Much has been written about plastic trash littering Planet Earth. But the latest report, about a remote, uninhabited island in the middle of the Pacific Ocean, where researchers found an estimated 38mn pieces of trash washed up on the beaches, highlights an ever worsening problem. The density of trash, mostly made from plastic, was the highest recorded anywhere in the world, despite Henderson Island’s extreme remoteness. Located about halfway between New Zealand and Chile, the island is recognised as a Unesco world heritage site.
A report published in the Proceedings of the National Academy of Sciences last week by Jennifer Lavers (Institute for Marine and Antarctic Studies, University of Tasmania) and Alexander Bond (Centre for Conservation Science, Royal Society for the Protection of Birds), contains some shocking information regarding the scale of plastic accumulation on the small island’s beaches. The researchers said Henderson Island is at the edge of a vortex of ocean currents known as the South Pacific gyre, which tends to capture and hold floating trash. Lavers and six others, who stayed on the island for a little over 100 days in 2015 while conducting the study, found the trash weighed nearly 18 tonnes with more than two-thirds buried in shallow sediment on the beaches.
The most common items they found were cigarette lighters and toothbrushes. By clearing a part of a beach of trash and then watching new pieces accumulate, Lavers and team were able to estimate that more than 13,000 pieces of trash wash up every day on the island, about 10km long and 5km wide. Oceanic gyres are known to accumulate a huge amount of plastic debris. The North Pacific Gyre has become colloquially known as the ‘Great Pacific Garbage Patch,’ although the name is somewhat misleading as the vast majority of the ‘garbage’ consists of microscopic particulate matter, rather than a floating waste disposal site. Nevertheless, the horrific figures from Henderson Island put the scale of the world’s plastic pollution problem into perspective, when one considers that Henderson is but a minute landmass in a circular current which rotates around an area of ocean about twice the size of Australia.
According to Lavers, plastic debris is an entanglement and ingestion hazard for many species, creates a physical barrier on beaches to animals such as sea turtles, and lowers the diversity of shoreline invertebrates. Research has shown that more than 200 species are known to be at risk from eating plastic, and 55% of the word’s seabirds, including two species found on Henderson Island, are at risk from marine debris. Some 98% of the debris found on Henderson Island is plastic, and packaging information shows that it comes from locations as distant as Japan and Chile, much of it several years old. The report notes that 61.8% of the recorded items found on the beaches are classed as ‘microplastics’, a much greater threat to many species than larger items, as they are too small to be seen and therefore easily ingested. According to some statistics, an estimated 300mn tonnes of plastic products are produced every year, of which some 8mn tonnes ends up in the ocean. The menace could be tackled only if people stop dumping plastic trash in the ocean.
