唑螨酯在土壤中的降解及淋溶特性

为研究唑螨酯在环境中的行为特性,采用室内模拟试验方法,研究了唑螨酯在土壤中的降解及淋溶特性,通过降解半衰期和比移值Rf来评价其在土壤环境中的安全性。结果表明:唑螨酯在3种土壤中的降解符合一级动力学方程,好气条件下,在黄壤、水稻土和石灰土的降解半衰期分别为81.5、96.3和84.5 d,唑螨酯在水稻土中较难降解,在黄壤和石灰土中中等降解;厌气条件下的半衰期分别为154.0、56.3和43.3 d,水稻土和石灰土中中等降解,黄壤中较难降解。唑螨酯在黄土、水稻土和石灰土中比移值Rf均为0.083,唑螨酯在3种土壤中均不移动,正常条件下不会对地下水造成污染。综上所述,唑螨酯在土壤环境中具有较强的稳定性,因此应严格掌握其使用量和使用时期,同时建议加强对唑螨酯残留的跟踪监测。

Degradation and Leaching of Fenpyroximate in Soils

The behavioral characteristics of Fenpyroximate in environment was investigated by using the method of laboratory simulation test. The degradation and leaching of Fenpyroximate in three tested soils were studied through degradation half-life period and R_f value to evaluate its safety in soil environment. The results showed that the degradation of Fenpyroximate in three tested soils satisfied the first-order kinetic equation. Under the aerobic conditions, the degradation half-life periods of yellow soil, paddy soil and calcareous soil were 81.5, 96.3 and 84.5 d, respectively. Fenpyroximate was most difficult to be degraded in paddy soil and more difficult to be degraded in yellow soil and calcareous soil; While under the anaerobic conditions, the half-life periods were 154.0, 56.3 and 43.3 d, respectively, Fenpyroximate was most difficult to be degraded in yellow soil and more difficult to be degraded in paddy soil and calcareous soil. R_f value of Fenpyroximate in yellow soil, paddy soil and calcareous soil were all 0.083. Fenpyroximate was not moveable in the three tested soils, thus, it would not pollute the underground water under normal conditions. Therefore, Fenpyroximate has strong stability in soil environment, thus, it is suggested that the dosage and application period of Fenpyroximate should be strictly controlled and the residual of Fenpyroximate also should be sternly monitored.