降砷修复剂对砷污染稻田的影响

Effects of Arsenic-reducing Repair Agent on Arsenic-contaminated Rice Fields

为治理砷污染稻田土壤,选取湖南省石门县某砷污染稻田,通过小区对比试验,研究降砷修复剂(硅灰石+沸石+氯化铁)对早、晚稻田土壤理化性质,稻谷产量、土壤中有效态砷及稻谷中无机砷含量等的影响。结果表明,在降砷修复剂2250、3750 kg/hm 2的施用水平下,早稻土壤pH能提高0.28~0.40,土壤阳离子交换量增加6.86~12.03 cmol/kg,有机质增加9.25~18.16 g/kg;晚稻土壤pH能提高0.32~0.45,土壤阳离子交换量增加8.17~12.06 cmol/kg,有机质增加10.80~19.91 g/kg;施用降砷修复剂,早稻土壤有效态砷含量分别降低36.94%、55.93%,晚稻土壤有效态砷含量分别降低53.21%、63.02%;早稻稻米中无机砷含量分别降低75.59%、85.04%,晚稻稻米中无机砷含量分别降低79.03%、89.76%,均达到国家食品污染物限量标准;同时,施用降砷修复剂能在一定程度上提高稻谷的产量,早稻稻谷产量增加3.76%、6.82%,晚稻稻谷产量增加8.52%、11.93%。总体来看,降砷修复剂在晚稻上的修复效果要优于早稻。

In order to remediate the soil contaminated by arsenic,the paddy soil in Shimen County Hunan Province were selected.It was investigated for remediation effect of the arsenic reducing repair agent(wollastonite+zeolite+ferric chloride)on soil physical and chemical properties,rice yield,bioavailable arsenic in soil and arsenic contents in early and late rice.The results showed that,under 2250 and 3750 kg/hm 2 arsenic reducing repair agent,the soil pH increased 0.28-0.40 units,soil CEC increased 6.86-12.03 cmol/kg,organic matter increased 9.25-18.16 g/kg in early rice;the soil pH increased 0.32-0.45 units,soil CEC increased 8.17-12.06 cmol/kg,organic matter increased 10.80-19.11 g/kg in late rice;the contents of available cadmium and available arsenic in early rice soil decreased by 36.94%and 55.93%,in late rice soil decreased by 53.21%and 63.02%.And,the content of inorganic arsenic in early rice grain decreased by 75.59%and 85.04%,in late rice grain decreased by 79.03%and 89.76%,respectively,which achieved the national food pollutant limit standard.At the same time,the application of soil restoration agent could improve the rice growth and yield to a certain extent,and the rice yield in early rice increased by 3.76%and 6.82%,in late rice increased by 8.52%and 11.93%.In general,the effect of arsenic reducing repair agent on late rice was higher than that on early rice.