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Speciation of heavy metals in sediment of Nhue and Tolich Rivers

Selective fractionation was applied to partition of heavy metals in river sediment of the rivers Nhue and Tolich Hanoi’s outskirts. The observed results showed a considerable difference of the proportion of various fractions of studied heavy metals. The residual fraction of Cu, Pb, Zn, Cd, Cr, and Ni stayed the highest portions. The portions/percentages of Cu, Pb, Zn, Cd as carbonate fractions were comparatively higher than those as Fe-Mn oxide fractions and organic fractions. | Journal of Chemistry Vol. 43 5 P. 600 - 604 2005 SPECIATION OF HEAVy METALS IN SEDIMENT OF NHUE AND TOLICH RIVERS Received 20 October 2003 VU Duc LOI1 LE LAN ANH1 TRINH ANH Duc1 TRAN VAN Huy1 PHAM GIA MON1 NICOLAS PRIEUR1 JORG SCHAFER3 GILBERT LAVAUX3 GERARD BLANC3 institute of Chemistry National Center for Natural Science and Technology Represent of CNRS France in Vietnam on French-Vietnamese water program 3University of Boxdeaux 1 D.G.O.URM CNRS 5805EPOC SuMMARy Selective fractionation was applied to partition of heavy metals in river sediment of the rivers Nhue and Tolich Hanoi s outskirts. The observed results showed a considerable difference of the proportion of various fractions of studied heavy metals. The residual fraction of Cu Pb Zn Cd Cr and Ni stayed the highest portions. The portions percentages of Cu Pb Zn Cd as carbonate fractions were comparatively higher than those as Fe-Mn oxide fractions and organic fractions. Conversely percentage of Cr as Fe-Mn oxide fraction was higher than those of as carbonate and organic fraction. The contents of Ni and Cr in carbonate and Fe-Mn oxide fractions were increased along the Nhue river. Percentage of nickel showed a similar ratio of carbonate over Fe-Mn oxide fraction. The contents of Cu and Cr as organic fractions in the Tolich river were higher than those of in the Nhue one. The mobility of heavy metals in the sediment was estimated to be in the sequence of Cd Pb Zn Ni Cr Cu. Keywords Contamination speciation heavy metals. I - INTRODUCTION Recently a considerable increase in number type and amount of contaminants introduced into the aquatic medium has been observed. Among these contaminants trace metals play a major role allowing the occurrence of bioaccumulation and biomagnifications processes which depending on the toxicity and degree of accumulation of a particular metal in aquatic organisms represent a potential danger to human being. Upon introduction of a metal into an aquatic environment the metal is .