ARCHIVED REPORTS_XR0008286 - Laserfiche WebLink

Home Browse Search

1 21 March 2006 AGE-NC Protect No 97-0290 ' Page 12 of 15 ' 7 3 5 Borehole Abandonment At the conclusion of soil boring activities, the borings were permanently sealed to prevent vertical ' migration of contaminants Under EHD oversight,the boreholes were backfilled with cement slurry from total depth to surface grade ' 8.0. FINDINGS ' Ground water elevation, flow direction, and gradient were determined from field data collected on 13 October 2005 The contaminant impact to ground water and soil was quantified from Iaboratory analysis of the ground water samples 8 1 GROUND WATER ELEVATION AND GRADIENT Depth to ground water at the site ranged between 48 26 feet(MW-4)and 53 34 feet(MW-2)below the tops of the well casings (btoc) Ground water elevation ranged between 0 86 feet and 1 30 feet below MSL in the monitoring wells (Table 3), the ground water elevation decreased an average of ■� 0 5 feet between the fourth quarter 2005 and the first quarter 2006 monitoring events The ground water flow direction at the time of the January 2006 monitoring event was inferred to be toward the south and southwest at a hydraulic gradient of 0 009 ft/ft,which is consistent with historical ground water flow directions A ground water elevation contour map for the first quarter 2006 monitoring event is illustrated on Figure 4 ' 8 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g and MTBE were not detected in the ground water samples collected from wells BTEX compounds were detected in the sample from well MW-2 at concentrations of 4 0 µg/1 toluene and 5 7 pg/l xylenes Analytical results of the water samples collected at the site are summarized in Table 2 The Iaboratory report (CTEL Project No CT214-0601115), chain of custody form, and quality assurance/quality control (QA/QC) report are included in Appendix C GeoTracker confirmation I pages of the submitted laboratory electronic deliverable format (EDF) files are included in Appendix D Advanced GeoEnvironmental,Inc