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The Changjiang (Yangtze) estuarine and offshore sediments were analyzed for total heavy metals concentrations and chemical fractions.Distributions of heavy metals show typical banded diffusion pattern,with high concentrations near the river mouth and following a decreasing trend in the offshore direction.According to chemical fractions,Fe/Mn oxide fraction is the major non-residual fraction in the Changjiang estuarine and offshore sediments.Higher percentage of non-residual fraction of Pb implies that,the industrial contaminations transported via the atmosphere and river input,may affect the non-residual fraction of heavy metals.Over past fifteen years,the concentration of Pb normalizing to Al presents significant increasing trend,corresponding to the effect of human activities.By comparison of heavy metals fractions in 2003 to 2006,it has been realized that increasing water and sediment may cause a higher percentage non-residual fraction of Cu in the southern part of offshore muddy sediments.
The Changjiang (Yangtze) estuarine and offshore sediments were analyzed for total heavy metal concentrations and chemical fractions. Distributions of heavy metals show typical banded diffusion pattern, with high concentrations near the river mouth and following a slow trend in the offshore direction. According to the chemical fractions, Fe / Mn oxide fraction is the major non-residual fraction in the Changjiang estuarine and offshore sediments .Herher percentage of non-residual fraction of Pb implies that, the industrial contamination through the atmosphere and river input, may affect the non- residual fraction of heavy metals. Over past fifteen years, the concentration of Pb normalizing to Al presents significant increasing trend, corresponding to the effect of human activities.By comparison of heavy metals fractions in 2003 to 2006, it has been realized that increasing water and sediment may cause a higher percentage non-residual fraction of Cu in the southern part of offshore muddy se diments.