Based on effect data, regulatory acceptable concentrations (RACs) are derived for surface waters to avoid unacceptable effects on the environment. RACs often relay on acute tests with single species, which may underestimate the effects under field conditions. Therefore, we applied a higher tier approach with artificial indoor streams (AIS). We exposed representatives of the benthic community in lotic surface waters to varying numbers (one to four times) of 12-hour deltamethrin pulses over a 35-day period with intervening recovery phases, to simulate multiple pesticide peak exposures caused by rain events or spray drift. The deltamethrin concentration of each pulse was equivalent to its RAC value of 0.64 ng/L and consequently should have no unacceptable effects on the tested species.

中文翻译：

---

极低的重复拟除虫菊酯脉冲会增加对水蝇幼虫 （Chaetopteryx villosa） 的有害影响并影响物种相互作用


根据效果数据，得出地表水的监管可接受浓度 （RAC），以避免对环境产生不可接受的影响。RAC 通常对单个物种进行急性测试，这可能会低估在现场条件下的影响。因此，我们应用了人工室内流 （AIS） 的更高级别方法。我们在 35 天内将本地表层水中的底栖生物群落的代表暴露在不同数量（1 到 4 次）的 12 小时溴氰菊酯脉冲中，并进入中间的恢复阶段，以模拟由降雨事件或喷雾漂移引起的多个农药峰值暴露。每个脉冲的溴氰菊酯浓度相当于其 RAC 值 0.64 ng/L，因此对测试物种没有不可接受的影响。