image: This image shows how Master Kong 500 mL water bottles, the most abundant bottle on Inaccessible Island, age over approximately three years view more
Credit: Peter G. Ryan
Researchers examine sources of plastic bottle pollution in the South Atlantic Ocean. Most oceanic plastic debris is thought to come from land-based sources, but support for this theory is limited. Peter G. Ryan and colleagues examined plastic bottles and containers washed up along the west coast of Inaccessible Island, a remote and uninhabited island located in the central South Atlantic Ocean. Following litter surveys at the island in the 1980s, the authors examined 3,515 debris items in 2009 and 8,084 debris items in 2018. Polyethylene terephthalate (PET) drinking bottles were the most ubiquitous type of debris and had the fastest growth rate among debris, increasing at 14.7% each year since the 1980s. The oldest container, found in 2018, was a high-density polyethylene canister manufactured in 1971, but most bottles were date-stamped within 2 years of washing ashore. In the 1980s, two-thirds of plastic bottles drifted to Inaccessible Island from South America. By 2009, bottles made in Asia were as abundant as those from South America; in 2018, Asian bottles accounted for 75% of bottles, most of which were made in China. The manufacturing dates suggest that plastic bottles discarded from merchant ships are the main drivers of plastic bottle pollution in the central South Atlantic Ocean, according to the authors.
Article #19-09816: "Rapid increase in Asian bottles in the South Atlantic Ocean indicates major debris inputs from ships," by Peter G. Ryan, Ben J. Dilley, Robert A. Ronconi, and Maëlle Connan.
MEDIA CONTACT: Peter G. Ryan, University of Cape Town, SOUTH AFRICA; tel: +27-216502966; email: peter.ryan@uct.ac.za
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Journal
Proceedings of the National Academy of Sciences