Unchecked Road Water Pollution: A Hidden Threat to English Waterways

The English waterways, renowned for their crystal-clear waters and diverse aquatic life, have been facing an insidious threat that goes unnoticed by many. A toxic mix of oil, chemicals, and bits of tyre from roads is polluting these waterways, and no one is regularly monitoring it, as the BBC discovered in a recent investigation.

Heavy rain forces run-off into streams and rivers, causing ‘absolutely horrific’ damage in places, including just downstream of where The Great British Bake Off is filmed. England’s major road network has more than 18,000 outflows or drains. The responsibility for monitoring water pollution in England rests with the Environment Agency, but it does not regularly monitor run-off, though it does test for pollutants from roads as part of its general water monitoring.

Campaigners have been doing their own testing and have found micro-plastics, heavy metals, toxic chemicals like arsenic, and carcinogenic compounds from car tyres. Some of these contaminants are known to damage DNA, impact the nervous system, and cause cancer. Prof Alex Ford, an expert on the impact of water pollution on aquatic organisms at the University of Portsmouth, said that these contaminants can be toxic to aquatic life and potentially contribute to the poor ecological status of some rivers.

The Environment Agency can issue permits for activities that have the potential to cause pollution. They set out the limits to the pollution and can set rules the polluter must follow to keep environmental harm to a minimum. Sewage outfalls have permits, and MPs have in the past urged the EA to put permits on outfalls. However, the EA has chosen not to, saying it ‘would not result in reduced pollution’. It did say that it was looking at ‘possible benefits of using permits for some of the most polluting outfalls’.

At the River Lambourn in Berkshire, the environmental impact of run-off can be seen very clearly. A chalk stream, the Lambourn’s crystal-clear water winds through Welford Park, home of The Great British Bake Off’s white tent, before passing underneath the M4 motorway. At that point, it turns brown and murky. Chalk streams are supposed to have clean gravel beds. Charlotte Hitchmough, the director of Action for the River Kennet (of which the Lambourn is a tributary), says as she scrapes a net along the bottom, ‘Look at this black gunk.’ In the past, she has sent samples of the ‘gunk’ away to be tested. ‘There’s some really scary pollutants in there. Things like arsenic, lots of heavy metals, lots of things from oil, microplastics from tyres, we can be sure that the road is having a really negative effect on the ecology of this river.’

National Highways has a statutory responsibility to make sure that discharges from its network do not cause pollution. It said this outfall had been assessed as ‘low risk’ and was not in line for any mitigation measures.

Just by the M6 services at Chorley, we visit an outfall that National Highways cannot find a record of on their database. ‘It literally keeps me awake at night,’ says Jo Bradley, a former Environment Agency employee who has now dedicated herself to raising awareness of road run-off. ‘This little stream should be beautiful,’ Jo says as we look at what the map says is Syd Brook, at this point a murky pool of water topped with foam. ‘It’s absolutely horrific.’ When it rains, water from the M6 motorway drains directly into the stream. Jo shows me a plastic bottle full of brownish black water that she gathered during heavy rain the day before. Her organisation Stormwater Shepherds has found tyre particles and dust from clutch and brake pads in the water. ‘Because of the toxicity and the poisons in the sediment, I would put this on a par with sewage (pollution) and to be frank, I’d probably put it above sewage,’ she says. ‘Because they’re not being monitored, no-one even knows the extent of the pollution and then nobody’s doing anything about it. Nobody wants to talk about this.’

National Highways is aware it has a problem and has been using a computer model to choose which outfalls to tackle. It has identified 1,236 locations that are ‘potentially high risk’ and is expecting after verification that about 250 will actually be ‘high risk’ and need some form of mitigation. Under its current plans, only about 30 of those high-risk sites will have mitigation in place by the end of 2025. A committee of MPs last year called that ‘unacceptably slow progress’.

‘We do take this incredibly seriously – we think it’s important and we think there’s more for us to do,’ Stephen Elderkin, National Highways director of Environmental Sustainability, told BBC News. ‘And so what we have set in place is a plan to identify those outfalls that present an elevated risk, to design mitigations that need to be put in place and then to deliver them before 2030.’

One of those mitigations is just off the A38 in Devon. At a cost of about £2.5m, National Highways in 2019 built a reed bed that filters run-off from the busy road. ‘This is a good news story,’ says Rob Ballard, senior ranger at Stover Country Park. He’s holding a picture that shows how the lake used to look, with much of it covered with water lilies. ‘It was almost like a Monet painting,’ he says. The water lilies aren’t fully back yet, but Rob says they’ve seen the return of a whole raft of species which suggest the health of the lake is improving. ‘We’ve got damselflies and dragonflies, little water boatmen, whirligig beetles, water scorpions, and because of all of them, we get all the birds that feed off them,’ he says. The next step is to dredge the lake of all the heavily polluted silt that remains at the bottom.

In conclusion, the toxic run-off from roads is a hidden threat to English waterways that goes unnoticed by many. The Environment Agency does not regularly monitor this pollution, and the consequences can be devastating for aquatic life. The toxic cocktail of chemicals and particles from tyres, oil, and other sources can damage DNA, impact the nervous system, and cause cancer. The situation is improving, with National Highways identifying and addressing high-risk outfalls, but more needs to be done to ensure the health and ecological status of English waterways.