ARCHIVED REPORTS XR0000734 - Laserfiche WebLink

Home Browse Search

i28-April 4999 AGE-NC Project No. 95-0106 Page 3 of 4 _ MW-3, MW-5, MW-6 (upper).or MW-6 (lower),and MW-7. Oxygenated•fuel additives were not. ' detected in any of the ground.water.samples Analytical results,of ground'water samples for the February 1999 monitoring event are summarized on.Table§ 2, and 3. The laboratory,report;(MAI Laboratory ID'04105 through 04112), QA/QC and chain-of-'custody are'included in Appendix B. 4.0. SUMMARY/CONCLUSIONS The following conclusions were drawn from the results of the,site investigation: : ' The round water radient-on 24 Feb 1999 was calculated to.be an average of 0.009 ft/ft _ . g g February g . . . _ with an average flow direction of approximately'N 9'W. ' Ground water'elevation.at the site increased an average 0.89 feet since the last quarterly monitoring event. ' , • Dissolved petroleum hydrocarbons were detected in ground water samples from monitoring wells MW-1 and MW-4, located .cross-gradient on-site and down-gradient off--site, S respectively; from the former UST excavation. • Oxygenated compounds were not.detected in any of the ground water samples by.EPA Method 8260m and have not been detected by this analytical method''for five quarters of ' monitoring. • Low concentrations of BTEX compqunds were detected in'the water samples collected'from MW-1 and MW-4._ • As can be seen on Table 2, the concentrations of analytes detected in the ground.water samples from the impacted on-site•monitoring well (MW-1)have generallydeclined over the ' course of the six previous sampling/monitoring events, but have rebounded during the"first quarter of 1999. ' Analytical data from monitoring.well MW-2 limits the:extent of dissolved hydrocarbons southward of-the site. 'Analytical data from •well.MW-3 and MW-6 limits the extent of dissolved hydrocarbons northeastward of the site:.Analytical data from monitoring.well•MW- ' ' 5 limits the extent of dissolved hydrocarbons westward of the site:.Analytical data from well MW-7 limits-the extent of dissolved hydrocarbons east of the site. Ascan be seen on Table 2, hydrocarbon concentrations were'generally higher'in ground water samples collected from'the offsite well MW-4 in.1998 after declining in 1997,but have declined in'the first quarter,of monitoring-in -1999. ' •. Continued detection of TPH-g and BTEX in ground water samples collected from the off-site ,well MW4 indicates that the plume,of impacted groundwater has migrated off-site towards Advunced.GeoEnvironmental,Inc.