Per- and polyfluorinated alkyl substances (PFAS) have raised international concerns due to their widespread use, environmental persistence and potential bioaccumulative and ecotoxicological effects. Therefore, the chemical industry has been dedicated to develop new generation fluorosurfactants which are aimed to replace the most concerning PFAS. Here we investigated the fate and effects of cyclic CO (cCO), a compound used as alternative to long-chain perfluorocarboxylic acids, in freshwater mesocosms located in the Mediterranean region (Spain) over a period of 90 days. cCO was applied as ammonium salt once at the following nominal concentrations: 0 µg/L (control), 1 µg/L, 20 µg/L, 400 µg/L, and 8,000 µg/L. The study shows that cC6O4 is relatively persistent in water (dissipation: 34–37 % after 90 days), has very low sorption capacity to sediments (sediment-water partition coefficient: 0.18–0.32 L/kg) and very limited bioconcentration (BCF: 0.09–0.94), bioaccumulation (BAF: 0.09–4.06) and biomagnification (BMF: 0.05–0.28) potential. cCO did not result in significant adverse effects on aquatic populations and communities of phytoplankton and zooplankton at the tested concentrations. As for the macroinvertebrate community, the ephemeropteran sp. showed a population decline at the highest test concentration on day 60 onwards, and a significant effect on the macroinvertebrate community was identified on the last sampling day at the same exposure level. Therefore, the calculated NOEC for cC6O4 in freshwater mesocosms exposed over a period of 90 days was 400 µg/L, which corresponded to a time weighted average concentration of 611 µg/L, given the water evaporation in the test systems. This concentration is about an order of magnitude higher than the highest exposure concentration monitored in freshwater ecosystems. Therefore, it can be concluded that cCO poses insignificant ecological risks for freshwater plankton and macroinvertebrate communities given the current environmental exposure levels.

中文翻译：

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新一代含氟表面活性剂（cC6O4）在淡水介层中的命运和影响

全氟和多氟烷基物质（PFAS）因其广泛使用、环境持久性以及潜在的生物累积和生态毒理学影响而引起国际关注。因此，化学工业一直致力于开发新一代含氟表面活性剂，旨在取代最受关注的PFAS。在这里，我们研究了环状 CO (cCO)（一种用作长链全氟羧酸替代品的化合物）在地中海地区（西班牙）淡水中生态系统中 90 天的命运和影响。cCO 以铵盐形式按以下标称浓度施用一次：0 µg/L（对照）、1 µg/L、20 µg/L、400 µg/L 和 8,000 µg/L。研究表明，cC6O4 在水中相对持久（消散：90 天后 34-37%），对沉积物的吸附能力非常低（沉积物-水分配系数：0.18-0.32 L/kg），并且生物浓缩性非常有限（BCF： 0.09–0.94）、生物累积性（BAF：0.09–4.06）和生物放大（BMF：0.05–0.28）潜力。在测试浓度下，cCO 不会对水生种群以及浮游植物和浮游动物群落造成重大不利影响。至于大型无脊椎动物群落，蜉蝣目 sp。从第 60 天开始，最高测试浓度下的种群数量出现下降，并且在最后一个采样日相同暴露水平下，发现对大型无脊椎动物群落产生了显着影响。因此，在暴露 90 天的淡水中环境中 cC6O4 的 NOEC 计算结果为 400 µg/L，考虑到测试系统中的水蒸发，这对应于 611 µg/L 的时间加权平均浓度。该浓度比淡水生态系统中监测到的最高暴露浓度高出大约一个数量级。因此，可以得出结论，鉴于当前的环境暴露水平，cCO 对淡水浮游生物和大型无脊椎动物群落构成的生态风险并不显着。