the fatal toll of plastic revealed

Helen BriggsBBC environment correspondent

Getty Images Two seal pups rest on the beach. One of the seals had a rope made of yellow and green plastic around its neck. — A seal pup entangled in plastic on the beach

Scientists analyzed 10,000 marine animal autopsies to understand how plastic consumption leads to death.

The study found that seabirds faced extreme risk after swallowing just 23 pieces of plastic, giving them a 90% chance of dying. While marine mammals reach similar danger with 29 pieces, sea turtles must swallow approximately 405 pieces to reach the same threshold.

Researchers were surprised to see how little of the plastic could be dangerous; Less than a football’s worth of soft plastic by volume can be fatal to a dolphin, while a seabird can die by swallowing several pieces of rubber smaller than the size of a pea.

They say the findings could help shape global efforts to protect wildlife.

Plastic pollution poses serious risk to seabirds from injury and poisoning

Getty Images A small gray bird perches on a blue plastic bottle floating in the gray sea. — Plastic pollution poses serious risk to seabirds from injury and poisoning

Lead researcher Dr. from the US-based environmental group Ocean Conservancy. “This is a really important reminder that plastic pollution poses an existential threat to ocean wildlife,” Erin Murphy said.

The analysis used autopsy data collected worldwide from seabirds, sea turtles and marine mammals such as seals, sea lions and dolphins. Almost half of the sea turtles, a third of seabirds and a tenth of marine mammals studied had eaten plastic.

Researchers estimated the risks of death from ingesting different types of plastic in each group of marine animals.

They found the type of plastic substances: Rubber is the most dangerous to seabirds; soft plastics and fish debris pose the greatest risk to marine mammals; Both hard and soft plastics threaten turtles.

Newborn green sea turtle trying to escape from plastic net

Getty Images A small turtle on the beach emerges from a tangled blue plastic net — Newborn green sea turtle trying to escape from plastic net

In the research, only plastics found in the stomachs of animals were examined. It did not evaluate chemical effects or entanglement, meaning the actual scale of harm would likely be higher.

Hundreds of marine species have been found to have plastic in their bodies. Birds often swallow pieces of plastic, and turtles mistake plastic bags for jellyfish. But until now, scientists didn’t have definitive data on how lethal plastic is to animals of different sizes.

Dr Murphy added: “To effectively tackle plastic pollution, the science is clear. We need to reduce the amount of plastic we produce, improve collection and recycling, and clean up what’s already there.”

The research was published at: Proceedings of the National Academy of Sciences.