Freshwaters are particularly vulnerable to pesticide contamination from adjacent agriculture and forestry. Cypermethrin is a commonly used pyrethroid insecticide, but information on its toxicity to non-target freshwater invertebrates is limited to a small number of taxa. We assessed cypermethrin toxicity to nymphs of the common European mayflies Baetis rhodani and Ecdyonurus venosus, and the stonefly Isoperla grammatica in 96 h static bioassays. The 96 h median lethal concentrations (LC50) we recorded for the three species were 0.08 μg/L, 0.15 μg/L, and 0.13 μg/L, respectively. The effective concentration (EC50), quantified as lack of escape response (implying inability to avoid drift, predation or abiotic stress), was usually 32 % of the LC50. All 96 h LC50 values were lower than the maximum concentrations detected in streams in UK and continental Europe. Alarmingly, the 96 h LC50 for B. rhodani was below the currently applied single-pesticide EU safe drinking water standard of 0.1 μg/L. Contrasts among species were most evident at 24 h LC50, when B. rhodani was approximately ten times more sensitive than the other two taxa. B. rhodani is a key algal grazer, ubiquitous in European streams, and its decline could exacerbate algal blooms. The order of taxa sensitivity to cypermethrin in our study contrasts with their sensitivity to organic pollution in the same region, which suggests a tolerance trade-off, and thus a compounding effect of simultaneous stressors. Mayflies and stoneflies are important prey for instream and riparian predators, and key components of most eutrophication indices globally, all of which could be compromised in presence of cypermethrin.

淡水特别容易受到邻近农业和林业的农药污染。氯氰菊酯是一种常用的拟除虫菊酯杀虫剂，但有关其对非目标淡水无脊椎动物毒性的信息仅限于少量的分类单元。我们评估了氯氰菊酯对欧洲常见may（Baetis rhodani）和cd虫（Ecdyonurus venosus）以及若蝇Is Isoperla grammatica的若虫的毒性。在96小时内进行静态生物测定。我们记录的三个物种的96小时中位致死浓度（LC50）分别为0.08μg/ L，0.15μg/ L和0.13μg/ L。有效浓度（EC50），量化为缺乏逃逸反应（暗示无法避免漂移，掠食或非生物胁迫），通常为LC50的32％。所有96 h LC50值均低于英国和欧洲大陆河流中检测到的最大浓度。令人震惊的是，若丹尼亚芽孢杆菌的96 h LC50低于目前应用的欧盟单一农药安全饮用水标准0.1μg/ L。物种之间的对比在LC50达到24小时时最为明显，当时罗丹芽孢杆菌的敏感性比其他两个分类单元高出十倍。罗丹尼是主要的藻类放牧者，在欧洲河流中无处不在，其下降可能加剧藻类的大量繁殖。在我们的研究中，分类单元对氯氰菊酯的敏感性顺序与它们对同一区域的有机污染的敏感性形成对比，这表明在容忍度之间进行权衡，因此同时存在压力源。f蝇和石蝇是河内捕食者和河岸捕食者的重要猎物，也是全球大多数富营养化指数的关键组成部分，在使用氯氰菊酯的情况下，所有这些都可能受到损害。