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1 1 <br /> 27 January 2006 <br /> AGE-NC Project No 98-0500 <br /> Page 9 of 10 <br /> • The shallow groundwater(HU 1)flow direction was inferred to be generally toward the north <br /> and northwest at the former UST location, deeper ground water (HU3/4 and HU6) flowed <br /> southeast <br /> • TPH-g was detected in ten of the ground water samples analyzed, TPH-d was only detected <br /> in the shallow HU1 wells MW-1, MW-2, and MW-16, the highest concentration was <br /> detected in shallow well MW-1 at the former dispenser area TPH-Stoddard was not detected <br /> in any of the wells at the site The TPH plume is defined <br /> • The highest concentrations of BTEX compounds were detected in the samples from wells <br /> on three sides of the dispenser area(MW-1,MW-2,MW-3,and MW-7) Low concentrations <br /> of BTEX compounds were again detected in the samples from well MW-8 west of the <br /> dispenser area and well MW-16 near the western edge of the building The BTEX plume is <br /> defined <br /> • The only fuel additive detected was 1,2-DCA 1,2-DCA was detected in a total of twenty-six <br /> ground water samples collected from six of the designated hydrogeologic units across the <br /> site, the highest concentration of 1,2-DCA was detected in well MW-1 (HU1) at 340 pg/l <br /> The estimated lateral extent and distributions of dissolved 1,2-DCA in three of the main <br /> hydrogeologic unit are shown on Figures 6,7, and 8 <br /> • The lateral extent of dissolved 1,2-DCA has not been defined The shallow limit of the <br /> dissolved 1,2-DCA plume is defined within the monitoring well network,however, 1,2-DCA <br /> concentrations observed in the newly installed wells were stable or decreased with depth <br /> across the hydrogeologic units down-gradient of the former UST release (west) <br /> • At the present time, 1,2-DCA concentrations at the northern edges of the plume appear <br /> stable <br /> 5.0. RECOMMENDATIONS <br /> Based on the findings of this investigation, AGE recommends <br /> • Continued quarterly ground water monitoring and soil-vapor extraction at the site <br /> 6.0. LIMITATIONS <br /> Our professional services were performed using that degree of care and skill ordinarily exercised by <br /> environmental consultants practicing in this or similar localities The findings were based mainly <br /> upon analytical results provided by an independent laboratory Evaluations of the hydrogeologic <br /> Advanced GeoEnvironmentai,Inc <br /> i <br />