Ingesting plastic is causing brain damage in seabird chicks, similar to Alzheimer’s disease in humans, according to a new study. This research adds to the growing evidence of plastic pollution’s severe impact on marine wildlife.

Scientists from the University of Tasmania analysed young shearwaters, a migratory bird traveling between Australia’s Lord Howe Island and Japan. Their findings revealed that plastic waste is causing internal damage not visible to the naked eye, including stomach lining decay, cell rupture, and neurodegeneration.

The study examined dozens of chicks, which spend 90 days in burrows before their first migration. Many had ingested large amounts of plastic fed to them by their parents.

Blood tests indicated severe health problems, with plastic disrupting the stomach, liver, kidneys, and brain. The study was published in the journal Science Advances.

“Plastic ingestion in seabirds is nothing new. We’ve known about it since the 1960s, but a lot of plastic research focuses on the birds that are really emaciated: they’re starving, they’re washing up on beaches and not doing too well. We wanted to understand the condition of birds that have consumed plastic but look visibly healthy,” said Alix de Jersey, a PhD student from the University of Tasmania’s School of Medicine, who led the study.

“[In blood tests], we found patterns of the proteins that were very similar to those in people that have Alzheimer’s or Parkinson’s disease. It’s almost equivalent to a small child having Alzheimer’s. These birds are really suffering the impacts from plastic, especially on their neuronal brain health,” she said.

Shearwaters are among the bird species most affected by plastic pollution. Previous studies found over 400 plastic pieces in a single chick, with plastic making up 5-10% of their body weight. While chicks can vomit some plastic before migrating, researchers noted that many cannot expel the vast quantities they ingest.

In this study, chicks had their stomachs pumped, allowing them to begin their journey to the Sea of Japan without plastic in their systems.

“It’s almost a death sentence for these chicks, which is unfortunate because they do look really fit and healthy. But knowing the condition which their body is in before they’re starting their migration, it’s quite challenging to imagine that they would make it to the other end,” said de Jersey.

Previous research indicates that fewer than 60 multinational companies are responsible for over half of the world’s plastic pollution, with just six accounting for a quarter of it.

The study underscores the urgent need to address plastic pollution, which poses a significant threat to marine life and ecosystems worldwide.