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09'August 1999 AGE-NC Project No. 98-0466 Page 5 of,10 would-be iinpacted.'Excavation of the:ramp would greatly increase the volume of excavated soil.For r simplicity, AGE assumes,that 700 cubic yards of impact d soil was rernoved. AGE believes that the ` volume of impacted'soil removed was actually.greater, but the 700 cubic yard figure will yield a minimal mass removed. The average concentration of TPH-d in'soil samples cc 11ected in the dispenser/piping area during the UST removal and in soil samples collected from the stockpile,of impacted soil was 1;712 milligrams per kilogram (mg/kg); individual soil sam le.TPH�d concentrations ranged from <10 -mg/kg up to 7,300 mg/kg. . . Assuming a weight of 1,225 kilograms per cubic.yard, a mass,of TPH-d.remove'd-can be estimated. -as follows: Mass (yards) x (I;225 kilograms/yard3) x'(0. 01712 kilogram TPH_d/kilograrn soil) ; Mass = 1,468 kg TPH-d; converting to pounds r Mass =.(1,468 kg TPH-d) x (2.2046 lbs/kilogr ) —co3,236.4 lb TPH-d; ' at approximately 7.00 lb/gallon for diesel fuel; the m s verts to a volume of 462.3 gallons of diesel fuel removed. This calculation is not intended 'to be exact, but to provide an order of magnitude of the mass and volume of diesel fuel removJd from the site by the excavation.remedial r action. To round off, AGE estimates that 3,200 lbs or 45 gallons of diesel fuel were removed from the site. 2.4. SITE STATUS FOLLOWING EXCAVATION PHS=EHD field diagrams indicate that the area of excavati.6n was the former dispenser and/or piping �`- locatioh, and suggest that the former UST did not contri lute significantly to.the,soil contamination. The,data andfield notes available strongly suggests-that Most of the'hydrocarbon-impacted soil has been excavated and that the vertical.extent of impacted soil.had been exceeded at 45 feet bsg'iri the excavation. The PHS-EHD.issued a letter dated 27 July_ 1998 notin .that;-based on the.data available, the site appeared to be a candidate for closure, but required verif cation of non-detectable'concentrations of TPH-d and BTEX in soil below 45,feet bsg and in'soil and round water at the round water/soil- g ground second PHS-EHD letter, dated.03 March. 1999, required a work plan to assess the vertical and lateral extent of contamination at theprevio s UST locatign. Following a,discussion of the site history and current status between AGE and Nis. arol Oz of the PHS-EHD'on 19 May 1999, it was decided-that;It would be.appropriate to:advance two soil borings in the area of the former UST ' Advanced Ge6Environmental,Inc.