RDE671 Regulatory threshold values for PFAS

Description

PFAS are a very large and chemically diverse group of synthetic fluorinated organic chemicals, 
widely used in industrial applications and consumer items. They are extremely persistent in the 
environment. Some PFAS bioaccumulate and are harmful to human health, with reported effects 
including reproductive and developmental effects and impaired immune function.
In the UK, available monitoring data for surface waters indicates significant environmental 
contamination by variable and complex mixtures of PFAS, especially in locations near sites with high 
PFAS use and release such as airports and PFAS manufacturing and formulation sites.
Understanding the impact of PFAS on the environment and on human health via environmental 
exposure is a rapidly developing area of research. Whilst a few PFAS, such as PFOA, are relatively 
well studied, the majority of PFAS lack sufficient data to fully identify and characterise their hazards. 
Additionally, there is uncertainty over how to assess mixture toxicity for this group of substances.
Development of adequately robust approaches for identifying and characterising the hazards for both 
individual PFAS and mixtures are an urgent need globally, as regulators and the scientific research 
community strive to interpret the significance of environmental PFAS concentrations measured and 
determine acceptable environmental thresholds for regulatory risk management action.
In the UK, there is currently an Environmental Quality Standard (EQS) for PFOS, which is used in the 
regulation of discharges of water. However, there is an operational need for robust, evidence-based 
thresholds for additional PFAS to assist the Environment Agency to manage environmental risk from 
other PFAS, either as individual chemicals or as a group. This includes those PFAS frequently 
detected in the water environment, for example, PFBS, PFHxS, PFHxA and PFPeA.
Several approaches for determining regulatory thresholds for PFAS have been proposed globally by 
regulatory authorities. This includes thresholds for individual PFAS as well as groups of PFAS. A 
recent example is a proposal published by the EU to use the Relative Potency Factor (RPF) 
approach to derive an EQS for 24 PFAS (EU, 2024)*. Varying approaches have been taken when 
deriving such thresholds to deal with the existing knowledge gaps on the hazardous properties of 
PFAS.
We require a review of the existing regulatory and research landscape to establish a robust scientific 
understanding of knowledge globally on approaches to standard setting for PFAS. This is needed to 
inform our future approach to derive robust regulatory thresholds for PFAS in England including 
future EQS derivation for PFAS.