Pollutants in Brünnich’s guillemots

Last updated 22 October 2025

Brünnich’s guillemot (Uria lomvia) is in steep decline. This species feeds on a range of key stone species in the ecosystem and serves as an important indicator of the state of the food web in the Barents Sea. Brünnich’s guillemot occupies the upper half of the food chain and primarily consumes small fish such as capelin and polar cod, as well as crustaceans. As a result, it is exposed to medium to high levels of environmental contaminants that biomagnifies in the food chain.

Status and trend

The level of PCB is presented in MOSJ as the concentration of PCB-153, the most stable congener of PCB. There is a strong correlation between PCB-153 and other PCBs, so the concentration of PCB-153 provides an accurate picture of the overall PCB levels in Brünnich’s guillemots.

Results show that PCB-153 levels have significantly declined due to international measures restricting the use of the compound. Measurements of PCB in Brünnich’s guillemot eggs began in 1993 in Kongsfjorden, and the decline was more pronounced up to 2007 compared to the years following. The decline at Bjørnøya has followed the same trend since monitoring began there in 2003. Levels of oxychlordane in eggs from 1993 to 2022 have also decreased in both Kongsfjorden and Bjørnøya.

There has been a marked reduction in β-HCH levels in eggs from 1993 to 2023. For HCB, an increase was observed between 1993 and 2014, but levels appear to have declined after 2014. Levels of DDE, a breakdown product of the pesticide DDT, were halved in eggs from Kongsfjorden between 1993 and 2007. From 2007 to 2022, DDE levels have shown a smaller reduction, most clearly in samples from Bjørnøya (data up to 2018).

PFOS is a stable perfluoroalkyl and polyfluoroalkyl substance (PFAS) in the environment. Industry has reduced PFOS production since the early 2000s, and PFOS was included in the Stockholm Convention in 2009. PFOS has been monitored in Brünnich’s guillemot eggs from 1993 in Kongsfjorden and from 2003 at Bjørnøya. Although levels vary slightly over time, there is a gradual decrease in PFOS concentrations in the eggs.

Causal factors

Brünnich’s guillemot occupies the upper half of the food chain and is therefore exposed to medium to high levels of environmental contaminants that accumulate in the food web. This explains the presence of stable organic pollutants such as PCB, oxychlordane, HCH, DDE, and HCB in the species. The reason these substances show varying degrees of decline from 1993 to 2022 is due to international regulation of these pollutants.

Strong measures have been implemented to limit emissions and the spread of PCBs and chlordanes. Efforts to regulate PCBs and chlorinated pesticides began in the late 1970s, and the international ban on these substances came into effect in 2004 through the Stockholm Convention. As a result, the main sources of emissions have ceased. These substances still persist in the environment because they degrade very slowly and bioaccumulate in the food chain.

The Stockholm Convention also regulates the international ban on the production and use of DDT (precursor to ppDDE), HCB, and HCH. Most Western countries introduced strict regulations on DDT already in the late 1960s and early 1970s. The use of HCB as a fungicide is prohibited, and industrial controls have reduced emissions. Lindane, which consists of an HCH mixture, was permitted in Norway until 1992. Around the year 2000, technical HCH and lindane were also banned in China and France, which were the main user countries in the late 1990s.

Production and use of other pollutants and PFOS have been restricted over the past 15–20 years. PFOS was included in the Stockholm Convention in 2009.

Consequences

The current concentrations of organic pollutants and mercury found in Brünnich’s guillemots is not considered to have negative effects on the health or reproduction of the birds.

No hunting of or collecting of eggs from Brünnich’s guillemots is permitted. Therefore, contaminant levels in this species have not been a concern in relation to food safety.

About the monitoring

Brünnich’s guillemot is an auk species with a northern circumpolar distribution. In the Northern Hemisphere, it is one of the most numerous seabirds, but the population on Svalbard has declined severely for more than 25 years. Due to this decline, the species is included in the Norwegian Red List for Species 2021 and is classified as Vulnerable (VU) on Svalbard and Critically Endangered (CR) in mainland Norway.

Brünnich’s guillemot primarily feeds on fish and crustaceans. It has been selected as an indicator species for monitoring pollutants in fish-eating seabirds, as it is important to understand contaminant levels throughout the Arctic food web. The substances included in the monitoring are organic pollutants and PFOS, which are found throughout the environment even though many are no longer in use.

Further reading