New research by experts from the University of Manchester has found that poor management of untreated and raw sewage by water companies is the main source of microplastic pollution in the UK’s rivers.
Three years ago, researchers at the University’s Department of Geography were the first to detect high levels of microplastic contamination in British river beds.
New research published in the journal Nature Sustainability has shown that water companies themselves are the cause of this contamination, as they release wastewater into river rivers in dry weather that are too sluggish to disperse microplastics downstream.
The quality of the habitats in the river bed underpins the entire ecosystem of the river, as many organisms live, feed and reproduce in this environment. When contaminated with microplastics, ecosystem exposure is maximized as the particles are stored on the bed for weeks or months before being washed away by flooding. The river bed is the worst place for extended periods of microplastic contamination as it increases the opportunities for aquatic uptake and movement through the food chain. Microplastics are also a vector for other contaminants present in wastewater.
The researchers say that conventional treatment removes most of the microplastic load in wastewater. River beds that are heavily contaminated with microplastics are therefore a clear indication of poor wastewater management.
The discharge of raw sewage into rivers is already controversial and has led to widespread condemnation. The UK Parliament’s Environmental Review Committee is currently conducting an investigation into water quality in rivers. However, the researchers are calling for more work to be done to address the problem.
“Water companies need to stop discharging untreated sewage and wastewater into rivers in dry weather as this causes riverbeds to be heavily contaminated with microplastics and maximizes habitat damage,” said Professor Jamie Woodward, who led the research. “Rivers are also the main supplier of microplastics to the oceans. To address the global problem of marine microplastics, we need to limit their entry into rivers.”