Assessment of exposure to pesticides, anticoagulant rodenticides, and PFASs in the blood of top-predator birds by LC-MS/MS analysis.

Chemical pollution of the environment is one of the main factors contributing to the global decline of wildlife populations. Both persistent organic pollutants (POPs) and new contaminants of emerging concern (CECs) can pose a threat to the health of humans and wildlife. Bird species, and raptors in particular, are used as sentinels for environmental pollution because they are at the top of food chains and can accumulate and biomagnify organic contaminants. In this context, 136 blood samples from chicks of four species (Eurasian eagle-owl, common buzzard, common kestrel, and white stork) were analyzed. A method based on miniaturized liquid-liquid extraction, followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed for the analysis of 112 organic pollutants, including plant protection products (PPPs), per- and polyfluoroalkyl substances (PFASs), and anticoagulant rodenticides (ARs). A total of 12 compounds (5 PPPs, 3 PFASs, and 4 ARs) were detected. The herbicide MCPA was detected in all species studied, with a maximum concentration of 30.9 ng mL-1. Linear PFOS was detected in all species, including 100 % of white stork samples (maximum concentration of 105.4 ng mL-1). First and second generation ARs were identified only in Eurasian Eagle-owls, with brodifacaoum showing the highest concentration (10.5 ng mL-1). We related the concentration of organic pollutants to the land use around the nest, observing that the presence of PPPs may be mainly related to agriculture, while PFASs may be related to urban areas, although with particularities for each species. This study highlights the extent of exposure to which wildlife is subjected, even in areas with low human activity.