噻虫嗪在油菜田中的残留规律及风险评估

Residue and Risk Assessment of Thiamethoxam in Oilseed Rape Field

为探讨噻虫嗪在油菜上使用的安全性,笔者建立了噻虫嗪及其代谢产物噻虫胺在油菜各部位和土壤中的分析方法,开展了噻虫嗪在江苏、湖南和青海三地油菜田中的残留规律研究,评估了噻虫嗪对非靶标生物的环境风险。结果表明,噻虫嗪在油菜各基质中的残留动态均符合一级动力学方程,相关系数均在0.75以上,半衰期为0.91~5.25 d。噻虫胺的主要生成部位是油菜的花序和叶片,并呈现先增多后减少的规律。最终残留试验结果表明,三地油菜籽中噻虫嗪和噻虫胺的最终残留量均小于或等于0.010 mg/kg,低于最大残留限量(MRL),符合食品安全国家标准。环境风险评估的结果表明,噻虫嗪对蚯蚓的急性风险以及鸟类的急性风险和短期风险均可接受,但对鸟类有一定的长期风险。相关研究结果为噻虫嗪在油菜上的合理用药提供了数据支撑。

In order to investigate the safety of thiamethoxam in oilseed rape,this study established a method for the analysis of thiamethoxam and its metabolite clothianidin in the rape and soil.The residue experiments of thiamethoxam were carried out in Jiangsu province,Hunan province and Qinghai province,and the environmental risks of thiamethoxam to non-target organisms were assessed.The results showed that the residual dynamics of thiamethoxam in each matrix of oilseed rape accorded with the first-order kinetic equation.The determination coefficients were more than 0.75,and the half-lives were in the range of 0.91 to 5.25 d.The main production sites of clothianidin were the inflorescence and leaves,and showed the first increase and then decrease.The final residue experiment results showed that the final residues of thiamethoxam and clothianidin in the three-place rapeseeds were less than or equal to 0.010 mg/kg,and lower than the MRL values,which meet the national food safety standards.The results of environmental risk assessment showed that thiamethoxam was acceptable for acute risk of earthworms,acute risk and short-term risk for birds,but had long-term risk for birds.Relevant results provided data support for the rational use of thiamethoxam in oilseed rape field.