Guo Chunjing, Li Guang, Lin Qiujun, Wu Xianxin, Wang Jianzhong
Institute of Agricultural Quality Standards and Testing Technology, Liaoning Academy of Agricultural Sciences, Shenyang, China.
Ministry of Agriculture and Rural Affairs Lab of Agricultural Product Quality Safety Risk Assessment (Shenyang), Shenyang, China.
PeerJ. 2021 Mar 2;9:e10789. doi: 10.7717/peerj.10789. eCollection 2021.
This study aimed to explore the residual dynamics and dietary risk of dimethoate and its metabolite omethoate in celery. Celery was sprayed with 40% dimethoate emulsifiable concentrate (EC) at either a low concentration of 600 g a.i./ha or a high concentration of 900 g a.i./ha. Plants in the seedling, transplanting, or middle growth stages were sprayed once, and the samples were collected 90 days after transplantation. Plants in the harvesting stage were sprayed two or three times. The samples were collected on days 3, 5, 7, 10, 14 and 21 after the last pesticide application. The dimethoate and omethoate compounds were extracted from the celery samples using acetonitrile, and their concentrations were detected using ultra-performance liquid chromatography-tandem mass spectrometry. Also, the dietary risk assessments of dimethoate and omethoate were conducted in various populations and on different foods in China. The metabolism led to the formation of omethoate from dimethoate in the celery. The degradation dynamics of dimethoate and total residues in greenhouse celery followed the first-order kinetic equation. The half-lives of the compounds were 2.42 days and 2.92 days, respectively. The celery which received one application during the harvesting stage had a final residue of dimethoate after 14 days, which was lower than the maximum residue limit (MRL) 0.5 mg kg for Chinese celery. The final deposition of the metabolite omethoate after 28 days was less than the maximum residue limit of 0.02 mg kg for Chinese celery. Furthermore, the risk quotients of dimethoate in celery were less than 1; therefore, the level of chronic risk was acceptable after day 21. Only children aged 2-7 years had an HQ of dimethoate more than 1 (an unacceptable level of acute risk), while the acute dietary risks to other populations were within acceptable levels. It was recommended that any dimethoate applications to celery in greenhouses should happen before the celery reached the harvesting stage, with a safety interval of 28 days.
本研究旨在探究芹菜中乐果及其代谢产物氧乐果的残留动态和膳食风险。用40%乐果乳油（EC）以600克有效成分/公顷的低浓度或900克有效成分/公顷的高浓度对芹菜进行喷雾处理。对处于幼苗期、移栽期或生长中期的植株喷雾一次，并在移栽90天后采集样本。处于收获期的植株喷雾两到三次。在最后一次施药后的第3、5、7、10、14和21天采集样本。采用乙腈从芹菜样本中提取乐果和氧乐果化合物，并用超高效液相色谱-串联质谱法检测其浓度。此外，还对中国不同人群和不同食物进行了乐果和氧乐果的膳食风险评估。代谢作用导致芹菜中的乐果形成氧乐果。温室芹菜中乐果及其总残留的降解动态符合一级动力学方程。这些化合物的半衰期分别为2.42天和2.92天。在收获期喷施一次的芹菜，14天后乐果的最终残留量低于中国芹菜0.5毫克/千克的最大残留限量（MRL）。28天后代谢产物氧乐果的最终沉积量低于中国芹菜0.02毫克/千克的最大残留限量。此外，芹菜中乐果的风险商小于1；因此，21天后慢性风险水平是可接受的。只有2至7岁的儿童乐果的危害商大于1（急性风险不可接受水平），而其他人群的急性膳食风险处于可接受水平。建议温室芹菜的乐果施药应在芹菜到达收获期之前进行，安全间隔为28天。
