Bottlenose dolphins (Tursiops truncatus) are keystone and sentinel species in the world’s oceans. We studied correlations between per- and polyfluoroalkyl substances (PFAS) and their stress axis. We investigated associations between plasma biomarkers of 12 different PFAS variants and three cortisol pools (total, bound, and free) in wild T. truncatus from estuarine waters of Charleston, South Carolina (n = 115) and Indian River Lagoon, Florida (n = 178) from 2003 to 2006, 2010–2013, and 2015. All PFAS and total cortisol levels for these dolphins were previously reported; bound cortisol levels and free cortisol calculations have not been previously reported. We tested null hypotheses that levels of each PFAS were not correlated with those of each cortisol pool. Free cortisol levels were lower when PFOS, PFOA, and PFHxS biomarker levels were higher, but free cortisol levels were higher when PFTriA was higher. Bound cortisol levels were higher when there were higher PFDA, PFDoDA, PFDS, PFTeA, and PFUnDA biomarkers. Total cortisol was higher when PFOA was lower, but total cortisol was higher when PFDA, PFDoDA, PFTeA, and PFTriA were higher. Additional analyses indicated sex and age trends, as well as heterogeneity of effects from the covariates carbon chain length and PFAS class. Although this is a cross-sectional observational study and, therefore, could reflect cortisol impacts on PFAS toxicokinetics, these correlations are suggestive that PFAS impacts the stress axis in T. truncatus. However, if PFAS do impact the stress axis of dolphins, it is specific to the chemical structure, and could affect the individual pools of cortisol differently. It is critical to conduct long-term studies on these dolphins and to compare them to populations that have no or little expose to PFAS.

中文翻译：

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研究全氟烷基物质和多氟烷基物质与宽吻海豚 (Tursiops truncatus) 应激生物标志物之间的联系


宽吻海豚（Tursiops truncatus）是世界海洋中的重要物种和哨兵物种。我们研究了全氟烷基物质和多氟烷基物质 (PFAS) 与其应力轴之间的相关性。我们研究了来自南卡罗来纳州查尔斯顿河口水域 (n = 115) 和佛罗里达州印第安河泻湖 (n = 178）从2003年到2006年、2010年到2013年和2015年。这些海豚的所有PFAS和总皮质醇水平之前都有报道；先前未报道结合皮质醇水平和游离皮质醇计算。我们测试了零假设，即每种 PFAS 的水平与每个皮质醇池的水平不相关。当 PFOS、PFOA 和 PFHxS 生物标志物水平较高时，游离皮质醇水平较低，但当 PFTriA 较高时，游离皮质醇水平较高。当 PFDA、PFDoDA、PFDS、PFTeA 和 PFUnDA 生物标志物较高时，结合皮质醇水平较高。当 PFOA 较低时，总皮质醇较高，但当 PFDA、PFDoDA、PFTeA 和 PFTriA 较高时，总皮质醇较高。其他分析表明了性别和年龄趋势，以及协变量碳链长度和 PFAS 类别影响的异质性。尽管这是一项横断面观察性研究，因此可以反映皮质醇对 PFAS 毒代动力学的影响，但这些相关性表明 PFAS 影响 T. truncatus 的应激轴。然而，如果 PFAS 确实影响海豚的应激轴，那么它是特定于其化学结构的，并且可能对各个皮质醇池产生不同的影响。 对这些海豚进行长期研究并将其与没有或很少接触 PFAS 的种群进行比较至关重要。