不同来源重金属污染的土壤对水稻的影响

摘要

采用人工污染土壤、尾矿砂、污泥等不同载体的污染源来模拟土壤污染，研究其对水稻生长、吸收养分和吸收重金属的影响。结果表明，不同污染载体对水稻生长的影响不同，其影响的大小顺序为人工污染土壤>尾矿砂>污泥>尾矿砂+污泥。不同污染载体对水稻吸收重金属的影响亦不同，以纯化学试剂的形式添加到土壤中的重金属最易被提取出来，植物从中吸收的Cu、Zn、Pb、Cd最多，而从以污泥为污染载体的土壤中吸收的Zn、Pb、Cd最少。研究表明，用添加纯化学试剂的方法来模拟污染土壤对生态与环境的影响是可行的，确定土壤负载容量是安全的，因为在实验条件下它对供试植物的影响最明显。%Effects of different pollution sources,simulated with different carriers of heavy metals such as contaminated soil,mine tailings,and sewage sludge,on growth of rice and transfer of nutrients and heavy metals in the soil-paddy rice(Oryza sativa L.) system were studied with pot experiment in greenhouse. Results showed that effects on plant growth varied with sources and were in the order of contaminated soil>mine tailings>sewage sludge>tailing+sewage sludge. The concentrations of Cu,Zn,Pb and Cd were higher in the plants growing in soil treated with contaminated soil due to higher extractability and toxicity of the heavy metals therein. Rice growing in the soil applied with sewage sludge and tailing+sludge had lower concentrations of Zn,Pb and Cd because of lower extractability and bioavailability of the heavy metals,which might get complexed with organic matter in the sewage sludge. Meanwhile plant growth was also related to nutrient uptake of the plants. It was also demonstrated that by adding chemical agents into soil to determine heavy metal loading capacity of the soil was feasible and safe,for under lab conditions response of the test plants would be the most apparent.