Assessing Contamination Profiles in Livers From Road‐Killed Owls

Abstract

Raptors are recognised as valuable sentinel species for monitoring environmental contaminants owing to their foraging behaviour across terrestrial and aquatic food webs and their high trophic position. This study monitored environmental contaminants in livers from road‐killed owls to evaluate differences in the exposure patterns due to factors as species, age, and sex of individuals. Carcasses of road‐killed individuals of eagle owl (Bubo bubo), long‐eared owl (Asio otus), little owl (Athene noctua), tawny owl (Strix aluco), and barn owl (Tyto alba) were collected in Alentejo (Portugal). Eighty one organic contaminants were analyzed, including organochlorine pesticides (OCPs), perfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals, in‐use pesticides, and organophosphate esters flame retardants (OPEs). Overall, 21 contaminants were detected. ∑OCPs were prevalent in all species at concentrations from 3.24 to 4480 ng/g ww, followed by PFOS, the only PFASs detected (from 2.88 to 848 ng/g ww) and ∑PCBs (1.98 to 2010 ng/g ww). ∑PAHs were ubiquitous but detected at the lowest concentrations (from 7.35 to 123 ng/g ww). Differences among species were observed according to Principal Component Analysis. Eagle owl and long‐eared owl presented the highest levels of ∑OCPs, ∑PCBs, and PFOS, consistently with its higher trophic position while ∑PAHs prevailed in tawny owl, barn owl and little owl, related with their frequent use of urban areas for nesting and roadsides for hunting. Adults presented higher concentrations of ∑OCPs and ∑PCBs than juveniles, while no differences were observed for PFOS and ∑PAHs. Pharmaceuticals, in‐use pesticides and OPEs were not detected. Overall, this study shows specific contamination patterns in 5 species with similar diet but with differences in habitat preferences.