摘要
为探究适合广安地区镉(Cd)污染稻田的原位修复技术,采用小区试验的方式,探究了水分管理和腐殖酸、碳酸钙两种钝化剂对农田中土壤和稻米Cd含量、稻米产量及土壤理化性质的影响。结果表明:在土壤全Cd含量为0.451±0.033mg/kg、土壤pH为4.80±0.16的酸性Cd污染稻田中,长时淹灌处理或施加钝化剂均能有效降低土壤有效Cd含量和稻米Cd含量。其中,与CK处理相比,施用腐殖酸可显著提高43.7%的土壤有机质含量,进而降低34.85%的土壤有效Cd含量和42.46%的稻米Cd含量,使稻米Cd含量低于国家食品污染物限量标准0.2mg/kg。其作用机制主要是通过有机络合反应使土壤溶液中易被水稻吸收的Cd^2+变为有机结合态Cd,从而实现了土壤中Cd的钝化。施用碳酸钙也能降低稻米Cd含量、同时能提高稻米产量,但部分碳酸钙处理的试验小区中稻米Cd含量超过国家食品污染物限量标准。同时,试验田灌溉水和所施用的化肥、农药中的Cd含量均满足相应标准。
In order to explore the in-situ remediation technologies suitable for Cd polluted paddy fields in Guangan city,a field plot experiment was conducted,the effects of water management and two passivating agents,humic acid and calcium carbonate,on Cd content,rice yield and soil physical and chemical properties in farmland were investigated.The results showed that at the polluted acidic soil with total Cd concentration of 0.451±0.033 mg/kg,and soil pH of 4.80±0.16,long-term flood treatment or passivation agents could effectively reduce the available Cd in soil and total Cd in rice.In detail,compared with the CK treatment,the humic acid treatment could significantly improve the soil organic matter content of 43.7%,and significantly reduce the available Cd content of 34.85%and rice Cd content of 42.46%,which was lower than the national standard limit of 0.2 mg/kg for food contaminant.The corresponding mechanism of action is that Cd%^2+,which is easy to be absorbed by rice in soil solution,becomes organic binding state Cd through organic complexation reaction,thus realizing the passivation of Cd in soil.Besides,application of calcium carbonate could also reduce the rice Cd content and increase the rice yield,however,the rice Cd content in some of the plots treated with calcium carbonate exceeds the national standard limit.Meanwhile,the Cd content in the irrigation water of the plot field,chemical fertilizer and pesticide were all lower than the corresponding standard.
作者
江林
郑良科
JIANG Lin;ZHENG Liang-ke(Guangan Environmental Monitoring Station,Guangan,Sichuan 638000,China)
出处
《四川环境》
2019年第5期162-167,共6页
Sichuan Environment
关键词
Cd污染修复
原位钝化
水分控制
腐殖酸
碳酸钙
Cadmium pollution remediation
in situ passivation
irrigation control
humic acid
calcium carbonate
