水稻及稻田环境中烯啶虫胺残留消解动态及膳食风险评价

Dynamics, Residue and Risk Assessment of Nitenpyram in Rice and Paddy Field

为评价烯啶虫胺在水稻中的残留及膳食摄入风险,于山东、河南、安徽进行了两年三地的田间试验。结果表明:烯啶虫胺在水稻和田水中的半衰期分别小于1.4 d和4.2 d,属于易降解农药。糙米最终残留量均低于0.05 mg·kg^(-1),低于日本设定的最大残留限量(MRL)0.5 mg·kg^(-1)。针对我国不同人群的膳食摄入及风险评估暴露,烯啶虫胺膳食暴露风险低,处于可接受的安全水平。

Residues dynamics, final residual levels and dietary intake risk of nitenpyram in rice and paddy field were investigated in three dif- ferent regions of China（Shandong, Henan and Anhui ）. A method was illustrated to detect nitenpyram residues in paddy, plant, brown rice, paddy water and soil. The residues in paddy and rice were extracted with methanol＋phosphate buffer（0.2 mol· L-1, pH=7.0）（60＋40）, adjust pH to 2.5, then cleaned up with solid phase extraction Column and 0.22 μm filter membrane, and then analyzed by HPLC with an ul- traviolet detector at 260 nm. When spiked 0.05, 0.5, 1.0 mg·kg-1, the recoveries of nitenpyram in paddy plant and brown rice were 78.4%- 94.7% and 84.0%-94.2%, respectively. The residues in paddy water and soil were extracted with phosphate buffer （0.2 mol·L-1, pH=7.0）, when spiked 0.01, 0.5, 1.0 mg· kg-1, the recoveries of nitenpyram in paddy water and soil were 84.6%-98.0% and 93.7%-97.1%, respective- ly, which indicated this method match the requirement of the detection. Two years results showed that nitenpyram belongs to easily degraded pesticides, because all half-lives were below 1.4 d in rice plant, as well as below 4.2 d in paddy water. Final residual levels of nitenpyram in rice were all below 0.05 mg·kg-1, which was far below the Japanese maximum residue limit （0.5 mg·kg-l）. The risk quotients （RQs） were low for different populations in China, which indicated its low risk in rice. Therefore, the rice with nitenpyram applied, according to the recom- mend method, 45 g·hm-2 application once, with 21 days collection interval, was safe.