Geochemical fractionation and ecological risks assessment of benthic sediment-bound heavy metals from coastal ecosystems off the Equatorial Atlantic Ocean

(整期优先)网络出版时间:2017-03-13
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Thisstudydeterminesthepollution,fractionation,andecologicalrisksofsediment-boundheavymetalsfromcoastalecosystemsofftheEquatorialAtlanticOcean.ContaminationFactor(CF),pollutionloadindex(PLI),andgeoaccumulationindex(Igeo)wereusedtoassesstheextentoftheheavymetalpollution,whilethepotentialecologicalriskwasevaluatedusingtherisksassessmentcode(RAC)andH?kansonpotentialecologicalrisk.Theanalysisrevealedconcentrations(mg/g,dw)ofthecadmium(Cd),chromium(Cr),copper(Cu),nickel(Ni),andlead(Pb)insedimentsforwetanddryseasonsvaryfrom4.40-5.08,14.80-21.09,35.03-44.8,2.14-2.28,and172.24-196.39,respectively.Theresultsalsoshowedthatthemetalfractionationpercentagesintheresidual,oxidizable,andreduciblefractionsarethemostsignificant,whiletheexchangeableandcarbonateboundtracemetalsarerelativelylow.TheRACvaluesindicatenoriskforCdandNiandlowriskforothermetalsatallthestudiedsitesduringbothseasons.PotentialecologicalriskanalysisoftheheavymetalconcentrationsindicatesthatCdhadhighinpidualpotentialecologicalrisk,whiletheothermetalshavelowriskatallinvestigatedsites.Themulti-elementalpotentialecologicalriskindices(R1)indicatehighecologicalriskinalltheecosystems.