PFAS - it's a topic we have heard plenty about in the Shoalhaven, especially in recent years.
Major investigations into PFAS contamination, through the historic use of fire fighting foams by Australian Defence Force personnel and Rural Fire Service members, have unsurprisingly led to PFAS contamination discoveries and later massive studies at local navy bases HMAS Albatross and HMAS Creswell, Jervis Bay Airfield and the Rural Fire Centre at West Nowra.
Per- and poly-fluoroalkyl substances (PFAS) are a group of chemicals that include perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS).
They were widely used in firefighting foams at a number of locations.
PFAS will be one of the topics up for discussion at the 8th International Contaminated Site Remediation Conference incorporating the 2nd International PFAS Conference which will be held at the Adelaide Convention Centre from Sunday, September 8 until Wednesday, September 11.
More than 600 scientists, engineers, regulators and other environmental professionals from more than 20 countries will attend the biennial International CleanUp Conference, organised by the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) and the University of Newcastle.
Representatives from universities, government and industry will discuss all aspects of contaminated site assessment, management and remediation.
Delegates will discuss some of the most pressing environmental problems facing the world today, including microplastics, chemical weapons, climate change, asbestos, and emerging contaminants such as per-and poly-fluoroalkyl substances (PFAS).
The PFAS Conference will focus on this increasingly important emerging contaminant, which is used in some firefighting foams.
In recent years, PFAS contamination has been identified at and adjacent to fire-training sites, in some cases affecting nearby residential communities.
Topics to be discussed include recent advances in contamination assessment; prevention of contamination; landfill evaluation and gas management; disposal of urban wastes; green approaches to managing wastes; methane effects on the environment and detection technologies; petroleum hydrocarbon.
Legal responses to site contamination; adverse impacts on agriculture; asbestos policy, assessment, and risks; the management of volatile substances; chlorinated hydrocarbon remediation; contamination from chemical weapons; Per- and poly-fluoroalkyl substances (PFAS); emerging contaminants; fractured rocks and innovative technologies are also on the agenda.
PFAS contamination has been detected in at least five sites across the Shoalhavenaccording to the NSW EPA investigation program.
Shoalhaven City Council also revealed the toxic chemicals have been found in small quantities at council sewage treatment works.
More recently council and the EPA has investigated the discharge of 100,000 litres of PFAS contaminated waste water into the Shoalhaven City Council sewerage system in March this year by Sikorsky Aircraft Australia, who provide maintenance services to HMAS Albatross, from the nearby Aviation Technology Park.
Although heavily treated that waste water eventually flowed into the Shoalhaven River.
Could an Australian invention provide a concrete solution to PFAS contamination?
Australian researchers have developed and patented an invention that prevents the spread of PFAS and other pollutants from contaminated concrete.
Fire-fighting foams have contaminated concrete and soils at fire-training and commercial sites across Australia and worldwide.
Many so-called aqueous film-forming foams contain per- and poly-fluoroalkyl substances (PFAS) chemicals, which can enter ecosystems and move through food chains, accumulating in animal and human bodies.
"The modified natural clay, called matCARE, soaks up toxic substances and binds them irreversibly," said managing director of the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Professor Ravi Naidu, based in Newcastle, NSW.
Clay has been widely used to absorb and clean up pollution.
CRC CARE researchers identified a type of clay that was especially effective at trapping PFAS.
They activated the fibrous clay, making it more effective at trapping pollutants.
The resulting product irreversibly locks up PFAS, preventing it from leaching into the environment.
"Concrete acts like a sponge. It has a very porous structure and can readily soak up PFAS. Rain can then wash these pollutants out of the concrete and into soil, creeks, rivers and groundwater," Professor Naidu said.
"A few kilograms of matCARE will successfully treat a typical contaminated site, protecting people and the environment. It is inexpensive and effective."
CRC CARE scientists Drs Jianhua Du and Danidu Kudagamage have created a nano-powder form of thematCARE clay slurry.
The tiny particles penetrate contaminated concrete, locking up thePFAS and preventing it from leaching into the surrounding environment.
There are estimated to be thousands of PFAS-contaminated sites in Australia.
"Many of the sites include contaminated concrete," he said.
"Treating these with nano-matCARE will often represent a better, more environmentally friendly and cheaper clean-up method than removing and transporting the concrete for further treatment."
CRC CARE tests at the University of Newcastle's Global Centre for Environmental Remediation show that nano-matCARE will immobilise 99.97 per cent of the PFAS chemical perfluorooctanesulfonic acid (PFOS) in contaminated concrete.
After 10 months, more than 99.61 per cent of the chemical remains immobilised.
The matCARE slurry also locks up other pollutants in concrete, such as hydrocarbons, and can be used to treat contaminated soil.