Perfluoroalkyl sulfonyl fluorides (PFASFs) have long been used as crucial synthetic intermediates in the production of various perfluoroalkyl substances. While, knowledge on the environmental occurrence and behaviors of PFASFs in the aquatic environment is still very limited, especially at the isomer-specific level. In this study, surface water, sediment, and fish samples were collected from the water environment near a wastewater treatment plant outlet, and analyzed them for five PFASFs. The highest mean water concentration was observed for linear perfluorobutyl sulfonyl fluoride (l-PFBSF; 122 ng/L, 10–457 ng/L). While, linear perfluorooctane sulfonyl fluoride (l-PFOSF) displayed the highest mean concentration in collected sediment (108 ng/g dw, 78–271 ng/g dw) and fish (113 ng/g ww, 48–244 ng/g ww). For detected PFASFs, their branched isomers accounted for mean 16–29 %, 8.2–11 %, and 16–25 % of total PFASFs (sum of linear and branched isomers) in water, sediment, and fish samples, respectively. Calculated log-transformed sediment-water partitioning coefficients (log Koc) of linear PFASFs linearly increased with the increasing carbon chain length, with the mean values ranging from 2.1 ± 0.36 (l-PFBSF) to 3.9 ± 0.18 (l-PFOSF). Calculated log-transformed bioaccumulation factors (log BAF) of linear PFASFs increased from 1.7 ± 0.34 (l-PFBSF) to 3.0 ± 0.27 (l-PFOSF) with the carbon chain length. Branched isomers of detected PFASFs displayed lower log Koc and log BAF values than their respective linear isomers. To our knowledge, this study provides the first evidence on isomer-specific environmental behaviors of PFASFs, which is crucial for assessing the ecological risks these compounds may pose.

中文翻译：

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全氟烷基磺酰氟的异构体特异性沉积物-水分配和生物积累


全氟烷基磺酰氟 （PFASF） 长期以来一直被用作生产各种全氟烷基物质的重要合成中间体。然而，关于 PFASF 在水生环境中的环境发生和行为的知识仍然非常有限，尤其是在异构体特异性水平上。在这项研究中，从污水处理厂出口附近的水环境中收集了地表水、沉积物和鱼类样品，并分析了五种 PFASF。观察到线性全氟丁基磺酰氟 （l-PFBSF;122 ng/L， 10–457 ng/L） 的平均水浓度最高。而线性全氟辛烷磺酰氟 （l-PFOSF） 在收集的沉积物（108 ng/g dw，78-271 ng/g dw）和鱼类（113 ng/g ww，48-244 ng/g ww）中的平均浓度最高。对于检测到的 PFASF，其支链异构体分别占水、沉积物和鱼类样品中 PFASF 总量（线性异构体和支链异构体之和）的平均 16-29%、8.2-11% 和 16-25%。计算的线性 PFASF 的对数转换沉积物-水分配系数 （log Koc） 随着碳链长度的增加而线性增加，平均值从 2.1 ± 0.36 （l-PFBSF） 到 3.9 ± 0.18 （l-PFOSF） 不等。随着碳链长度的增加，线性 PFASF 的计算对数转化生物累积因子 （log BAF） 从 1.7 ± 0.34 （l-PFBSF） 增加到 3.0 ± 0.27 （l-PFOSF）。检测到的 PFASF 的支链异构体的 log Koc 和 log BAF 值低于其各自的线性异构体。据我们所知，这项研究提供了 PFASF 异构体特异性环境行为的第一个证据，这对于评估这些化合物可能造成的生态风险至关重要。