湿地系统中植物和土壤在治理重金属污染中的作用

重金属污染环境的治理是目前环境工程的核心课题。湿地作为水陆相互作用形成的独特生态系统，在重金属污染治理中的作用倍受关注。对湿地植物、土壤在治理重金属污染中所起的关键作用及其机理做一综述，并对治理重金属污染的湿地构建提出几点建议。

The Role of Wetland Plants and Soils in Decontamination of Heavy Metals

Recent studies on decontamination of heavy metals by wetland plants and soils are reviewed. Wetland plays an important role in removal of heavy metal contamination, which is under intensive study. Most researches have been focused on the function and the processes of wetlands. The functional compositions of wetland include plants, microbes, water and soil, among which plants play a key role in the removal of heavy metals. Phytoremediationis contributed mainly from three parts: phytoextraction, phytovolatilization and phytostabilization. Plants have great effects in heavy metal removal via modulating pH, transporting O2, stimulating microbes, etc. The detaining of heavy metals in soils is related to soil particle size and other traits, such as the basic elements of soil, organic material, pH,etc. It is proved that the organic material content has the effect of concentrating heavy metals via cation exchange, surface adsorption, chelation with solid organic material, etc. But it is also found that the stability of the organic complexation, chelating with acid, is highly pH dependent. Wetland, therefore, is a system in which most of the factors will work together and affect each other. The function of wetland, especially those with rich biodiversity,is extremely complex. In artificial wetland construction and research, more attention should be paid to the cooperation of various factors than the function of individual one.