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Moderated by Arja Rautio, Webinar #5 explores how newer contaminants such as PFAS add to the health risks already posed by legacy persistent organic pollutants (POPs). The webinar features presentations by Pál Weihe, who presents decades of research from the Faroe Islands on PFAS exposure and immune function, and Christian Sonne, who examines PFAS exposure in East Greenland through a One Health perspective, linking wildlife, ecosystems and human health.

Segment 1

The Faroe experience: vaccination under pressure

For almost four decades, Pál Weihe and his colleagues have followed birth cohorts in the Faroe Islands to understand how environmental contaminants affect human health. Originally established to investigate exposure from the traditional consumption of pilot whale meat and blubber, these long-term studies have become one of the world’s most important sources of knowledge on contaminant exposure in Arctic populations.

One area of particular concern has been the immune system. Using routine childhood vaccinations as a natural experiment, the researchers measured antibody responses after vaccination and compared them with PFAS concentrations in children’s blood. Because every child receives the same vaccines at the same age, vaccination response provides a practical way to assess immune function.

The results showed a clear association between higher PFAS exposure and reduced antibody responses to childhood vaccines. Some children produced antibody levels below the threshold considered protective, requiring additional booster vaccinations. According to Weihe, this represented a direct public health consequence of environmental pollution rather than simply a laboratory finding.

The Faroe Islands cohorts also illustrate the complexity of Arctic public health. Breastfeeding, normally recognised as highly beneficial for infants, is simultaneously an important pathway for transferring PFAS from mother to child. Likewise, traditional marine foods provide valuable nutrients and remain an important part of Faroese culture, while also contributing to contaminant exposure. These examples demonstrate the difficult balance between protecting public health and respecting cultural traditions.

Although PFAS concentrations have generally declined over time, Weihe emphasises that many important questions remain unanswered. Researchers are still investigating when exposure is most harmful, which PFAS compounds are primarily responsible for immunotoxic effects, and how these chemicals may influence allergies, autoimmune diseases and other health outcomes.

Key takeaways from Segment 1

• Long-term cohort studies provide unique insight into the health effects of PFAS exposure.
• Higher PFAS concentrations were associated with reduced responses to routine childhood vaccinations.
• Some children required additional booster vaccinations because antibody levels fell below protective thresholds.
• Breastfeeding and traditional diets illustrate the complex public health challenges associated with PFAS exposure.
• Important questions remain regarding timing of exposure, individual PFAS compounds and long-term immune effects.

Segment 2

High PFAS exposure in East Greenland

Christian Sonne expands the discussion from human health to a broader One Health perspective, showing how contaminants move through Arctic ecosystems before ultimately reaching both wildlife and people. He explains that long-range transport from industrial regions continues to make the Arctic a sink for contaminants, while climate change is altering how these substances circulate through ecosystems.

Sonne places PFAS within the context of the triple planetary crisis: climate change, biodiversity loss and pollution. These challenges interact rather than occur independently, affecting ecosystems, wildlife and Arctic communities simultaneously. As sea ice retreats and environmental conditions change, contaminant pathways and food webs also change, creating new patterns of exposure.

Marine mammals remain among the most highly exposed species because PFAS, mercury and legacy POPs biomagnify through Arctic food webs. Polar bears, seals and toothed whales accumulate particularly high concentrations, while Indigenous communities relying on traditional marine foods may also experience elevated exposure. In East Greenland, some communities consuming large amounts of polar bear meat have some of the highest PFAS concentrations measured in human blood.

Sonne also presents recent research demonstrating how climate-driven changes in polar bear diet may influence contaminant exposure. As declining sea ice alters prey availability, polar bears increasingly feed on different seal species carrying different contaminant burdens. This illustrates how climate change can affect pollutant exposure even when emissions of certain contaminants are declining globally.

Using polar bears as sentinel species, researchers are also investigating how PFAS may affect the brain, hormone regulation and behaviour. These studies help improve understanding of contaminant effects in wildlife while also providing valuable insights relevant to human health through a One Health approach.

Key takeaways from Segment 2

• PFAS adds to the risks already posed by legacy pollutants in Arctic ecosystems.
• Climate change, biodiversity change and pollution interact through the triple planetary crisis.
• Marine mammals and Arctic communities experience high exposure because contaminants biomagnify through food webs.
• Changes in wildlife diets can alter contaminant exposure despite declining emissions.
• One Health provides an important framework for understanding the links between ecosystems, wildlife and human health.

To sum it all up

Webinar #5 demonstrates that understanding pollution in the Arctic requires looking beyond individual chemicals. Legacy contaminants, PFAS and climate change interact in ways that influence both wildlife and human health, making exposure increasingly complex.

Together, the presentations by Pál Weihe and Christian Sonne highlight the value of long-term health studies, Arctic monitoring and One Health research. By connecting evidence from human cohorts, wildlife and changing ecosystems, they show why addressing Arctic pollution requires an integrated perspective that considers environmental, animal and human health together.