According to data from the Environment Agency, analysed by The Guardian and Watershed Investigations, almost 500 different chemicals, some of which are banned, will have been found in various mixtures across all 171 river and groundwater catchments in England by 2024.
According to the European Chemicals Agency (ECHA), more than half of these substances are classified as very toxic, toxic or harmful to aquatic life. A banned, cancer-causing “forever chemical” was among the 20 “substances of very high concern” found.
“This shows that the way we monitor and manage chemicals in our rivers is completely unfit for purpose,” said Alistair Boxall, professor of environmental science at the University of York.
“Although it depends on the concentrations, many of these chemicals are very toxic. We know they target algae, invertebrates and fish. If you have a mixture of a few hundred chemicals, they may work together and exacerbate the effect,” Boxall explains.
Environmental groups are calling chemical pollution the silent killer in our waterways. The world has lost 83% of its freshwater life in 50 years, and in British waters the sturgeon and burbot have disappeared and the Atlantic salmon is under threat.
“Our invertebrate monitoring shows clear evidence of significant chemical impacts in all 100+ rivers we monitor,” said Nick Measham, CEO of WildFish. “It links chemical presence to widespread ecological impacts. It makes river poop look like a second-order problem.”
Neonicotinoid pesticides are banned for use on all outdoor crops in the UK and EU due to the high risk to pollinators. However, the data shows that all three banned neonics were used in 29 river and groundwater areas, including thiamethoxam, which the UK government still allows for sugar beet crops. The Environment Agency said it was changing policy to prevent this use.
Another neonic agent, imidacloprid, is still legally used as a flea treatment for dogs and cats, which experts say is nonsense.
“Imidacloprid is like novichok to insects,” said Dave Goulson, professor of biology at the University of Sussex.
“One teaspoon of this pesticide is enough to deliver a lethal dose to 1.25 billion honeybees. It is worrying that our rivers are being flooded with a powerful insecticide.”
The majority are downstream of sewer outlets, suggesting they come primarily from owners washing their pets and bedding at home. The chemicals are more toxic to insects than to vertebrates, but there are health concerns, and research in Switzerland has found neonics in the cerebral spinal fluid of children.
The most common chemicals are classic markers of road runoff, where pollutants from things like car exhaust pipes and tires accumulate on roads and are then washed into streams and rivers when it rains. Fluoranthene, which is highly toxic to aquatic life, and pyrene were found in 80% of water catchments. Both are substances of very high concern because they are persistent, bioaccumulative, and toxic, meaning they do not break down easily and can build up in our bodies.
“I found fluoranthene at concentrations more than 100 times the maximum permitted concentration in samples of runoff from the M6,” said Jo Bradley, a former Environment Agency official who runs the non-profit Stormwater Shepherds. She said runoff from roads often exceeded legal limits.
“National Highways identified fluoranthene and pyrene as potentially significant pollutants back in 2002. It is particularly sad that they have not installed treatment systems at their highway exits to control this pollution in the past 20 years.”
National Highways says it is “committed to improving water quality, and our Water Quality Plan sets out a high-level programme of work to address all of our high-risk discharges by 2030.”
Farm runoff was another major source of contamination, with about 30% of the substances commonly used as insecticides, fungicides, pesticides and livestock medicines. About 34% of the substances found were pharmaceuticals, caffeine and sweeteners, likely discharged from sewage treatment plants.
Sewage is the main reason the Medway catchment does not meet good status, followed by agriculture, according to the Environment Agency. It, along with the Tees estuary, has the highest concentrations of different chemicals in its waters. The highest concentrations of the recreational drug ketamine were found here, as well as an insecticide used to control aphids on crops.
“There are parts of the River Medway that are off-limits, where there is no river life and where we are not allowed to fish,” said Ian Tucker of the Royal Tunbridge Wells Angling Society.
Sewage companies could install tertiary treatment plants to remove many chemicals, but this is expensive.
“We have a lack of investment in wastewater treatment and we haven’t made any progress in removing chemicals,” said Chris Gardner of the South East Rivers Trust. “We need a regulator to make improvements.”
Water UK, the water industry organisation, points out that water companies are not responsible for the presence of these pollutants in the water system and supports the ‘polluter pays’ principle.
“Water companies are planning to invest almost £12 billion to stop sewage discharges from storm flooding and remove chemicals during the treatment process,” a Water UK spokesperson said. “We now need Ofwat to fully approve these plans so we can get started. But prevention is better than cure and we need more action from government and other sectors to stop this material entering the environment in the first place.”
In the nation’s chemical capital, the Tees Estuary, the site of a series of mass shellfish deaths in 2021, seven of the top 10 chemicals with the highest sum concentrations found are highly toxic, toxic or harmful to aquatic life. For example, the highest levels found in any sample in England are of a pesticide 200 times higher than the predicted no-effect concentration and highly harmful to aquatic life.
“As this study confirms, the scale of chemical pollution in our waterways is staggering, impacting aquatic life and having major consequences for human health.“, said Rob Collins of the Rivers Trust. “It is of great importance that we as a government urgently see a robust chemical strategy, in which tackling chemical pollution at source is given priority.”
An Environment Agency spokesman said: “Our analytical techniques are highly sensitive and allow us to detect over 1,500 compounds at low levels to support our work on managing chemical risks in the environment. These tests are specifically targeted at sites where we want to better understand chemical risk.
“We are working closely with other regulators and the water industry on a range of chemical research programmes to better understand how chemical compounds affect our aquatic environment.”
But experts remain concerned.
“The big picture is that we are all being exposed to a cocktail of synthetic toxins from conception,” Goulson warned. “The impact of the mixtures is completely unknown … and it is unavoidable.”