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-19.December-2003 `^ AGE-NC Project No.,95-01-28 . . .- ..Pae 4 of 12 77 MW-13throughMW-16 MTBE.was-detectedinth'e.S' samples collectedfrom,thirty;feetbsgfrom-_ > borings MW 15 and:MW16;these-coiicentrations maybe more reflective of impacted-ground water " . 1 - in-the'pore spa cesof_tho soil than of adsorbed MTBE: 'The highest concentration of dissolved hydrocarbons quantified-as TPH-g,TPH-land-overall BTEX: compounds occurs"in tle'areaseast and=northeast of.the dispenser islands, ori-site -The highest w ~ r .concentration:ofMTBE detected ft the ground-water occurs'ih monitoring wW el1�-M -11,which t situated:in'the median-of-,Pacific Avenue. Lower or'rlon-detectable concentrat ons' w.the-down gradient and cross gradient wells define the dissolved MTBE plume toward the north aid west:This .-suggests that the-dissolved'.MTBE plume is detaching from the TPH/BTEX hygrocarliori plume r- In-September'and=Octobet.2001,:a-low=flow,:ground wa'ter:extraction'and'treatinebt-system"wag ..-` aF*; , installed at the site The system utilizes the newly installed ground water.extraction well onsite and = - a small volume treatrnentsystem A volume of--179,479.gallons was extracted-between 10 March and F_:`' i r ll' September 2003:A totalPof 1,570;378_.9 gallons have been extracted.since the inception of the. 1 : ground.water.treattn_ent in'Ocfober_2001._During:the}this reporting'period;approxlmafely'0:38-lbs` of MTBE; 0:225~lbs-of benzene grid .1:86 lbs of TPH `g-were'relnoved from the'site and-treated by y - tlie'ground water extraction system °A total of 9.3 lbs of MTBE;:4.38:lbs of BTEX and"'673 lbs of VI TPH-g have been removed since October 2001 - Ori Q4 and 05 Februai*2003 two add itionalground rvater-monitoring.wells were installed off-site as partof the investigation. Boring MW17_was completed as-ground Water monitoriwell MW 17' using two-inch diameter PV C casing with 0.020�irich slotted screen installed from approxlmate1y25- = t ;feet to•45 feet bsg and boring MW 1--8.was'completed as ground;watermoriitaring well Mw-18 using--:. �rtF n. °two-inch diameter-PVC, gwlth.0 020-lncli sfiotted screen.instal:led-from.appidin ately.:60 feet`s to 65 feet bsg and_with blank casing extended to tYie surface.A't thattirrie;_the dissolved MTBE plume` i ` has been definedeasf ofwell MW=iG=bywells MW 17118.The lateral'extent of the_ 1, solved MTBE _ :=A _ plume is:depicted in Figure 2._ - - 3.0: SCOPE.-'OF WORK-PLAN Based on the current analytical'results of sarripling, the distribution--of the hydrocarbon'impacted .J= . I media at the site,the EHD is requiring ground water and-soil remediation of.peti oleurn hydrocarbon=' .impacted areaat-the site..This workplan details procedures for the installation ofth•ree=additional soil', vapor extraction{SVE)wells on site to perform vapor extraction Tli_ewapor extraction wells will be yJ I installed easvof the releaseiarea, located 'witli soil_'boring.B2L10 and'north"of the release area, J �. .r surrounding the previously installed vapor well .A soil vaor. pextraciion system will be.installed and. .• j _ "operated. "Advanced GeoEn'vironmental,lnc �7 { t