Accumulation and seasonal variation of heavy metals in Phragmites australis and Scirpus mariqueter

Analysis on the concentrations of Cu、Pb、Fe、Mn、Zn、Cr、Cd in the roots and stemleaves of Phragmites australis and Scirpus mariqueter which grows on the muddy tidal flat of Shanghai shown that both of Phragmites australis and Scirpus mariqueter are higher concentrations of Fe、Mn、Zn、Cu, but Pb、Cr、Cd lower concentrations. Mn content in the roots of the two plants is similar or higher than in the stemleaves, while the percentage content of Fe is very lower in the stemleaves. Hierarchical cluster analysis results whown that Pb and Cr absorbed by the roots have a possibility to be transported to the stems and leaves, and Zn、Cd、Cu showed the same law. Heavy metals were first largely absorbed by Phragmites australis and Scirpus mariqueter in summer and spring separately, then released in autumn and enriched in winter again. Except Cr, the concentrations of other heavy metals in Scirpus mariqueter are higher than in Phragmites australis.