A new study has found that long-lasting and potentially harmful chemicals might be harming some of our much-loved marsupials.
University of Melbourne researchers in the Australian Laboratory for Emerging Contaminants (ALEC) and the Melbourne Veterinary School measured the concentrations of human-made per- and polyfluoroalkyl substances (PFAS), a synthetic ‘forever chemical, in possums from the greater Melbourne region.
Associate Professor Jasmin Hufschmid from the Melbourne Veterinary School at the University of Melbourne said we know that generally speaking, the PFAS compounds we found can negatively affect reproduction, the immune response and can even cause cancer.
“To investigate this further, ideally, we’d like to look at a range of health indicators in possums, such as blood values, immune response indicators and pathological changes in tissues,” she said.
“In the possums we sampled, it was not possible to investigate health impacts as they had already been dead for some time.
PFAS has been used in a wide variety of products for decades, including but not limited to fire-fighting foams, non-stick pans, waterproof clothing, and cosmetics, meaning there is no shortage of potential exposure points for possums and other animals.
PhD candidate and lead researcher Ellis Mackay explained that the research group investigated PFAS concentrations in the livers of common ringtail and brushtail possums that had been euthanised on welfare grounds or died under circumstances unrelated to the study.
“All the possums we examined had been exposed to PFAS – we found 45 types of PFAS in their livers – and median levels were among the highest recorded in any small terrestrial mammal worldwide,” Ms Mackay said.
“PFAS have been studied widely in aquatic animals, but we know very little about the health impacts of PFAS in terrestrial wildlife, and this is the first study to investigate PFAS levels in Australian marsupials.
“The possums in this study are sentinels warning us that broad PFAS contamination of Australian ecosystems and native species is highly probable.”
Human exposure also poses a problem, with the Australian Bureau of Statistics’ most recent National Health Measures Survey finding PFAS in the blood of more than 98 per cent of Australians tested.
Ass Prof Hufschmid said it’s important to continue this research both to address impacts in wildlife and animals, but also to see them as sentinels of what is going on in our environment more broadly.
“By looking at PFAS levels in a range of different species, representing different levels of exposure (due to their location, but also due to their ecology (e.g. home range) and life history), we will be able to get a much better understanding not only of the potential impacts in the species we examine, but also the distribution of these chemicals throughout the ecosystems, of which, after all, humans are also a part of,” she said.
“PFAS can be widely transported and distributed through water but also subsequently the soil, it is likely possums are exposed through water and soil (e.g. by feeding on plant matter and invertebrates that are exposed to the soil).
“PFAS is also present in rain, which means that it potentially settles on a wide range of surfaces (vegetables, flowers, trees etc) outside. In addition, it is possible that some brushtails access human rubbish (e.g. garbage bins).”
Research into the health impacts of PFAS on a range of other animals, including endangered species like the Leadbeater’s Possum, are needed with PFAS occurring almost everywhere in the world.
Ass Prof Hufschmid said there is a lot of location-based variation in the levels of PFAS contamination and it is likely that locations closer to cities, industry and air-bases, have higher contamination levels.
“We are hoping to help raise awareness of the ubiquitousness of PFAS in our environment with the public and our regulators, but also to draw attention to the fact that we continue to contaminate the world with a vast number of man-made chemicals, which accumulate in our bodies in substantial amounts, but of which we have very little understanding what it actually does to us, and the world surrounding us,” she said.
“In particular, we are very interested in getting a better understanding of the impacts of environmental pollutants on free-ranging wildlife, and what these impacts tell us about potential risks to humans.”
The research was published in the journal Science of the Total Environment.
ALEC leader and co-author of the published paper, Associate Professor Brad Clarke, said that certain PFAS have been linked to serious health effects, including cancer, developmental harm, and immune system disruption.
“Globally, we are producing and using hundreds of thousands of synthetic chemicals including PFAS, with limited understanding of their long-term impacts,” he said.
“Building on this study, we are keen to investigate how different landscapes affect animals’ exposure to environmental contaminants, as well as examining the health impacts of exposure more closely.
“We are likely to see increasing health impacts from contamination of our ecosystems and food chains with synthetic chemicals, so tighter control of their production and use is essential.”
