Department of Food Quality & Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZiyyon, 7505101, Israel.
Kimron Veterinary Institute, Department of Toxicology, Bet Dagan, 50250, Israel.
Chemosphere. 2021 Jun;272:129923. doi: 10.1016/j.chemosphere.2021.129923. Epub 2021 Feb 10.
Although amitraz is one of the acaricides most commonly applied within beehives, to date, its time-dependent oral toxicity in honeybees has not been investigated, due to amitraz's instability in aqueous media. In aqueous media such as honey, amitraz rapidly forms a continuously changing tertiary mixture with two of its major hydrolysis products, DMF and DMPF. The contribution of each hydrolysis product to the overall oral toxicity of this acaricide is not known. Therefore, we aimed to characterize the depletion and formation kinetics of amitraz and its hydrolysis products in 50% sucrose solution provided to caged honeybees, including the calculation of the 50% lethal oral concentration (LC) of amitraz. We sought to determine the contribution of each component of the mixture to the overall observed toxicity. We also investigated the time- and concentration-dependent toxicity of the amitraz mixture and its hydrolysis products. A novel approach based on the analysis of the areas under the depletion and formation curves of amitraz and its hydrolysis products revealed that DMPF, amitraz and DMF accounted for 92%, 7% and 1% (respectively) of the overall toxicity of the mixture. The chronic oral LC of amitraz was 3300 μmol/L, of similar magnitude as that of the non-toxic hydrolysis product DMF. The toxicity of DMPF and the mixture decreased over time; whereas the toxicity of DMF increased over time. Amitraz's instability in aqueous media and the highly toxic profile of DMPF, suggest that DMPF is the actual toxic entity responsible for amitraz's toxicity toward honeybees.
尽管咪鲜胺是蜂箱中最常用的杀螨剂之一，但由于其在水介质中的不稳定性，迄今为止，尚未研究其在蜜蜂体内的时间依赖性口服毒性。在水介质（如蜂蜜）中，咪鲜胺会迅速与两种主要水解产物 DMF 和 DMPF 形成不断变化的叔混合物。每个水解产物对该杀螨剂整体口服毒性的贡献尚不清楚。因此，我们旨在描述咪鲜胺及其水解产物在提供给笼养蜜蜂的 50%蔗糖溶液中的耗竭和形成动力学，包括计算咪鲜胺的 50%致死口服浓度 (LC)。我们试图确定混合物中每个成分对整体观察到的毒性的贡献。我们还研究了咪鲜胺混合物及其水解产物的时间和浓度依赖性毒性。一种基于分析咪鲜胺及其水解产物的耗竭和形成曲线下面积的新方法表明，DMPF、咪鲜胺和 DMF 分别占混合物总毒性的 92%、7%和 1%。咪鲜胺的慢性口服 LC 为 3300 μmol/L，与无毒水解产物 DMF 的 LC 相似。DMPF 和混合物的毒性随时间而降低；而 DMF 的毒性随时间而增加。咪鲜胺在水介质中的不稳定性和 DMPF 的高毒性特征表明，DMPF 是导致蜜蜂中毒的实际有毒实体。
