Untreated sewage is the main source of microplastics in the UK’s rivers.
Although the vast majority of microplastics are screened out from sewage by treatment works, 87% of the treated sewage is sent to farms and the microplastics that were removed from the sewage are spread on farmland as fertiliser.
An article by George Monbiot in The Guardian: Microplastics in sewage: a toxic combination that is poisoning our land also reveals that microplastics are known to move through soil and to poison some of the animals that live in it.
Microplastics are sometimes spread deliberately on soil by farmers, while plastic is also added to fertilisers, either to stop them caking or to delay the release of nutrients.
When those microplastics decompose into nanoparticles, they can be absorbed by soil fungi and taken up by plants.
“We currently have no idea what the consequences of eating these contaminated crops might be,” writes Mr Monbiot.