三元除草剂二甲四氯·莠灭净·敌草隆在甘蔗及土壤中的消解特性研究

Degradation Dynamics of MCPA·Ametryn·Diuron Residues in Sugarcane and Soil

以目前在甘蔗生产中大量使用的二甲四氯、莠灭净、敌草隆三元混剂为研究对象,建立并优化三元除草剂在甘蔗及土壤基质中的残留检测方法,探索三元农药在甘蔗使用后其在甘蔗及环境土壤中的降解特性,结果表明,以2 628 g/hm2在甘蔗及土壤中使用后,二甲四氯、莠灭净、敌草隆在甘蔗植株中原始沉积量分别为3.662~13.864,22.235~84.879,5.376~21.003 mg/kg,在土壤中分别为：0.572~5.163,0.385~18.545,0.516~3.094mg/kg。二甲四氯、莠灭净、敌草隆在甘蔗植株中的降解半衰期分别为：3.6~9.5,1.6~13.6,2.2~18.2 d,在土壤中分别为：2.4~7.9,4.8~28.9,15.8~28.9 d。各国的研究均表明二甲四氯、莠灭净、敌草隆均已证实对环境特别是环境地下水体有较高的残留风险,从本文的研究结果看,莠灭净及敌草隆在土壤环境中的DT50最长可达28 d以上,对甘蔗种植区环境土壤及水体存在较大的残留风险。

An analytical method was developed to extract and determine 2-methyl-4-chlorophenoxyacetic acid（ MCPA）,ametryn and diuron and their degradation dynamics in sugarcane and soil. The results showed that MCPA,ametryn and diuron initial residues in sugarcane were 3. 662- 13. 864 mg / kg,22. 235- 84. 879 mg / kg and 5. 376- 21. 003 mg / kg,respectively. MCPA,ametryn and diuron initial residues in soil were 0. 572- 5. 163 mg / kg,0. 385- 18. 545 mg / kg and 0. 516- 3. 094 mg / kg,respectively. The half-lives of degradation of MCPA,ametryn,diuron in sugarcane were 3. 6- 9. 5 d,1. 6- 13. 6 d,2. 2- 18. 2 d,respectively. And 2. 4- 7. 9 d,4. 8- 28. 9 d,15. 8- 28. 9 d in soil,respectively. Many studies had showed that MCPA,Ametryn,Diuron were often detected in the underground water in the United States,EU and other countries. The results of this study showed that the DT50 of ametryn and diuron in soil would be up to 28 days,wide application would bring a high residual risk and high residual pressure.