Heavy metals in water, soils and plants in riparian wetlands in the Pearl River Estuary, South China

Samples collected from sites of 26 for water, soils and two native plants (Scirpus tripueter Linn. and Cyperus malaccensis Lam.) in riparian wetlands were analyzed to investigate the distribution of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in Panyu-Nansha area of Pearl River estuary. The results indicated that concentrations of heavy metals among three compartments were in the order: soils >plants >water and no obvious correlations were found between in soils and water, water and plants. Pb is the only metal accumulated in both plants that correlated with its concentrations in soils. The weak or lack correlations among metals in water, soils and plants suggest that other factors existed influence the metal uptake and storage in plants other than absorbing from soils and water. The plants had the same trend in metal accumulation that was Cd >Zn >Cu >Ni >Cr >Pb. The translocation factors showed that metals accumulation was mostly occurred in roots for these two plants. Compared to the other heavy metals, Cd seemed to be much more hazardous. Principal Component analysis and Cluster analysis were used to analyze the relevance of different metals and identify the major sources. The results showed two factors dominated the metals variability (83.4% of total variance) that Cd and Pb, were dominated by PC1 whereas Cr, Cu and Ni charged by another factors and Zn was affected by both two components. Analysis of CA for the sampling sites showed that among all of anthropogenic pollutions, industrial wastewater was major sources of heavy metals especially for Cd, Cr, Cu and Zn in the PRE. (C) 2010 Published by Elsevier Ltd.