WASHINGTON (Reuters) - More than 10 million pieces of trash were plucked from the world’s waterways in a single day last year. But for Philippe Cousteau, the beach sandals that washed up in the Norwegian arctic symbolized the global nature of the problem of marine debris.

A boy collects plastic materials near a polluted coastline to sell in Manila April 9, 2008. REUTERS/Cheryl Ravelo

“We saw flip-flops washing ashore on these islands in far northern Norway near the Arctic Circle,” Cousteau, a conservationist and grandson of famed oceanographer Jacques Cousteau, said in a telephone interview.

Cousteau was commenting on marine debris statistics released Tuesday by the Ocean Conservancy group.

“People don’t wear flip-flops in the Arctic, at least not if they’re sane,” Cousteau said. “I think people are starting ... to realize that this is a global problem.”

The report detailed the amount and kind of trash that volunteers gathered on one day in 2009 along coastlines of six continents and the banks of inland waterways, stressing that as much as 80 percent of marine litter starts on land.

“Trash travels, and no beach, lakeshore or riverfront is untouched -- no matter how remote,” Vikki Spruill, Ocean Conservancy’s CEO, wrote in the report’s introduction.

Last year, 10,239,538 pieces of junk were retrieved from shorelines on one day, September 19, 2009, by about half a million volunteers in the conservancy’s annual international coastal cleanup. This year’s cleanup day is September 25.

More than 40 percent of that total was collected in the United States, including everything from bottle caps and plastic six-pack holders to cigarette butts, washing machines, construction materials, diapers, condoms and medical waste. The United States had the most volunteers, nearly triple the number in the Philippines, which had the second-most.

Nearly 20 percent of the items collected threaten public health, including bacteria-laden medical waste, appliances, cars and chemical drums, the report said. Some debris is a threat to marine animals, which can become tangled in dumped fishing nets and line or ingest floating plastic junk.

As plastics break down in the oceans, they look a lot like organisms called plankton that form the base of the food chain, Cousteau said.

“Fish and other animals are ingesting them and in so doing ingesting the toxins that these plastics absorb,” he said. “And then guess who eats the fish?”

Cousteau said these plastics contain high levels of dioxins, PCBs and other chemicals that can affect hormones, and also lack any nutritional value, so marine creatures can die with stomachs full of plastic.