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Toxic chemicals four times the legal limit found in drinking water in Cambridgeshire

Jennifer Ellis and Jessica Harrison explain why residents experiencing health problems as a result of consuming the contaminated water may be entitled to compensation.

Posted on 11 February 2022

Cambridge Water has admitted to the Guardian that homes in South Cambridgeshire were supplied with contaminated water containing a toxic chemical known as perfluorooctane sulphonate (PFOS).

Water was found to contain four times the regulatory limit of PFOS. Whilst the supply of such contaminated water was halted in June 2021, Cambridge Water failed to notify 1,080 residents living in Stapleford and Great Shelford that their water supply had been contaminated. The length of time residents were exposed to the toxic chemical in their drinking water is unknown.

“Forever Chemicals”

PFOS belongs to the perfluoroalkyl and polyfluoroalkyl substance (PFAS) family, a group of manmade chemicals known as ”forever chemicals” due to their inability to break down in nature. It is reported that forever chemicals are “now found within the blood of virtually every person on the planet, including those of unborn foetus”.

The chemicals were historically championed for their waterproof and ”stain proof” properties which resulted in their use within many household products such as non-stick cookware and water-repellent clothing from the late 1950’s to 2000s.

The Environment Agency stated that PFAS are ”extremely persistent, toxic and bioaccumulate through the food chain”. They are considered a global pollutant and are known to cause a multitude of health issues. PFOS (a type of PFA) have been linked to altered thyroid hormone levels in adults, elevated cholesterol, attention deficit hyperactivity disorder in children, chronic kidney disease and impaired fertility.

PFAS / PFOS within the UK

Industrial discharges, landfill sites and local historical contamination are significant sources of PFOS within the UK. Sites such as military bases and airports may be contaminated following their use for firefighting training, where AFFF foam containing PFOS was used from the late 1960s until the early 2000s. Whilst the cause of exposure to residents living in Stapleford and Great Shelford is under investigation, it appears that the aqualifer which supplies the South Cambridgeshire area is located close to Duxford Airfield. Airfields historically used firefighting foam, however the Guardian reported Duxford airfield’s spokesperson said no banned substances “are knowingly used anywhere across our estate” and that it no longer uses firefighting foam “and haven’t for years, as we are aware of the sensitivity of the aquifer that Duxford sits on top of”.’


Most uses of PFAS have now been banned or phased out under International, EU and UK legislation. The new European Chemicals Strategy announced in 2020 that they are committed to banning use of all PFAS, only allowing their use where they are proven to be irreplaceable and essential to society. It is unclear if the UK government intend on taking a similar approach.

In the UK, the Drinking Water Inspectorate limits levels of PFOS to 100 nanograms per litre of water. Many other countries prescribe to a lower level of acceptance within their drinking water. In addition, unlike many other countries, the UK government has not introduced a nationwide testing scheme for drinking water to identify PFAS. Accordingly, water companies are not routinely expected to test for PFAS but instead they are required to simply ‘consider’ PFOS and PFOA within their risk assessments.


It is not clear what action, if any, Cambridge Water will face from the regulator. In January 2021, a landmark class action in the US settled for $4 billion to compensate those allegedly harmed from the historic use of highly toxic PFAS. It follows that UK Courts may well be asked to consider claims of a similar nature.

The introduction of mandatory testing of drinking water for all PFAS would likely help to protect the health of the public. One option could be for the UK Government to make a clear commitment to banning use of all PFAS in the UK, only allowing their use where they are proven to be irreplaceable and essential to society.

Access to safe drinking water is a right that should be afforded to every individual, and consumers should have confidence that their water supply is free from toxic chemicals that can cause them serious health problems.

We would encourage residents who believe that they have been experiencing health problems following the consumption of contaminated water to contact Leigh Day by email postbox@leighday.co.uk