Laserfiche WebLink
1 <br /> ' 15 January 1997 <br /> AGE-NC Project No 95-0137 <br /> tPage 5 of 6 <br /> 3 4 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> Figure 3 - Relative Ground Water Elevations illustrates the relative ground water elevation on 19 <br /> December 1996 Depth to ground water at the site ranged from 18 65 to 19 52 feet bsg The data <br /> indicates an average decrease in ground water elevation at the site of 0 25 feet since September 1996 <br /> The depths to ground water and relative ground water elevations are depicted in Table 2 - Relative <br /> Ground Water Elevation <br /> Historically, ground water flow direction at the site has vaned from northwest to southeast at a <br /> ' consistently shallow gradient During December 1996, the ground water gradient was calculated to <br /> be 0 0006 ft/ft, with a northwesterly flow direction <br /> 3 5 LABORATORY RESULTS OF MONITORING WELL GROUND WATER SAMPLES <br /> Concentrations of dissolved petroleum hydrocarbons remained nearly constant or increased in <br /> samples from all wells between August and December 1996 TPH-g and/or TPH-d were detected to <br /> all wells at concentrations as high as 11,000 ppb Benzene was detected in samples from MW-1 <br /> through MW-3 at concentrations as high as 1,300 ppb Toluene, ethylbenzene and xylenes were <br /> detected in wells MW-1 through MW-4 at concentration up to 870 ppb(xylenes,MW-2) MTBE was <br /> ' detected only in the sample from monitoring well MW-I at 6 7 ppb <br /> Analytical results of ground water samples are summarized in Table 3 -Analytical Results of Ground <br /> ' Water Samples The laboratory report (MAI Laboratory Nos 72296 through 72300) and chain-of- <br /> custody are included in Appendix E <br /> t 4 0. <br /> CONCLUSIONS AND RECOMMENDATIONS <br /> ' 41 CONCLUSIONS <br /> t Based upon data collected during the October 1996 subsurface investigation and the December 1996 <br /> monitoring, AGE has the following conclusions <br /> ' Elevated concentrations of petroleum hydrocarbons were detected in the soil sample <br /> collected from 10 feet bsg in probe boring B 15, located near the former dispenser area on the <br /> Junco Truck Stop The detection of petroleum hydrocarbons in shallow soil near the former <br /> ' dispensers, identifies this area as a potential source of hydrocarbon contamination <br /> • It appears that MW-4 and probe boring B17 are near the western and southwestern extent of <br /> 1 <br />