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PFAS are a group of toxic chemicals found across the globe. They have permeated into the environment, our food chain and are estimated to be found within 90% of the global population. They are known as forever chemicals because they don’t break down easily and are therefore likely to leave a long lasting legacy within our environment. 

PFAS (Poly and perfluoroalkyl substances) represent a group of approximately 12,000 chemicals that are used for their indestructible and non-stick properties. These same properties mean they are highly persistent and mobile. As a result they are shown to bioaccumulate (build up in concentration especially up the food chain) in organisms. 

There’s clear evidence that PFAS are accumulating in our oceans, wildlife and our bodies. Their widespread use is creating a toxic legacy.

Baby turtle, Mexico – Image source:

PFAS are found in aquatic environments throughout the world both in water and biota. They are almost inescapable. Firstly, they are used in so many of our everyday products such as stain, fire and water repellent textiles, non-stick pans and packaging. 

Secondly, because they have been used so abundantly since the 1940s they now have also pervaded into our ecosystems through landfill leachate and industrial processes, fire fighting foams and more. CL:AIRE has recently published Technical Bulletin TB22 (March 2023) listing some of the key activities that could be key continuing sources. As a result they are in the water that comes out of our taps and the food that we buy from the supermarket.

Industrial sources of PFAS

Fire-fighting (AFFFs and as fire suppressants)  Military basesAirfieldsFire fighting training grounds
Metal finishing and plating  Hydraulic fluids  fluoropolymer productionPaper products and packaging  paper millsphotographic development studios, in printing facilities where inks are used in photolithography Semiconductor manufacturing  Manufacturers of textiles, leather and apparel (including carpets and furniture) 
Cleaning products (including industrial surfactants) Refrigeration Waste water treatment worksLandfillsLand spread with sewage sludgeFluorochemical, rubber and plastics industries  Aviation/ Aerospace IndustriesSurface cleaners, car waxes and treatmentsCoatings, paint and varnish industriesBuilding and construction – weatherproofing, anti corrosion and stain resisting materials.

Once these contaminants are being used industrially or within the everyday goods that we use they will disperse into our environment as shown in the source pathway receptor model below. Further details of which can be found in CL:AIRE TB19.

Sources of PFAS and pathways for environmental exposure1

Source Pathway Receptor model showing the movement of PFAS through our environment. – Image source: Chief Scientist’s Group report, August 2

Types of PFAS

PFAS are a chemical group and within that there are several specific chemicals of note, both of which are perfluoroalkyl acids (PFAAs): perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Interest is widening to include shorter chain PFAS, PFAA precursors and perfluoroalkyl ethers.

Toxicity of PFOS

Worryingly, research carried out in America suggests that PFOA has been linked to high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer and pregnancy induced hypertension. Whilst PFOS has been linked to problems with the immune system, low birth weight and birth defects.

As a result of this research there is mounting concern about this chemical and hence more research and regulation is likely to follow over the coming years.

The scale of the problem

The UK Drinking Water Inspectorate has specified a limit of 100ng/l. If this is exceeded, the water companies must immediately act to reduce levels. 

A map has been created to identify where PFAS are located across the UK. This is based on information from Water companies, Drinking water, EA groundwater and rivers, CEFAS sediment and fish samples.

Approximately 17,000 sites across the UK and Europe have been found to have PFAS. At 640 of these sites PFAS have been found at concentrations of more than 1,000ng/litre. At 300 locations, levels have been found >10,000ng PFAS. At the River Wyre the highest levels were found of 12000ng/l in discharge from a chemical plant.

Image source: The Guardian article: Revealed: scale of ‘forever chemical’ pollution across UK and Europe

“These sorts of concentrations raise concerns with me,” said Prof Crispin Halsall, an environmental chemist at Lancaster University. “You have the risk of livestock gaining access to those waters and [then PFAS is] in the human food web.” Halsall says there are also risks involving people “accessing wildlife as food sources like fishing and wildfowl”. (Guardian, 2023)

What can be done? – Regulation, Remediation, Data


The UK is awaiting the outcome of a PFAS regulatory management options analysis (RMOA). These will consider the best way to manage risks posed by PFAS. This is being carried out by the UK Health and Safety Executive and the Environment Agency and began in 2020. We are expecting further regulation soon.


With the rise in focus, new remedial processes are being devised. In America, Carey et al (2002) have reviewed a method using colloidal activated carbon (CAC) injection at PFAS sites. The conclusion has demonstrated that the injection of CAC to facilitate in situ PFAS remediation has been generally successful for both short‐and long‐chain PFAS in the short‐term (0.3–6 years). This could provide a solution for the long term clean up of this legacy of contamination.

Further remediation techniques are being discovered such as Canadian scientists at a university in British Columbia who have made a recent breakthrough and discovered a new method to absorb PFAS and to break them down. 

Waste water treatment works can remove some PFAS from drinking water using activated carbon. 

Data and assessment

We provide data and map packs including clear historical mapping, recorded pollution incidents as a result of fire as well as details of former permitting to enable the identification of the potential sources of ongoing contamination. 

Our project consultants will review all pollution incidents as a result of a fire with the view that they could have a PFAS element, particularly following the mitigation of the fire or through potential materials on site. This is built upon the quality and quantity of our historical mapping and our pollution incident archive, in order to provide clients with the best possible appreciation of the potential for PFAS. 

In Summary…

For more information on our approach and consideration of PFAS among other site contaminants as part of our site risk assessment and project work, get in touch at or call us on 01273 257 755. 

  2. Ross, I., Hurst, J., 2019. Managing Risks and Liabilities associated with Per- and Polyfluoroalkyl Substances (PFASs). CL:AIRE Technical Bulletin TB19. CL:AIRE, London, UK
  4. Longevity of colloidal activated carbon for in situ PFAS remediation at AFFF‐contaminated airport sites. Grant R. Carey. Remediation, 2022.