It has never been more important to protect our rivers

Mike Hedges – MS for Swansea East

It has previously been reported that nearly one in five rivers in Wales is polluted with sewage, affecting wildlife and human health. Analysis by a water consultancy found 17% of rivers in the area managed by Welsh Water were affected.

As with air it is the particles that you cannot see that are the most dangerous. With air it is Nitrogen oxide pollution which is linked to asthma, heart disease, and premature death. PM 10 and PM2.5 are particles too small to see with the naked eye, PM 2.5 being roughly thirty times smaller than the width of a human hair and PM10 roughly an eighth of the width of a human hair, smaller still are nanoparticles.

Professor Jamie Woodward, from the Department of Geography in Manchester university has created a report from his research into the alarming levels of microplastic pollution in UK rivers and calls for urgent action to protect them.

While Natural resources in Wales grant permits to allow the discharge of untreated wastewater after heavy rainfall, new research shows water companies in Wales like those in England routinely breach this condition.

Hotspots of extreme microplastic contamination have been found by Professor Woodward, which have been missed by previous studies, and that cannot form
during heavy rainfall events.

Tiny particles of plastic have been found everywhere from the deepest places on the planet such as the Mariana Trench, to the top of Mount Everest. And now more studies are finding that microplastics, defined as plastic pieces less than 5 millimetres, in diameter are also in our bodies.

In recent years, microplastics have been documented in all parts of the human lung, in maternal and foetal placental tissues, in human breast milk and in human blood.

Microplastics scientist Heather Leslie, and colleagues found microplastics in blood samples from 17 of 22 healthy adult volunteers in the Netherlands. Some laboratory experiments suggest microplastics increase brain inflammation and cell damage, alter gene expression, and change brain structure. Aside from the effects of the microplastic particles themselves, microplastics could also pose risks if they carry environmental toxins or bacteria into and around the body.

The presence of microplastic hotspots in riverbeds is a clear indicator of poor
wastewater management; monitoring riverbeds for microplastic content could be an
effective way to police water company practices.

Sewage

There is a critical need to strengthen legislation surrounding what constitutes a safe level of microplastic pollution in rivers, and to ensure these limits are properly enforced.

Releasing large volumes of untreated wastewater laced with microplastics and
sewage severely compromises water quality and poses a threat to freshwater
habitats, marine life and ultimately human health.

Microplastics from rivers then go on to supply most of the microplastics in the oceans. There are also significant concerns that concentrated sewage deposits provide a breeding ground for genetic mutation and antibiotic resistance.

A Panorama investigation showcased the impact of solid waste such as sanitary
products and wet wipes on rivers and provided evidence of the widespread and
routine discharge of raw sewage. Research shows that such discharges can result in extremely high levels of river and riverbank microplastic contamination.

Previous studies into microplastic pollution in UK rivers have commonly
underestimated the extent of the problem. These studies have focused on sampling
microplastics in the flowing river water. However, concentrating solely on
microplastics in the water column can yield a very limited picture of microplastic contamination.

The Manchester study observed that microplastics of all types accumulate on riverbeds in very high concentrations and often reside there for weeks or months, until a significant flooding event disturbs the bed and washes them
downstream.

Toxins

This has profound implications for the ecological health of the rivers. Many aquatic animals live, feed, and reproduce in these contaminated channel beds; they face prolonged exposure to microplastics as a result of sewage spills.

Allowing microplastics to accumulate on the riverbed maximises opportunities for primary and secondary ingestion by aquatic animals. Microplastic hotspots can amplify the effects of sewage-borne toxins to further degrade river ecosystems.

Much of this river and river bank microplastic pollution is avoidable because existing wastewater treatment is capable of removing up to 99% of the microplastics entering rivers.

Where microplastics are found in high concentrations on riverbeds, it forms
one of the clearest indicators of poor wastewater management. Without unlawful
sewage discharges, microplastic hotspots would not be found. Analysing riverbed
sediment for its microplastic content offers a highly effective method for monitoring and policing wastewater treatment practices.

In addition, specific legislation must be introduced to provide a legal limit for microplastic content in rivers. If wastewater is properly treated in the first place and only discharged during periods of heavy rainfall, the major source of microplastics would be removed and riverbed ecosystems would not be subjected to prolonged exposure.

The link between sewage disposal and acute microplastic contamination of river
habitats is now clear. Microplastic pollution in rivers will become more severe as the climate warms and urban populations grow.

This will have increasing impacts on river ecology, the environment and public health. It has never been more important to protect these ecosystems.

We must act now to strengthen legislation to prevent the shameful yet widespread practice of routinely discharging untreated sewage into UK rivers.