ARCHIVED REPORTS XR0010943 - Laserfiche WebLink

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G4 03 June 2002 AGE-NC Project No. 97-0360 Page 6 of 7 4.0. SUMMARY AND CONCLUSIONS 'J Based on the data collected from the site,AGE concludes: Ground water flow at the site on 11 February 2002 was inferred to be toward the r west-southwest at a gradient of 0.003 feet/feet. =" Generally, gray to brown, damp to saturated, clay was encountered from surface grade to approximately 20 feet bsg in well borings MW4, MW5 and EW1, from surface grade to approximately 15 feet bsg in well borings MW1 and MW3 and from 25 feet to 30 feet bsg in well boring MW2. Dark brown,saturated,silty sand was encountered from 15 feet bsg to 20 feet bsg in well borings MW1 and MW3 and from30 feet to 35 feet bsg in well boring MW2. �Jb,�trtylalp3 TPH-g was deteted in lthe soil samples collected from MW 1,MW3,MW4,MW5 and EW 1 at 10 feet bsg . TPH-d was detected in the same samples, with the exception of EW1 at concentrations as high as 3,800 mg/kg. • TPH- was detected in the ground water samples collected from all the wells sampled,with g �' p p the exception of MW3, at concentrations as high as 380[ig11. The lateral extent of petroleum hydrocarbon-impacted soil has not been n defined.The vertical j extent has been defined, and does not extend beyond 20 feet bsg. • The lateral extent of petroleum hydrocarbon-impacted ground water has only been defined toward the west of the former UST area; impacted ground water does not extend beyond MW3. The vertical extent has not been defined. An isoconcentration map illustrating the approximate extent of dissolved TPH-g is presented in Figure 6. 5.0. RECOMMENDATIONS Based on the findings of the environmental activities recounted in this report, AGE recommends, initiation of quarterly monitoring of the ground water monitoring wells on-site.The next monitoring { event should be performed in May 2002.' Advanced GeoEnvironmental,Inc. I