Soil-interactions-with-petroleum-hydrocarbons-Abio

SOILTECHNOLOGYELSEVIERSoilTechnology10(1997)133-153Soilinteractionswithpetroleumhydrocarbons:AbioticprocessesP.Fine,E.R.Graber*,B.YaronInstituteofSoilsandWater,ARO,TheVolcaniCenter,P.O.Box6,BetDagan50250,IsraelReceived18January1995;accepted22January1996AbstractSoilandgroundwaterresourcesinmanypartsoftheworldarethreatenedbyspilledpetroleumproducts,Theseproductsgenerallyconsistofcomplexmixturesofvolatilehydrocarbonswithdifferentvaporpressures.Thevolatilizationoflighthydrocarbonfractionsleadstochangesinviscosityanddensityoftheresidualnonaqueousliquid.Thismaycausechangesinthetransportcharacteristicsoftheporousmatrixandoftheresidualliquid.Differingvolatilizationandsolubilitycharacteristicsresultindifferentialdistributionofreleasedhydrocarboncomponentsinair,soil,andwaterenvironmentalcompartments.Soilfrequentlyservesasthesiteofpetroleumspillsandhencethecapacityofthesoiltofilter,retain,orreleasehydrocarbonsisfundamentalindeterminingthetypeandextentofenvironmentalcontamination.Retention,volatilization,andtransportofhydrocarbonsasaffectedbysoilphysicalandchemicalpropertiesisreviewed.Keywords:Petroleum;Soil;Retention;Volatilization;Transport1.IntroductionSoilandgroundwatercontaminationbyleakingpetroleumproductsthreatenimpor-tantresources,jeopardizelocalandregionalecologicalsystems,andmayevenposethethreatofexplosioninurbanareas.Soilfrequentlyservesasthesiteofpetroleumspillsandhencethecapacityofthesoilcompartmenttofilter,retain,orreleasehydrocarbonswillbefundamentalindeterminingthetypeandextentofenvironmentalcontamination.*Correspondingauthor.Tel.:[phone];fax:[phone];e-mail:[e-mail].00933-3630/97/$15.00Copyright01997ElsevierScienceB.V.Allrightsreserved.PI2SO933-3630(96)00088-8134P.Fineetal./SoilTechnology10(1997)133-153Extensiveenvironmentalcontaminationbyhydrocarbonshasunderscoredtheimpor-tanceofunderstandingthedynamicsofhydrocarbondistributionindifferentenviron-mentalcompartments.Thefateofpetroleumproductsreleasedintothesoilwillbeparticularlyvariedbecausetheseproductsgenerallyconsistofcomplexmixturesofhydrocarbonswithgreatlydifferingvaporpressuresandwatersolubilities.Differencesinthesephysicalandchemicalpropertieswillleadtodifferentialdistributionofreleasedhydrocarboncomponentsinair,soil,andwater.Theredistributionandfateofpetroleumhydrocarbonsspilledonthelandsurfacewilldependonbothbioticandabioticprocesses.Theabioticprocessesoccurringwithinporousmediawhichareinstrumentalincontrollinghydrocarbondistributionincludesorption,volatilization,transformation,andtransport.Sorptionofhydrocarbonmoleculesatthesolidsurfacemayoccurfromthenonaqueousliquid,vapor,oraqueousphases.Vaporizationfromthenonaqueousliquid,ordesorptionofsorbedmoleculestothevapororaqueousphasesmayalsoplayanimportantroleinhydrocarbonredistributioninthesoil.Ultimately,hydrocarbonsaretransportedeitherinbulk,asanonaqueousliquid,invapor,orinlowconcentrationsintheaqueousphase.Abioticaspectsofsoil-petroleumhydrocarboninteractionswerereviewedrecentlybyCalabreseandKostecki(19881,Yaron(1989),MercerandCohen(19901,andKosteckiandCalabrese(1991).Theaimofthecurrentworkisnotageneralliteraturereview,rather,adiscussionemphasizingthemainimpactsofsoilmaterialsonthefateofpetroleumproductsinthesoilcompartment.Soilpropertiesincludingmineralogy,texture,andmoisturestatus,andtheireffectonsorption,retention,volatilization,andtransportwillbepresentedanddiscussedbasedonresultsfromourownresearchgroup(Acheretal.,1989;Yaron,1989;Yaronetal.,1989;Galinetal.,1990a;Galinetal.,1990b;FineandYaron,1993;Gerstletal.,1994;Nyeetal.,1994;Jarsjoetal.,1994.Afterapetroleumspillonthelandsurface,petroleumhydrocarboncomponentswillberedistributedinthesoil.Retentiononthesolidphasewilloccurbyentrapmentinporesorsorptionatmineralandorganicmattersurfaces.Thehighlyvolatilefractionwillvolatilizeintothegasphaseoftheporousmedium.Fromthereitmaybelosttotheatmosphere,sorbedontosoilsolids,ordissolvedintosoilwaterorgroundwater.Lessvolatilecomponentswillbetransportedinthenonaqueousphasethroughtheporousmedium.Finitebutdifferingaqueoussolubilitiesforthedisparatecomponentswillalsoresultindifferentialdissolutionandtransportassolutesinsoilwater.Iftheamountofpetroleuminthesoilzoneisgreaterthanitsretentioncapacity,thehydrocarbonmixturewilltravelintothevadosezoneasaseparate,nonaqueousphase.Petroleum-soilinteractionswillbediscussedinthelightofthisscenario.2.MaterialsandmethodsTheexperimentsreviewedbelowwereperformedonabroadspectrumofsoilswhosecharacteristicsaresummarizedinTables1and2.Fivepetroleumhydrocarbons(m-xylene,isopropylbenzene(ps-cumene),t-butylbenzene,n-decaneandn-dodecane)andacommercialpetroleumproduct‘kerosene’characterizedbyamixtureofmorethan100differenthydrocarbonswereusedintheexperiments.P.Fineetal./SoilTechnology10(1997)133-153135Table1Characteristicsofsoilsusedintheexperiments(afterGerstletal.,1994)SoilseriesTexture(wt%)SSA”(m’“/g)organicMoisturecontent(wt%)andclaysiltsandmatterHYGb-33kPaC-1OOkPahorizon(wt%)1.Golan(Ap):very-fineclayey,montmorillonitic,thermictypicchromoxerert74.4-10.6-