Sources of PFSAs and PFCAs to the Arctic

The origin and transport pathways of PFSAs and PFCAs in the Arctic is a topic of interest that has received considerable attention by researchers. In particular, two hypotheses have been proposed to explain the sources of PFSAs and PFCAs to the Arctic. It is important to note that proponents of both hypotheses agree that both transport routes are likely to occur simultaneously. However, the relative importance of each transport route is unknown. 

The alternative hypothesis suggests a direct route, where long-range oceanic transport can account for the presence of PFCAs in the Arctic Ocean and thus in Arctic biota [14,163, 164]. As will be discussed later in more detail, PFOS, PFOA, PFNA and PFHxS have been reported in open ocean waters of the Pacific and Atlantic and in coastal waters of Japan, Korea and China [95,112,165]. Modelling studies indicate that the observed PFOA concentrations in oceans can be accounted for by historical and projected PFOA emissions [14, 163, 164]. 

Stock et al. [166] identified that, in addition to the direct and indirect sources discussed above, a third route by which PFCs reach the Arctic is local contamination. PFOA, PFHpA, PFHxS and PFOS were observed in Resolute Lake in the Canadian Arctic at concentrations (up to 90 ng/L) that were nearly 60 times that observed in other, nearby Arctic lakes. The contamination of Resolute Lake was proposed to be as a result of a nearby airport wastewater input and did not appear to be widespread. 

---