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' 07 May 2004 i AGE-NC Project No 98-0534 ' Page 3 of 14 , detected in one of the seventeen soil samples analyzed from the UST area TPH-d was detected at low concentrations in the former,dispenser area and in the mid product Iine ' trench TPH-g and BTEX were also detected in the mid portion of the product line trench TPH-g and TPH-d were detected in 16 stockpile soil samples BTEX compounds were detected In eleven stockpile soil samples analyzed 441 Ground water samples analyzed were impacted with TPH-g and TPH-d at concentrations up to 77,000 micrograms per liter(µg/1) and 70,000 gg/l,/as well as BTEX compounds at concentrations ' up to 7,890 µg/1 of benzene MTBE was detected at a maximum concentration of 3,100 gg/l by EPA method 8020 Qat 3, 04 /1. 'b memo,&( B.aL o 8 ' 23 PRELIMINARY SITE INVESTIGATION Based on analytical results of soil samples collected during the UST removals, a preliminary site investigation was required by the EHD by letter dated 09 March 1999 (Appendix A) prior to ' • obtaining a site closure for the former USTs The following is a brief summary of the site assessment investigations conducted at the site to date I G 04June 1999- two separate excavations were established in the area of the former dispenser and mid-product line An additional 50 cubic yards of significantly petroleum-impacted soil was removed and stockpiled on site Excavation DT was dug at the location of southern ' dispenser, along Navy Drive and T1 was dug at the location of a product release in the central portion of the product line trench The total depth of the DT excavation was nine feet below surface grade(bsg)on the west end and six feet bsg on the eastern end The total depth ' of the T1 excavation was five feet bsg Field observations indicated a minor hydrocarbon- impact to soil in the floor of excavation T 1 Hydrocarbon-impacted soil in the DT excavation was not observed Soil samples were collected from the DT and the T1 excavation side walls ' at depths of 3 feet bsg and two soil samples were collected from floor of the T1 excavation at a depth of five feet bsg TPH-g was detected at concentrations of 1 4 mg/kg in soil sample - T 1-F2 (floor sample) and 3-1'm—g'/-kg-in soil,sample DT-E (trench east) TPH-d was detected 4 ' in three soil samples at concentrations up to 140 mg/kg (DT-E) BTEX compounds were detected in two of the thirteen soil samples analyzed from the excavation Soil sample T1-1 contained toluene at a concentration of 0 006 mg/kg and xylenes at a concentration of ' 0 03 mg/kg Soil sample T1-F2 contained xylenes at a concentration of U 19 mg/kg MTBE was detected in seven of the thirteen soil samples analyzed by EPA Method 8020, at concentrations up to 0 52 mg/kg (T1-1) The analytical results of selected soil samples are r ' summarized in Tables 3 Eand 4 Results of the June 1999 excavation were reported in Preliminary Investigation and Evaluation Report, dated 18 April 2000, prepared by AGE ' Advanced GeoEnvironmental,Inc I� s