The amount of plastic debris in the ocean waters of the British islands in the South Atlantic — some of the most remote places on the planet — has increased hundredfold in the last 30 years, according to a new study in the journal Current Biology. Today, the density of plastic near the South Atlantic islands is approaching the pollution levels along industrialized North Atlantic coasts, the study finds.

“Three decades ago, these islands were near-pristine,” marine ecologist David Barnes of the British Antarctic Survey (BAS), lead author of the new study, said in a statement. “Plastic waste… is now so common it reaches the seabed. We found it in plankton, throughout the food chain, and up to top predators such as seabirds.”

The plastic came from many sources, including landfills, the shipping and fishing industries, and debris carried out to sea by coastal storms, Nexus Media reported.

Barnes and his colleagues collected plastics data during four research cruises on the BAS ship RRS James Clark Ross between 2013 and 2018. Scientists from 10 organizations sampled ocean waters and the seabed near the remote islands, combed beaches, and examined more than 2,000 animals across 26 species. More than 90 percent of the debris found on beaches was plastic; this included up to 300 plastic items per meter of shoreline on East Falkland and St. Helena islands — 10 times higher than recorded a decade ago.

“These islands and the ocean around them are sentinels of our planet’s health,” biologist Andy Schofield, a co-author of the new study, said in a statement. “This is a very big wake-up call. Inaction threatens not just endangered birds and whale sharks, but the ecosystems many islanders rely on for food supply and health.”