Pollutants in char (Salvelinus alpinus)

Arctic char with lure
Photo: Guttorm Christiansen / akvaplan-niva

Pollutant levels in char are generally low in the Arctic. Some of the highest PCB values in arctic freshwater fish are, nevertheless, measured in stationary char from Ellasjøen, a lake on Bjørnøya. There are two reasons for these high levels. The largest and oldest fish eat younger char. In addition, guano from seabirds reaches Ellasjøen, making char in this lake particularly exposed.

What is being monitored?

Pollutants in char from Ellasjøen, Bjørnøya

Loading chart ...

The figure shows organic pollutants in char from two lakes, Laksvatn and Øyangen, on Bjørnøya. The data show an overall decline for all the substances except HCB, which is rising.

Loading chart ...

The figure shows organic pollutants in char from two lakes, Laksvatn and Øyangen, on Bjørnøya. Click on the name of the substance and/or the margin of error to view or conceal the data. The data show an overall decline for all the substances except HCB, which is rising.

Loading chart ...

The figure shows organic pollutants in char from the lake Richardvatnet on Spitsbergen. The data show that all the substances are declining, but with only two measurement points the year-to-year variation is uncertain.

Status and trend

The amount (concentration) of organic pollutants, PCBs (industrial chemicals), DDT, HCB, toxaphene (herbicides) and the brominated flame retardant PBDE-47, is declining in general in the environment. This is because agreements have nationally and internationally regulated the use and discharge of these substances. In most cases, there is a total ban on their manufacture and use, but some exceptions exist. The Stockholm Convention regulates the manufacture and use of organic pollutants.

The figures show that the concentrations in Øyangen/Laksvatn on Bjørnøya have dropped. In 2009, they were around 10–30 % of what they were in 1996, except for HCB, whose concentration is unchanged.

We do not see this pattern in Ellasjøen, which is situated 4 and 10 km south of Øyangen/Laksvatn, respectively. Here, there is no change in the concentration between 1996 and 2009, except for the brominated flame retardant PBDE-47, which was halved from 1999 to 2009. Ellasjøen has, in general, a much higher level of organic pollutants than Øyangen/Laksvatn. In 2009, the figures for the various substances show that there are 10–100 times more pollutants in fish from Ellasjøen than in fish from Øyangen/Laksvatn. Several factors explain this difference. Ellasjøen has a larger catchment area than Øyangen/Laksvatn. It also receives more precipitation due to the hills in the south of the island. Ellasjøen is deeper so that the circulation time in the lake is longer. However, the most important factor is that large numbers of seabirds deposit guano in the catchment area and directly into the lake. A large colony of little auks nests in the scree above the lake, and seabirds like kittiwakes and glaucous gulls use Ellasjøen to wash and rest. Organic pollutants are transported from the marine environment to Ellasjøen in this way.

Causal factors

The reason for the decline of organic pollutants in the environment is their reduced use and discharge, because many of them are regulated. We see a reduction of most of the organic pollutants in char in all the three lakes that are monitored, the exception being HCB which is rising in Ellasjøen and Laksvatn on Bjørnøya. Moreover, the reduction is not as distinct in Ellasjøen. There are probably several reasons why the pattern for Ellasjøen differs from that in the other lakes. Ellasjøen differs from other lakes on Bjørnøya and elsewhere in Svalbard in several ways; it is deep, it receives more precipitation than other parts of Bjørnøya and Svalbard, and there is a new supply of pollutants from run-off from old and new guano (seabird impact). This, combined with the substances being stable and the life span of char being long (char can be 25 years old), means that it takes time for the pollutant concentrations in char to drop.

Consequences

The total load of pollutants in Ellasjøen, Bjørnøya, impacts on the enzyme system (EROD, CYP1A) which is involved in the degrading of pollutants and disturbs the sexual hormones (induction of vitellogenin) (Wiseman et al. 2011).

About the monitoring

The char is the only freshwater fish in Svalbard and Jan Mayen. In most lakes, it is stationary and is affected by pollutants transported in the atmosphere from inhabited areas on the continents. Some lakes are located such that char can migrate to the sea in the summer to feed and return as anadromous fish in the autumn. They may thus be affected by pollutants in the sea and the lake. The impact of both long-transported and marine pollutants can be monitored in carefully selected lakes.

Places and areas

Relations to other monitoring

Monitoring programme
International environmental agreements
Voluntary international cooperation
Related monitoring