城市郊区水稻土重金属污染状况调查与评价——以湘潭市郊响水乡为例

Investigation and evaluation of heavy metal pollution in suburban paddy soils——A case study of Xiangshui Township,Xiangtan City

城市郊区农田重金属污染已成为人们关注的焦点,本研究对湘潭市郊响水乡稻田重金属污染现状进行调查,结果表明:该乡稻田土壤重金属污染面积占水田总面积的68.84%,稻田Cd的空间分布与距工厂或湘江的距离关系密切;在黄泥田中,重金属分布具有表聚性特征,主要以难溶性形态存在;水稻对重金属有一定富集作用,稻草富集重金属的能力大于稻米,一般稻草对重金属Cd、Hg、As、Pb的富集系数是稻米的1.8倍以上,土壤Cd污染导致水稻产量和品质下降。总之,响水乡稻田土壤重金属污染较为严重,其中Cd污染较为严重,Hg污染较轻,且存在Cd、As复合污染。

Heavy metal pollution in agricultural fields has drawn tremendous concern in suburban regions. This study focuses on heavy metal pollution in the paddy fields of Xiangshui Township, Xiangtan City. The results indicate that 68.84% of planted areas in Xiangshui Township is polluted by heavy metals. Spatial distribution of Cd in paddy soils is closely related with distance to industrial plants and Xiangjiang River. Heavy metal accumulation, mainly in the insoluble form, is recorded in yellow mud soils. Heavy metal accumulation is also found in rice crops, where accumulation coefficient of Cd, Hg, As and Pb in rice-straw is 1.8 times that in half-polished rice. Furthermore, Cd contamination decreases crop yield and rice quality. It is concluded that paddy fields in Xiangshui Township are heavily contaminated with heavy metals. The soils are severely polluted by Cd, slightly by Hg, and As and Cd pollution are closely related.