Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy.
Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, USA.
Environ Int. 2020 May;138:105642. doi: 10.1016/j.envint.2020.105642. Epub 2020 Mar 13.
Agricultural pesticides are key contributors to pollinator decline worldwide. However, methods for quantifying impacts associated with pollinator exposure to pesticides are currently missing in comparative risk screening, chemical substitution and prioritization, and life cycle impact assessment methods. To address this gap, we developed a method for quantifying pesticide field exposure and ecotoxicity effects of honey bees as most economically important pollinator species worldwide. We defined bee intake and dermal contact fractions representing respectively oral and dermal exposure per unit mass applied, and tested our model on two pesticides applied to oilseed rape. Our results show that exposure varies between types of forager bees, with highest dermal contact fraction of 59 ppm in nectar foragers for lambda-cyhalothrin (insecticide), and highest oral intake fractions of 32 and 190 ppm in nectar foragers for boscalid (fungicide) and lambda-cyhalothrin, respectively. Hive oral exposure is up to 115 times higher than forager oral exposure. Combining exposure with effect estimates yields impacts, which are three orders of magnitude higher for the insecticide. Overall, nectar foragers are the most affected forager type for both pesticides, dominated by oral exposure. Our framework constitutes an important step toward integrating pollinator impacts in chemical substitution and life cycle impact assessment, and should be expanded to cover all relevant pesticide-crop combinations.
农业用农药是全球传粉媒介减少的主要原因。然而，在比较风险筛选、化学物质替代和优先级排序以及生命周期影响评估方法中，目前缺乏与传粉媒介接触农药相关影响的量化方法。为了解决这一差距，我们开发了一种量化蜜蜂（世界上最重要的经济传粉媒介物种）对农药的田间暴露和生态毒性影响的方法。我们定义了蜜蜂摄入量和皮肤接触分数，分别代表单位质量应用的口服和皮肤暴露，并用两种施用于油菜的农药对我们的模型进行了测试。我们的结果表明，暴露量因觅食蜂的种类而异，对于拟除虫菊酯（杀虫剂），花蜜觅食蜂的皮肤接触分数最高为 59 ppm，对于苯醚甲环唑（杀菌剂）和拟除虫菊酯，花蜜觅食蜂的口服摄入量分数最高分别为 32 和 190 ppm。蜂箱的口服暴露量比觅食蜂的口服暴露量高 115 倍。将暴露量与效应估计值相结合会产生影响，对于杀虫剂，影响高达三个数量级。总体而言，对于这两种农药，花蜜觅食蜂是受影响最大的觅食蜂种，主要是通过口服暴露。我们的框架是将传粉媒介影响纳入化学物质替代和生命周期影响评估的重要步骤，应该扩展到涵盖所有相关的农药-作物组合。
