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I I28 January 2004 . AGE-NC Project No 97-0230 Page 7 of 8 I depths of 30 feet bsg, however area no 2 appears to extend vertically to maximum depths of 40 feet bsg (Figures 6, 9 and 12) in the vicinity of soil boring P-3 ' • Diesel-impacted and motor oil-impacted soil is apparent in the same three above mentioned gasoline-impacted areas (area nos 1, 2 and 3), albeit much more laterally extensive in area nos 2 and 3 From the former tank pit area, area no 1 appears to be laterally limited to a ' radius of 5 feet,however, from the former tank pit, area nos 2 and 3 may extend outward in excess of 40 feet Generally, diesel-impacted and motor oil-impacted soil does not extend vertically to depths greater than 10 feet bsg (Figures 7, 10 and 13) N d P S d, 0,1,J-(I S 0 • Significant TPH-d and TPH-mo and residual benzene, MTBE and 1,2-DCA were detected from the P-9 grab ground water sample at a depth between 65 feet and 68 feet bsg, it is possible that ground water south-southwest of P-9 has been impacted I • The apparent volume ofgasoline-impacted soil encompasses approximately 21%cubic yards, and yields approximately 0 25 gallons of gasoline,or 16 pounds remaining in soil(Appendix I C) • The apparent volume of MTBE-impacted soil encompasses approximately 209 cubic yards, and yields approximately 0 59 gallons of MTBE, or 3 63 pounds remaining 1n soil • (Appendix C) • The apparent volume of diesel-impacted and motor oil-impacted soil encompasses approximately 952 cubic yards, and yields approximately 12 7 gallons of dieseUmotor oil, which 1s equivalent to 79 5 pounds remaining in soil (Appendix C) _ 5.0. RECOMMENDATIONS Based upon data collected from the site, AGE recommends • Installation of at least one additional on-site ground water monitoring well in the area between soil borings P-3 and P-9 to augment the existing ground water monitoring wells, which were screened above the water table (i e dry wells) and have not produced ground water since March 2001 • Installation of one off-site ground water monitoring well approximately 50 to 75 feet south- southwest of soil boring P-6 to determine the extent of off-site petroleum-impacted ground Iwater and provide a repeatable ground water monitoring location I Advanced CeoEnvironmcntal,Inc I