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' 26 November 2002 • AGE-NC Project No 95-0184 ' Page 4of5 ' • The ground water flow direction over much of the site is generally northeast, but can vary from north near the northwest corner of the site to east along the east side of a ground water finger in the northern portion of the site The ground water gradient ranged widely, from ' 0 023 ft/ft along the northwestern edge of the site to 0 007 ft/ft in the southern portion of the property • Detectable concentrations of TPH-g were found in all of �e ground water wells sampled 1 ' BTEX compounds were found in all groundwater sample except for MW-3,these samples contained one or more analytes at concentrations above Caforma's Maximum Contaminant ' Levels (MCLS), except for MW-7 (ethylbenzene 2 1 pg/1) • No free product was measured dunng this sampling event,however,most of the well screens are drowned and are not likely to produce direct evidence of free product ' • The oxygenated volatile organic compound MTBE was detected at a concentrations ranging from 22 µg/l (VW-5C) to 510 pg/l (VW-4);none of the other oxygenated volatile organics ' were detected at concentrations above laboratory reporting limits r • The concentrations of MTBE, EDB and 1,2-DCA in the ground water samples exceed the ' • DHS MCLS for drinking water r i • Naththalene, 1,2,4-tnmethylbenzene, 1,3,5-tnmethylbenzene and n-propylbenzene were detected in ground water samples at concentrations above the DHS-recommended drinking ' water action levels • The vertical and lateral extent of impacted soil and ground water has not yet been defined 5.4. RECOMMENDATIONS ' Based upon data collected from the site AGE recommends ' Continued ground water monitoring, the next quarterly monitoring event will be scheduled for September 2002 Since analyzing for BTEX compounds and MTBE is included in the full-scan EPA Method 8260 required for the site, analyzing BTEX compounds and MTBE again by EPA Method 8021 is redundant and should be discontinued Two of four proposed cone-penetrometer test(CPT)soil borings were advanced to a maximum depth I of 180 feet bsg on 13 to 15 November 2001 to assess the vertical and lateral extent of Impacted soil ' and ground water, to define hydrogeologic flow units at the site, and to optimize locations of j additional monitoring and extraction wells, however, ground water was still impacted at 180 feet Advanced GeoEnvironmental,Inc I