螺螨酯在土壤中的淋溶和降解特性

Leaching and Degradation Characteristics of Spirodiclofen in Soils

为了解螺螨酯安全使用及风险性评价提供理论依据,在室内模拟条件下,通过土壤薄层层析法研究螺螨酯在3种土壤中的淋溶作用以及在土壤中的降解情况,通过比移值（Rf）和半衰期（T0.5）评价其在土壤环境中的安全性。结果表明：螺螨酯在黄土、水稻土和石灰土中均分布在0～6cm土层中,其中0～3cm土层中含量占总量的96.97%、95.01%和95.16%,其在3种土壤中的Rf均为0.08。好气条件下,螺螨酯在黄土、水稻土和石灰土中的T0.5分别为138.6d、9.9d和3.1d;厌氧条件下的T0.5分别为23.9d、3.9d和2.8d。结论：螺螨酯在3种土壤中均为不移动,很难进入地下水体。好气和厌气条件下,螺螨酯在3种土壤中降解速率由快到慢为石灰土、水稻土和黄土。螺螨酯进入水稻土和石灰土后,在土壤中持留时间较短,对土壤的危害性很小;在黄壤中的持久性较长且不移动,存在一定的风险性,对水环境的风险性较小。

To provide a theoretical basis for safe handling and risk assessment of spirodiclofen,under indoor simulated conditions,soil TLC was employed to explore the leaching and degradation status in three soil types,Rfand T0.5were used to evaluate their safety in soil environment.Results：Spiral mite ester in loess,paddy soil and lime soil ranged from 0to 6cm.0～3cm segment content accounted for 96.97%,95.01% and 95.16%respectively.Rfwas all 0.08 in the three kinds of soil.Under aerobic condition,T0.5was respectively 138.6d,9.9dand 3.1d.Under anaerobic condition T0.5 was 23.9d,3.9dand 2.8d separately.Conclusion：The ester in three kinds of soil are not moving,it is difficult for it to enter the underground water.Under aerobic and anaerobic conditions,degradation of screw mite ester decreases from calcareous soil to loess in turn.The harm of the screw mite este to the paddy soil and lime soil is very small for the stay time in short.In comparison,it stays long in the yellow soil and moves little,so there is some risk and the risk for water environment is small.