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dLtLLILd In thL iip,,m am ,,urf,ILL vvatcr ,,anip1L (DDN) coIlLLted from the drainage ditch loc.atLd east of the site
<br /> NonL of thL other B I LX constituents or I PI4-6 "erL detected at or above the laboratory reporILd dctLLtion
<br /> luhhit,, In this ,,aniplc BTLX and TPH-G werL not dLtected in any of the three remaining surface water samples
<br /> MTBE was dLtLeted at or above the laboratory rLporkd deteLthon limit in all of the surface water sanhplc.,, exLLpt
<br /> the sample LollcLted from the vicinity of the pump house In the island drainage channel (IDCW) NonL of the
<br /> rulnaining selected L,asoilnc oxygenates/additives were detected at or above the laboratory reportLd detLLtIOI1
<br /> hints in an} of the ,,urlac c v<ater Sample,,
<br /> M 1131 (20 fig/1) vv a,, the only analyte detected at or above the laboratory reported detection limits In thL marina',,
<br /> prL-trL.htL(i drinking water Onl) Lhlorolorm bromodichloromethane, and dibromochloromethane vvcre detected
<br /> In tliL 1n.lrina 1, trLatLd drinking water at or abovL the laboratory rLportLd detLLIIOn limits (at LoncLntratlons of
<br /> 18, 6 1 and 3 11 lig/I re,,peLtivLly) C hloroform bromodiLhloroiriLthanL and dibromoLh]oromLthane appear to
<br /> be by produLt,, of the marina ,, drinking water treatment syslem
<br /> Un ULLLmbLr 30 1998, ( ondor LonductLd quarterly groundwater and ,urtaLe vvatLr monitoring at Ilerman &
<br /> Ilelen s Marina IoLated at VLn1Le Island I'Lrry in StOLkton, California Laboratory analytical results indiLated
<br /> that thL gatiollne nxvgLilatL M IBE was det,ctLd In ,,ampleS LoI]ectLd from monitor wells MW-1, MW-2, MW-3,
<br /> and MW-4 at eo1lCUltratloil,, of 1 3 lig/I, 11,000 µg/1, 3,500 µg, 1, and 1 5 Ihg/l, respectively Tertiary-butanol was
<br /> detected In thL groundvvat,,r samples collLLted from monitor nLll,, MW-2 and MW-3 at concentrations of 150
<br /> fig/1 and 130 lig/l rL,,pcctively TAMF was dLteetLd in the groundwater samples collected from monitor wLlls
<br /> MW-2 and MW-3 at cone,ntrations of 37 pg/1 and 8 3 µg/l, rLspectivLly Non,. of the other oxygenates/additives
<br /> werL dLtLCtLd at or abovL thL laboratory reported detection limit,, in any of thL groundwatLr,,amples
<br /> IoILILIlL vv a,, del(AALd In thL groundwatLr sanlplL Lollectid from monitor vvLil MW-2 at a concLntration of 1 2
<br /> lig/1 B I F X constltuLnls wLrc. dLtected In thL groundwater samplL LollLctcd from monitor vvLll MW-4 at
<br /> conLentrations of 24 lhfi/l 0 4 lig/I, 2 3 jig/] and 22 µg/l, respeLlINLly BIFX conSWUCI t,, vvcrL not dctLcted in
<br /> the groUnLlwatLr ,,ample,, coI1LLtLd from monitor wells MW-1 and MW-3 1 PII-Cr was detected in the
<br /> groundvvatLr sample LoIILLtLd from monitor vv ell MW-4 at a conLLntratioti of 0 2 mg/I TPI I-G vva,, not detected
<br /> in thL groundwater sample,, LOI1LLtLd from monitor v<LIIS MW-1, MW-2, or MW-3
<br /> Intrinsic bioremediation te,,tmg was discontinued at the site following the third quarter, 1998, monitoring event
<br /> bLcauSL of inLonclu,,tvL re,,ults and because the petroleum hydrocarbon contamination at the site Is probably of
<br /> ,,econdar} conc.Lrn relativL to the presence of gasoline oxygenate,, rhe Intrinsic bioremediation tc,,ting results
<br /> for thL four quarter,, beginning with thL fourth quarter, 1997, groundwater monitoring event and Lnding with the
<br /> third quartLr, 1998 groundwater monitoring event indicated that sub,,urfaLL conditions at the site appeared to be
<br /> conducive Io thL aLrobic and/or anaerobic breakdown of pLtroleum hydrocarbons However, the results did not
<br /> LonOusivcly mdlcatL that Intrinsic bioremediation ',vas ocLurrmg at the Site No well-defined differences In the
<br /> intrinoc biorLmLdiation paramctLrs were established up-gradient (MW-1), 1n thL plume center (MW-4), and
<br /> down-,radILiit (MW-2 and MW-3) at the ,,ite This may bL in part relatLd to the relatively low concentrations of
<br /> petroleum hydrocarbon,, present at MW-4 and the vLry short residence time of groundwater in the soil at the site
<br /> Groundwater elevation measurements collected at the site on December 30, 1998, indicated that the average
<br /> dLpth to groundwater was approximately 4 6 feet bgs which i,, approximately one-half foot higher than the
<br /> average groundvaater elevation measured on Septernber 30, 1998 Groundwater elevation contours for December
<br /> 30 1998 indiLated that the groundwater gradient at the site wa,, generally consistent with that measured on
<br /> September 18, 1997, DLcember 31, 1997, March 27, 1998 JUI1L 26, 1998, and September 30, 1998
<br /> B FhX and I P1 141 wLrL not dLtected at or above thL laboratory reported dL.tection limits In any of tIlL ,,urface
<br /> v.ater I ow concentration,, of M I131, (1 4 and 1 0 ligll) wLre detected in the upstream ,,urface water
<br /> ,,amp]L (DDN) and thL down,,tream surlaeL vvat(-r ,,aiThplL (DDS) ILSPLLtivLly None of the remaining sLlected
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