Distribution of perfluoroalkyl compounds in rats: Indication for using hair as bioindicator of exposure

Hair analysis is potentially advantageous in exposure assessment of perfluoroalkyl acids (PFAAs) as a non-invasive method, combined with the ability to reflect long-term exposure. The present study aims to assess the feasibility of using hair as an indicator of PFAA exposure. Adult male and female rats were subchronically exposed to selected PFAAs, including perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorooctanesulfonate (PFOS), for 90 days. Hair, serum, and other tissues, including liver, kidney, spleen, lung, brain and heart, as well as the urine and feces excretions, were analyzed for PFAA levels. PFOA/PFNA/PFOS were detected in rat hair in a dose-dependent manner, in the order of PFOS>PFNA>PFOA. Hair PFAA concentrations were higher in male rats than the female rats, except for PFOS at low dose. Moreover, significant positive correlations as well as similar PFAA profiles were observed between hair, serum, and other tissues. Besides, hair PFAAs were negatively correlated with the urinary excretion rate. Although the influencing factors in humans still need further investigation, the results suggested that hair is capable of reflecting PFAA exposure, and could be employed as an alternative exposure bioindicator of PFAAs.