When “Forever” is a Deadly Problem

Previous studies have found there are short-term health risks from exposure to concentrations of per- and polyfluoroalkyl chemicals for both humans and wildlife, but there has been limited understanding of the long-term effects of exposure to PFAS – or ‘forever chemicals’ as they are also called – on aquatic ecosystem-dependent animals. A joint study by scientists from CSIRO and the Queensland Department of the Environment, Tourism, Science and Innovation, and published recently in the journal Science of the Total Environment, has found populations of Queensland’s freshwater turtles (Emydura macquarii macquarii) have not only declined, but biochemical changes have been observed in turtle adults and their hatchlings.

Lead author David Beale, Senior Research Scientist at CSIRO, said major health impacts were observed in wildlife at sites with high concentrations of PFAS. Air-breathing aquatic animals, such as freshwater turtles and amphibians, are particularly vulnerable to PFAS contamination due to bioaccumulation, exposure pathways, physiological sensitivity, an inability to eliminate the chemicals via their lungs, and their long lifespans. This bioaccumulation increases the impacts on aquatic ecosystems, and terrestrial and semi-terrestrial wildlife such as birds, fish, marine mammals and reptiles.

“Exposure to high concentrations of PFAS impacted essential metabolic processes in the turtles sampled. Adults had a high potential of forming gout, which is deadly in reptiles. We also found that eggs had altered ratios of essential minerals, and hatchlings had a high rate of defects in their shells,” Beale said.

The three-year study involved the capture of 350 freshwater turtles that were measured and tagged before being released. Researchers detected PFAS concentrations up to 30 times higher in the blood and organs of turtles from the highly contaminated area, compared to control sites where levels of PFAS in the water were lower.  

Co-author Suzanne Vardy, Principal Scientist at DETSI, said there was a lack of juveniles at the more contaminated site, and modelling predicted that over time these impacts could result in a population collapse.

“Our research made use of omics-based tools, which are advanced techniques used to assess thousands of molecules within an organism to find out how it’s responded to a contaminant or disease. These tools offer a holistic insight into animals’ metabolism, the life-sustaining chemical reactions which turn food into energy,” she said.

Beale said the approach that involved a deep analysis on thousands of biochemical molecules, proteins, and lipids to understand the trajectory of the turtles’ health in contaminated environments, was revolutionary and had allowed researchers to draw the link between levels of PFAS contamination and impacts on animal health.

“It lays the groundwork for omics-based techniques to be used in future research assessing how PFAS affects a range of biological processes in Australian wildlife, and to better understand the impacts on our wildlife where these contaminants are accumulating in the environment,” he said.

DETSI is undertaking a range of regulatory activities to manage PFAS, including taking part in an interdepartmental committee, funding ground-breaking research into ways of removing PFAS from the environment, and collaborating with other government agencies to provide a coordinated response to managing PFAS in Queensland.

Although a small number of turtles were euthanised for the study – with peer-approved animal ethics approval – the research builds on previous studies that conducted blood tests on approximately 100 turtles.

Given their widespread presence globally, the researchers said freshwater turtles could serve as valuable indicators for assessing PFAS in aquatic ecosystems, offering deeper insights into their concentration and impacts for wildlife.

Anne Layton-Bennett

‘Forever chemicals don’t make hero mutant ninja turtles’ is available at doi.org/10.1016/j.scitotenv.2024.176313 

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