Millions of pieces of plastic are piling up on an otherwise pristine Pacific island

More than 37 million pieces of plastic debris have accumulated on a remote island in the South Pacific, thousands of miles from the nearest city, according to estimates from researchers who documented the accumulating trash.

Turtles get tangled in fishing line, and hermit crabs make their homes in plastic containers. The high-tide line is demarcated by litter. Small scraps of plastic are buried inches deep into the sandy beaches.

It's the highest density of debris reported anywhere in the world, scientists say. Their research on trash accumulated at Henderson Island, largest of the the Pitcairn Islands, was published Monday in the Proceedings of the National Academy of Sciences.

The island is uninhabited and visited by scientists only once or twice a decade, according to the University of Tasmania. But ocean currents bring a steady stream of plastic trash from around the world, from litter swept into storm drains to debris dropped off fishing boats.

"What's happened on Henderson Island shows there's no escaping plastic pollution even in the most distant parts of our oceans," lead author Jennifer Lavers said in a statement released by the university. "Far from being the pristine 'deserted island' that people might imagine of such a remote place, Henderson Island is a shocking but typical example of how plastic debris is affecting the environment on a global scale."

There are no major factories or towns within 3,100 miles of the island, the scientists say. So all that trash — more than 17 tons of it, with thousands of new individual pieces arriving each day — travels long distances through the ocean before arriving on the white-sand beaches.

The researchers call the pace of accumulation "exceptional." And it has consequences: The trash interferes with sea turtle nests and poses a threat to seabirds that can get caught in the debris.

But the scale of the problem extends far beyond this isolated island, which is a UNESCO World Heritage site. In their paper, the researchers note that the masses of trash on Henderson Island "account for only 1.98 seconds' worth of the annual global production of plastic."

It's hard to keep track of where exactly all that plastic goes; much of it is "lost," vanishing into the ocean for parts unknown.

Based on their research, Lavers and co-author Alexander Bond suggest that some of the trash winds up in remote, uninhabited, otherwise pristine islands — "which have become reservoirs for the world's waste," they write.