In 1984, 2009, and 2018, researchers made the trek to Inaccessible Island, which sits between Argentina and South Africa in the South Atlantic. They describe it as a "remote, uninhabited island ... that has a very high macrodebris load"—and that debris is what they were there for. In a study published Monday in the Proceedings of the National Academy of Sciences, they write that "most plastic debris floating at sea is thought to come from land-based sources, but there is little direct evidence to support this assumption." What their direct evidence suggests is that the major source is an entirely different kind: Chinese merchant ships. Based on their labels, the plastic bottles collected during their first visit largely came from South America, which sits 2,000 miles west.
By 2009 Asia was the biggest source, and in 2018, 73% of the accumulated bottles collected and 83% of those that arrived during their monitoring were from Asia, mostly China. And of that latter category, 90% were date-stamped within the last two years, meaning they couldn't have started their journey in Asia itself, as that journey via currents would last three to five years. "It's inescapable that it's from ships, and it's not coming from land," author Peter Ryan tells AFP, explaining that many of the bottles retained their lids but had been crushed, as would happen on ships to save space. And while there's been no spike in the number of Asian fishing vessels in the last few decades, the count of Chinese cargo vessels in the Atlantic has surged. (Read more discoveries stories.)