Co-occurrence of microplastics and endocrine-disrupting chemicals in subantarctic seabirds

Despite the remoteness of their breeding sites, subantarctic seabirds are susceptible to anthropogenic pollutants (e.g. microplastics) and other chemical stressors (e.g. plastic additives) that are released from ships and research stations, arrive in ocean currents, are transported in the atmosphere, or are ingested when the birds feed north of the Antarctic Polar Front. In this study, we investigated the presence and levels of microplastics and several groups of endocrine-disrupting chemicals (EDCs) in adults or chicks of seven seabird species breeding at the subantarctic islands of South Georgia. A total of 1275 anthropogenic particles were recovered in the gastrointestinal tracts of 76 seabirds, with a frequency of occurrence of 97.4%, a mean value of 16.78 ± 18.79 particles per individual and of 0.03 ± 0.03 particles/g body weight. Ten percent (n = 130 particles) of the particles were identified chemically using microFTIR spectroscopy, of which 59% were synthetic, 18% were natural, 19% were anthropogenic unknown and 4% were anthropogenic cellulosic. Of the EDCs, only polybrominated diphenyl ethers (PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) congeners occurred at levels above the limit of quantification. Liver samples consistently exhibited the highest concentrations of both contaminant groups. The highest concentrations of PBDEs were in adult brown skuas (133.96 ng/g) and of MeO-PBDEs were in wandering albatross chicks (6.50 ng/g). This research provides evidence of plastics and plastic additives in subantarctic seabirds, underscoring the need to strengthen measures aimed at reducing marine pollution.