Mechanical devices to remove plastic and litter from marine environments can trap marine organisms, according to a study.
Researchers from the University of Plymouth’s International Marine Litter Research Unit say the devices are increasingly being considered as a way to address plastic pollution found across the world.
They studied a Seabin device, which continuously sucks water inwards and filters it before returning the cleaned water to the surrounding area, in Plymouth, Devon, between April and June 2021.
During 750 hours of operation, the device retained 1,828 items – 0.18kg of litter.
This was equivalent to 58 items per day and mainly comprised plastic pellets, polystyrene balls and plastic fragments.
At its current state of development, this study suggests that manual cleaning of ports, harbours and marinas, is more efficient and cost-effective
Florence Parker-Jurd, lead author
The Seabin captured one marine organism for every 3.6 items of litter, about 13 organisms per day, including species such as sand eels, brown shrimp and crabs.
About 60% of these organisms were found to be dead on retrieval, with the study indicating that some died after entering the device, the researchers say.
During the study, which is published in Marine Pollution Bulletin, five manual trawls were conducted at the same marina using nets from pontoons or vessels.
Manual cleaning collected an average of 19.3g of litter during cleans of up to five minutes, while the Seabin captured the equivalent of 0.0059g in a similar timeframe.
Florence Parker-Jurd, research assistant at the University of Plymouth and the study’s lead author, said: “At its current state of development, this study suggests that manual cleaning of ports, harbours and marinas, is more efficient and cost-effective.
“Notably manual cleans are selective, and this could lessen any potential risk to marine life.
“Given the increasing reliance on technological innovations, formal evaluations are necessary to their efficiency as similar may apply to other types of device.”
The research was supported by the European Union Interreg France (Channel) England-funded project Preventing Plastic Pollution, co-financed by the European Regional Development Fund.
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