A chemical that the NSW government recently partially banned in fighting fires has been found in endangered Australian sea lion pups and Australian fur seals.
This discovery represents another possible blow to the survival of Australian sea lions. Hookworm and tuberculosis are already threatening their small and shrinking populations, which have fallen by more than 60 percent in four decades.
The new research – part of a long-term study into seal and sea lion health in Australia – identified the chemicals in animals at several colonies in Victoria and South Australia from 2017 to 2020.
As in puppies, chemicals (per- and polyfluoroalkyl substances – “PFAS”) have been detected in juvenile animals and in an adult male. There was also evidence of transfer of chemicals from mothers to newborns.
PFAS have been reported to cause cancer, reproductive and developmental abnormalities, endocrine disorders, and can compromise the immune system. Exposure can come from many sources, including contaminated air, soil and water, and common household products containing PFAS. In addition to being used in fire-fighting foams, they are frequently found in stain repellants, varnishes, paints and coatings.
Researchers believe seals and sea lions ingested the chemicals through their diets 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 easily degrade in the environment. They were not banned in Victoria.
Posted in Total environmental science, this is the first study to report concentrations of PFAS in seals and sea lions in Australia.
The concentrations of PFAS in some animals were comparable to those in northern hemisphere marine mammals, including southern sea otters and harbor seals.
Particularly high concentrations of chemicals have been found in newborns – transferred during gestation or through breast milk. “This is of particular concern, given the importance of immune system development in newborn animals,” said research co-lead Dr Rachael Gray of the Sydney School of Veterinary Science.
“Although it was not possible to examine the direct effects of PFAS on the health of individual animals, the results are crucial for continued surveillance. With the Australian sea lion now considered endangered and Australian fur seals suffering from colony-specific population declines, it is critical that we understand all of the threats to these species, including the role of the products. man-made chemicals, if we are to implement effective conservation management.
Food chain implications
The findings have implications for the entire food chain of which puppies are a part, including adult seals and sea lions, fish and even humans.
“Because PFAS are long lasting, they can concentrate in the tissues of living things. This increases the potential for exposure to other animals in the food chain, especially major predatory marine mammals like seals and sea lions.” said Dr Gray.
“Humans can also be exposed to PFAS by eating contaminated seafood, drinking contaminated water, or even eating foods grown in contaminated soil.
“So not only do PFAS threaten endangered native species like the Australian sea lion – 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, mainly undertaken by Shannon Taylor, a doctoral student at the University of Sydney, was partly carried out on site in the colonies of animals, with subsequent testing of animal livers at the National Measurement Institute in Sydney. The livers were analyzed using a complex method called high performance liquid chromatograph / 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 / charge ratio. In this way, specific chemicals and their abundance can be measured.
The endangered Australian sea lion
Dr Rachael Gray and his team of scientists conducted world-class research in South Australia to save the endangered sea lion.
The Australian sea lion is the only pinniped species 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 decreasing population trend (International Union for the Conservation of Nature’s Red List) from a low baseline attributed to 19th century commercial hunting.
The small population size increases the risk of catastrophic disease for the species, as shown by the New Zealand sea lion where neonatal sepsis and meningitis contributed to 58 percent of pup deaths between 2006 and 2010.
Hookworm infection provides existing disease pressure for the Australian sea lion. In addition, recovery after a significant impact of the disease would be limited by the low reproduction rate of the species. The majority (82 percent) of offspring births occur in South Australia, where there is dependence on only eight large breeding colonies, including Seal Bay, on Kangaroo Island.