A Bad Start in Life? Maternal Transfer of Legacy and Emerging Poly- and Substances to Eggs in an Arctic Seabird

In birds, maternal transfer is a major exposure route for several contaminants, including poly-and perfluoroalkyl substances (PFAS). Little is known, however, about the extent of the transfer of the different PFAS compounds to the eggs, especially for alternative fluorinated compounds. In the present study, we measured legacy and emerging PFAS, including Gen-X, ADONA, and F-53B, in the plasma of prelaying black-legged kittiwake females breeding in Svalbard and the yolk of their eggs. We aimed to (1) describe the contaminant levels and patterns in both females and eggs, and (2) investigate the maternal transfer, that is, biological variables and the relationship between the females and their eggs for each compound. Contamination of both females and eggs were dominated by linPFOS then PFUnA or PFTriA. We notably found 7:3 fluorotelomer carboxylic acid-a precursor of long-chain carboxylates-in 84% of the egg yolks, and provide the first documented finding of ADONA in wildlife. Emerging compounds were all below the detection limit in female plasma. There was a linear association between females and eggs for most of the PFAS. Analyses of maternal transfer ratios in females and eggs suggest that the transfer is increasing with PFAS carbon chain length, therefore the longest chain perfluoroalkyl carboxylic acids (PFCAs) were preferentially transferred to the eggs. The mean n-ary sumation Sigma(PFAS) in the second-laid eggs was 73% of that in the first-laid eggs. Additional effort on assessing the outcome of maternal transfers on avian development physiology is essential, especially for PFCAs and emerging fluorinated compounds which are under-represented in experimental studies.

Automated summary

Maternal transfer is a major exposure route for contaminants in birds, with PFAS compounds like linPFOS dominating in females and eggs. The study also found fluorotelomer carboxylic acid and ADONA in egg yolks for the first time, with emerging compounds below detection limit in female plasma. The transfer of PFAS to eggs was linearly related to the females, and PFCAs with longer carbon chains were preferentially transferred. The second-laid eggs had 73% of the PFAS levels compared to the first-laid eggs. Further research on the impact of maternal transfers on avian development physiology is warranted, especially for under-represented PFCAs and emerging fluorinated compounds.