Perfluoroalkyl substance concentrations in a terrestrial raptor: Relationships to environmental conditions and individual traits

Accumulation of persistent organic pollutants (POPs) in wildlife may be influenced by the physical and biotic environment, and
concentrations vary greatly among areas, seasons, and individuals. Different hypotheses about sources of variation in perfluoroalkyl
substance (PFAS) concentrations were examined in eggs (n¼107) of tawny owls (Strix aluco) collected over a 24-yr period (1986–2009)
in Norway. Predictor variables included the North Atlantic Oscillation (NAO), temperature, snow, food availability (vole abundance), and
individual traits such as age, body condition, and clutch size. Concentrations of both perfluoro-octane sulfonate (PFOS) and perfluoroalkyl
carboxylates (PFCAs) varied several fold in the population, both inter- and intra-annually. Moreover, individuals laid eggs with several
times higher or lower PFAS concentrations within few years (1 yr–5 yr). After controlling for temporal trends (i.e., declining PFOS and
increasing PFCA concentrations), both PFOS and PFCAs were positively associated to the winter NAO in the previous year (NAOy – 1),
suggesting that atmospheric transport may be affecting the input of PFASs to the local ecosystem. Perfluoro-octane sulfonate was
negatively related to temperature, but the pattern was complex as there was an interaction between temperature and the feeding conditions.
The PFOS accumulation was highest in years with high vole abundance and low to medium temperatures. For PFCAs, there was an
interaction between NAOy – 1 and feeding conditions, suggesting that strong air transport toward Norway and high consumption of voles
led to a moderate increase in PFCA accumulation. The individual traits, however, had very little impact on the concentrations of PFASs in
the eggs. The present study thus suggests that annual variation in environmental conditions influences the concentrations of PFASs in a
terrestrial raptor such as the tawny owl. Environ Toxicol Chem 2014;9999:1–8. # 2014 SETAC
Keywords: Perfluoroalkyl substance Owl Climate Age Persistent organic pollutant