“Forever chemicals” are pervasive, and researchers have in recent years been ringing the alarms about the negative impacts on human health. But humans aren’t the only animals to be concerned about.
Freshwater turtles in Australia exposed to per- and polyfluoroalkyl substances, or PFAS, experienced changes to their metabolic functions, environmental biochemist David Beale and colleagues report in the Dec. 15 Science of the Total Environment. “We found a whole range of biomarkers that are indicative of cancer and other health problems within reptiles,” says Beale, of the Commonwealth Scientific and Industrial Research Organisation in Dutton Park, Australia.
Much of the research on PFAS and health is focused on humans. It’s less clear what the ubiquitous chemicals are doing to other animals. Most of that research has been lab-based, and those data are then used to set acceptable levels of contaminants.
But labs can’t replicate all the complexities of a natural environment, Beale says. “There’s a massive gap in our understanding of what these chemicals do to wildlife, and they’re being equally exposed — if not more exposed — because they can’t get respite.”
Beale and colleagues captured freshwater turtles (Emydura macquarii) from three sites around Queensland: one site with a high level of PFAS, one with a moderate amount and one with barely discernable levels, all with no other contaminants. In a lab, some of the female turtles were hormonally induced to lay eggs. Then the wild-caught adults and their lab-incubated hatchlings were given physical and chemical exams, and their eggshells were tested to see if there was a link between shell strength and PFAS exposure.
“What makes this study really unique is we’re not only measuring the contaminant concentration, but we’re really diving deep into that health aspect as well,” Beale says.
Just as in humans, these turtles offloaded PFAS contamination to their babies via fats and nutrients. Most PFAS bioaccumulation in the adults was found in the ovaries of the females, though the researchers found it also in other organs such as the liver, kidneys and heart.
The lab hatchlings were also born with high amounts of PFAS in their bodies and with a concerning level of deformities, Beale says, mostly of their scales. “We concluded that we’ve got significant health problems in these turtles that isn’t immediate, but over a generation would be quite profound.”
The two PFAS-polluted sites lack juveniles, suggesting these animals have short lives. That could be because their deformities make them an easy dinner, or their health problems are causing them to die early.
There were also differences in the number and size of eggs laid: For instance, turtles from the moderately PFAS-polluted site laid more but smaller eggs, versus those from the relatively clean site. But the researchers note they don’t have definitive evidence that links those two factors to PFAS exposure.
The findings are “a little scary,” says Jean-Luc Cartron, a biologist at the University of New Mexico in Albuquerque who was not involved with the research.
“We really need to jump on this issue of ecological toxicity,” Cartron says. “If the [study] authors are right, and the lack of juveniles that they see out in the environment is caused by PFAS, we don’t want to wait until we’re missing one whole full generation of animals.”
As aquatic animals with long lives and few predators, freshwater turtles are living environmental monitors for PFAS bioaccumulation, Beale says. Surprisingly, he says, even the animals from the site with the lowest level of contamination had PFAS-related health problems. “We still saw evidence of harm.”
While continuing this work with freshwater turtles, the team is also looking at PFAS impacts on more sites and more animals, including freshwater crocodiles, cane toads and frogs in Queensland, New South Wales and Victoria.
“All these animals that we love in the wild are being exposed to these chemicals, and we’re just not seeing the obvious impacts of those exposures,” Beale says. “My greatest fear is in 10, 15 years’ time, we might see those impacts and it might be too late.”
