Polyfluorinated compounds (PFCs) are authorized for use as greaseproofing agents in food contact paper. As C8-PFCs (8-carbons) are known to accumulate in tissues, shorter-chain C6-PFCs (6-carbons) have replaced C8-PFCs in many food contact applications. However, the potential of C6-PFCs for human biopersistence has not been fully evaluated. For the first time, we provide internal exposure estimates to key metabolites of 6:2 fluorotelomer alcohol (6:2 FTOH), a monomeric component of C6-PFCs, to extend our understanding of exposure beyond estimates of external exposure. Pharmacokinetic data from published rat and human studies on 6:2 FTOH were used to estimate clearance and area under the curve (AUC) for its metabolites: 5:3 fluorotelomer carboxylic acid (5:3 A), perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA). Internal exposure to 5:3 A was the highest of evaluated metabolites across species and it had the slowest clearance. Additionally, 5:3 A clearance decreased with increasing 6:2 FTOH exposure. Our analysis provides insight into association of increased internal 5:3 A exposure with high biopersistence potential of 6:2 FTOH. Our results identify 5:3 A as an important biomarker of internal 6:2 FTOH exposure for use in biomonitoring studies, and are potentially useful for toxicological assessment of chronic dietary 6:2 FTOH exposure.

多氟化合物（PFC）已被授权在食品接触纸中用作防油剂。由于已知C8-PFC（8碳）会在组织中积累，因此在许多食品接触应用中，短链C6-PFC（6碳）已取代了C8-PFC。但是，尚未完全评估C6-PFC对人类生物持久性的潜力。我们首次为6：2含氟端粒醇（6：2 FTOH）（C6-PFCs的单体成分）的关键代谢物提供内部暴露估算，以使我们对暴露的了解超出了对外部暴露的估算。使用来自已发表的大鼠和人体研究的6：2 FTOH的药代动力学数据来估算其代谢产物：5：3氟调聚物羧酸（5：3 A），全氟己酸（PFHxA）和全氟庚酸的清除率和曲线下面积（AUC）酸（PFHpA）。内部暴露于5：3 A是物种中评估的代谢产物最高，清除速率最慢。此外，随着6：2 FTOH暴露的增加，清除率降低了5：3。我们的分析提供了内部5：3 A暴露增加与6：2 FTOH的高生物持久性关联的见解。我们的研究结果确定5：3 A是内部6：2 FTOH暴露的重要生物标志物，可用于生物监测研究，并且可能对慢性饮食6：2 FTOH暴露的毒理学评估有用。