Monitoring PFAS pollutants in king penguins

New research shows how organohalogen pollutants affect different tissue types in king penguins. The work shows how various contaminants, including per- and polyfluoroalkyl substances (PFAS) and organochlorine compounds, find their way into the seabirds’ fatty and protein-rich tissues.

Halogenated chemical pollutants are a global problem, found almost everywhere – in soil, rainwater, rivers and tap water. Because these compounds are difficult to break down, they persist in the environment and can bioaccumulate in food chains.

Now, a team led by Alice Carravieri from the University of La Rochelle, France, has analysed the levels of organohalogens in blood samples taken from king penguins in the Crozet Islands in the southern Indian Ocean. Specifically, the team took samples from penguins that were fasting during their moulting and breeding periods. By monitoring changes in the concentrations of the contaminants, the researchers could gain insight into how the different compounds are mobilised while different tissues are metabolised.

Over 25-day fasting periods, the researchers noted that the total concentration of pollutants in the penguins’ blood plasma doubled. This is because the contaminants are released into the bloodstream when fatty and protein-rich tissues in which they accumulate are burned for energy.

Of the 36 compounds that the researchers searched for, 26 were detected in penguins’ blood. Perfluorooctanesulfonic acid (PFOS) was by far the most prominent contaminant, accounting for 60% of the total pollutant concentration. While compounds like PFOS and hexachlorobenzene were shown to increase in the blood plasma of both breeding and moulting penguins, levels of perfluoroundecanoate and perfluorotridecanoate decreased in the blood of moulting penguins. The researchers suggest that a significant amount of these pollutants are incorporated into the penguins’ feathers.

The researchers also note that the mobilisation of PFOS and long-chain perfluoroalkyl carboxylic acids is a cause for concern, as these compounds are highly toxic and can be transported to sensitive tissues including eggs and the brain. They say that further research is urgently needed to monitor the impacts of these compounds on the physiology and fitness of seabirds, particularly during prolonged periods of fasting.