Speciation of heavy metals in sediments of the lagoon of venice collected in the industrial area

摘要

In this study a procedure of sequential extration of metals from dediments was applied to samples from the lagoon of Venies.Compared to the measurement of total concentrations the knowledge of metal partitioning gmong sediment phases can help in estimating the risk posed by metal polluted sediments and give information of comamination sources and on the factors that influence metal enrichment in sediments.The results permitted to estimate for each metal the percentage of hte total content that could be potentially remobillzed from sediments owing ot changes in environmtrion of the total content.An imporat proportion of most metals9except for Zn Cd and Cu) was associated to residual phases and therefore was not expected to be released under the mormal enivronmental conditions.The large amounts of metals bound to Fe-Mn oxides/hydroxides confirmed the strong scavging efficiency of this phase The carbonate phase was the preferential associative form for Ph Cd and Zn whereas Cu was bound in prevalence to the organic matter/sulphide phase.