The recent $4bn settlement reached by DuPont and it’s spinoffs in the US may seem a long way away and largely irrelevant to many public and private sector organisations in the UK (EA 01-Feb-21). However, this pay-out relates to the resolution of personal injury claims as a result of exposure to chemicals within a class termed per- & polyfluoroalkyl substances (PFASs), which have been and continue to be used extensively by many UK organisations.

The film ‘Dark Waters’ is widely available in the UK and dramatised some of the DuPont litigation but the impact of PFAS to the UK is, upon first glance, not obvious. This film was associated with the use of PFASs in fluoropolymer production to make polytetrafluoroethylene (PTFE) known by many of us as TeflonTM, Fluon® or DyneonTM. However, communities are increasingly forming class actions to instigate litigation against users of PFAS emanating from use of firefighting foams, as a result of their detection in drinking water above standards deemed to be safe.

PFAS are a large group of some 5,000 individual compounds, many of the polyfluorinated PFAS go undetected by commercial chemical analysis, but biotransform in the environment to form the extremely persistent and regulated perfluorinated PFAS, so are termed precursors. As the risks posed to human health and the environment from a very limited number of individual specific legacy PFAS are assessed, a series of extremely conservative (low) standards have been promulgated globally in regulatory regimes covering drinking water, surface waters etc. However, the number of individual PFASs that are regulated is increasing beyond the legacy "long-chain" PFAS. Little is known about the replacements to these legacy PFAS, with polyfluorinated forms bioactive and having uncertain toxicological effects.

UK organisations may discover they hold large quantities of PFASs and have legacy land contamination issues associated with use or losses of PFASs. The widespread use of PFASs since the 1940s in applications across many industrial and public sectors, especially those involving fire extinguishment, means that many organisations need to understand the commercial implications of their legacy and manage ongoing uses of PFASs. Investigating legacy uses, assessing the application of viable alternatives and avoiding any future discharges of PFAS and losses to ground, is a prudent approach.

This article aims to describe how the accelerating international regulatory attention to PFAS and potential ramifications from the recent DuPont settlement might impact the UK and briefly review what is known about PFAS distribution.

PFAS uses

PFASs are a large group of emerging contaminants that have been used in a wide array of commercial goods and products including:

  • Class B firefighting foams
  • Carpet and textile treatments
  • Non-stick coatings (e.g. TeflonTM, Dyneon®, FluonTM)
  • Aviation hydraulic fluids
  • Electronics manufacturing
  • Car waxes
  • Floor polishes 
  • Metal plating
  • Plastics
  • Lubricants
  • Photography
  • Photolithography
  • Paints

As a result of these multiple uses there can be many sources of PFAS to the environment.

Environmental Impact

As PFASs show no sign of biodegradation at all, they have been described as "forever chemicals" meaning they are now permanently in the environment. PFASs are generally water soluble and hence very mobile in the environment, meaning they can be transported with groundwater well beyond the original location where they were lost to ground, termed a source area. However, as many PFASs are surfactants they can also coat soils and concrete surfaces, exhibiting multilayered waterproofing effect as a PFAS storage zones, where they slowly release because of rainfall. This behaviour means that PFASs can potentially continue to leach from source zone soils and concrete surfaces for decades potentially impacting immense volumes of groundwater usually referred to as large plumes. Depending on the site setting (i.e. the topography, geology, hydrology and hydrogeology), coupled with the location of drinking water supply wells, crop spray irrigation, surface waters and business using water, PFASs may then pose a risk of harm.

For example, some fire training activities in Australia have impacted a towns’ drinking water supply some nine miles from the training area, with nearby farmers and residents informed not to consume the fruit grown on their property. In the US a PFAS 'megaplume’ has impacted 97 square miles of groundwater and four major drinking water aquifers. US dairies have been closed down as a result of PFAS detections in milk caused by fire training activities and PFAS laden wastewater treatment plant sludge sold as biosolids. PFAS have also been detected in beer and cider, indicating brand and reputational risks associated with food and beverages. As the science identifying links between human health conditions and exposure to certain PFASs develops, it adds weight to litigation proceedings. As such concerns regarding this class of chemicals continues to grow.

Firefighting foams

The Class B "film forming" and fluoroprotein-based firefighting foams – such as aqueous film-forming foams (AFFF) used to extinguish liquid hydrocarbon fires – contain PFAS. These foams are used at civil airports, defence sites, petrochemical sites and by fire brigades for incident response and repeated equipment testing and fire training events. As firefighting activities represent one of the most environmentally emissive uses of PFASs, it is perceived to cause an increased potential for environmental contamination. Fire training and testing areas are likely to be ongoing sources of PFASs to groundwater, even if use of these foams was curtailed decades ago. Fire fighting foams in fire suppression systems such as sprinkler systems to protect against fires from flammable liquids usually contain PFAS. These include vehicle maintenance garages, aircraft hangars, warehouses holding alcohol, industries where fuel tanks require protection, automotive production lines, pharmaceutical production etc. So uncontained deluge events and accidental discharges are likely to result in release of PFAS to ground. Firefighting foams containing PFAS are still widely available to purchase while fluorine-free alternatives have been surpassing extinguishment tests for nearly 20 years. These fluorine-free alternatives comprise the sensible option for many businesses, with bans on all PFAS in firefighting foams being proposed or enacted in many jurisdictions.


Regulatory levels in drinking water are being proposed to exceptionally low levels, with the US EPA adopting a 70 ng/L advisory level for two PFASs in 2016, this resulted in 6.5 million Americans drinking water being considered unsafe. More recently New Jersey mandated a concentration of 13 and 14 ng/L for the same 2 PFASs in drinking water. California adopted lower notification levels at 6.5 ng/L and 5.1 ng/L, while Illinois recently adopted 2 ng/L advisory level for one PFAS.

PFAS in the UK

The recent release of new UK drinking water quality guidance for two legacy PFASs, perfluorooctane sulphonate (PFOS) and perflurooctanoic acid (PFOA) may have impact on contaminated site management and mean that a significantly larger volume of UK drinking water requires treatment to remove PFASs.

The new drinking water standards follow a 3-tier system where the concentration of PFOS or PFOA requiring monitoring is set at 10 ng/L (decreased from 300 ng/L). The concentration requiring treatment, as they represent a potential danger to human health, is set at 100 ng/L for PFOS or PFOA (decreased from 1,000 ng/L for PFOS and 5,000 ng/L for PFOA) and the concentrations at which exposure from drinking water should be reduced within 7 days is set at 1 µg/L for PFOS or PFOA (decreased from 9 µg/L for PFOS and 45 µg/L for PFOA).

The revised DWI guidance places responsibility on water companies to use Regulation 27, which requires risk assessments of historic uses of PFOS and PFOA within catchments they abstract from. However, given the diversity of sources of PFOS and PFOA and the ongoing use and storage of firefighting foams containing PFOA (and it’s precursors) this will not be an easy task. A diverse array of long lasting sources of PFASs impacts to aquifers have been identified, including car washes, landfilled or land applied biosolids from wastewater treatment plants, waste incinerator ash pits, landfills, photolithography, metal plating etc. With such an array of potential sources a detailed understanding of the legacy and ongoing uses of PFAS is required to risk assess the potential for PFAS to impact a drinking water catchment. Firefighting foams are typically retained in suppression systems for many decades, so bulk quantities of legacy PFASs remain stored, but accidental releases occur, so can be an ongoing source of PFASs to catchments. Firefighting foams containing PFOA (and it’s precursors) are still available for sale and many businesses use these foams in sprinkler systems meaning a vast array of industries could be sources of PFAS to drinking water aquifers.  

An assessment of the occurrence of PFASs within UK waters was undertaken by the Environment Agency in 2006 which identified PFASs at 26% of selected groundwater sites, including those located away from potential sources. PFAS were detected at 52% of surface water sites at drinking water abstraction points. This study indicates PFASs to be widespread at µg/L concentrations within the UK surface and groundwaters assessed. In 2008 a limited study of drinking water, assessing only 20 locations found PFASs to be present at 18 sites at concentrations up to 370 ng/L.

A publication in 2009 identified 238 ng/L of one PFAS in the River Severn, flowing at 33 m3/sec, with a more recent report in 2018 identifying up to 18 ng/L PFOS and 11 ng/L PFOA in the River Thames with 118 ng/L of sum PFASs, which represented the highest concentration from ten major international rivers assessed in Asia, Europe and the US. In 2006 drinking water supplied by Anglian Water, feeding some 57,000 people was described to require treatment to bring levels below 300 ng/L PFASs.

The widespread detections of PFAS in UK waters suggest multiple sources and not just emissions from fluorochemical manufacturing, as described in Dark Waters. There are, however, reports that PTFE production started in the UK in 1947, as a result of a technology sharing agreement between DuPont and ICI. Manufacturing in Widnes commenced until the plant exploded in 1950, so production was moved to the Hillhouse facility near Blackpool, where in 1956 some 200 tons per annum of PTFE was being produced.

The Nordic Council of Ministers recently performed a socioeconomic analysis of environmental and health impacts linked to exposure to PFAS to determine the cost of inaction. The reported estimates for annual health-related costs were €52-84 billion for the European Economic Area (EEA) countries.

The questions that seem to need answering  include: now that new lower drinking water standards are promulgated in the UK, is a proportion of UK drinking water out of compliance? Will similar lawsuits to the DuPont settlement and those associated with use of firefighting foams in the US and Australia emerge in the UK? and given the existing impacts to UK waters - what is the socio-economic impact to the UK and how will PFASs be managed?

Ian Ross is a technical director at Tetra Tech and global PFAS practice lead, he has focused on PFAS in a global role for the last 7 years, with a PhD in microbial biodegradation of industrial chemicals and over 30 years’ experience considering the environmental management of pollutants.