PFAS in Our Rivers: Who’s Responsible?

You probably don't think about PFAS when you pull on a waterproof jacket, open a takeaway box or cook with a non-stick pan.

But these chemicals are all around us.

PFAS: per- and polyfluoroalkyl substances are a huge family of man-made chemicals used because they are incredibly good at resisting water, grease, heat and stains.

Many PFAS are extremely persistent. They don't readily break down in the environment, which is why they're often called ‘forever chemicals’.

And once they get into our water, getting them back out isn't easy.

PFAS a hot topic at the Enviro Expo in Birmingham

So what makes them so stubborn?

PFAS contain chains of carbon and fluorine atoms. The carbon–fluorine bond is exceptionally strong, helping give these chemicals their remarkable resistance to heat, water and chemical reactions.

Some PFAS can move through soil and water, and some can accumulate in wildlife and people. There are thousands of different PFAS, and they don't all behave in exactly the same way or have the same evidence around their health effects.

But their persistence alone is enough to make us stop and think.

If a chemical is designed to resist breaking down, what happens when we lose control of it?

Look beneath the surface

When we talk about polluted rivers, we often picture what we can see.

Plastic bottles. Sewage.Foam.Oil.

But some of the most persistent pollution is invisible.

Natural Resources Wales has been monitoring groundwater for decades. In 2023, it tested 70 groundwater monitoring sites for two PFAS: PFOA and PFOS. At two locations, concentrations were above the Drinking Water Inspectorate's Tier 1 guideline value. NRW says it is developing its monitoring so that a wider range of PFAS can be measured in future.

We need to have abetter understanding of PFAS in our catchment.

Where are these chemicals coming from?

How are they moving through our catchments?

Which activities are contributing to them?

And how do we stop them entering the water in the first place?

Because once persistent chemicals are in the water cycle, cleaning them up is a much harder job.

This isn't just about consumer products

PFAS have been used across a huge range of industries, including textiles, electronics, manufacturing, firefighting and semiconductor production.

And as technology changes, so does the conversation.

What does AI have to do with it?

AI might feel like it lives somewhere in the cloud.

It doesn't. It lives in enormous buildings packed with powerful computers.

Those computers produce enormous amounts of heat, and keeping them cool is becoming one of the biggest challenges for the data-centre industry.

Some advanced cooling technologies have used fluorinated fluids, including PFAS-related substances. In two-phase immersion cooling, for example, electronic equipment can be immersed in a liquid that absorbs heat, boils into a vapour and then condenses back into a liquid.

But this isn't a story about every data centre using PFAS. There are other cooling systems, including water-based approaches, and the industry is actively looking at alternatives.

As AI grows, we need to ask what chemicals are being used to build and run the infrastructure behind it and what happens to those chemicals when they're no longer needed.

The chips powering AI are made in semiconductor factories, where fluorinated chemicals are used in processes including etching and cleaning. The US EPA also identifies fluorinated heat-transfer fluids used in semiconductor manufacturing.

Some semiconductor processes have also used PFAS in materials such as photoresists and coatings.

So when we talk about the environmental impact of AI, we shouldn't only ask:

How much electricity does it use?

We should also ask:

What chemicals does it depend on?

And where do those chemicals go?

Who pays when they reach the river?

This is where we need to rethink how we deal with pollution. Too often, responsibility sits at the end of the pipe line.

Eventually, someone discovers that the chemical doesn't break down and has entered the environment. Then the expensive questions begin:

How do we monitor it?

How do we remove it?

How do we protect drinking water?

How do we clean up contaminated land?

Who pays?

Why aren't we asking those questions before the chemical is used?

If a manufacturer chooses a persistent chemical because it makes a product work better, surely that manufacturer should have a responsibility to understand what happens to that chemical throughout the product's entire life. Not just when it leaves the factory.

Prevention has to come first

We need better monitoring of Welsh rivers, groundwater and coastal waters. We need to understand where PFAS are coming from and we need transparency about which products and industrial processes use them.

We need investment in safer alternatives and where safer alternatives exist, we should be moving towards them.

Because asking a water company to remove a persistent chemical after it has entered the water cycle is not the same as stopping it getting there.

The best pollution is the pollution we prevent.

And the responsibility for doing that shouldn't sit entirely with consumers.

People shouldn't need a chemistry degree to work out whether the products they buy contain persistent pollutants.

Manufacturers know what they put into their products. They know why they're using it and they should be responsible for finding safer alternatives and for the environmental consequences of what they put into the world.

Our rivers are not a test site

Wales is a country shaped by water and they are already under pressure. NRW's 2024 assessment found that only around 40% of Welsh water bodies were at good or better overall status.

What's in the products we buy?

What's being used by the industries we are investing in?

Where does it go when we're finished with it?

And if a chemical is designed not to break down:

why are we putting it into our environment in the first place?

Our rivers should be places for people and nature. Not the final destination for chemicals that were designed to last.

PFAS pollution shouldn't be something we learn to live with.

We need to stop it at source.