Fractionation studies and bioaccumulation of sediment-bound

重金属论文

EnvironmentInternational29(2003)1001–

1008

http://doc.guandang.net/locate/envint

Fractionationstudiesandbioaccumulationofsediment-boundheavy

metalsinKollerulakebyediblefish

K.ChandraSekhara,*,N.S.Charya,C.T.Kamalaa,D.S.SumanRajb,A.SreenivasaRaoc

AnalyticalChemistryandEnvironmentalSciences,IndianInstituteofChemicalTechnology(IICT),Hyderabad500028(A.P),India

b

CentreforEnvironment,IPGSR,JawaharlalNehruTechnologicalUniversity(JNTU),Hyderabad500028(A.P),India

c

DepartmentofAppliedEnvironmentalChemistry,CollegeofEngineering,GandhiInstituteofTechnologyandManagement(GITAM),

Vishakapatnam-530045(A.P),India

Received21January2003;accepted18March2003

a

Abstract

KollerulakeisthelargestfreshwaterlakeinthedistrictsofEastandWestGodavariofAndhraPradesh,India.Manyanthropogenicsourcescontributetotheheavymetalpollutioninthelakeandthebioaccumulationofheavymetalsinfishhelpsinassessingtheaquaticpollution.Totalcontentsandfractionationofselectedheavymetals,viz.,Zn,Cu,Cd,Pb,Cr,http://doc.guandang.netrgefractionsofZn,CdandCuwereassociatedwithmobilefractionofsedimentandshowedgreaterbioaccumulationinfishwhereasNiandCowereleastmobilisable.TheresultsclearlyindicatethatthefishofKollerulakearecontaminatedwithmetalsandnotadvisableforhumanconsumption.

D2003ElsevierScienceLtd.Allrightsreserved.

Keywords:Heavymetals;Fractionation;Bioavailable;Sediments

1.Introduction

Bottomsedimentsareknowntoactasasinkforheavymetalsintroducedtothelakewatersfrombothnaturalandanthropogenicsources(Pempkowiaseetal.,1999).Industrialeffluents,agriculturalrunoffs,transport,burningoffossilfuels,animalandhumanexcretionsandgeologicweatheringanddomesticwastecontributetotheheavymetalsinthewaterbodies(MooreandRamanaMoorthy,1984;Adnano,1986).Whenenvironmentalconditionschange(pH,sedi-mentredoxpotential,etc.)sedimentscanactassourceofmetals(Forstner,1989a,b;Izquierdoetal.,1997;Zoumisetal.,2001;Morilloetal.,2002).GeochemicalstudiesoflagoonalsedimentsandwaterareverylessinIndia.ThereareonlyfewstudiesattemptingtoestablishtheconcentrationofheavymetalsinthesedimentsofChilkalake(Asthana,1976),Pulicatlake(PadmaandPeriakali,1999),Dallake

*Correspondingauthor.

E-mailaddresses:kavi@iict.ap.nic.in,kavi223@http://doc.guandang.net(K.ChandraSekhar).

0160-4120/$-seefrontmatterD2003ElsevierScienceLtd.Allrightsreserved.doi:10.1016/S0160-4120(03)00094-1

(Shahetal.,1988)andHussainsagarlake(Sreenivasetal.,2001).ThereisnoreporteddataontheconcentrationofheavymetalsintheKollerulakesedimentsexceptforonebyoneoftheauthors(SreenivasaRaoandRamamohanRao,2001a).KollerulakeisthelargestnaturalfreshwaterlakeofAndhraPradeshinIndiaandlocatedbetweenlatitudes16j32Vand16j47VNandlongitudes81j05Vand81j27VE.ThelakeisconnectedtotheseathroughtheUpputeruriver,adistanceof60km.Thecatchmentareaofthelakeis4763km2andisoccupiedbyagriculturalfieldsandaquaticponds(AnjaneyuluandDurgaPrasad,2003).Agriculturalrunoffs,agriculturaleffluentsanddomesticeffluentsdirectlyenterintothelakethroughdrains,channelsandrivers(AmaraneniandPillala,2001).Inaddition,industrieslikedairyfarms,tanneries,papermills,sugarplantsanddistillerieslocatedinthevicinityofthelakedischargeeffluentsintothelake(SreenivasaRaoandRamamohanRao,2001b)(Fig.1).Agriculture,aquacultureandfishingaretheprimaryactiv-itiesofthepeoplelivingintheKollerulakebasin.

Itisnowwidelyacceptedthattheroleofaquaticsedimentsasasinkformetalpollutantscannotbefullyassessedby

重金属论文

1002K.ChandraSekharetal./EnvironmentInternational29(2003)1001–1008

Fig.1.LocationofsedimentsamplesfromKollerulake.

measuringthetotalmetalconcentration(Christineetal,1994).Inaddition,determinationoftotalelementdoesnotgiveaccurateestimateofthelikelyenvironmentalimpact(Christineetal,1994).Hence,contaminantspeciationanditseffectsonbioavailabilityarecriticaltounderstandingeco-toxicity(Shine,2001).Metalspeciationoccurringinthesedimentsisinturnexpectedtoinfluencemetalbioavail-ability,andtherebymetalcontentinbiota,inparticularinthesofttissuesoffishandmussels(Pempkowiaseetal.,1999;Yapetal.,2002).Sinceavailabilitycriticallydependsuponthechemicalforminwhichametalispresentinthesediment,considerableinterestexistsintraceelementspeciation(Chris-tineetal,1994).InthepresentstudysequentialextractionschemeproposedbyTessieretal.(1979)hasbeenappliedsuccessfullytoevaluatethepropertiesofmetalsboundtodifferentphasesofsedimentmatrix.Thisprocedureallowsustoobtainthedistributionofmetalsinthefollowingfractions:(a)looselyadsorbedtothesurfaceofsedimentparticles;(b)boundtocarbonates;(c)boundtoironandmanganeseoxides/hydroxides;(d)complexedbyorganicmatter;and(e)incorporatedintoclayminerallattices(Fergusson,1990;Forstner,1989a,b).Metalfraction(a)isconsideredtobethemostbioavailable(Forstner,1989a,b).Thedifferencesofmetalcontentsdeterminedinbiotawereexplainedonthebasisofvaryingbioavailability.Sincemetalcontentinthetissuesoffishisspecies-dependent,threespeciesofediblefish,viz.,Channastriata,CatlacatlaandOreochromismossambicuswereretrievedfromthelakeforthepresentstudy.Noinformationisavailableontherelationshipbe-tweendifferentgeochemicalfractionsofmetalsinsediments

andmetallevelsinediblefishofKollerulake.Thisstudywascarriedoutwiththeaimofassessingthemetalbioaccumu-lationinthesofttissueandmuscleofediblefishandthepossibleriskassociatedwiththeconsumptionofthesefishbyhumans.

2.Experimental

2.1.Methodsandmaterials

2.1.1.Reagents

Allchemicalsusedwereofanalyticalreagentgrade.Allsolutionswerepreparedindeionizedwater.Calibrationstandardsofeachmetalwerepreparedbyappropriatedilutionofthestocksolutionsof1000ppmJ.T.Baker/EMerckstandards.

Physico-chemicalcharacterizationwascarriedoutforallthe16sedimentsofKollerulakeusingstandardmethodsandarepresentedinTable1.

AnElicodigitalmodelLI-120pHmeterequippedwithacombinedglasselectrodewasusedinpHmeasurementandadjustment.AnR8Claboratorycentrifuge,manufacturedbyR …… 此处隐藏：24569字，全部文档内容请下载后查看。喜欢就下载吧 ……