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A new exhibition in London (open until February 2026) called highlights how civilizations have treasured—and been intrinsically linked to—safe, clean water.

As a chemist, I research how freshwater is polluted by modern civilization. in rivers include , (which degrade further when ), and forever chemicals or (PFAS) (some of which are ).

Synthetic toxic chemicals are introduced into the environment from the products we make, use and dispose of. This wasn't a problem centuries ago, where we had a totally different manufacturing industry and technologies.

Some, such as PFAS from stain-resistant textiles or nonstick materials such as cookware, can be particularly difficult to remove from wastewater. PFAS don't degrade easily, they resist conventional heat treatments and can easily pass through wastewater treatments, so rivers or lakes that are sources of our drinking water.

Testing for pollutants is even more critical in developing nations that lack sanitation and . Having to protect and conserve drinking water and its sources is as it always has been.

For this exhibition, curator at the Wellcome Collection in London, , has selected 125 historical objects, photographs and feats of engineering that link to drought, rain, glaciers, rivers and lakes. These three artifacts from Thirst illustrate how our relationship with water contamination has evolved:

1. Ancient water filters

Made from natural materials such as clay, water jug filters have been used for hundreds of years in every continent by ancient civilizations. They show that purifying water for drinking was commonplace. The sand and soil particles that naturally get suspended in water and removed by these filters would have carried microbes.

But in ancient times, pharmaceuticals and other drugs, , and would not have been a problem. Those filters could work relatively well despite being made of simple materials with wide pores.

Today, those ancient filters would no longer be effective. Modern water filters are made using more advanced materials which typically have small pores (called micropores and mesopores). For example, filters often include (a highly porous type of carbon that can be manufactured to capture contaminants) or membranes that filter water. Only then is it safe for people to drink.

2. Roman water pipes

Lead water pipes (known as fistulae) were useful parts of a relatively advanced plumbing system that distributed drinking water throughout Roman cities. They are still common in water systems . In the US, there are about 9.2 million . Exposure to lead . Lead exposure, not necessarily from drinking water only, was attributed to more than .

It's now understood that lead is neurotoxic and it can diffuse or spread . Lead from paints and batteries, including car batteries, can also contaminate drinking water.

To protect us from lead leaching or flaking off from pipes, are calling for the replacement of lead pipes with copper or plastic pipes. Water companies routinely add phosphates (mined powder that contains phosphorus) to drinking water to help capture potential and make it safe to drink.

3. The horror of unhealthy water

One caricature titled The Monster Soup by artist William Heath (1828) is part of the Wellcome Trust's permanent collection. The graphics read "microcosms dedicated to the London Water companies" and "Monster soup, commonly called Thames Water being a correct representation of the precious stuff doled out to us." The cartoon shows a lady so terrified at the sight of microbes in river water from the Thames that she drops her cup of tea.

Even today, many at the toxic contamination and sewage pollution .

, 2 billion people will still not have safely managed drinking water and 1.2 billion will lack basic hygiene services. Drinking water will still be contaminated by bacteria such as E. coli and other dangerous pathogens that . So advancing technologies to filter out contamination will be just as crucial in the future as it has been in the past.

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