Plasma concentrations of organohalogenated pollutants in predatory bird nestlings: Associations to growth rate and dietary tracers

The extent to which persistent organic pollutants (POPs) with different physicochemical properties originated from the food
(dietary input) was assessed in raptor nestlings. Lipophilic polychlorinated biphenyl (PCB) 153, 1-dichloro-2,2-bis(p-chlorophenyl)
ethylene (p,p’-DDE), and hexachlorobenzene (HCB), and protein-bound perfluorooctane sulfonate (PFOS), were measured repeatedly in
blood plasma of individual goshawk (Accipiter gentilis) and white-tailed eagle (Haliaeetus albicilla) nestlings, 1 to 3 wk after hatching and
near fledging. Maternally derived POPs dilute as nestlings grow (growth dilution), and increasing plasma concentrations would indicate
dietary input. First, plasma concentrations given no dietary input were estimated, and concentrations of p,p’-DDE, HCB, and notably
PFOS were significantly higher than predicted from a growth-dilution scenario (approximately 1.5-fold to 2.5-fold higher; p<0.001). In contrast, PCB 153 declined in both species, although concentrations were still higher than predicted in white-tailed eagle nestlings (p<0.05). Second, the relationships between plasma POP concentrations and trophic position (d15N) and dietary carbon source (d13C) were analyzed, controlling for growth rate. Both d15N and d13C (measured in body feathers) were significantly associated to the accumulation of most POPs, except PFOS. In conclusion, pollutant data acquired in plasma of nestling raptors should be interpreted and further investigated in the light of individual feeding ecology, and the use of raptor nestlings as sentinels for POP monitoring could be optimized by correcting for different factors such as body condition, brood size, and age. Persistent organic pollutants (POPs) Polyfluorinated alkyl substances (PFAS) Raptors Terrestrial Marine