ARCHIVED REPORTS_XR0005034 - Laserfiche WebLink

Home Browse Search

05 February 2002 • AGE-NC Project No 98-0432 ' Page 3 of 4 the top of the well casing (btoc) (Table 1) The ground water elevations at the site ranged from 18 25 feet to 19 56 feet above mean sea level in monitoring wells MW-6 and MW-5, respectively (Table 1) Ground water elevation in the monitoring wells decreased an average of 3 feet since the ' previous monitoring event in July 2001 A ground water elevation contour map for July 2001 Is illustrated on Figure 3 Based on ground water elevation data, ground water flow direction is away from a ground water high projecting across the central portion of the site,from well MW-I to MW-2 ' northwest The typical groundwater flow direction at the site is north to northwest The ground water elevation value from well MW-5, up-gradient,was not used for the ground water elevation contour map, the value was out of range of all other values by one foot It should be noted that at this low ' gradient, small measurement variations can cause significant changes In the inferred ground water flow direction ' 32 GROUND WATER ANALYTICAL RESULTS ' TPH-d was detected In the ground water samples collected from wells MWA and MW-2 at concentrations of 100 microgram per liter(pg/l) and 190 pg/l, respectively The highest concentration of MTBE detected was in sample MW-1 at 13,000 µg11 MTBE was also detected in the samples from wells MW-2 at 990 pg/l, MW-4 at 59 µg11 and MW-5 at 2 6 µg/1,EPA ' Method 8260 Modified There were no reported detections of fuel oxygenating compounds In any of the other ground water ' samples analyzed In addition, there were no reported detections of BTEX, TPH-g or other fuel additives in any of the ground water samples analyzed ' Analytical results from ground water samples are summarized in Tables 2 and 3 The laboratory reports(MAI Laboratory ID 82304 to 82309,quality assurance and quality control(QA/QC)reports and chain-of-custody forms are included in Appendix B 4.0. SUMMARY AND CONCLUSIONS ' The following conclusions were drawn from the results of this investigation ' e During this quarter, the prevailing ground water floe direction is towards the northeast, overall This inconsistent flow direction may be due to a surface water release near northern portion of the site and will be verified by further sampling events or may be due to small ' measurement variations with ground water at a very low gradient • TPH-d, detected only in MW-1 and MW-2, was at concentrations of 100 µg/1 and 90 µg/l, ' respectively Advanced GeoEnwronmentel,Inc