Helping water companies address PFAS risks in groundwater catchments

The Drinking Water Inspectorate (DWI) requires water companies to assess PFAS risks in their water supply catchments. WSP has been assisting UK water companies in updating their groundwater risk assessments and adapting to the evolving DWI requirements.

In July 2022, the Drinking Water Inspectorate (DWI) mandated water companies to conduct PFAS risk assessments for all their water supply catchments.¹ The goal was to ensure that water companies understand the risks and take the right action to continue to provide wholesome potable water. As part of this requirement, water companies were obligated to review their action plans and collaborate with the DWI if the final water exceeded 10% of the guideline potable standards for 47 listed PFAS.²

Location

United Kingdom

Our role supporting water companies

WSP have supported UK water companies in protecting their groundwater resources through updating their groundwater catchment risk assessments and responding to the challenging and rapidly changing DWI requirements for a risk based approach to PFAS.

Highly mobile and persistent, PFAS pose a particular risk to groundwater which is difficult to clean up once polluted. WSP undertook several critical actions to address PFAS risks related to groundwater abstractions, including:

GIS-Based approach to risk scoring: Leveraging available datasets on land use and activities that can emit PFAS to groundwater, we developed Geographic Information System (GIS)-based approaches to help quantify the risk of PFAS pollution to groundwater abstractions.
Risk Assessment and Validation: We checked the results of our GIS-based assessments against water quality data. Then for catchments identified as having a high risk of PFAS pollution, we conducted desk-based investigations. These investigations aimed to confirm both current and historical sources of PFAS contamination.

How our work will help

The evidence gathered by WSP will be used to work with catchment partners and regulators to help reduce any further emissions of PFAS to groundwater, to protect their potable abstractions and understand potential future risks.

PFAS are released into the environment from a much broader range of activities than any other groundwater pollutant. These activities span from waste streams to manufacturing processes and atmospheric deposition. The persistent nature of PFAS in groundwater means that the pollution detected today might have originated from activities that no longer exist. This poses a significant challenge when attempting to robustly identify a specific source or polluter.

Susie Roy Technical Director – Water Quality and Catchment Management

Susie Roy Technical Director – Water Quality and Catchment Management

WSP has found that the spatial information on the majority of PFAS sources could be gathered either from freely available data, or through information requests, to local fire services for example, around major fires. There remain gaps in understanding of the potency of certain PFAS sources and forever chemicals. However, over time and with advancements in analytical processes, these gaps are likely to be narrowed.

WSP stands as a leading expert in the field of PFAS risk assessment and management, ready to provide support and advice to ensure the continued protection of groundwater resources.

PFAS Management, Investigation and Treatment

Our team of professionals have been addressing Per- and Polyfluoroalkyl Substances (PFAS) impacts since the days when this class of contaminants was still unknown to many.

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