was risible, detections were as high as 7400 ppm. <br /> (;nN�,-TTgTQNS OF SOTC, ;�TTGA,riON <br /> An estimate of the extent of the soil contamination is shown in <br /> Figures 1-5, 1-6 and 1-7. The horizontal extent of the contamination <br /> can be roughly estimated from the analytical results if movement of <br /> the oil 'has been predominantly downward. Borings 1. 2, and 8 <br /> encount,. .d no contaminated soil on the north and west sides of the <br /> sampling site. 'Phew findings suggest that lateral movement of the <br /> oil has been limited, In addition, the deepest contaminated soil <br /> (Boring 6) was found directly below Tank # 2 where the highest <br /> concentration of TPHs was found in the previous investigation. No <br /> evidence was obtained during this investigation that suggests that <br /> lateral movement of the oil would be greater in one direction than in <br /> any another. The greater extent of contamination on the east side of <br /> the sampling site may be due to greater leakage from the east side of <br /> the tanks, or the tanks themselves may have been located further east <br /> than previous drawings indicated. This would have placed the <br /> eastern-most borings closer to the former tank locations than the <br /> western-most borings. Thus, the lateral extent of the contaminant <br /> plume may not extend more than a few feet beyond the western <br /> perimeter borings. <br /> 1-ll <br />