0319 GMT October 24, 2019
Concern has been growing about the effect of tiny plastic fragments on seabirds, fish and other life in the oceans with a United Nations Environment Project report also warning that their presence in seafood “may present an attributable risk to human health”.
Such fears prompted the UK Government to ban plastic microbeads in cosmetics, reported the Independent.
Now one of the first studies to look at the problem in freshwater environments has discovered large amounts of plastic pollution in river sediments.
And a significant proportion of this was made up of plastic paint that has washed off roads.
The researchers looked at four sites in the Thames Valley, two on rivers in countryside areas and two just downstream from the town of Bracknell.
In the most polluted site, just outside the town, they found an average of 66 microplastic particles in every 100g of sediment, which is about a handful, according to an article in the Marine Pollution Bulletin.
But even at the cleanest rural site on the River Leach, there was an average of 18.5 particles per 100g.
Lead researcher Dr. Alice Horton, an ecotoxicologist at the Center for Ecology and Hydrology, said: “I was quite surprised by the number of particles I was finding.
“I chose two control sites because I thought they would be really clean, but actually I did find quite a lot even in sites where there’s quite a low population.”
Some of the particles did not look like the usual microplastic.
“I thought, ‘What are these? They don’t look like something that should be here but also don’t look like what would break down from a plastic bottle or something like that,” Horton said.
The researchers used spectroscopy to determine what the particles, which were mostly red and yellow and between one and four millimeters in size, were made from.
They then matched them to paint on nearby road surfaces with Horton saying there was no doubt about their origin.
“There was this road surface where the whole surface of the road was completely red. They’ve incorporated paint into the surface of the tarmac for whatever reason,” she added.
It is not clear how serious the problem is.
“The very smallest organisms like invertebrates and snails might not be likely to eat them, but scavengers, things like fish and birds, potentially could eat them,” Horton said.
“It’s a concern that it’s there … they could be associated with other potentially harmful chemicals. It’s obviously a pollutant.”