ARCHIVED REPORTS_XR0007537 - Laserfiche WebLink

Home Browse Search

I 30 September 2005 • AGE-NC Project No 99-0657 Page 5 of 8 ' 25 feet and 50 feet bsg A line of cross section is illustrated on Figure 2 and a stratigraphic cross section is depicted in Figure 3 The soil boring logs are provided in Appendix B Documents confirming the upload of electronic deliverable format(EDF)files and depth to water measurements to GeoTracker are included in Appendix G ' 32 ANALYTICAL RESULTS OF SOIL SAMPLES A total of 20 soil samples were analyzed for the constituents listed in section 2 4 , no analytes were ' detected at or above laboratory reporting limits in the soil samples collected from pilot boring MW-9 ' TPH-g was detected in soil samples collected from boring B-1 at depths of 25 feet to 60 feet bsg and 90 feet to 110 feet bsg at concentrations ranging from 1 1 milligrams per kilogram (mg/kg) in the 50-foot soil sample to 900 mg/kg in the 35-foot sample One or more BTEX compound were ' detected in the same samples, as well as the 130-foot soil sample, at maximum concentrations of 8 5 mg/kg benzene,47 mg/kg toluene,29 mg/kg ethylbenzene and 167 mg/kg xylenes(B 1-35) The most significantly BTEX-impacted soil is located at the depth of the water table or near 35 feet bsg ' . MTBE was also detected in the samples collected from depths of 25 feet to 60 feet bsg and 90 feet to 110 feet bsg,with the exception of the 100-foot soil sample MTBE was detected at concentrations ranging from 0 036 mg/kg(B 1-60) and 14 mg/kg(B 1-30) ' Analytical results of soil samples are summarized on Table 2 The laboratory reports CTEL Lab yt p rY p ( ' Project No CT214-0501124), quality assurance and quality control (QA/QC)report and chain-of- custody forms are included in Appendix E Documents confirming the upload of laboratory electronic deliverable format (EDF) files to GeoTracker are included in Appendix G 3 3 GROUND WATER GRADIENT AND FLOW DIRECTION ' At the time of the January 2005 sampling event,depths to ground water ranged from 35 73 (MW-7) feet to 39 04 (MW-9) feet below the tops of the well casings Ground water elevation at the site ' averaged approximately 4 64 feet above mean sea level (MSL), which is a decrease in elevation of approximately 0 34 feet since the October 2004 monitoring event(Table 1) During this monitoring event,the ground water levels in the wells were at least five feet below the tops of the well screens, ' indicating that the wells are screened properly to yield representative shallow ground water samples Ground water flow was inferred to be flowing toward the southwest under an average hydraulic gradient of approximately 0 004 foot/foot (ft/ft) This flow direction remains consistent with the . previous monitoring events Figure 4 shows the contoured ground water elevations as measured on tAdvanced GeoEnvironmental,Inc I