Accumulation of lipophilic and proteinophilic halogenated organic pollutants (HOPs) in the different types of feathers of laying hens

Abstract

This study investigated the bioaccumulation of halogenated organic pollutants (HOPs) in three types of feathers from laying hens through exposure experiments. The HOPs included lipophilic polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), as well as proteinophilic perfluoroalkyl carboxylic acids (PFCAs). Concentrations of PCBs, PBDEs, and short-chain PFCAs (≤8) were significantly higher in the body feathers than in the primary feathers, while long-chain PFCAs (>8) showed no significant differences among primary, tail, and body feathers. The concentration order in the feathers was ∑₁₂PFCAs > ∑₇PBDEs > ∑₁₃PCBs, which was completely reversed by the exposure dose. The transfer rates (TRs) (concentration ratio of feather to serum) of PFCAs (0.11–6.8) were one order of magnitude higher than those (0.01–0.30) of PCBs and PBDEs. These results indicate that PFCAs preferentially accumulate in feathers compared to PBDEs and PCBs. TRs, regardless of whether they were lipophilic or proteinophilic HOPs, were significantly and positively correlated with the protein-water partition coefficient (log K_pw). Strong and significant correlations between feathers and inner tissues were primarily observed in body feathers. Egg-laying significantly affects PFCA accumulation in feathers and even distorts the actual exposure dose in hens; however, its impact on PCBs and PBDEs is limited. These findings provide crucial insights into HOP deposition in bird feathers.