The first worldwide estimate of where the ocean’s massive amounts of plastic garbage comes from points at China and developing economies in Asia.
The study, published online on Friday in the journal Science, estimates that China’s heavily coastal population contributes 1.3 million to 3.5 million metric tons of plastic to the world’s oceans each year, largely from mismanaged waste.
Eight of the top 10 contributors were in Asia, including Indonesia, the Philippines, Vietnam, Sri Lanka, Thailand, Malaysia and Bangladesh, according to the study, which estimated that 4.8 million to 12.7 million metric tons of plastic wound up in the world’s oceans in 2010.
“Our low-end estimate is equivalent to the amount of tuna fished from the ocean in a single year,” oceanographer Kara Lavender Law of the Sea Education Associatio. in Woods Hole, Massachssets, said during a news conference on Friday. “We are taking out tuna and putting in plastic,” she added.
Even the middle range, or 8 million metric tons, “is the same as five [trash]bags filled with plastic for every foot of coastline in the world,” added co-author Jenna Jambeck, a University of Georgia environmental engineer.
Few of the top contributing countries have adequate infrastructure for handling trash disposal, the study noted.
Even with a well-developed infrastructure to handle solid waste, the United States contributed 40,000 to 110,000 metric tons per year, and ranked 20th, the study found. A high per capita use of plastic and dense coastal population means that litter had a bigger impact, Jambeck said.
“It’s not about finger-pointing, but examining things that strongly influence a country’s rank on this list,” Jambeck said.
Although flotillas of plastic trash have been reported in Earth’s oceans since the 1970s, there has been little attempt to quantify its origin, largely because data are incomplete or difficult to obtain.
The ecological effects of the long-lasting trash, much of it matted up in massive ocean gyres, are becoming more clear. Fish and other sea animals can ingest large pieces of plastic that clog their intestines, or they can become entangled and suffocate, studies show. As the plastic breaks down to smaller pieces, it can be ingested by smaller invertebrates that are the base of the food chain.
A study last year found that the amount of floating plastic in the oceans had not increased since the 1980s, despite increased plastic production. Researchers involved in that work suspect the plastic is still there, but has been breaking down into small pieces that sink. Marine life may be mistaking it for zooplankton and ingesting it.