Despite their unique and valuable properties, PFAS (per- and polyfluoroalkyl substances) are generating concern due to their extreme persistence, mobility and potential to bioaccumulate with some linked to a range of health problems. They have been termed ‘forever chemicals’ as they do not biodegrade in the environment.

In fact, PFAS, are likely in the blood of almost every person in the world. The substances are found in a huge variety of consumer products, from clothes and home furnishings to food packaging and fire-fighting foam as well as industrial materials where they provide water and stain repellency. Their significance is well understood in America, Australia and parts of Europe, but less so in the UK.

The UK regulatory landscape

New drinking water guidelines for two specific PFAS compounds came into effect in January 2021 which significantly lowered the thresholds for monitoring, consultation and action to ensure the wholesomeness of supply. Requirements to undertake risk assessments and test for 47 other PFAS compounds in short time frames all add to pressures and potential costs facing water companies.

PFAS detections in UK surface waters have highlighted the poor removal of PFAS by wastewater treatment plants which may receive PFAS discharges from domestic and industrial sources, including landfills. Restrictions and pre-treatment requirements on industrial and landfill discharges are emerging in the US and may foretell the trend in the UK. Instances of PFAS migrating into food, livestock and the environment following land application of biosolids are also being carefully assessed with the new Environment Agency (EA) Sludge Strategy set to include focus on emerging chemical hazards.

More broadly, there is an increasing trend for regulation of an increasing number of PFAS compounds to ever lower thresholds including a proposal to restrict all PFAS to essential uses in Europe. In the UK, Defra have asked the EA and HSE to undertake a Regulatory Management Options appraisal (RMOA) which will consider how to manage PFAS including potentially regulating PFAS as a class, rather than individual compounds.

Staying ahead

Water companies are certainly not responsible for putting PFAS into water, but responsibility to manage them is increasingly at their doorstep.

Robust risk assessments and safety plans for PFAS are complicated by the wide range of potential source sites and require understanding historical PFAS usage, modern replacements and prioritising significant sources in sensitive locations. Such risk assessments are supported by growing groundwater and surface water datasets, such as from the EA and Chemicals Investigation Programme. Targeted catchment and source site investigations may follow, working collaboratively with regulators and other stakeholders, and can valuably inform future investment requirements.

Management of PFAS within the wastewater cycle requires a holistic, cost-effective response which is facility specific to reflect differing inputs and treatment processes. Understanding PFAS inputs and behaviour during treatment is important to target any investment in treatment, however, wider source controls and catchment management may often be more pragmatic.

Arcadis is currently delivering over €120 million in PFAS related projects globally and actively research and develop new solutions. Our specialists have authored multiple detailed reviews, research papers and textbooks; winning awards for PFAS projects here and abroad. The widespread use and distribution of PFAS involve many interlinked sectors and services, for example across portfolio risk screening and GIS vulnerability tools; liability management, analytical forensics and regulatory liaison; industrial wastewater, landfill and municipal water treatment; fire training area design as well as PFAS alternatives, fluorine-free foam transition and infrastructure clean out.

Treating the issue

PFAS are challenging to treat using most traditional techniques and their unique properties can thwart effective treatment, and obscure ‘real’ versus ‘perceived’ treatment. However, this also presents opportunities for novel removal and destruction mechanisms. In soils, stabilisation/solidification, soil washing, containment and high temperature thermal approaches are often shortlisted. UK landfills do not typically test or treat PFAS in leachate which raises liability management concerns.

In water, the focus tends to be on activated carbon with ion exchange resins and other sorbents potentially combined for more comprehensive treatment where needed. However, carbon systems are expensive and involve significant carbon emissions and so a range of supply management, dilution, blending and abstraction restrictions are typically considered first.

Arcadis is already supporting several of our UK water sector clients by providing advice to help further understand the potential impacts and issues associated with PFAS. Through robust risk-based assessments, digital tools and global expertise, we can provide innovative and pragmatic solutions to deal with the challenge now facing the UK water sector.

Protecting drinking water supplies in Guernsey

When PFAS were identified in the surface waters which supply the island's drinking water, Guernsey Airport needed help to investigate possible sources of contamination. Arcadis was commissioned to assess soil, groundwater and surface waters, implement interim emergency response measures as well as design and support a bespoke water treatment system. PFAS can be bio-accumulative, so it was vital that concentrations were reduced to well below current UK drinking water criteria to help keep the people of Guernsey safe.

Assessment to investment

Increased regulatory and public awareness has raised PFAS up the agenda and there will no doubt be further changes ahead. Raising awareness and expertise within organisations is key to getting ahead and there is a need to keep up to date with the range of activities and pressures now driving PFAS management in the UK.

Initial robust assessment of potential PFAS risks associated with raw water supplies, wastewater inputs and biosolids will inform the need for any future investment. It will also ensure that investment to protect human health and the environment is done in a balanced, cost-effective and sustainable way.


Jake Hurst
Jake Hurst
Arcadis UK PFAS Lead