Pollutants in Brünnich’s guillemots (Uria lomvia)

Brunnichs guillemot at sea
Photo: Stein Ø. Nilsen / Norwegian Polar Institute

The population of Brünnich’s guillemot has suffered a serious decline over the last decade, due to partially unknown reasons. It is an important indicator for monitoring the status of the food chain in the Barents Sea, as it is very numerous and preys on several key species in the ecosystem. The Brünnich’s guillemot mainly eats small fish like capelin and polar cod, and crustaceans. As it is not a top predator, it is less exposed to pollutants.

What is being monitored?

Persistent organic pollutants in Brünnich’s guillemots eggs

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The figure shows the trend in the content of organic pollutants in Brünnich’s guillemot eggs on Bjørnøya since 2003. The levels of PCB, oxychlordane and HCH are halved, whereas the brominated flame retardant, PBDE-47, is now a third of what it was before monitoring began in 2003. The consentrations of DDT and its breakdown product, DDE, have also declined. International bans or restrictions have been introduced on the use of most of these substances. However, the level of another pollutant, HCB, increased until 2014. This may be because HCB is to some extent still reaching the natural environment as a by-product of other chlorinated chemicals and climate change may be helping HCB to leak from secondary sources such as the soil and ice in the Arctic.

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The figure shows that the content of many pollutants which were previously in use has declined in Brünnich’s guillemot eggs from Kongsfjorden in Svalbard in the past 20 years. For instance, the level of PCB-153 has declined by a third since 1993. The reduction has gradually flattened out to some extent, but is still distinct in 2014. A corresponding trend over the past 20 years is seen for the other organic pollutants, except HCB. The reduction is due to measures that have been put in place, such as international bans. The reason why HCB is not declining may be that climate change is helping HCB to leak from secondary sources like the soil and ice in the Arctic, in addition to HCB being a byproduct in the production of other chlorinated chemicals.

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The concentration of PFOS in Brünnich’s guillemot eggs from Kongsfjorden is reduced by 46.8% from 2012 to 2013. PFOS is only measured in eggs from Evjebukta, Bjørnøya, in 2013 and the concentration is higher than that detected in eggs from Kongsfjorden in the same year. This could be due to Brünnich’s guillemots from Bjørnøya being exposed to higher levels of PFOS through their diet, but this remains uncertain.

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The level of PFOA in Brünnich’s guillemot eggs sampled in Kongsfjorden is reduced by 12.2% from 2012 to 2013. PFOA is only measured in eggs from Evjebukta, Bjørnøya, in 2013 and the concentration is higher than that measured in eggs from Kongsfjorden in the same year. This could be due to Brünnich’s guillemots from Bjørnøya being exposed to higher levels of PFOA through their diet, but this remains uncertain.

Mercury (Hg) in Brünnich’s guillemot eggs

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The figure presents concentrations of mercury in eggs from Brünnich's guillemot in Svalbard and Bjørnøya. In general, the concentration of mercury in Brünnich's guillemot is low. The concentration of mercury in eggs from Kongsfjorden increased from 2012 to 2013 by 30% while the level of mercury in eggs from Bjørnøya remained stable in that same time period. More data is required in order to determine whether the increase in mercury concentration in eggs from Kongsfjorden is due to random fluctuations or an increase.

Status and trend

The level of PCB is shown in MOSJ as the concentration of PCB-153, the most stable variant of the 209 possible PCBs. There is a very good link between PCB-153 and the other PCBs. The concentration of PCB-153 therefore gives a correct picture of the trend of the PCB levels in Brünnich’s guillemots.

The results show that PCB-153 have been reduced significantly in eggs as a result of international bans. The reduction is most profound in the measurements from Kongsfjorden and Krossfjorden, but is also evident from Bjørnøya. The levels of PCB in eggs were 3 times higher in 1993 than in 2007.

Levels of DDE, a metabolite of the insecticide DDT, have halved from 1993 to 2007. There is also a slight reduction in the concentration of DDT in eggs from both Kongsfjorden and Bjørnøya, and the level of DDT is considerably lower than that of DDE.

Levels of the brominated flame retardant PBDE-47 in Brünnich’s guillemot eggs was 5 times higher in 1993 than in 2007. PBDE-47 is a stable component in penta-BDE, a compound which was the first whose use was regulated just after the year 2000.

Levels of oxychlordane show a large reduction from 1993 to 2014.

PFOS is the most stable of the perfluoroalkyl and polyfluoroalkyl substances (PFASs) in the environment. After it was realised that PFASs were taken up in the environment, the industry has reduced their manufacture and an international ban is being considered. PFOS has been reported in both lipid weight (lw) and wet weight (ww) and those two cannot be directly compared to each other. The reduction of PFOS (lw) from 2002–2003 to 2007 may be a result of less being manufactured and used, although there is an increase again in 2014. Overall there are only four points of data and thus no conclusion regarding the time trend can be drawn yet. PFOS (ww) decreased from 2012 to 2013 in eggs sampled in Kongsfjorden. Similarly, PFOA (ww) decreased in Brünnich’s guillemot eggs from Kongsfjorden from 2012 to 2013. In both these cases there are only two points of data and consequently not enough data to draw any conclusion from.

There is an increase in concentration of HCB in Brünnich’s guillemot eggs from 1993 to 2014.

The concentration of HCH in Brünnich’s guillemot eggs was considerably reduced from 1993 to 2014.

The concentration of mercury in Brünnich’s guillemot eggs sampled from Kongsfjorden and Bjørnøya is low. There is a slight increase in mercury levels from 2012 to 2013 in eggs from Kongsfjorden, but more data is required before any conclusions regarding a time trend is possible.

The first time the pollutants PCB and DDT were found in Brünnich’s guillemots was in birds from Bjørnøya in 1972. The same study also revealed these pollutants in glaucous gulls. Their concentrations, however, were more than 100 times higher in glaucous gulls. This difference remains little altered to the present day because the glaucous gull eats higher in the food chain and thus acquires more pollutants.

In general, samples from Brünnich’s guillemot eggs collected in 1993, 2003, 2007 and 2014 show that the concentrations of PCB, chloro-organic pesticides (DDT/DDE, oxychlordane and HCH), brominated flame retardants (PBDE-47) and the heavy metal, mercury, have declined in Brünnich’s guillemots. The pesticide, HCB, which may also be a by-product of industrial processes, and the PFASs, PFOS and PFOA, show no clear trends.

 

Causal factors

The Brünnich’s guillemot is in the upper part of the food chain and will therefore be exposed to medium to high levels of pollutants which become more concentrated higher up in the food chain. This explains why the persistent organic pollutants, such as PCB, DDT, chlordane, HCB, bromide and fluoride compounds are found in Brünnich’s guillemots. The reason why most of the substances show a more or less marked decline from 1993 to 2014 is the introduction of national and international regulations of these pollutants. Very many western nations banned DDT in the early 1970s. New uses for PCB were banned in most western countries in the early 1980s. In addition, many countries placed focus on dealing with PCB in waste materials during the out-phasing period, and this was probably important since PCB was used in very large quantities and in many products.

The Stockholm Convention concerning persistent organic pollutants was ratified in 2004. It regulated 12 of the worst organic pollutants, and nine new substances were added in 2009. Work is continually taking place to assess new substances and implement their inclusion in the Convention, where PFOA is under consideration of inclusion.

Mercury (Hg) is a highly poisonous heavy metal which reaches the atmosphere from a number of natural sources like volcanoes, forest fires and evaporation from the sea. The most important anthropogenic sources are the burning of coal and rubbish. The anthropogenic emissions have been reduced in North America and Europe since the 1990s, whereas those in Asia have risen. This reduction in the emissions explains why the values in Brünnich's eggs are as low as they are. However, it is important to keep track of the levels because the emissions from Asia are continuing and mercury is transported over long distances in the atmosphere.

Consequences

There is no reason to assume that the present concentrations of organic pollutants and mercury found in Brünnich’s guillemots will have negative effects on health or reproduction.

As it is not permitted to either hunt Brünninch’s guillemots or collect their eggs, pollutant levels in this species have not been a topic in relation to food safety.

About the monitoring

The Brünnich’s guillemot is a member of the auk family and has a northern circumpolar distribution. It is one of the most abundant seabird species in the Northern Hemisphere, but its population in Svalbard has suffered a serious decline over the last decade, causing it to be categorised as Vulnerable on the 2015 version of Norwegian Red List and Near Threatened on the Svalbard Red List.

The Brünnich’s guillemot mainly eats fish and crustaceans. It has been selected as an indicator species to monitor pollutants in fish-eating seabirds because it is important to know the pollutant levels in every part of the arctic food chain. The monitored substances are organic pollutants and mercury, which are found throughout the environment, even though many are no longer in use.

Places and areas

Relations to other monitoring

Monitoring programme
International environmental agreements
Voluntary international cooperation
Related monitoring