An assemblage of microplastic particles from a contaminated river bed. The large microbead at lower left is about 200 microns in diameter. Image credit: Jiawei Li
Water companies have been urged to “shoulder their responsibilities” by researchers who found that “poor management” of sewage was the main source of microplastic pollution in UK rivers.
Experts from the University of Manchester’s geography department claimed water firms were not properly treating or disposing of wastewater, causing microplastic particles to sit on riverbeds for “weeks and months” and putting wildlife at risk.
Conventional treatment of sewage water carried out by the firms should remove most microplastics from wastewater. This process should ensure that, in theory, microplastics do not make it onto river beds.
But the researchers, who were also the first to demonstrate major microplastic contamination on the UK’s river beds in 2018, said the high levels were a “clear indication” of poor wastewater management.
Green Party peer Jenny Jones said the new research should spur ministers into action.
“This research should come as a wake-up call to the government, who for so long have allowed water companies to get away with criminal acts against nature without appropriate sanction,” Jones said.
Professor Jamie Woodward, who led the research, told The Big Issue he had identified “extraordinarily high” concentrations of microplastics, something which could only be down to the behaviour of water companies and not disposing of waste at the correct time.
“We basically found that the only way high concentrations of microplastics could accumulate on river channel beds on the bottom of the channels is if wastewater is getting into the rivers during low flows, when the rivers are flowing to sluggishly to wash and disperse those microplastics downstream,” Woodward said.
“What that means is where you’ve got very high concentrations of microplastics on the riverbed, it is a very clear indication of poor wastewater management and that wastewater has been put into rivers at times when it’s inappropriate.
“We have one site near the River Tame near Manchester, for example, which is currently, as we understand it, the most contaminated site in the world.
“We’ve established a very clear link between the wastewater practices and microplastic contamination.”
Microplastics are plastic particles smaller than 5mm which have broken off larger pieces of plastic or are used in cosmetic and personal care products.
Experts have said they pose a risk to human health as they can enter the human body through bottled water, certain foods and even dust in the air.
But they also have a major impact on the natural world. The researchers from Manchester said microplastics can cause ecosystem damage as the quality of the river bed is essential for many creatures which live, feed and reproduce there.
“When they get into the environment, items of plastic packaging like bottles, bags and films, break down over time into smaller pieces. Eventually the pieces degrade into tiny particles called microplastics,” explained Nina Schrank, senior campaigner at Greenpeace.
“We know that many species in UK rivers have been swallowing microplastics, otters, lots of species of fish and even crabs in the Thames. British birds called dippers have been ingesting them and feeding them to their young.
“Nature has been sounding the alarm on plastic pollution for years. The government, supermarkets and brands must take drastic action to reduce the amount of plastic we’re producing and stop the flow of yet more plastics to our rivers and seas.”
Woodward added: “From an ecological point of view, the worst thing that you can do to a river system in terms of microplastic pollution is to pollute the river channel bed.
“The quality of that habitat underpins the quality of the entire river and ecosystem. So there are many creatures that are invertebrates that actually live in the channel bed. Many creatures like birds and fish, they feed on the channel bed and other creatures reproduce on the channel bed. It’s kind of the building block of the whole ecosystem.”
The discharge of raw sewage to rivers already is already a controversial issue and is currently being looked into by parliament’s Environmental Audit Committee. Woodward called for more to be done to tackle the problem.
“We want the water companies to be guided by the science,” he added.
“We want them basically to shoulder their responsibilities and just treat the wastewater – that’s why we pay our bills.
“The existing regulations around sewage discharge are very clear, what we want the Environment Agency to do is to enforce those and uphold those, because at the moment the Environment Agency is not being especially effective in controlling these discharges.”
Jones added: “Microplastic pollution is a serious threat to river wildlife and its presence, alongside unregulated toxic chemical and sewage discharge, has not been sufficiently controlled.
“The government has the responsibility to to protect our natural environment- and as Greens we would also support an ecocide law, to enable swifter legal redress.”
An Environment Agency spokesperson said: “We take our responsibility to protect the environment very seriously. Water companies have a legal duty to avoid pollution and must act quickly to reduce any damage that happens as a result of their activities.
“Permits do not allow the discharge of untreated wastewater in normal dry conditions and we assess monitoring data from storm overflows to ensure there has been no breach.
“We are driving forward change through the Storm Overflows Taskforce, and are working hard to reduce microplastic emissions from wastewater treatment works by aiding water industry research in this area.”