One section of the River Tame was found to have 517,000 plastic particles per square metre of sediment – double the previous record for any waterway or ocean in the world
A riverbed in Denton has the world’s highest recorded level of plastic pollution.
High levels were also found across Greater Manchester – in the Irwell, the Croal and the Roch – with tiny fragments of plastic even finding their way into the tiny streams around Saddleworth.
Many viewers of David Attenborough’s Blue Planet were horrified to see the toll plastic pollution is taking on marine life.
But scientists have now categorically proven that the problem really does start much closer to home.
The team of investigators from the University of Manchester tested for microplastics – tiny pieces of plastic from microbeads in cosmetics, microfibres from synthetic clothing and fragments – across 40 sites along 10 rivers in the region.
And one section of the River Tame, near to Reddish Vale Country Park, was found to have 517,000 plastic particles per square metre of sediment – double the previous record for any waterway or ocean in the world. The beaches off South Korea were the next worst.
The average across the Irwell and Mersey, fed by the Tame, was 84,030 pieces per square metre.
All these waterways eventually lead to the oceans, where this form of pollution is fatal to marine life.
On the bed of Salford Quays, the team even found microplastics in tiny worms which will be eaten by fish and potentially work their way up the food chain.
Prof Jamie Woodward, head of Geography at the university, said: “We expected higher concentrations in cities and urban rivers, but in those the levels were extraordinarily high.
“We found that wherever you have people you have plastics – and where you have high concentrations of people with industry you have high levels of plastics.”
When the team tested again after the flooding of Boxing Day 2015, they found the levels had dramatically diminished – by 70 per cent – meaning they had flowed into the Irish Sea.
The plastic is thought to come from industrial sites near the river, storm water drains and sewage overflow pipes connected to homes and businesses.
Because the fragments are so tiny, they are not filtered out by sewage plants and flow into rivers and eventually the sea.
Here, they are ingested by shellfish and plankton and often end up being eaten by humans.
Plastic particles have been found in almost three quarters of ocean fish.
Although there is a growing body of research, it’s still not fully known how plastic contamination affects humans and animals.
However, it’s thought it can cause obstructions in the body and, if small enough, could pass into the bloodstream. It can also carry other toxins into the body.
Prof Woodward, who led the study along with Rachel Hurley and James Rothwell from the Department of Geography, said: added: “It’s a concern. A lot of shellfish in Britain are contaminated with microplastics – most people in Britain will have consumed it.”
He said similar levels of microplastic would likely be found elsewhere in the country if testing was carried out.
The solution, he said, lies in stricter controls on how waste – both domestic and industrial – is disposed of to avoid plastics ending up in our waterways.
And we can all help by using less plastic.
At the start of this year, Michael Gove introduced a ban on microbeads and the team plan to test again to see if this makes a difference in coming months.
The team tested riverbeds in the Irwell, the Roch, the Croal, the Tonge, the Irk, the Medlock, the Mersey, the Tame, the Etherow, the Goyt and the Manchester Ship Canal. They found microplastics everywhere.
The types of plastic pollution varied. For example, in the Lower Irwell, one site near a sewage treatment works was mostly made up of microbeads, while immediately downstream in a suburban area, microplastic fragements dominated.
This was followed by a return to microbead dominance at the next site in Manchester city centre – where more people live and there is therefore more sewage overflow.
An Environment Agency spokesman said: “We are working with the water industry and leading academics to investigate the types and quantities of microplastics entering the environment. This research will feed into plans to tackle this type of pollution at the source.
“Plastic pollution is a threat to our natural environment and by working together, we can reduce the amount which enters our land, rivers and the sea and protect wildlife for future generations.”
More than 40 billion plastic particles were flushed into the sea from the ten rivers during floods in the area in 2015-16, the study says.