PFAS (forever chemicals)

PFAS are from a chemical family of at least 10,000 individual substances.

They are sometimes referred to as ‘forever chemicals’ because of their persistence in the environment.

In manufacturing, PFAS are favoured for their durability and useful properties such as non-stick, water repellence and anti-grease. PFAS are used in the manufacture of many domestic products, including:

• skin creams and cosmetics
• car and floor polish
• rinse aid for dishwashers
• textile and fabric treatments
• food packaging and microwave popcorn bags
• baking equipment
• frying pans
• outdoor clothing and shoes.

They also have many widespread uses in industry, including in firefighting foam.

There are PFAS compounds currently being used in various industries.

Certain PFAS compounds, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), have been restricted in England and Wales through UK REACH, the regulatory framework for the Registration, Evaluation, Authorisation and Restriction of Chemicals.

PFOA was primarily used in the production of non-stick cookware, firefighting foams and water-resistant clothing. PFOS was primarily used in the production of firefighting foams, hydraulic fluids and protective coatings for textiles.

Work is being carried out by the European Chemicals Agency (ECHA) to restrict the production, use and import of all PFAS, and discussions are taking place on PFAS use in the UK through the UK Parliament Environmental Audit Committee.

Some PFAS compounds, such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), have been associated with adverse effects in animal and human studies at sufficient levels of exposure. This has led to the restricted use of some of these substances in a variety of global markets.

For many PFAS compounds, there is a lack of toxicological data, and research is still ongoing to better understand the health effects associated with low levels of exposure over long periods of time.

Recognising the potential for longer-term accumulation of some PFAS in the human body, the independent quality regulator for drinking water, the Drinking Water Inspectorate (DWI), has set guidance levels for PFAS that provide a precautionary margin of safety in advance of further international research on PFAS toxicology.

Based on current knowledge, the DWI states that the low levels of PFAS detected in some untreated water abstracted for public drinking water supplies have no acute or immediate impact on human health.

Drinking water is a recognised route of exposure to PFAS. However, it accounts for a small proportion of possible exposure, alongside various foods, other drinks, household dust and products we use in everyday life.

PFAS have been found in rivers and other waterbodies around the world, including in the UK. Water companies need to treat this water to ensure PFAS (and other chemicals) are reduced to acceptable levels.

We monitor PFAS at our sites based on risk assessments, following DWI's guidance.

Where PFAS concentrations are above the DWI guidance value, they can be removed from water at varying rates using granular activated carbon (GAC), powdered activated carbon (PAC), ion exchange and reverse osmosis membranes. Water supplies can also be managed, and concentrations can be diluted through blending water.

Water companies are working together to understand other available treatment technologies and advance innovative treatment solutions.

Drinking water in our region is clean, reliable and consistently of a high quality, with water in the UK being considered some of the best in the world. We use the World Health Organisation risk-based water safety planning approach to identify and mitigate any potential risks to drinking water from source to tap.

The water industry regulatory system and standards are designed using the precautionary approach with a high level of conservatism and include health-based limits. Our water supplies are managed using risk assessment, sampling, monitoring and treatment processes to achieve stringent water quality regulatory standards.

We, along with other water companies, are routinely monitoring for PFAS and providing this data back to DWI, who report on the findings and provide insight into the overall picture of PFAS for drinking water in England and Wales annually.

We have a strategy for PFAS with clear action processes in place to progressively reduce PFAS concentrations, which includes identifying potential sources of PFAS within our catchments and developing treatment solutions where needed.

We will continue to monitor our sites on a risk-based approach, along with developing our risk assessments as more data becomes available. We are continuing to work with other water companies and stakeholders to further our understanding of PFAS sources and treatment options, while also improving our monitoring capabilities.

We are also supporting the DWI in working closely with the UK Health Security Agency, the Environment Agency and the government to adopt the most up-to-date information regarding standards and toxicology. We will also continue to support the work being done by several groups advocating for a national PFAS action plan to manage and reduce PFAS from the environment, including water bodies.

‘Sludge’ is a byproduct of sewage or wastewater recycling processes. Treated sludge or ‘biosolids’ is often applied to agricultural land as a fertiliser because it provides a rich source of nutrients and organic matter.

Studies show that certain PFAS compounds, such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are likely to become attached to sludge during treatment. As a result, it is important to understand the potential environmental and human-health impacts of applying biosolids containing PFAS to land.

We have collected and analysed samples from several of our water recycling centres to determine the levels of PFAS in sludge. We are looking to expand these investigations to form an established PFAS monitoring programme for sludge.

Through the Chemicals Investigation Programme 4 (CIP4), alongside other water companies and the Environment Agency, we are carrying out a comprehensive analysis of how sludge treatment processes affect the content of PFAS (and other substances) in sewage sludge.

This will give us a better understanding of how PFAS interact with sludge and provide more information on the potential impacts of sludge containing PFAS being spread on land.

PFAS ‘destruction’ and ‘removal’ mean different things. Recent evidence states that the destruction of PFAS in sewage sludge requires temperatures of at least 1100◦C, which can be achieved using high-temperature incineration processes.

However, ‘Advanced Thermal Conversion’ (ATC) technologies such as ‘pyrolysis’ can provide effective PFAS removal in the absence of combustion, particularly for specific PFAS compounds, such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).

Standard sludge treatment processes such as anaerobic digestion or lime stabilisation have little impact on PFAS levels.

We are carrying out internal investigations on the potential sources of PFAS in sludge and looking to establish a sludge monitoring programme for PFAS.

We are also working with other water companies, regulators and landowners to implement longer-term strategies to enhance our understanding and prevent harmful impacts from PFAS in sludge being applied to soils. For example, we are considering incorporating innovative technologies, such as ATC (see above), into our sludge treatment.

We also work actively with farmers to promote adherence to the sustainable biosolids recycling practices provided as part of the Biosolids Assurance Scheme (BAS).