Researchers have warned of high levels of ‘chemical cocktails’ in a well-known Berkshire river, following an analysis of water samples at several locations in the county.

They say the chemicals are polluting the waterways and poisoning wildlife and new laws have called for changes to prevent these substances from ending up in rivers and waterways.

The analysis was carried out by the Wildlife and Countryside Link and the Rivers Trust using Environment Agency data.

This data found out what chemical compounds are present in the water.

One spot in Twyford on The Loddon, was among the worst affected locations in the county.

Chemicals found at the A4 Road bridge included pesticides and pharmaceuticals, as well as so-called 'forever chemicals', which do not break down naturally.

Five harmful mixtures were found. After testing, these turned out to be:

  • Ibuprofen,
  • Perfluoro Octanoic Acid,
  • 2,4-D / 2,4-Dichlorophenoxyacetic acid,
  • Perfluorooctane sulfonate (PFOS),
  • Perfluorobutane sulfonate and Perfluorohexane sulfonate

Sites in the area that were also found to have evidence of toxic chemicals include CUT at Cokeley Bridge and Bull Brook at Warfield Park Farm.

Thames Water have commented that although sewage works are not designed to remove toxic chemicals, they will be undertaking extensive research to understand the sources and possible treatment options.

To discover this, the work will be carried out and supported by the Environment Agency and Defra.

A Thames Water spokesperson said: “We have several sewage treatment works which already have permits in place for us to monitor for specific chemicals. In our next five-year asset management period (AMP8) cycle, we expect there will be some sites also receiving new permits for monitoring chemicals which we will work to achieve. 

“Our research will continue to understand how chemical concentrations change in the sewage we receive and how treatment technologies may be applied where they are required by the Environment Agency to protect our rivers. Thames Water will continue to meet the requirements for discharge water quality set by the Environment Agency for our sewage works.

“Sewage treatment works are not the only pathway for chemicals to enter the environment. Use by other sectors, such as agriculture also contribute to the load of chemicals found in our rivers. The persistent nature of PFOS and PFOA is well documented, and source control is the key to reducing concentrations found in water, land and air.

“We are investigating source control options for certain chemicals, to prevent expensive and carbon intensive treatment solutions needing to be built on our sewage treatment works, to be able to meet future permits set by the Environment Agency.”

The Environment Agency has said that they have now started to use a more sophisticated and advanced approach to testing waterways in England.

An Environment Agency spokesman said: “Since the 2000s, the government has increased monitoring and either banned or highly restricted a number of per- and polyfluoroalkyl substances, or PFAS, both domestically and internationally.

“We are working with government to assess the levels of PFAS occurring in the environment, their sources and potential risks to inform future policy and regulatory approaches. Defra is due to share details of further actions in the upcoming UK REACH Work Programmes and Chemicals Strategy later this year.

“Anyone who suspects pollution in waterways can call the Environment Agency’s incident hotline: 0800 807060.