Accumulation and Distribution of Heavy Metals in <i>Phragmites australis</i> in the Wetland of Liaohe River Estuary

Abstract

Phytoextraction has been recognized as an alternative technique for the remediation of wetland contaminated by heavy metals. The objective of this paper is to investigate the characteristics of heavy metal phytoextaction by phragmites australis and the distribution in soils and phragmites australis of 13 sampling points distributed in fields of Zhaoquanhe, Yangjuanzi and Dongguo in Liaohe estuary.The results showed that the content of heavy metal of Cu and Zn is close in the three phragmites australis fields. The content of heavy metal of Pb in Dongguo field is higher than the others. The content of heavy metal of Cd is lowest for all the heavy metals in the three fields. For the content of heavy metal in different layer soils in the three phragmites australis fields, the content of heavy metal of Cu, Pb, Zn in soils of 0-10 cm, 10-20 cm is higher than in other layer soils. for Cd in soils of 0-30 cm is higher than in other layer soils. And the content of heavy metal in siols of 30-40 cm is lowest for all the heavy metals. The transfer and interaction of Cu, Zn, Cd and Pb in the soil- phragmites australis systems in the three fields is studied, the content of heavy metal of Cu, Zn, Cd is that soils>phragmites australis of aerial part>phragmites australis of underground part, and for the content of heavy metal of Pb, soils>phragmites australis of aerial part≈phragmites australis of underground part. The biological concentration factor of heavy metal of Cu, Zn, Cd is low and transfer coefficient is high relatively .