Perfluoroalkyl acid (PFAA) profile and concentrations in two co-occurring tit species: distinct differences indicate non-generalizable results across passerines

Eggs of terrestrial bird species have often been used to biomonitor both legacy and emerging anthropogenic contaminants, such as perfluoroalkyl acids (PFAAs). However, few, if any, studies have examined whether results obtained in a given model species can be generalized across bird species. Therefore, we compared potential differences in egg PFAA profile and concentrations between two widely studied passerine species, great tit (Parus major) and blue tit ((Cyanistes caenileus), which arc similar in many aspects of their ecology and life history. Whole clutches of both species were collected from the same breeding season and at the same place (Antwerp, Belgium), enabling us to study laying order effects. Additionally, we evaluated how egg PFAA concentrations for both species changed along a distance gradient from a PFAA point source. Although the sum PFAA concentrations did not significantly differ between great tits and blue tits, large differences in PFAA profile and laying order effects were observed. Great tits showed a more diverse PFAA detection profile, including periluorooctane sulfonic acid (PFOS) and various long-chain perfluorocarboxylic acids (PFCAs) but no short-chain compounds. Contrarily, short-chain PFCAs (periluorobutanoic acid (PFBA) and perfluorohexanoic acid (PFHxA)) were only detected in blue tit eggs. The variation of perfluoroocianuic acicl (PFOA) concentrations within clutches was large in both species, although laying order effects on PFOA concentrations were only found in blue tits. Although egg PFOA concentrations of both species decreased similarly from the fluorochemical point source onwards, more variation in egg PFOA concentrations could be explained by distance from the fluorochemical plant in great tits (60%) than in blue tits (15%). Results showed that both species markedly differed in terms of egg PFAA profile and concentrations, must likely reflecting differences in diet, foraging habits and egg protein composition. Finally, biumonituring results of PFAAs in eggs arc likely not generalizable across bird species. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

There are differences in egg PFAA profiles and concentrations between great tits and blue tits, likely reflecting differences in diet, foraging habits, and egg protein composition.