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1 - <br /> 1 SITE ASSESSME <br /> NT ACTIVITIES <br /> An initial subsurface assessment was performed by VVaterWork Corporation <br /> advanced to a depth of approximately 35 feet below surface grade(bsg)nar tank q oil boring was <br /> was encountered at 32 feet bsg DGround water <br /> tails of the initial investigation were summarized in a Preliminary <br /> Assessment Report dated 12 January 1990, prepared by WaterWork <br /> inary <br /> Five soil borings(B 1 through 135)were drilled at the site by Geological Audit Service <br /> 11 and 14 February 1994'Borings$1 through s,Inc between <br /> as ground wMW-1 through MW-4,respectively Free Product was encountered n and removed MW-4 aetedtr removed <br /> beetween , <br /> wells <br /> September and November 1994 Total petroleum hydrocarbons quantified as g asoline(TPH-g)and <br /> volatile aromatics(benzene, toluene,ethylbenzene and xylenes,BTEX)were detected in <br /> TPH as diesel (TPH-d) was detected in MW-4 each well <br /> From 19 to 26 February 1996,six he born <br /> Inc Boring MW-7 was advanced to a depth of 60 feet were advanced attandlte wa y odmpl to Gs a ground <br /> ronmentaound waterr <br /> monitoring well Bonng VW-1, drilled at an angle of 30' from verb aI directed N <br /> advanced to a vertical depth of 55 feet bsg with a horizontal run of 31 8 feet and was 34oE' was <br /> surface grade Borings VW-2, VW-3 and VW-4 were advanced vertically to a depth of 55fe backfilled to <br /> f were completed as vapor extraction remediation wells (VW-2 double-com fete p 55 feet and <br /> drilled at an angle of 10' from vertical directed N 80° W, was advanced to a depth of 55 Boring VW-5t <br /> bsg with a honzontal run of 7 feet and was tnPle-completed as a vapor extraction rem vertical feet <br /> Petroleum hydrocarbons were detected in each boring at concentrations remediation well <br /> (milligrams per kilogram, equivalent to parts per million a high as 23,000 mg/kg <br /> ppm, V WS at 1 S feet) <br /> Sample VW3-40 and VW5.30 were analyzed for bioenumeration and physicochemi <br /> Very low populations of both general and selective microbial populations we cal properties <br /> rved N <br /> concentrations were below optimal for biodegradation of hydrocarbons Additional ba kit ounn <br /> information is summarized in the AGE-prepared Quarterly Report-August 1997 d <br /> On 13 and 14 November 2001, two off-site,paired soil borings CPT- <br />' immediately south of the site (Figure 2) utilizingg ( z and CPT-3)sere advanced <br /> maximum depth of 157 feet bsg and CPT-3 was duan ed t technology et CPT <br /> -L �o advanced to a <br /> results detected the highest petroleum hydrocarbon-impacted CPT water samples from fine-grained Laboratory analytical <br /> soil intervals between approximately 50 and 85 feet bsg and between 135 and 160 feet e wined <br /> southern tanks location(CPT-2), the impacted ground water plume extends laterally at all sg at the <br /> the CPT-3 location BTEX compounds were detected at all depths in the CPT bon depths to <br /> crater samples collected from CPT-2 exceeded the DHS Is Maximum Contaminant LevelsgBTEX in <br /> for BTEX in ground grater,however, benzene�,�,as the only$TEX compounds exceed ACLS) <br /> m water samples collected from CPT-3 VOCs were detected at all depths in the CPT borings 1 2_ <br /> exceeding the MCL <br /> DCA was present in HU2 and HU12/13 at concentrations exceeding the MCL g <br /> naphthalene,n-propyl benzene, 1,2,4-triinethylbenzene and 1,3,5-trimethylbenzene concentrations <br /> If'HLJ3 and HLI12/13 exceeded their respective action le � addition, <br /> veli, and n-propyl benzene exceeded its <br /> action level n HU2 The vertical and lateral extent of ontaminated soil and ground water have been defined at the site not <br /> Adv­ *4 GeaE'nvlronmental,Inc <br />