Per‐ and polyfluoroalkyl substances (PFAS) often occur together as contamination in exposure media such as drinking water or food. The relative potency factor (RPF) methodology facilitates the risk assessment of mixture exposure. A database of liver endpoints was established for 16 PFAS, using data with the same species (rat), sex (male), and exposure route (oral) and comparable exposure duration (42–90 d). Dose–response analysis was applied to derive the relative potencies of 3 perfluoroalkyl sulfonic acids (perfluorobutane sulfonic acid, perfluorohexane sulfonic acid, perfluorooctane sulfonic acid), 8 perfluoroalkyl carboxylic acids (perfluorobutanoic acid, perfluorohexanoic acid, perfluorononanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluorooctadecanoic acid), 2 perfluoroalkyl ether carboxylic acids (tetrafluoro‐2‐[heptafluoropropoxy]propanoic acid, 3H‐perfluoro‐3‐[(3‐methoxy‐propoxy)propanoic acid]), and 2 fluorotelomer alcohols (6:2 FTOH, 8:2 FTOH) compared to perfluorooctanoic acid (PFOA), based on liver effects. In addition, the RPFs of 7 other perfluoroalkyl acids were estimated based on read‐across. This resulted in the relative potencies of 22 PFAS compared to the potency of index compound PFOA. The obtained RPFs can be applied to measured PFAS quantities, resulting in the sum of PFOA equivalents in a mixture. This sum can be compared with an established PFOA concentration limit (e.g., in drinking water or food) or an external health‐based guidance value (e.g., tolerable daily intake, acceptable daily intake, or reference dose) to estimate the risk resulting from direct oral exposure to mixtures. Assessing mixture exposure is particularly relevant for PFAS, with omnipresent exposure in our daily lives. Environ Toxicol Chem 2021;40:859–870. © 2020 SETAC

中文翻译：

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全氟和多氟烷基物质混合物的风险评估：一种相对效力因子方法

全氟烷基物质和多氟烷基物质 (PFAS) 通常作为污染物一起出现在饮用水或食品等暴露介质中。相对效力因子 (RPF) 方法有助于混合物暴露的风险评估。使用相同物种（大鼠）、性别（雄性）和暴露途径（口服）和可比暴露持续时间（42-90 天）的数据，为 16 种 PFAS 建立了肝脏终点数据库。应用剂量反应分析得出 3 种全氟烷基磺酸（全氟丁磺酸、全氟己烷磺酸、全氟辛烷磺酸）、8 种全氟烷基羧酸（全氟丁酸、全氟己酸、全氟壬酸、全氟十一烷酸、全氟十二烷酸、全氟十四烷酸、全氟十六烷酸、全氟十八烷酸），2 个全氟烷基醚羧酸（四氟-2-[七氟丙氧基]丙酸、3H-全氟-3-[(3-甲氧基-丙氧基)丙酸]）和 2 个氟调聚物醇（6:2 FTOH、8:2 FTOH）与基于肝脏作用的全氟辛酸 (PFOA) 相比。此外，基于交叉读取估计了其他 7 种全氟烷基酸的 RPF。这导致 22 PFAS 的相对效力与指数化合物 PFOA 的效力相比。获得的 RPF 可应用于测量的全氟辛烷磺酸量，从而得出混合物中全氟辛酸当量的总和。该总和可以与既定的 PFOA 浓度限值（例如，在饮用水或食物中）或基于健康的外部指导值（例如，可耐受的每日摄入量、可接受的每日摄入量或参考剂量）进行比较，以估计直接导致的风险口服接触混合物。环境毒物化学2021；40:859–870。© 2020 SETAC