Levels Of Dioxin High In Greenland Halibut

NIFES has initiated a comprehensive mapping of the background levels of different environmental pollutants in Norway’s most important commercial fish stocks, referred to as baseline studies.

Greenland halibut is the second species that the institute has established a baseline study for, following one conducted on Norwegian Spring Spawning Herring.

The baseline study on Greenland halibut shows that the levels of dioxins and dioxin-like PCBs, as well as mercury are high in fish from several locations.

However, when the results are evaluated as lots in accordance with EU legislation the levels of dioxin and dioxin-like PCBs in Greenland halibut exceed EU’s upper limit, at two positions northwest of Traenabanken and one in Eggakanten outside Lofoten.

A total of 1288 Greenland halibut from 27 locations from four areas; south of Lofoten, Lofoten to Tromsoeflaket, East-Finnmark and West of Bjoernoeya towards Svalbard have been collected and analysed for several environmental pollutants. Between 30 – 55 fish were collected from each location.

Baseline studies are carried out in order to get a comprehensive overview of the levels of environmental pollutants in seafood from Norwegian waters, and are tools to ensure an appropriate surveillance of species in the future.

The fish sampling system is tailored with this in mind, and therefore deviates from the requirements set by EU-legislation, used to evaluate food safety and assess the necessity of actions in order to meet potential challenges.

Legislation states that measurement uncertainty should be subtracted from an analytical result before comparing the value to EU’s upper limits for environmental pollutants in food. This is done in order to ensure that levels which exceed the EU`s upper limit, do so without ‘reasonable doubt,’ and to ensure that any actions is based on a high level of certainty.

In addition, EU-legislation states that pooled samples of five fish should be taken when a catch is between 50 and 500 kg. The analytical results in the present report on Greenland halibut have generally been presented without subtracting the measurement uncertainty.

In order to evaluate the results according to EU-legislation, several calculations have been presented in an Appendix of the report. These has been sent to the Norwegian Food Safety Authority to take appropriate actions.

When the measurement uncertainty is subtracted from the analytical data, there appears to be no samples which exceed the EU’s upper limit for mercury in fish of 0.5 mg/kg wet weight.

However, there are samples from five locations which exceed EU’s upper limit for dioxins and dioxin-like PCBs. The probability of identifying a sample which exceeds EU’s upper limit for the sum of dioxins and dioxin-like PCBs of 8 ng TEQ/kg wet weight in a catch is; approximately six per cent for two of the locations, approximately 35 per cent for one, around 31 per cent for another and 13 per cent at the last.

The levels of other environmental pollutants which were analysed, for example arsenic, cadmium and lead, are generally low in Greenland halibut, and are not a concern for seafood safety.

One of the objectives of the baseline studies on fish is to determine the strategy for future surveillance of environmental pollutants in a given species.

The results for Greenland halibut suggest that surveillance should be annual, and 30 fish should be sampled from a total of 10 locations.

Eight sampling locations should be in the area from 70 oN and 63 oN (from Vesteraalen and going south), and two locations in the area west of Bjørnøya to Svalbard.

This will enable spatial and temporal monitoring of the content of mercury and dioxins, and dioxin-like PCBs. Greenland halibut is also an important species in the integrated management plan of the marine environments of the Barents Sea and the Norwegian Sea (White paper 37 2008-2009).

The proposed monitoring programme will also support the management project already underway for this area.