Current challenges in the risk assessment and management of PFAS in drinking water and the environment

Per- and polyfluoroalkyl substances (PFAS) have been used for decades in the manufacture of many consumer products and medical devices, and used in many industrial processes. These compounds have been shown to be highly mobile and persistent in the environment and are known to bioaccumulate in humans, wildlife and the environment. This has led to the global contamination of groundwater, drinking water and soils. There are ongoing efforts to better understand the levels of PFAS compounds in drinking and surface waters.

To protect human health, the risk assessment of unintentional consumer exposures to PFAS in drinking water is aided by the application of health-based water guideline values, which also support the risk management following human exposures to PFAS in drinking water. Despite the abundant evidence of adverse health effects associated with exposures to PFAS in drinking water, no statutory standards for PFAS in drinking water have been derived in the UK.

A need for harmonisation

Within the toxicology community, there has been significant disparity across national and international regulatory and advisory bodies in their selection of the critical effects (the most sensitive adverse health endpoint of concern) from studies carried out on animals and humans on which the health-based guideline values are based. Some of the challenges stem from the applied methodologies for the consideration of the differences that exist between the animal data or the biological differences between animals and humans. In addition, differences have arisen in the methodologies applied to the quantification of the uncertainties and the assumptions applied to exposure scenarios. This has led several competent authorities, including the World Health Organization, to derive provisional health-based guideline values in anticipation of the publication and assessment of new evidence, and has highlighted the need for harmonisation among the scientific community in relation to the risk assessment of PFAS compounds.

Some of the critical health effects that have been identified as relevant to humans in the derivation of these health-based guideline values have ranged from developmental effects, liver toxicity and effects on the mammary gland for compounds like perfluorooctanoic acid (PFOA); and reduced pup weight, thyroid effects, suppressed immune response and developmental neurotoxicity for perfluorooctanesulfonic acid (PFOS).

Risk assessment and critical effects

The assessment of the potential risks to ecological systems also requires the selection of critical effects, as well as the identification of sensitive species from relevant ecotoxicological studies, to aid and inform the risk of impact assessments of exposures to PFAS in different environmental matrices (water, sediment, soil, tissue); and the identification of methods to efficiently measure or predict the bioaccumulation and biomagnification potential of PFAS.

Notwithstanding some of these toxicological challenges - in relation to public and environmental health that impact on our ability to adequately assess the risks associated with exposures to PFAS compounds - the detection and remediation of PFAS compounds also presents challenges. A recent study commissioned by the Royal Society of Chemistry (RSC, 2023) reports on the lack of standardised analytical methods that are available for the detection of individual and total PFAS, and highlights the inability to adequately compare data across different regions in the UK. From a water treatment perspective, although different technologies are available for the removal of PFAS compounds from water, there is a need to adequately assess the effectiveness of some of the available remediation technologies.

Join the discussion about the future of PFAS

Understanding the current scientific uncertainties and challenges are crucial for supporting the risk assessment, detection, remediation and risk management of potential risks associated with exposures to PFAS in drinking water.

WRc, led by their National Centre for Environmental Toxicology team, will launch the PFAS and Emerging Contaminants Expert Forum on 18 April 2024. This Forum will bring together expert voices in the water treatment, risk management and risk assessment of PFAS and emerging contaminants to discuss the ongoing challenges and uncertainties in this area.

Anyone with interests in human health risk assessment, environmental risk assessments or impact assessments and wastewater treatment will gain insight from this forum and will learn more about:

• the latest research developments and regulatory perspectives, ensuring members remain ahead of relevant news and innovations on PFAS
• practical solutions for the treatment and remediation of PFAS
• practical implications of meeting policies and guidelines.
  

Register and get involved with the PFAS and Emerging Contaminants Expert Forum today, and join the discussion on emerging issues and best practice, sharing learnings from around the UK water industry.

To join the Forum, please email Portfolio@wrcgroup.com – by COP Wednesday, 10 April.