Jochen Mueller is funded by an ARC Future Fellowship (FF 120100546). Entox is a joint venture of the University of Queensland and Queensland Health. The National Research Centre for Environmental Toxicology is co-funded by Queensland Health. “
“Per- and polyfluoroalkyl substances (PFASs)

are chemicals that have Transmembrane Transporters modulator been used for industrial applications and in consumer products since the 1950s (Buck et al., 2011). Perfluorooctane sulfonic acid (PFOS), and related chemicals such as N-methyl and N-ethyl perfluorooctane sulfonamido ethanols (Me- and EtFOSEs) and -sulfonamides (Me- and EtFOSAs) have been manufactured by electrochemical fluorination (ECF) as a mixture of linear (70%) and branched (30%) isomers (Martin et al., 2010). Production of PFOS and related chemicals was phased out in North America and Europe in 2002 by its main producer. Perfluoroalkyl carboxylic acids (PFCAs) have been manufactured by both ECF (producing both linear and branched isomers) and telomerization processes (producing only linear isomers), and major industrial buy MAPK Inhibitor Library companies have committed to reduce production and eliminate emissions of PFCAs with a chain length ≥ C8, and other chemicals that can degrade to these long-chain PFCAs by

2015 (US EPA, 2006). Human biomonitoring studies have shown that the general population in several countries has been exposed to perfluoroalkyl acids (PFAAs) such as PFOS and PFCAs, as well as to numerous precursors for Niclosamide several decades and that this exposure has changed over time (Glynn et al., 2012, Lee and Mabury, 2011, Loi et al., 2013, Yeung et al., 2013a and Yeung et al., 2013b). Ingestion of dust, food, drinking water and inhalation of air have all been identified as human exposure pathways (De Silva

et al., 2012; Filipovic and Berger, in press;Gebbink et al., submitted for publication and Shoeib et al., 2011). PFOS and PFOA exposure of the general population has previously been estimated (Trudel et al., 2008), and in a later study the role of precursor exposure was estimated in human exposure to PFOS and PFOA (Vestergren et al., 2008). Human exposure to PFOS and PFCAs via one or multiple exposure pathways is considered as direct exposure, while exposure to their precursors and subsequent biotransformation of these precursors to PFOS and PFCAs is considered as indirect exposure to PFOS and PFCAs. Precursors that can act as an indirect exposure source to PFOS (i.e. they are biotransformed in humans) include FOSEs, FOSAs, and intermediates such as perfluorooctane sulfonamidoacetic acids (FOSAAs) (Tomy et al., 2004, Xie et al., 2009 and Xu et al., 2004).