Fire Retardant Fur Seals: A Team Interview
BY FARRAH LEONE
Nothing has caught my eye in the same way that “Firefighting chemicals found in sea lion and fur seal pups” did on my monthly google search for blog topics. The real paper is called “Per and polyfluoroalkyl subtances (PFAS) at high concentrations in neonatal Australian pinnipeds”. Researchers from the University of Sydney analyzed levels of PFA’s found in three pinniped species: Australian Sea Lion (N. cinerea), Australian Fur Seal (A.p. doriferus), and Long-nosed Fur Seal (A. forsteri). PFA’s (identified as PFOA’s and PFOS’s through out the article) are fire retardant chemicals that can be found in products such as fire fighting foams, “stain repellents, polishes, paints and coatings”. These chemicals have been linked immunosuppression (the decreased or total stop of the immune system’s impact on the body) and immunotoxicity (when a chemical negatively impacts the immune system as a result of chemical exposure).
The Australian Sea Lion (N. cinerea) is endemic to Australia and listed as endangered under the IUCN Red List with only ~6,500 mature Sea Lions left. N. cinerea is in no place to deal with a chemical that negatively effects the immune system as the population is currently threatened by Hookworms and Tuberculosis.
The field work was performed in Southern Australia and Victoria using fecal swabs. PFA’s have been found in animals through out the globe, but concentrations in A.p. doriferus were greater than any pinniped pups in the southern and northern hemisphere.
Australian Fur Seal Pup (Photo Credit: Dr. McIntosh)
I started my research journey talking to Dr. Rachael Gray, a who is a senior lecturer in Veterinary Pathology at University of Sydney, AU. She graciously pointed me in the direction of her teammates.
Shannon Taylor is a PhD candidate also at the University of Sydney studying toxicants in pinnipeds (seals, sea lions, and walruses) who is the co-lead on this project with Dr. Gray. Another PhD candidate on the project is Mariel Fulham who researches human-cultivated pollution and antimicrobial resistance in microbiome of pinnipeds. Find a follow up interview on the threats facing Australian sea Lions here. The project also brought in the help of Dr. Rebecca McIntosh, scientist at Phillip Island Nature Parks in Victoria, Australia.
1.Where did the idea for this research come from?
My supervisor Dr. Rachael Gray wanted to identify links between toxicants and health in seal populations and so the direction for my PhD was to be on anthropogenic toxicants, specifically heavy metals and persistent organic pollutants. Rachael has always been very encouraging and supportive of the research I was going to undertake for my PhD, without us really knowing what we would find.
The pups are at a vulnerable age when they are susceptible to the effects of toxicants including immunosuppression. As the Australian sea lion pups are threatened with endemic hookworm with high mortality rates, as well as declines in pup production at specific Australian fur seal colonies, we wanted to assess the health impacts of toxicants on these seals. The neonatal age group is already susceptible with their immune systems still in development. When put under further threat by a range of toxicants that cause immunosuppression, this is of great concern and puts them at risk of being unable to combat disease.
When I started my lab work for my PhD, we had been focusing on toxicants including PCBs and dioxins which are legacy toxicants that have known health impacts. As I was undertaking my laboratory analysis PFAS was still emerging in Australia with testing happening around defence bases and known contaminated land. When I started researching what was known in Australian marine mammals there is limited literature with no known concentrations identified for Australian pinnipeds. I then included PFAS in the laboratory analysis so that we could determine baselines for these species and found the pup samples to have high concentrations. - PhD Candidate Shannon Taylor
Shannon Taylor working up a pup (Photo Credit: Louise Cooper)
2. On a scale of 1-10 (1 is lowest, 10 is highest) how high were the levels of PFA’s in wildlife?
It is hard to quantify the concentrations on a scale. For Australia these are a 10 in the pups as we have no baseline to compare to and they could be at concentrations that cause health impacts in the neonatal age group. When assessing the results, I identified a huge range specifically in the Australian fur seal pups, as compared to results from the northern hemisphere, some pups could be scaled as a 6 and one outlier would be a 10. An outlier (>2000 ng/g ww) in the fur seal pup group had a concentration greater than studies that showed associations with PFAS and disease/immunosuppression in adult marine mammals, as well as a concentration greater than polar bears which are known to have the highest toxicants concentrations.
Some of the Australian sea lion concentrations could be considered a 5 if compared to wildlife in the Antarctic (which are low) and then wildlife in the northern hemisphere (high), however these are primarily adults with limited neonatal animal studies to compare to. - PhD Candidate Shannon Taylor
3. The results state that A.p. doriferus accumulated higher concentrations of certain substances (PFOS, PFDA, PFUdA, PFSOA, PFDoA, PFNS and PFPeS) and N. cinerea has high concentrations of others (PFOA). What conclusion can you draw from the difference in concentration between the two species?
The significant differences I identified between the species show there is a likely variation in PFAS sources and pollution in South Australia and Victoria. Identifying point sources was out of the scope for this study but I speculated the differences between the two species are most likely because of PFAS contamination in their respective geographical foraging range. This could be due to the number of sources and their respective environmental release in the regions (greater in the Victoria). There could also be different types of sources between South Australia and Victoria, some being more centred around industrial applications (leaching from land fill) or release of the Aqueous Film Forming Foams used at defence bases and firefighting training grounds. As both the Australian sea lions and Australian fur seals forage using benthic behaviour it is unlikely the trophic level of prey they consume is a factor. As these are differing species there could be differences in toxicokinetics, and then differences in what is transferred to the pups from their mothers, however this was beyond the scope of this study. - PhD Candidate Shannon Taylor
4. Why are the livers sampled for PFAS as opposed to other parts of the body?
In this study, we used liver samples opportunistically collected from animals found dead. Liver tissue is a great matrix for analysis – we can obtain suitable sample volumes from individuals and many of the organic compounds including PFAS, preferentially bioaccumulating in hepatic tissue. The liver is also considered the detoxifying organ for mammals and other animals, as such, it makes sense to investigate the concentrations of PFAS in the liver. The study did attempt to analyse PFAS concentrations in blubber tissue, however, the high lipid content of the seal and sea lion blubber proved problematic. PFAS can also be measured in blood. In the future, we plan to determine PFAS concentrations in the blood of pinniped pups and see if we can determine any direct correlations between blood PFAS concentrations and changes in parameters of health. - Dr. Gray
Dr. Rachel Gray and her camera shy friend (Photo Credit: Dr. Rachel Gray)
5. How do PFAS get flushed out of animals?
The most effective way to reduce concentrations of PFAS in animals is to reduce their exposure to them.
PFAS as considered to be ‘forever chemicals’ such that are not readily (if ever) degradable in the environment nor in animal tissues. However, they can be ‘excreted’ from the body by a number of routes including urinary excretion, across the placenta to the foetus during gestation and in the milk. As such, these routes are considered excretory routes for these toxicants (and others including heavy metals) for individual animals. This is of particular concern for neonatal animals that are receiving these toxicants though the milk and through gestation. Given the role of some PFAS in immunomodulation and immunosuppression and development effects, and the role of other toxicants like dioxin-like PCBs on the developing endocrine system, the implications for pup health and susceptibility for disease require further investigation. - Dr. Gray
6. How long do you think it will take for these populations to see a decrease in PFAS in their systems?
This is an impossible question to answer! PFAS are a group of anthropogenic substances within a larger group called persistent organic pollutants- their very name suggests their ongoing legacy in the environment and tissues. While some countries have banned their production and use, they are still ubiquitous globally. For example, in Australia, one of the key sources of PFAS into the environment is the use of PFAS containing aqueous film forming foams (AFFF) in firefighting. While the use of these firefighting foams was banned in South Australia (location where Australian sea lions are) in 2018 and partially banned (still permitted for fire-fighting but no longer for training and demonstrations) in March 2021 in New South Wales, their use is not banned in Victoria where a significant proportion of the Australian fur seal population is found. Importantly, we now have values established that we can use to compare future concentrations in these pinniped populations. - Dr. Gray
Shannon Taylor performing field research
(Photo Credit: Louise Cooper)
7. Since the foraging ranges of these populations do not overlap, that implies there is a wide range that these chemicals have spread and to many different species. Are you concerned about this spread? What other ecosystems or populations could it impact that you are concerned about?
We have not done the research required to specifically identify the sources of the PFAS chemicals but there many known sites that are contaminated (https://pfas.australianmap.net/) where such chemicals are entering the ocean and then moving up the food chain. I am very concerned about the number of sites identified with PFAS contamination and all the sites that have not yet been identified. PFAS chemicals are legacy chemicals and they are persistent so even after the chemicals are banned or limited to emergency use, they remain in the environment for unknown lengths of time. PFAS is a flame retardant and water repellent used in many products so it is difficult to ban them completely, and some applications have limited alternatives. They enter the ocean by leaching from landfill or contaminated areas into freshwater sources and then into the ocean, or via ocean outfall pipes from water treatments plants or water drains. PFAS chemicals are known to be toxic and cause cancer and endocrine disruption so I am concerned about them for all ecosystems and wildlife, including the health of the fish we eat and human health. Fur seals and sea lions are high level predators and are therefore good indicators that these chemicals are ubiquitous and pervasive along our coastlines - and further afield as ocean currents and migratory species move them around. - Dr. McIntosh
8. What do you believe is the biggest contribution to the accumulation of these chemicals?
We believe the fur seals and sea lions are ingesting the chemicals through the food they eat, but we haven't tested the top prey items yet.
Females leave the breeding colony to forage for fish, squid and octopus and then return to feed their pups, so the females are ingesting the contaminated food and the pups are receiving the chemicals through the placenta and the milk they rely on. Unfortunately mothers are giving it to their pups.
The Australian sea lion is endangered and pup production is declining. Anything that affects reproductive success is a concern for this species. The Australian fur seal at Seal Rocks has higher levels of PFOS and more individual chemicals contributing to the contaminant load compared to the Australian sea lion, and they have also experienced a reduction in pup numbers since 2007. Seal Rocks is close to the city of Melbourne and many industrial sites as well as a defense base, likely contributing the higher levels of contamination. - Dr. McIntosh
Dr. Rebecca McIntosh (Photo credit to Dr. McIntosh)
9. Why do you believe that A.p. doriferus pups were exposed to eight more PFA’s than N. cinerea pups?
Given the greater diversity of compounds detected in A. p. doriferus pups compared to N. cinerea pups, there is likely to be an active source of exposure in areas in which the former forage. However, determining point sources was beyond the scope of the project, so at this stage this is conjecture. However, the Australian fur seal population of Seal Rocks is closer to a large urban/industrialised city compared to many of the Australian sea lion colonies, and it is known that PFAS concentrations are generally higher in urban compared to rural areas, due to the greater likelihood of PFAS sources in developed areas. However, PFAS can travel great distances in the atmosphere and in water bodies including the ocean, as such, the sources of exposure could be distant from the site of foraging. Finally, the most likely source of PFAS for the pups is gestation and lactation, for this reason, maternal foraging sites are the source for pups. Inter-individual foraging preferences of geographical location and/or prey items could also be contributing to the greater diversity of PFAS seen in A. p. doriferus. - Dr. Gray
10. What is one thing you want other scientists to know about your research?
Pups are a vulnerable age group susceptible to impacts from toxicants which are unavoidable due to their sole reliance on their mothers. The concentrations identified in these Australian pups aged from neonatal to 3 months are very concerning and could play a role in health indicating the need to assess this age cohort more readily for toxicants. Pups are just as important for recruitment to population and this research has displayed the potential threat of associated morbidity with toxicants such as PFAS, however further investigation is needed. Understanding the role of toxicants in disease for the endangered Australian sea lion is paramount when needing to manage and mitigate their population and bring awareness to threats for recovery plans specifically in the pup age group. - PhD Candidate Shannon Taylor
That we need to do more! One of the limitations of our study was the lack of comparative PFAS data for marine mammals. If we can start to build a body of data across species and geographical areas, we will be able to better understand the extent of PFAS contamination of the marine environment. Importantly, I think it is critical that we use a multidisciplinary and collaborative approach to research such that we can value add to overall research outcomes. Toxicant analysis is expensive, so if we can utilise data in several ways (for example, in investigations of potential causal effects in addition to establishing baseline values for species/sites), we can start to address these key knowledge gaps in marine mammal and marine ecosystem health. - Dr. Gray
We have found a broad range of PFAS chemicals in two seal species that do not overlap in foraging range. Both species are experiencing declines in pup numbers and one is endangered. Research into environmental toxicology and contamination levels for threatened species is vital for understanding changes in population. Vital rates, such as survival and fecundity, are critical to affect legislative changes to halt the continued contamination of the oceans and our fisheries. We also need to identify unregistered contaminated sites to allow for remediation. Some states of Australia have not yet banned the use of these chemicals for fire fighting practice and training, this research puts governments and regulators under pressure to follow what other states and countries have done control the use of these chemicals and reduce further harm. - Dr. McIntosh
Dr. McIntosh and Dr. Gray enjoying the view (Photo Credit: Dr. McIntosh)