Revealed: The gaps in DEFRA’s knowledge about toxic PFAS pollution in the UK

PFOS and PFOA were found at over 99% of surface water sites sampled.  David C Tomlinson/Getty Images PFOS and PFOA were found at over 99% of surface water sites sampled. David C Tomlinson/Getty Images

PFAS is ‘ubiquitous in the environment’, according to the Environment Agency

Poly- and perfluoroalkyl substances (PFAS) are known as ‘forever chemicals’ because they never break down in the environment. There are around 9,000 of them and they are used in a vast range of applications in consumer products and industrial processes. 

They are highly toxic

They are bioaccumulative and have been strongly linked to kidney cancer, testicular cancer, thyroid disease, pregnancy induced hypertension, high cholesterol and ulcerative colitis. They have also been linked to a much broader range of problems such as immune system problems, low birth weight and miscarriage. A recent study found that 100% of women tested had PFAS in their breast milk. It has been found in animals at the top of the trophic scale, such as killer whales and dolphins.

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The health effects of just two of the 9,000 substances are partially understood

The use of PFOA and PFOS are banned or restricted following years of research into their toxicity. Little is known about the remaining substances because the science has not been undertaken, but it is widely thought that some of them will have similar impacts, and that some could be even worse.  

A new report sets out the extent of DEFRA’s knowledge on PFAS pollution

DEFRA’s chief scientist’s report, published yesterday, reveals that knowledge of PFAS pollution in the UK is limited, with major evidence gaps in important areas such as groundwater, soils and atmospheric deposition.

Knowledge is limited

The reports says that approximately 100 individual PFAS are potentially supplied to the UK in amounts of one tonne per year or more, based on European information, although the picture is incomplete. “We have limited knowledge about their use, the quantities actually on the UK market or their presence in imported goods. There are gaps in our understanding of the potential for release during their life cycle (for example, leaching of residual amounts of PFAS additives and processing aids from polymer products), including recycling and waste disposal,” it states. 

Limited monitoring has taken place

Between 2014 and 2019, some groundwater, surface waters, freshwater fish and marine fish have been sampled, and a Cefas study on estuary sediments was published this year, which was funded by DEFRA. The Environment Agency says it sampled 470 freshwater sites and approximately 55 estuarine and coastal locations in England. For groundwater, “in most cases only a single sample has been taken from each site”, states the report, and the screening method was not quantitative, so important concentrations are not reported. 

PFAS has been found everywhere

The Environment Agency says its monitoring data in “rivers, lakes, groundwaters, estuaries and coastal waters suggests that PFAS is likely to be widely present in English surface waters and groundwaters”. Detectable levels of PFOS are found at over 99% of surface water sites sampled and detectable levels of PFOA at over 99% of freshwater sites and over 96% of estuarine and coastal sites sampled, it reports. Some PFAS are very frequently detected in surface water samples, it says. PFBS is detected at 97% of sites, PFOA and PFOS at 96% of sites sampled and PFHxA and PFHxS at 94% and 90% of sites respectively. In surface waters in England a quarter of all water bodies fail Water Framework Directive standards for PFOS.

Drinking water is not routinely tested for PFAS

Water companies are required to risk-assess their catchments to ascertain whether there is a likely source of PFAS pollution in the area that could affect drinking water supplies. If they do not conclude there is a risk of contamination then the water is not tested for PFAS. 

It’s in fish, shellfish, birds, otters and cetaceans

PFAS was detected in a range of wildlife, according to the report, with PFOS found in all fish at all 78 sampled locations and were highest in fish taken from the Humber and the Thames. Cardiff University is running an ongoing programme monitoring otter livers for PFAS, which has been detected. A predatory bird monitoring scheme continues to find PFAS in bird eggs and it has been found in the livers of harbour porpoises. 

And it’s stored in sediments

PFAS was found in 85 out 103 sediment samples collected by the agency and its partners, with PFOS and PFOA detected most frequently in 50% of samples and 32% of sediment samples respectively. PFOS was often present in samples in the highest concentration. Five out of 103 sites exceeded an advisory limit in sediment that is protective of 99% of benthic species in the marine environment for PFOS in sediment and none for PFOA, according to the chief scientist’s report.  

There is no monitoring for PFAS in the air

“PFAS are known to be released to air from a variety of sources and may travel significant distances in air, depending on the physico-chemical properties of the substance. The presence of PFAS in remote locations such as the Arctic demonstrates their potential for long-range atmospheric transport,” state the chief scientist’s report, but it does not give a reason why it is not monitored. 

“Surface deposition of atmospheric PFAA emissions followed by leaching of PFAS to groundwater has been demonstrated at sites in the vicinity of industrial emissions of PFAS,” it adds. 

Nor is there soil monitoring for PFAS

This is despite concerns about atmospheric deposition and sewage sludge. The latter is likely to contain PFAS from industrial wastewater inputs and is spread on farmland. “The significance of atmospheric transport and subsequent deposition to UK soils is another exposure pathway identified as an evidence gap,” state the chief scientist’s report. “We have collated available data on human health endpoints and physico-chemical properties and during 2021 will be deriving indicative soil guideline values for PFAS for use in the early stage management of land contamination,” it adds. 

There does not appear to be any decline in environmental levels

A review of evidence mentioned in the chief scientist’s report suggested that for PFOS in environmental samples there are no clear patterns of declining trends yet. “Insignificant and decreasing trends were equally predominant in studies reporting times series concentrations of PFOS in fish, mussels and loggerhead sea turtles,” it added. 

The agency promises better monitoring in future

“Future monitoring from 2021 onwards will include a broader range of PFAS substances and use a recently developed quantitative analytical method,” the Environment Agency says. “From 2021 we will be sampling groundwater using a quantitative method which will allow us to report measured concentration of a range of PFAS in groundwater.” The agency says it will also be sampling more surface waters, freshwater and marine fish, landfill leachate and wastewater effluent and sludge. 

DEFRA has been consulting on an update to its Stockholm Convention implementation plan

Much of the update to the UK's national implementation plan for the Stockholm Convention on Persistent Organic Pollutants, the first since 2017, is given over to plans for further research and monitoring, rather than implementing measures to tackle the chemicals. 


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