呋虫胺在水稻生态系统中的残留消解及膳食风险评估

为评价呋虫胺在水稻生态系统中的残留消解行为和产生的膳食摄入风险,于2014年在海南、湖南和黑龙江进行了规范残留试验,建立了高效液相色谱法（HPLC）的分析方法检测呋虫胺在水稻糙米、稻壳、稻株、土壤、田水中的残留,并对我国不同人群的膳食暴露风险进行了评估。样品经乙腈提取,NH₂柱层析净化,高效液相色谱-紫外检测器（HPLC-UV）检测,外标法定量。结果表明,在0.02~0.5 mg/kg添加水平下,呋虫胺的平均回收率在75%~114%之间,相对标准偏差（RSD）在0.5%~19.0%之间;呋虫胺的最低检测浓度（LOQ）,稻株与稻壳中为0.1 mg/kg,糙米中为0.05 mg/kg,土壤与田水中为0.02 mg/kg;呋虫胺最小检出量（LOD）为0.08 ng。呋虫胺的消解基本符合一级动力学方程,半衰期在稻株中约0.5 d,田水中约1 d,土壤中约5 d。距末次施药后14 d糙米中呋虫胺的残留中值为0.058 mg/kg,最大残留值为0.13 mg/kg,低于我国规定的最大残留限量1 mg/kg。风险评估表明中国人群对稻米中呋虫胺长期膳食摄入的慢性风险较低。

Dissipation,Residues and Dietary Risk Assessment of Dinotefuran in Rice Ecosystem

To evaluate the residue behavior and dietary intake risk of the dinotefuran in rice ecosystem, the residual trial of dinotefuran in rice was carried out in Hainan, Hunan and Heilongjiang in 2014. The method for the residue determination of dinotefuran in soil, paddy water, rice plant, brown rice, and rice husk was developed using high performance liquid chromatography with ultraviolet detector (HPLC-UV). The dietary risk assessment for China population based on dinotefuran residues data in rice was investigated. The samples were extracted by acetonitrile, purified by NH₂ column, detected by HPLC-UV. Results showed that the limit of detection (LOD) of dinotefuran was 0.08 ng. The limits of quantification (LOQ) of dinotefuran in rice plant, rice husk, brown rice, soil and paddy water was 0.1, 0.1, 0.05, 0.02, and 0.02 mg/kg, respectively. At fortified levels of 0.05 to 2 mg/kg, the average recoveries varied from 75% to 114% with the relative standard deviation of 0.5% to 19.0%. The dissipations of dinotefuran in rice plant, paddy water and soil were basically consistent with the first-order kinetic equation. The corresponding half-lives were about 0.5, 1, and 5 days, respectively. At the 14 ^th day after the last application, the terminal residues of dinotefuran in rice indicated that the supervised trials median residue (STMR) was 0.058 mg/kg, the highest residue (HR) was 0.13 mg/kg. STMR and HR were all below the Chinese MRL of 1 mg/kg. Risk assessment indicated a lower chronic risk after a long-term dietary intake of dinotefuran in rice for China population.