ARCHIVED REPORTS XR0006989 - Laserfiche WebLink

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i ,Iddrtn LS were. detecttd at or ahuvc. the laboratory reported detention lunrt5 III an) (It thL grmindwaler samples I ulus,nc. was (tLteLILd in the groundwater sample colleLted from monitor welt MW-2 at a LOJILLntr atron Ot 12 a,—,/I BTE,X (_onstituents wort, detected in the groundwater sample colleLted f:Irm mzinit0i V�Lll \4W-1 at LonLentrat:ons of 24 ]tgd 0 4 µg/I 2 3 µg71 and 22 ag/1 iLSpLLtiyely 1311 X Lonstrtuents vsere not detLLted in the groundwater samples LolkuLd t:om m0nitor �vLlls MW-1 and MVA -, I PI-I--(I was dLteLted :n the groundwater Sample colleLted floor monitor wL11 VIW-t at a LanLLutration of 0 2 nig/1 IPH-(, was not deteLted in the groimdwatCr SailIpILS L«IILLted lrnm m(Jnitot wells VIW-I MW-2 or MW-3 IntrinS:L IiiorLnlLdlation tLsltng was d1sLontrmred at thi _ site following tht- third quarter 1998 rn(rIIItul ln1 L\LIit 1)L(,,IUSe pit inLnnLluSII c results and bLLause the petroleum hydroLarbon Lontamination at the site :s probably of SCLondary LonLLrn relative to the, presenLC 01 gasoline urNgLnates I bL Intrinsic hiol-U-lediation tcsinig rLSults for the tour quarters beginning with the Ioui-th quartLr 199, groundwater monitoring event and ending with the third quarter 1998 groundwatLi monitoring Lvcnt indicated that subsurtaLL Londitions at the site appeared to be LuinduLlye to flit, aLrobic and/or anaerobiL brLakdown of petroleum hydrocarbons HowLver the ILSults did nut Lonclusively IndiLate that IntlmsiL bioremLdiation was oLcurting at the SILL No well-defined dittLrcrices in the tntrrnSIL bioremediation parameters were established up-gradient (MW-1 ) In thL plunlL cLnter (MW-4) and down-gradient (MW-2 and MW-3) at the site I Ills may be in part relattd to the relatively low concentrations of petraletnn hydrocarbons present at MW--4 and tbL vLry short residenLC tIMC, Of groundwater in the soil at the site (iroundwater C1Lvation mLasururnents collected at thL site on DLLLmber 30 1998, indicated that 10 thL avLraue depth to groundwatLr waS approximately 4 6 feet bgs which is approximately one- hall toot Iitghei than the average groundwater LILvatron measured on SLptember 30 1998 ' (1Ioundwater elLvation contours for DCLCmber 30 1998 Indicated that the g,roundwatLr gradient at thL Srtt ',NLS gLllLrally Lonsistent with that measured on September 18 1997, DLCember 31 1997 MarLh 27 1998 June 26 1998 and September 30 1998 ' 13 1 I X and I PH-C, were not detected at of above the laboratory reported detection limits in any of the surface water samples I ow LoneLntrations of MTBF (1 4 and 1 0 µg/l) were detected in the upstrearn SurfaLC watLr sample (DDN) and the downstream surfaLC water sample (DDS) ILSPLLtrvLly 'nolle of the remaining SLICLted gasoline oxygenates/additives were deteLted at or above the I iboratoly reported detection limits in any of the surface water samples ' On March 26 1999 C ondor Londucted first quarter, 1999, groundwater and surface water moilltorint-r at HLrman & Helen s Marina Laboratory analytical results of the groundwater samples Lollected during the first quarter 1999 monitoring event were generally consistent with ' h Istoi ical quarterly groundwater analytical data ()Ioundwatel CILvation measurements collected at the site on March 26, 1999, indicated that the ' avetage depth to f;ioundwater was approximately 5 5 feet below the monitor well and surface water station measul ing points This average depth to water is 0 1 feet greater than the average depth to watL1 measured on December 30, 1998 Groundwater elevation contours for March 26, 1999 Indicated that the groundwater gradient at the site was generally consistent with the ' historical groundwater gradient 1 aboi atoi v analvtio al results of the surfaLC water samples collected during the first quai-tt r 1999, ' monitor Ings event were generally consistent with historical surface water analytical data for BTLX 1