Short-chain perfluoroalkyl carboxylic acids (PFCAs) have been detected in the environment globally. The presence and persistence of these compounds in the environment may lead to chronic wildlife exposure. We used northern leopard frog (Rana pipiens) tadpoles to investigate the chronic toxicity and the bioconcentration of two short-chain PFCAs, perfluorobutanoic acid (PFBA) and perfluorohexanoic acid (PFHxA). We exposed Gosner stage 25 tadpoles to PFBA and PFHxA (as individual chemicals) at nominal concentrations of 0.1, 1, 10, 100, and 1000 µg/L for 43–46 days. Tadpoles exposed to 0.1 to 100 µg/L of PFBA and PFHxA had significantly higher mean snout-to-vent lengths, mean masses, and scaled mass indexes than control tadpoles. These results indicate that exposure to short-chain PFCAs influences tadpole growth. Further investigation into the mechanism(s) causing the observed changes in tadpole growth is warranted. We observed a significantly higher proportion of males in the PFBA 1 µg/L treatment group, however further histological analyses are required to confirm visual sex identification before making concrete conclusions on the effects of PFCAs on amphibian sex ratios. PFBA concentrations in tissues were higher than PFHxA concentrations; a pattern that contrasts with previously published studies using fish, suggesting potential differences between taxa in PFBA and PFHxA bioconcentration. Bioconcentration factors were <10 L/kg wet weight, indicating low bioconcentration potential in tadpoles. Our results suggest that PFBA and PFHxA may have effects at environmentally-relevant concentrations (0.1–10 µg/L) and further investigation is required before these compounds can be deemed a “safe” alternative to their long-chain counterparts.

全球环境中已检测到短链全氟烷基羧酸 (PFCA)。这些化合物在环境中的存在和持续存在可能会导致野生动物的长期暴露。我们利用北方豹蛙 ( Rana pipiens ) 蝌蚪研究了两种短链 PFCA：全氟丁酸 (PFBA) 和全氟己酸 (PFHxA) 的慢性毒性和生物浓度。我们将 Gosner 25 期蝌蚪暴露于标称浓度为 0.1、1、10、100 和 1000 µg/L 的 PFBA 和 PFHxA（作为单独的化学品）中 43-46 天。暴露于 0.1 至 100 µg/L PFBA 和 PFHxA 的蝌蚪比对照蝌蚪具有显着更高的平均吻部到排气口长度、平均质量和标度质量指数。这些结果表明，接触短链 PFCA 会影响蝌蚪的生长。有必要进一步研究引起观察到的蝌蚪生长变化的机制。我们观察到 PFBA 1 µg/L 治疗组中雄性的比例明显较高，但在就 PFCA 对两栖动物性别比例的影响做出具体结论之前，需要进一步的组织学分析来确认视觉性别识别。组织中 PFBA 浓度高于 PFHxA 浓度；这种模式与之前发表的使用鱼类的研究形成对比，表明 PFBA 和 PFHxA 生物浓度中的分类群之间存在潜在差异。生物富集因子<10 L/kg湿重，表明蝌蚪的生物富集潜力较低。我们的结果表明，PFBA 和 PFHxA 可能在环境相关浓度 (0.1–10 µg/L) 下产生影响，需要进一步研究才能将这些化合物视为长链对应物的“安全”替代品。