Microplastics found in Weddell seal placenta in Antarctica, potential threatening marine ecosystem health

Microplastics (MPs) have become emerging contaminants of global concern, yet their presence in the reproductive tissues of Antarctic marine mammals remains poorly understood. In this study, COI gene sequencing confirmed that 59 naturally expelled placentas, collected accidentally from Prydz Bay, East Antarctica, originated from the Weddell seal Leptonychotes weddellii. MPs were isolated from placental tissues and characterized. A total of 30 MP items were detected, with an average abundance of 0.024 ± 0.029 items/g (wet weight). Fibers dominated (73.33 %), followed by films (16.67 %) and fragments (10.00 %). Red (60.00 %) and blue (23.33 %) were the most common colors. Particle sizes ranged from 48.69 to 1207.97 μm, with 26.67 % of MPs smaller than 200 μm. Fourier transform infrared spectroscopy (FTIR) revealed five polymer types, with acrylic (53.33 %) and polyester (23.33 %) being the most prevalent. These results provide the first report of MPs in the placenta of Antarctic marine mammals and establish baseline evidence of MPs presence at the maternal-fetal interface, supporting further assessment of potential implications for placental function and early development.