Plastic bottles equipped with electronic tags and released in the Ganges River show plastic pollution can travel hundreds of miles in just a few months.
The study, led by researchers from the University of Exeter and the Zoological Society of London, was conducted as part of the National Geographic Society’s Sea to Source: Ganges expedition. Researchers from the University of Georgia College of Engineering were partners in the study.
The research team fitted plastic bottles with GPS and satellite tags in the Ganges and the Bay of Bengal. One bottle travelled 1,768 miles (2,845km) in 94 days.
“Our ‘message in a bottle’ tags show how far and how fast plastic pollution can move,” said lead author Emily Duncan, a postdoctoral researcher at Exeter’s Centre for Ecology and Conservation. “It demonstrates that this is a truly global issue, as a piece of plastic dropped in a river or ocean could soon wash up on the other side of the world.”
In general, bottles in the Ganges moved in stages, occasionally getting stuck on their way downstream. Bottles at sea covered far greater distances, following coastal currents at first but then dispersing more widely.
The study used 25 500-milliliter bottles with size, shape and buoyancy intended to mimic the movement of any plastic bottle. The hardware inside each plastic bottle is entirely open source, ensuring researchers can replicate, modify or enhance the system to track other plastics or environmental waste.
“In plastic pollution research, we still rely on models of how much plastic makes its way from land to a river, and then once in the river, how an item like a bottle might travel to the sea,” said Jenna Jambeck, a professor in the UGA College of Engineering and Scientific Co-Lead of the Sea to Source Expedition. “This research demonstrates open-source technology that can help fill the knowledge gap regarding plastic movement with real-time measurements of how far an item can travel in aquatic systems and into the ocean.”
Amy Brooks, a Ph.D. candidate in Jambeck’s research group at UGA and a National Geographic Explorer, is working with similar technology to explore the movement of litter on land.
“Embedding electronics inside plastic bottles also presented a unique opportunity to use both cellular and satellite transmitters, ensuring we could track the movement of each bottle through urban waterways where mobile phone networks were available, switching to satellite connectivity once the bottles reached the open ocean,” said Alasdair Davies, of the conservation technology organization Arribada and the Zoological Society of London.
The researchers hope the bottle tags could be a powerful tool for education and raising awareness about plastic pollution.
The research team included the universities of Plymouth (U.K.), Dhaka (Bangladesh) and technology consultancy Icoteq Ltd.
The paper, published in the journal PLOS ONE, is titled: “Message in a bottle: open source technology to track the movement of plastic pollution.”