“As a formal investigation continues into the use of certain fire-fighting foams in New Zealand, airports are being identified as still having stocks of the foams, use of which has been restricted since 2006.
Fire-fighting foams manufactured with the chemicals PFOS and PFOA were the standard from the 1970s until the early 2000s. Since 2011, no import, manufacture or use of the compounds is permitted in New Zealand.
Australia has had an ongoing response to the use of these fire-fighting foams in recent years – we asked an Australian expert to discuss the chemicals and some of the potential issues…
Dr Amy Heffernan, NHMRC-ARC Dementia Development Research Fellow, The Florey Institute of Neuroscience & Mental Health, Australia.
There are concerns in New Zealand about chemicals used in fire-fighting foam, specifically PFOA and PFOS. What are these chemicals and what are they used for?
‘PFOS and PFOA are part of a family of chemicals known as per- and poly-fluoroalkyl substances (PFAS). PFAS are used mainly as surfactants, that is, as detergents, foaming agents, and emulsifiers. They have many industrial and household applications, including fire-fighting foams (also called ‘aqueous film-forming foams’), non-stick cookware (e.g. Teflon), waterproof clothing (e.g. Goretex) and stain repellents (e.g. Scotchgard). The two most commonly used and studied PFAS are perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA).’
What do we know about how these chemicals act in the environment? How long do they take to break down?
‘All members of the PFAS family, including PFOS and PFOA contain fluorine atoms. The carbon-fluorine bond is exceptionally strong, and this property is what makes them useful for industrial applications. It also means PFAS don’t break down easily in the environment, can travel long distances (e.g. through contaminated groundwater), and bioaccumulate in the food chain. In humans, it takes 4-5 years for the amount of PFAS in your blood to reduce by half (3.8 years for PFOS and 5.4 years for PFOA).’
Have there been any moves internationally to control the use of these chemicals?
‘In 2009 PFOS and PFOA were listed were listed under the Stockholm Convention, an international environmental treaty that aims to eliminate the use of persistent organic pollutants. Participating countries are required to eliminate or reduce the release of these chemicals into the environment. Australia and New Zealand are both signatories to the original agreement, but have not ratified the amendments covering PFOS and PFOA. The Australian Department of Environment called for ratification in October 2017.’ “
Read the full press release by Science Media Centre.