Abstract:

In order to determine the residue risks of zineb and its metabolite ETU on Chinese flowering cabbage, lettuce and celery, the residue dissipation and dietary risks of zineb residues were evaluated in field trials. Field trials were designed to evaluate the dissipation and residue of 65% zineb wettable powder in Chinese flowering cabbage, lettuce and celery in Heilongjiang, Hunan, Yunnan, Henan, Shandong and Guangdong. The dietary risks of zineb residues were evaluated by risk quotient method. The vegetables samples were decomposed by HCl-SnCl₂ into CS₂ gas, absorbed by hexane, and quantitatively determined by GC-FPD-S detector. The content of CS₂ was determined and the analysis and calculation of zineb were carried out. The Chinese flowering cabbage, lettuce and celery vegetables samples were extracted with acetonitrile containing NH₃·H₂O, and the extracted supernatant was cleaned up by GCB adsorbents. The ETU in resulting samples was detected of by HPLC-MS/MS. The results demonstrated that dissipation of zineb in Chinese flowering cabbage, lettuce and celery were in accordance with the first order kinetic equation with half-lives from 4.0 to 6.0 d, 2.8 to 6.9 d and 4.1 to 4.6 d, respectively. The maximum residual ETU of final test were 8.62, 9.61 and 7.22mg/kg, the final residual maximum counted by zineb were 813.3, 658.0 and 410.1 mg/kg, in Chinese flowering cabbage, lettuce and celery, respectively. The final residue of zineb gradually decreased over time. Dietary intake risk assessment results showed that the risk probability of zineb was less-than 100% at 7 d after application of zineb in three vegetables. Rational use of zineb in accordance with the recommended dose during the growth of Chinese flowering cabbage, lettuce and celery is safe to consumers’ dietary health.

Key words: zineb, ETU, metabolite, vegetables, residues, dietary risk assessment, half-life, chinese flowering cabbage, lettuce, celery