A chemical that the New South Wales government recently partially banned in firefighting has been found in endangered Australian fur seal pups and Australian fur seals.
The discovery represents another blow to the survival of Australian sea lions. Hookworm and tuberculosis are already threatening their small, dwindling population, which has fallen by more than 60% in four decades.
The new research – part of a long-term study of the health of seals and sea lions in Australia – identified the chemicals in animals at several colonies in Victoria and South Australia from 2017 to 2020 .
In addition to puppies, the chemicals (per- and polyfluoroalkyl substances – “PFAS”) were detected in juvenile animals and in an adult male. There was also evidence of transfer of the chemicals from mothers to newborns.
PFAS have been reported to cause cancer, reproductive and developmental abnormalities, endocrine disruption, and can compromise the immune system. Exposure can occur from many sources, including contaminated air, soil and water, and common household products containing PFAS. In addition to being used in fire fighting foam, they are frequently found in stain repellents, varnishes, paints and coatings.
Researchers believe the seals and sea lions ingested the chemicals through their diet of fish, shellfish, octopus and squid.
Although South Australia banned the use of fire-fighting foams containing PFAS in 2018, these chemicals persist and do not degrade easily in the environment. They weren’t banned in Victoria.
Posted in Total Environmental Sciencethis is the first study to report PFAS levels in seals and sea lions in Australia.
PFAS concentrations in some animals were comparable to those in northern hemisphere marine mammals, including southern sea otters and harbor seals.
Particularly high concentrations of the chemicals have been found in newborn babies – transferred during gestation or via their mother’s milk. “This is of particular concern, given the importance of immune system development in newborn animals,” said co-lead researcher Dr Rachael Gray from the Sydney School of Veterinary Science.
“While it was not possible to examine the direct health impacts of PFAS on individual animals, the results are crucial for continued monitoring. With the Australian sea lion now listed as endangered and fur seals furbearers suffering from colony-specific population declines, it is essential that we understand all of the threats to these species, including the role of man-made chemicals, if we are to implement effective management preservation.”
Implications in the food chain
The findings have implications for the entire food chain of which pups are a part, including adult seals and sea lions, fish and even humans.
“Because PFAS are long-lived, they can concentrate inside the tissues of living things. This increases the potential for exposure to other animals in the food chain, especially top predators of marine mammals like seals. and sea lions,” Dr Gray said.
“It is also possible for humans to be exposed to PFAS by eating contaminated seafood, drinking contaminated water, or even eating food grown in contaminated soil.
“So not only do PFAS threaten endangered native species like the Australian sea lion, but they could also pose a risk to humans.”
A collaboration between the University of Sydney, the National Measurement Institute and Phillip Island Nature Parks, the research, primarily undertaken by University of Sydney PhD student Shannon Taylor, was partly carried out on site at the colonies from animals, with subsequent testing in animal livers at the National Measurement Institute in Sydney. The livers were analyzed using a complex method called high performance liquid chromatography/triple quadrupole mass spectrometry. In its most basic form, this method ionizes a molecular compound, then separates and identifies the components based on their mass-to-charge ratio. In this way, specific chemicals and their abundance can be measured.
The endangered Australian sea lion
Dr Rachael Gray and her team of scientists conducted world-class research in South Australia to save the endangered sea lion.
The Australian sea lion is the only species of pinniped endemic to Australian waters, ranging from the Houtman Abrolhos Islands off the west coast of Western Australia to the Pages Islands in South Australia. The species is endangered, with a declining population trend (International Union for Conservation of Nature Red List) from a low reference level attributed to commercial whaling in the 19th century .
Small population size increases the risk of catastrophic disease impact for the species, as seen in the New Zealand sea lion where neonatal sepsis and meningitis contributed to 58% of pup deaths between 2006 and 2010.
Hookworm infection provides an existing disease pressure for the Australian sea lion. In addition, recovery after a major disease impact would be limited by the species’ low reproductive rate. The majority (82%) of puppy births take place in South Australia, where only eight major breeding colonies are relied upon, including Seal Bay, Kangaroo Island.
Funding for this research was provided by the Ecological Society of Australia through a Holsworth Fellowship to PhD student and lead author Shannon Taylor. The Hermon Slade Foundation provided funding for field support of these ongoing investigations and the Sydney School of Veterinary Science Bequests also provided financial support. Staff from Seal Bay Conservation Park, Department of Environment and Water, South Australia and Phillip Island Nature Parks provided logistical support.