Researchers have warned of high levels of 'chemical cocktails' near a stretch of the River Thames, following an analysis of water samples at several locations in the county.

They say the substances are polluting the waterways and poisoning wildlife and have called for changes in the law to prevent them from ending up in rivers.

The analysis was carried out by the Wildlife and Countryside Link and the Rivers Trust and used Environment Agency data to find the number of chemical compounds present in water.

One spot, near Datchet, Old Windsor, Horton and Wraysbury, was significantly polluted, with a concerning amount of chemicals found in the waterways and lakes.

These included pesticides and pharmaceuticals, as well as so-called 'forever chemicals', which do not break down naturally.

The chemicals found include:

  • Perfluorooctanesulfonic acid PFOS (L) and (B)
  • Perfluorooctane sulfonate (PFOS)
  • pFoctanoate

Sites in the area found to have evidence of toxic chemicals include the Windsor Liquid Lesiure site, Silver Wing Sailing Club and the Jubilee River at Manor Farm. 

Thames Water has 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 with the help of 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 contributes 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."

Meanwhile, the Environment Agency has begun to use more advanced means to test water across the UK.

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 the 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."