Data on isomer-specific transplacental transfer of perfluoroalkyl substances (PFASs) are very scarce. This study investigates transplacental transfer of 23 PFASs, including isomers of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS), by analyzing 63 paired maternal and cord whole blood samples collected in Hubei, China. Significant correlations (r = 0.311–0.888; p ≤ 0.013) were observed between the concentrations in maternal and cord blood for most PFASs, indicating that PFASs could be efficiently transported from mother to fetus. For perfluorocarboxylates, a U-shaped trend of transplacental transfer efficiencies (TTEs) with increasing carbon chain lengths was confirmed. For PFOA and PFOS branched isomers, TTEs generally increased as the branching point moved closer to the carboxyl or sulfonate moiety, and branched isomers transferred more efficiently than their linear isomers did. This is the first report of the TTEs of PFAS isomers based on human whole blood samples and the first calculation of the TTEs of perfluorooctane sulfonamide. For almost all PFASs, the TTEs we reported are lower than those from previous studies based on serum or plasma. Whole blood is recommended for risk assessment of PFAS placental transfer considering that PFASs exhibit different partitioning behaviors between blood matrices. More accurate parameters for the health risks of PFASs during prenatal exposure are provided here.

中文翻译：

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人类全血中全氟烷基物质的异构体特异性跨胎盘效率

关于全氟烷基物质（PFASs）的异构体特异性胎盘转移的数据非常稀少。本研究通过分析湖北省收集的63对成对的母体和脐带全血样本，研究了23种PFAS的经胎盘转移，包括全氟辛酸酯（PFOA）和全氟辛烷磺酸（PFOS）的异构体。显着的相关性（r = 0.311–0.888; p对于大多数PFAS，母体和脐带血中的浓度之间的差异≤≤0.013），这表明PFAS可以有效地从母亲转运到胎儿。对于全氟羧酸盐，证实了随着碳链长度的增加，胎盘转移效率（TTE）呈U形趋势。对于PFOA和PFOS支链异构体，随着分支点移近羧基或磺酸酯部分，TTE通常会增加，并且支链异构体的转移效率要高于其线性异构体。这是基于人类全血样本的PFAS异构体TTE的首次报道，也是全氟辛烷磺酰胺TTE的首次计算。对于几乎所有的PFAS，我们报告的TTE均低于基于血清或血浆的先前研究的TTE。考虑到PFAS在血液基质之间表现出不同的分配行为，建议将全血用于PFAS胎盘移植的风险评估。此处提供了有关产前暴露期间PFAS的健康风险的更准确参数。