Kumar Vipin, Tewary Dhananjay Kumar, Ravindranath Sringapuram Desikachar, Shanker Adarsh
Institute of Himalayan Bioresource Technology, Council of Scientific and Industrial Research, Palanpur 176 061 H P, India.
Food Chem Toxicol. 2006 Apr;44(4):596-600. doi: 10.1016/j.fct.2005.10.010.
Fenazaquin is a non-systemic acaricide/insecticide used widely in controlling mites and other related pests in fruits, vegetables and tea. The objective of this research was to investigate the disappearance trend in tea of fenazaquin residue level and its transfer in brew. Fenazaquin was applied on a tea crop at two rates, 125 and 250 g AI/ha in wet and dry seasons under field conditions. Samples (green shoots, made tea and its brew) were analyzed for fenazaquin and quantification was by high performance liquid chromatography using a UV detector. The residue dissipated faster in the wet season than in the dry season. Seven days after the treatment (normal round of plucking) the residues observed in the green shoots at the two rates were 2.17, 3.07 mg/kg and 2.04, 2.84 mg/kg in the wet and dry seasons, respectively. However, the degradation rale in both seasons followed first-order kinetics. Half-lives in green shoots were in range 1.43-1.70 and 2.10-2.21 days and in made tea 1.59-1.73 and 1.87-1.94 days for wet and dry seasons, respectively. During processing of green shoots to made tea considerable loss (42-70%) of residue was observed. The transfer of residue from made tea brew was in the range 3-22%. In brew residue were below 0.02 mg/l after 5 days of application at both the rates in either of the seasons. The estimated intake with brew (normal consumption of 10 cup/day/adult) thus would be below the acceptable daily intake for fenazaquin (0.005 mg/kg-body weight). To avoid health hazards due to the toxic effect of residues in brew, a waiting period for plucking the tea shoots after fenazaquin application of more than 5 days for both the seasons at recommended rate (125 g AI/ha) may be suggested and considered quite safe.
喹螨醚是一种非内吸性杀螨剂/杀虫剂，广泛用于控制水果、蔬菜和茶叶中的螨虫及其他相关害虫。本研究的目的是调查喹螨醚在茶叶中的残留水平消失趋势及其在冲泡液中的转移情况。在田间条件下，于湿季和干季以125和250克有效成分/公顷两种用量将喹螨醚施用于茶树。对样品（绿梢、成品茶及其冲泡液）进行喹螨醚分析，并使用紫外检测器通过高效液相色谱法定量。残留量在湿季比干季消散得更快。处理后七天（正常采摘轮次），两种用量下绿梢中观察到的残留量在湿季分别为2.17、3.07毫克/千克，在干季分别为2.04、2.84毫克/千克。然而，两个季节的降解速率均遵循一级动力学。绿梢中的半衰期在湿季为1.43 - 1.70天和2.10 - 2.21天，在成品茶中湿季为1.59 - 1.73天，干季为1.87 - 1.94天。在绿梢加工成成品茶的过程中，观察到残留量有相当大的损失（42 - 70%）。成品茶冲泡液中残留量的转移范围为3 - 22%。在任一季节，两种用量下施药5天后冲泡液中的残留量均低于0.02毫克/升。因此，按正常饮用（成人每天10杯）估算，从冲泡液中的摄入量将低于喹螨醚的每日可接受摄入量（0.005毫克/千克体重）。为避免因冲泡液中残留的毒性作用而对健康造成危害，建议在按推荐用量（125克有效成分/公顷）施用喹螨醚后，两个季节采摘茶梢的等待期均超过5天，这被认为是相当安全的。
