Forever chemicals found in 55 per cent of Scottish drinking water

Potentially toxic ‘forever chemicals’ – including some linked to cancer – were found in more than half of samples of Scottish drinking water taken in 2023, according to new data obtained by The Ferret.

Per- and poly-fluoroalkyl substances (PFAS) were identified in 349 of the 631 samples taken by Scottish Water at drinking water sources around the country last year, in its first annual survey for the chemicals.

PFAS are a group of thousands of chemicals which repel water and oil. This makes them perfect for use in a range of domestic and industrial products, including non-stick pans, waterproof clothing, and firefighting foam.

But PFAS take a very long time to break down in the environment and the human body, earning them the moniker ‘forever chemicals’. They have been found almost everywhere, from human blood to the Arctic circle. 

Health experts have linked the build-up of some PFAS in the body to a higher risk of certain cancers, thyroid disease, immune system and fertility problems, and developmental defects in unborn children. Drinking water contaminated with PFAS is one of the most common ways for them to enter our bodies.

None of the samples showed levels of PFAS that would require Scottish Water to take action to protect the public under Scottish rules. But recent studies suggested that, for some of the PFAS found in our drinking water, there is no safe level to consume.

One expert said the findings were proof that ‘forever chemicals’ are “widespread” in our environment and underlined the need to move “towards a PFAS-free economy as quickly and effectively as possible”.

But the Scottish Government argued that Scots continue “to enjoy a supply of very high quality drinking water” and said it is aligned with EU standards on PFAS in tap water. 

Scotland continues to enjoy a supply of very high quality drinking water, with regulatory standards that are among the most stringent in the world.

Scottish Government

The data from Scottish Water was released after a freedom of information request by The Ferret. 

Last year was the first year that widespread testing of Scottish drinking water sources for PFAS was carried out. Campaigners have previously complained about a lack of monitoring for the chemicals in Scotland compared with other parts of the UK.

Scottish Water tested for 20 of the PFAS that are considered to be of most concern. All of the tests were carried out as water left treatment works and entered the pipes that transport it to consumers.

The two samples which showed the highest combined levels of these PFAS were found at a water treatment works on Fair Isle, between Orkney and Shetland, in November and December. 

Scottish Water confirmed to The Ferret that its sampling found concentrations of PFAS were generally higher at rural water treatment works – an issue it is now investigating. 

Treatment works	Sample date	Sum of PFAS (ng/l)
Fair Isle	30/11/2023	23.1
Fair Isle	13/12/2023	10.7
Benbecula	20/09/2023	9.4
Fort William (Camisky)	19/09/2023	8.4
Port Charlotte	18/09/2023	8.2
Penwhirn	12/06/2023	6.7
Amlaird	15/10/2023	5.6
Penwhirn	21/09/2023	5.5
Penwhirn	25/09/2023	5.5
Penwhirn	02/08/2023	5
Lerwick, Sandy Loch	25/09/2023	4.9

Under new regulations introduced in 2022, Scottish Water has to take emergency measures to prevent the supply of water to consumers if it contains more than 100 nanograms of PFAS per litre of water.

None of the samples in 2023 came close to exceeding this threshold. But other countries, including the US and Denmark, have much stricter limits and the Royal Society of Chemistry recently called for a tightening of UK rules. PFAS also accumulate in the environment so concentrations will keep increasing unless action is taken to reduce them. 

One of the most studied forever chemicals which has caused particular health concern is perfluorooctanoic acid (PFOA). It was found in 217 of Scottish Water’s samples last year. 

PFOA was previously used in the manufacture of Teflon, used as a non-stick coating for pans and other cookware. It has been banned in the UK since 2005 but still persists in the environment, while other legal PFAS can break down into PFOA. 

In 2022, the US Government’s Environmental Protection Agency (EPA) effectively said that no level of PFOA is safe to drink. The EPA said the main reason it had made this assessment – other than links between PFOA and cancer – was because exposure to PFOA can reduce the effectiveness of vaccines in children.

PFOA is featured in the 2019 film, Dark Waters, in which Mark Ruffalo stars as real-life lawyer Robert Billott, who exposed how chemical giant DuPont had allegedly contaminated a small US town with the substance.

In 2017, Bilott won a $671m (£529m) settlement on behalf of 3,500 people who had claimed they contracted diseases like kidney and testicular cancer from water which had been contaminated by DuPont. DuPont allegedly knew that PFOA may have been dangerous for decades before the contamination

Another chemical regarded as high risk by the EPA – perfluorooctane sulfonic acid (PFOS) – was also found in sampling of 69 Scottish drinking water samples.

Philippe Grandjean, a professor in environmental medicine at the Harvard School of Public Health, has been warning of the dangers of PFAS in drinking water for years.

He told The Ferret that the findings about PFAS in Scottish drinking water were “not surprising” and could come from a “lot of potential sources” including rainwater, leaching from rubbish dumps and the spraying of pesticides. 

Grandjean questioned the accuracy of the safety limits on PFAS applied by the EU and followed by the Scottish Government. “The EU agency that calculated safe intake limits made errors in their calculations, while the much lower US EPA limits are correct from a toxicological point of view,” Grandjean said. 

Hannah Evans, who researches PFAS at the environmental charity Fidra warned of the risks of the substances accumulating and having “detrimental impacts on both public and environmental health”.

“We know PFAS are widespread in our environment, in wildlife and in our bodies,” Evans told The Ferret. “We must learn from previous examples of environmental contamination and transition towards a PFAS-free economy as quickly and effectively as possible.”

The Scottish Liberal Democrat MSP, Willie Rennie, said Scottish Water and environment regulator, Sepa, need to “keep the prevalence of these chemicals under close review”.

Rennie added: “When I asked the Scottish Government what steps it was taking to improve testing and monitoring for PFAS in the environment, they were keen to emphasise that research was ongoing and new analytical techniques were being investigated.

“However, there will be pressure to demonstrate that these measures are robust enough given the comments from the Royal Society of Chemistry and others. 

“In particular people living in Fair Isle will need reassurances about what measures are being taken to mitigate the risks that these chemicals hold,” Rennie added.

A Scottish Government spokesperson said drinking water standards were changed in 2022 to “reflect health-based standards for PFAS”. “The standards reflect those that are contained in the EU’s recast Drinking Water Directive which were reviewed by the World Health Organisation,” they said.

“Scotland continues to enjoy a supply of very high quality drinking water, with regulatory standards that are among the most stringent in the world,” the spokesperson continued.

They also noted that the Scottish Government will align with EU plans to address pollution at source “rather than through expensive treatment”.

Last year, Fidra called for the Scottish Government and its regulators to increase monitoring at high risk areas for PFAS including military bases, airfields, and industrial sites. 

That was after a report by the UK-wide Health and Safety Executive said it had omitted Scottish data from its analysis of the risk of forever chemicals because English data was “more extensive” and could be used to build a “relevant picture for the whole of the UK”.

Between 2015 and 2017, one of the few studies of PFAS in Scotland that has been conducted found ‘forever chemicals’ in effluent discharged from wastewater treatment sites across the country.

Monitoring of 20 sites found that both PFOA and PFOS, the two chemicals deemed highest risk, had been found in treated wastewater released into rivers. 

The highest concentrations of PFAS in effluent at that time were found at a wastewater plant in Livingston, followed by one in Newbridge and one in Dalmarnock.

Main image: Miriam Alonso

This Ferret story was also published in the Sunday National. Our partnerships with other media help us reach new audiences and become more sustainable as a media co-op.  Join us to read all our stories and tell us what we should investigate next.