Laserfiche WebLink
07 December 1998 <br /> AGE-NC Project No: 95-0106 <br /> ;Page 6of7 1 : , <br /> The ground water gradient on 27 May 199 was calculated to be an average of 0.0034'..ft/fi <br /> directed radially northward, with the ground'water flow direction ranging from northwest to ,. , <br /> northeast. <br /> Groundwater,elevation at the site decreased an aver_age 0.;11 'feet since the last quarterly <br /> ` monitoring event: <br /> Dissolved petroleum hydrocarbons were detected only :in:the sample,-from well MW-4;:,; <br /> located off-site and down-gradient (north)of the former U_ ST excavation. <br /> Oxygenated compounds were not detected' in .any of the ground water Samples,-by-EPA <br /> Method 8260m. <br /> Low concentrations of VOCs were detected in the.water sample collected•from MW 4'' <br /> r The concentrations of analytes detected iri the ground water samples from the,impactcd on- <br /> site monitoring well, "(MW l) have generally declined'over'over the ' course of,. six' <br /> sampling/monitoring events to,date. <br /> Analytical data-from monitoring well MW-2 limits the extent.of dissolved hydrocarbons •, <br /> southward of the site: ,Analytical data from.well MW-3 and MW.-6 limits the extent of <br /> dissolved'hydrocarbons northeastward of the site.Analytical data from monitoring well MW- <br /> S limits.the extent of dissolved hydrocarbons westward of the site. Analytical data from we11.• <br /> MW-7.limits the exterit'of dissolved hydrocarbons eastof the site. ` <br /> • „ After declining,in 1997, hydrocarbon concentrations have been generally higher in ground ; <br /> water-sarnples collected from'the offsite well MW 4 in 1998 <br /> •''' Cont_inued detection of TPH-g and'BTEX in ground water"samples collected'from the off;site <br /> well"MW4 indicates that the plume of impacted ground water has migrated off-site towards <br />' the north.The extent of:the plume around MW4is constrained by,data fro ."M W6�.toward <br /> the`nortli-northeast; MWS toward the 'southwest and P4;toward the.'southeast.relative o'; " <br /> MW4: The northwestern extent of the plume is_not constrained.' <br /> RECOMMEND'ATIONS. . x' ' <br /> }: Based on the results-of this investigation; AGE recommends. °s <br /> Collection of soil and ground water samples to characterize a 'd.delrneate.the.off--site pluirie <br /> of im acted ground water. AGE is preparing.a work plan toaddress this issue ` <br /> -. .. : <br /> • Saturated•hydrocarbon-impacted soil both'on-site and off,-site is not easily accessible, due <br /> 'to being located;urider structures (Le. roadway,,building) associated with the site..AGE does <br /> F' 4dranced GeoEFi ironmenial Inc. <br />