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10 <br /> . 06 March 2002 <br /> AGE-NC Project No 01-0865 <br /> Page 3 of 9 <br /> • Based on information obtained from the quarterly monitoring event conducted in December <br /> 2001, ground water depth beneath the site is approximately 3 to 6 feet below surface grade <br /> (bsg)and was inferred to be flowing toward the southeast However, flow direction may be <br /> both locally and seasonably variable <br /> A more detailed description of previous investigations at the site can be found in the <br /> Condor-prepared documents Quarterly Ground Water Monitoring Report Second Quarter 2001, <br /> dated 31 July 2000,and Soil and Ground water Investigation and Sensitive Receptor Survey Report, <br /> dated 02 October 2000 Ground water monitoring and sample analytical data from September 1997 <br /> to the present are summarized in Tables 1 and 2 <br /> 3.0 PROCEDURES <br /> On 27 and 28 December 2001 and on 18 and 21 January 2002,ten soil borings were advanced at the <br /> site to assess the lateral and vertical extent of MTBE-impacted ground water The field work was <br /> conducted as outlined in the Condor-prepared Additional Ground Water Investigation Work Plan, <br /> dated 07 May 2001 <br /> 31 DRILLING <br /> Soil probe borings B 1 through B 10 were advanced utilizing a van-mounted Geoprobe 5400 equipped <br /> with 1 125-inch diameter probe rods with an attached 2 15-inch diameter soil sampler,using"direct <br /> push" technology The probe borings were advanced vertically to depths ranging from 20 feet bsg <br /> to 50 feet bsg <br /> 32 SOIL SAMPLING <br /> Discrete soil samples were collected continuously from borings Bl, B3 and B6 and at 5-foot <br /> intervals, beginning at 5 feet bsg, in borings B5 and B7 Soil samples were not collected from <br /> bonngs B2, B4, B8, B9 and B-10 Continuous soil samples were retrieved using a Geoprobe <br /> four-foot macro core barrel loaded with one four-foot acetate sleeve Soil samples collected every <br /> 5 feet were collected using a Geoprobe two-foot soil sampling assembly loaded with four pre- <br /> cleaned 1 125-inch by 6-inch brass sleeves Soil samples were preserved by covering both ends of <br /> a separated,6-inch portion of an acetate sleeve or a selected brass sleeve with Teflon sheets,capping, <br /> and sealing with tape Each sample sleeve was labeled with soil probe boring location, depth, time, <br /> date and sampler's initials <br />