Determination of heavy metals in inner continental shelf near the Pearl River estuary by BCR sequential extraction method

Author(s): LinglongCao, Ping Shi, JianXie, HaitaoTian, LiangWang

Utilizing the sequential extraction procedure(acid soluble, reducible, oxidizable, and residual) proposedby The European Community Bureau of Reference (BCR),the metals present in the sediments of the inner continental shelf nearthe Pearl River Estuary (IPRE)were determined. The sediment sampleswere collected from 22 sampling sites and analyzed toidentify the concentrations ofCr, Ni, Cu, Pb Zn, Cd and As. Results show the contents of selected metals decreases from land to sea as the water depth increase. As the results of BCR sequential extraction showed in the area, Cr,Ni,Cu and As appear mainly as the residual form and thus of low bioavailability, Cd appears mainly in acid-soluble formand thus of high potential mobility, Pb appears mainly as reducible form, Zn appears mainly in residual form and acid-soluble form. The order of migration and transformation sequence was Cd >Pb> Zn> Cu>Ni>As>Cr and the same order as the degree of pollution. Correlation and principal component analyses indicate that most ofthe metals primarilyoriginate from natural sources, and then from anthropogenic activities.

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