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Forever chemicals - that's the snappier name given to PFAS, or per- and polyfluoroalkyl substances. They're everywhere.
They've been used since the 1940s in everything from waterproof fabrics to fast-food packaging. They are also critical to the manufacture of semiconductors and other materials crucial to the green transition. But what makes them so practical and ubiquitous in the products we use is also what makes them so harmful. They are resistant to water, oil, and temperature changes, but they don't break down in the environment and are now associated with health issues ranging from decreased fertility to cancer. They can also be found in our food and drinking water. Traces of PFAS have been found in the blood of 97 per cent of Americans.
A nutrient-rich byproduct of municipal wastewater is sewage sludge or biosolids. These biosolids are sometimes used as a fertiliser. In the US, for example, it's thought that this has been spread across about 5 per cent of the country's farmland. Forever chemicals have been found in this sludge. The worry is that as they don't break down they become concentrated over time, circulating through our fertilisers, water, food, and bodies.
PFAS pollution from industrial sites and firefighting foam have also contaminated our soil and water supplies. These harmful chemicals could be around for millennia unless we can find ways to destroy them. Increasing pressure from lawmakers to ban or restrict PFAS has prompted a start-up race to find technology either to replace them, which for some industries, such as semiconductors, could be nigh on impossible, or at least to eradicate those already in the environment. Revive Environmental, based in Michigan, has a machine they call The Annihilator that uses a technique called supercritical water oxidation and acts as a kind of pressure cooker to break apart the chemicals. Onvector, a water treatment company, uses plasma technology where high-energy electrons obliterate the chemicals.
Researchers have also joined the cause. Studies have shown that a charcoal-like substance made from waste timbers can absorb the chemicals from sewage sludge for them to be destroyed. Meanwhile, American chemists from Northwestern and Los Angeles University have developed an inexpensive and low-energy process that breaks down two of the most critical types of PFAS into harmless chemicals. A team at the University of California uses ultraviolet light to break them down without producing any byproducts, and another team at the university have found soil bacteria that can do something similar.
Getting rid of the various types of forever chemicals will require different methods and be far from easy. Many of these methods look promising, but all require a lot more time and investment to be effective. But for those willing to take on the challenge, a market worth a potential $20bn is up for grabs.
