Evaluation of per- and polyfluoroalkyl substances and organochlorine pesticides in great tit eggs from areas with different anthropogenic pressures in Padova, Italy.

This study investigates the contamination of per- and polyfluoroalkyl substances (PFAS) and organochlorine pesticides (OCPs) in eggs of great tits (Parus major) from urban, agricultural, and woodland areas from Italy. PFOS was the most prevalent PFAS, followed by long-chain perfluorocarboxylic acids (PFCAs). Agricultural areas showed the highest PFOS concentrations, while woodland areas exhibited higher concentrations of PFUnDA and PFTrDA. The observed PFCA chain length patterns across different locations highlight the influence of atmospheric chemistry, especially the oxidative breakdown of PFCA precursors, in determining contamination profiles. OCP contamination was dominated by DDT metabolites, especially p,p'-DDE, with higher concentrations in urban areas, reflecting historical pesticide use and the limited soil disturbance in these environments, which prevents the dilution and breakdown of persistent compounds like DDT. Agricultural areas showed elevated PFOS concentrations, likely due to the use of biosolid fertilizers. Principal component analysis revealed distinct contamination patterns across the studied environments, with urban and agricultural areas influenced by local sources, while woodland areas exhibited contamination linked to atmospheric deposition. These results highlight the persistence of both PFAS and OCPs in the environment, underscoring the need for continued monitoring and the utility of great tit eggs as effective bioindicators for assessing the impact of historical and ongoing pollution sources.