中文摘要：

采集珠江口湿地土壤,采用室内培养和Tessier化学逐级连续浸提方法研究了外源重金属在珠江河口湿地土壤中的化学形态转化,探讨了盐分变化对重金属形态转化的影响。试验结果表明,外源重金属进入珠江河口湿地土壤后主要以可利用态和潜在可利用态存在,Ni、Zn、Cu、Cr和Pb主要向铁锰氧化物结合态转化,而Cd主要向可交换态和碳酸盐结合态转化。土壤盐分含量递增对重金属Cu、Zn、Ni和Cr的形态分布无显著影响,对重金属Pb和Cd的影响主要体现在可交换态。在土壤盐分添加量不超过80 g.kg-1时,随着土壤含盐量的上升,土壤Cd和Pb的可交换态比例逐步增大。

英文摘要：

Transformation of chemical forms of extrogenous heavy metals in the wetland soil collected from the Pearl River Estuary were studied using laboratory incubation and the Tessier chemical fractionation method to explore effects of salinity on their chemical forms in the soil.Results show that extrogenous heavy metals existed in the wetland soil mainly in available or potentially available form,but after eight months of incubation,very little remained to be in residual form.With increasing loads of heavy metals in the soil,the percentage of residual form decreased,while the percentages of the other four fractions increased.Ni,Zn,Cu,Cr and Pb tended to be bound with Fe-Mn oxides,while Cd to be transformed into exchangeable form or bound into carbonate.Soil salinity did not have much impact on Cu,Zn,Ni and Cr in fractionation,but did on Pb and Cd,particularly their exchangeable forms.Exchangeable forms of Cd and Pb in the soil increased with increasing soil salinity until soil salt reached 80 g·kg-1.