Stranded porpoises, dolphins and seals had average of 5.5 particles in their guts
Microplastics are being widely ingested by Britain’s marine mammals, scientists say, with samples found in every animal examined in a study.
Researchers at the University of Exeter found microplastics in all 50 animals they studied in a recent survey of beached marine mammals, including 10 species of dolphins, seals and whales.
Synthetic fibers constituted the majority of plastic debris recovered from the animals, strands from clothes, fishing nets and toothbrushes. One quarter of the animals contained plastic fragments, likely from food packaging and plastic bottles.
The marine mammals involved in the study died of different causes, from natural causes to injuries. However, all of them were found to have microplastics inside them. ( Pixabay )
"It's shocking -- but not surprising -- that every animal had ingested microplastics," lead author Sarah Nelms, researcher at University of Exeter and the Plymouth Marine Laboratory, lead author of the research published in the journal Scientific Reports.
And Professor Brendan Godley, of the Centre for Ecology and Conservation at Exeter University said: “Marine mammals are ideal sentinels of our impacts on the marine environment, as they are generally long lived and many feed high up in the food chain. Our findings are not good news.”
Because scientists found relatively low concentrations of microplastics in the marine mammals, scientists think most of the debris would have eventually passed through their intestines or been regurgitated. But that doesn't mean the pollution can't harm large animals.
"We don't yet know what effects the microplastics, or the chemicals on and in them, might have on marine mammals," Nelms said. "More research is needed to better understand the potential impacts on animal health."
“Given the apparently almost ubiquitous nature of microplastics in our ocean life, this is an area we really need to understand in more detail.”
Autopsies showed the beached animals died for a variety of reasons. Those that died from infectious disease hosted slightly higher concentrations microplastics, suggesting the debris could hamper the mammals' immune systems. But scientists say more research is needed to confirm such a link.
"We are at the very early stages of understanding this ubiquitous pollutant," said Brendan Godley, researcher at Exeter's Center for Ecology and Conservation. "We now have a benchmark that future studies can be compared with."
The new study -- published this week in the journal Scientific Reports -- isn't the first to reveal the ubiquity of microplastics in the guts of marine species, but it's worrisome news, nonetheless.
"Marine mammals are ideal sentinels of our impacts on the marine environment, as they are generally long lived and many feed high up in the food chain," Godley said.
“This study provides more evidence that we all need to help reduce the amount of plastic waste released to our seas and maintain clean, healthy and productive oceans.”