Research traces water contaminants back to the source

Tuesday, 02 April, 2019

Research traces water contaminants back to the source

Multimillion-dollar research is underway at UNSW’s Water Research Centre (WRC) to determine how to treat and neutralise emerging contaminants in our water supplies. Insidious per- and poly-fluoroalkyl substances (PFAS) are travelling long distances via our waterways, but their unique signature can give researchers clues leading to the contaminants’ source so they can be cleaned up.

Professor O’Carroll, WRC Director and Deputy Director at UNSW’s Water Research Laboratory, explained that he is undertaking a complementary piece of research into how these contaminants move through our environment. “If we know how they move, we can trace where they’ve come from and clean them up at the source,” he said.

PFAS are manufactured chemicals that have been used in products like firefighting foams, paints and waterproofing sprays since the 1950s. These emerging contaminants were not originally thought to be an environmental concern; however, over the last two decades PFAS have been increasingly scrutinised throughout the world, particularly in Australia, the US, Europe and Canada.

One of the most shocking findings relating to PFAS is where they can be found. In the US, 97% of the population has measurable quantities of these contaminants in their blood. Prof O’Carroll commented, “Some studies suggest that almost every person on Earth has them in their bloodstream, which gives some indication of the scale of the problem.

“There is still much uncertainty and debate around the health implications, but they have been linked to cancer and immune suppression in infants.”

Although alarm bells about the potential health and environmental impacts of these substances have been ringing among the scientific community since the 1990s, regulatory bodies have only just caught up. Agencies have started regulating PFAS down to the nanogram per litre, but 70 years of constant use means they are already prolific in the environment.

“One of the key problems is that we don’t actually know that much about them,” Prof O’Carroll said. “We don’t know how to treat them or how they travel through the environment.”

PFAS were designed to extinguish fires. When poured over a fire they go straight to the interface between the oil and the oxygen, creating a layer which smothers the oxygen and puts out the fire. But having put out the fire, they continue to travel long distances through the environment via the interfaces. Although other contaminants might stay in water or soil, PFAS travel easily from water to soil to animal to fish to human and so on. This makes the science complicated, and monitoring and treatment very challenging.

In one well-publicised Australian incident, toxic chemicals used in firefighting foam leaked from the Williamtown RAAF Base in NSW and were found kilometres away in the groundwater, sea water, and agricultural and seafood supplies.

So how will Prof O’Carroll’s team track PFAS? “We’re quite enthusiastic about that,” he said. “PFAS are made up of thousands of molecules which have their own unique signature. This means you can look at the signature of the contaminant downstream, identify if it came from a groundwater source or a surface water source, then track it backwards.”

This is important because the signature of the compound enables researchers to work out the best way to treat it and prove who is responsible for the contamination.

“Let’s say you’ve got an airport with fire training facilities located next to a company that treats carpets. Either might be responsible for a water source contamination problem, but our methods should allow us to pinpoint with certainty where they came from. You can imagine how useful this would be in the clean-up, as well as any potential future litigation.”

The primary benefit of the research is a clean, uncontaminated environment for human beings and ecosystems to thrive in. But in getting to that point, Prof O’Carroll said there are tangible benefits for industry too. “There will be huge opportunities for industry to use our research to develop cost-effective solutions to identify and clean up the source. “If we could do that rapidly, that would be ideal.”

Image caption: Professor Denis O’Carroll investigating PFAS in the lab. Image ©University of New South Wales

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