氰戊菊酯在植烟土壤中的降解

Degradation of fenvalerate in planted tobacco soils

为了评价氰戊菊酯在烟田使用后的生态环境行为与效应,采用室内模拟方法,借助气相色谱分析技术研究了氰戊菊酯在6种植烟土壤(分别来自湖南湘西、云南保山、广东南雄、河南三门峡、福建光泽、山东泰安)中的降解半衰期(T1/2)与土壤理化性状的关系.结果表明:氰戊菊酯在河南三门峡的植烟土壤中降解最快,T1/2为8.27 d,而在福建光泽的植烟土壤中降解最慢,T1/2为12.62 d;随着植烟土壤中有机质含量的增加,氰戊菊酯的降解半衰期延长;在pH值为6.35～6.60的植烟土壤中,氰戊菊酯降解半衰期较短,在此范围外,随着pH值的升高或降低半衰期均有延长趋势;氰戊菊酯降解半衰期与植烟土壤粘粒含量的关系较为复杂,粘粒含量低于180 g/kg时以物理吸附为主,大于180 g/kg时以化学吸附为主.

In order to assess its eco-environmental behavior and effect of fenvalerate, the degradation behavior in six kinds of soil planted tobacco was analyzed by methods of gas chromatography and the indoor simulation, those soil tested come from the following areas：Hunan Xiangxi, Yunnan Baoshan, Guangdong Nanxiong, Henan Sanmenxia, FujianGuangze, andShandongTai＇an, respectively. The results showed that the degradation rate of fenvalerate in the soil from Henan Sanmenxia was the fastest, its T1/2 was only 8.27 d, and the degradation rate of fenvalerate in the soil from Fujian Guangze was the slowest, its T1/2 was 12.62 d; With the increasing of organic matter content in soil planted tobacco, the degradation half-life of fenvalerate extended, as well. When the pH value of soil changed from 6.35 to 6.60, the degradation half-life of fenvalerate was relatively short, tended to extend beyond this pH value. The relationship between the degradation half-life of fenvalerate and the clay content in soil was complicated, characterized mainly by physical adsorption with clay content lower than 180 g/kg, otherwise, by chemical adsorption with clay content higher than.