Last updated 4 December 2018

The polar cod (Boreogadus saida) feeds on large plankton, and is an important food item for other fish such as cod, and for seals, whales and sea birds. Tests taken during the last few years have shown that the levels of environmental contaminants in polar cod in the Barents Sea are very low.

Pollution in Arctic cod
Photo: Peter Leopold / Norwegian Polar Institute

What is being monitored?


POPs in polar cod

Among the chlorinated pesticides, HCB and dieldrin are among the few that have been found in measurable levels during the whole period. The levels have varied greatly, and in 2018 the average HCB level was higher than measured previously.
(Cite these data: National Institute of Nutrition and Seafood Research (NIFES), Institute of Marine Research (2022). HCB and dieldrin in polar cod. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL: http://mosj.no/en/influence/pollution/pollutants-polar-cod.html)


The total level of sum PBDE7 in 2018 was less than a third of the level in 2006. The level of PBDE in polar cod is however clearly above the environmental quality standard (EQS) for PBDE6 at 0.0085 µg/kg wet weight.
(Cite these data: National Institute of Nutrition and Seafood Research (NIFES), Institute of Marine Research (2022). Brominated flame retardants (PBDE7) in polar cod. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL: http://mosj.no/en/influence/pollution/pollutants-polar-cod.html)

Details on these data

Last updated13 December 2018
Update intervalYearly
Next update2024
Commissioning organizationMinistry of Trade, Industry and Fisheries
Executive organizationInstitute of Marine Research
Contact personsSylvia Frantzen

Method

Environmental contaminants in polar cod has been monitored by the National Institute of Nutrition and Seafood Research (NIFES) every year since 2006. Sampling is primarily carried out during the Norwegian Institute of Marine Research ecosystem missions during the spring and autumn. In general, sampling is carried out at three different positions, often in different areas from year to year.

The following environmental contaminants are analysed every year:

  • metals: including arsenic, cadmium, copper, lead, mercury
  • organic pollutants: including PCB7, brominated flame retardants (PBDE), dioxins and PCB’s.
  • a number of pesticides: including DDT and its metabolites, HCB, HCH, chlordane and toxaphene
  • per- and polyfluorinated alkyl compound (PFAS) (some years)

Quality

Sampling of environmental contaminants is performed in different parts of the Barents Sea. The results are therefore representative of the whole of the Barents Sea. The amount of environmental contaminants in polar cod can vary a great deal throughout the year and sampling is performed at different times of the year. This means it can be difficult to detect any changes over time.

Reference level and action level

Reference level for an unaffected condition of pollution of substances that are purely man-made will be equal to zero (detection limit). For naturally occurring substances reference level will be the natural background level.

Action limits:

If polar cod is to be used directly as food for humans, EU and Norway’s maximum levels set for food safety will be relevant (Commission Regulation (EC) 1881/2006 and Forskrift 03.07.2015 nr. 870 om visse forurensende stoffer i næringsmidler). These maximum levels exist for cadmium, mercury, lead, sum of dioxins and furans, sum of dioxins and dioxinlike PCB and the sum of non-dioxinlike PCBs (PCB6).

Maximum levels for feed and feed materials (Directive 2002/32/EC) can be used to assess the levels in polar cod if they are used as raw material for feed production, but this must be done with caution. The reason is that the fish goes through an industrial preparation to fish meal and –oil and subsequently to feed, which will change the content of contaminants from the raw material to the final feed product. It is only when the Food Safety Authority sample ingredients such as fish meal and fish oil or the final feed product that the maximum levels are applied in practice.

The water management regulation (Water Management Regulation 15.12.2006 no. 1446) has defined a set of EU defined threshold limits called environmental quality standards, EQS (Directive 2008/105/EC). Norway has in addition defined their own EQS values for substances and media not covered by the EU’s list. EQS is applied as a common term for both sources. Even if a fish contains contaminant levels exceeding the EQS, it does not mean that the fish itself is harmed, but it shows that the level is high enough that other parts of the ecosystem may be harmed, such as sea mammals feeding on polar cod.


What is being monitored?


Heavy metals in polar cod

The level of cadmium in whole polar cod has been above the EU and Norwegian maximum level for food safety during the period 2012-2016 and for several earlier years. In 2017 and 2018, however, the average level was below the maximum level. The levels of lead and mercury were low in 2018, as in earlier years. For most of the years we have data for, the levels have been either close to or below the lowest measurable levels. Hence, mercury was also well below the EQS for mercury of 0.02 mg/kg.
(Cite these data: National Institute of Nutrition and Seafood Research (NIFES), Institute of Marine Research (2022). Mercury, cadmium and lead in polar cod, wet weight. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL: http://mosj.no/en/influence/pollution/pollutants-polar-cod.html)


The level of arsenic in Polar cod has varied since 2006, with the highest levels in 2009 and 2011 and lowest in 2007-2008 and 2012-2013. Levels of copper have not varied as much as arsenic.
(Cite these data: National Institute of Nutrition and Seafood Research (NIFES), Institute of Marine Research (2022). Arsenic and copper in Polar cod. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL: http://mosj.no/en/influence/pollution/pollutants-polar-cod.html)

Details on these data

Last updated13 December 2018
Update intervalYearly
Next updateJanuary 2023
Commissioning organizationMinistry of Trade, Industry and Fisheries
Executive organizationInstitute of Marine Research
Contact personsSylvia Frantzen

Method

Environmental contaminants in polar cod has been monitored by the National Institute of Nutrition and Seafood Research (NIFES) every year since 2006. Sampling is primarily carried out during the Norwegian Institute of Marine Research ecosystem missions during the spring and autumn. In general, sampling is carried out at three different positions, often in different areas from year to year.

The following environmental contaminants are analysed every year:

  • metals: including arsenic, cadmium, copper, lead, mercury
  • organic pollutants: including PCB7, brominated flame retardants (PBDE), dioxins and PCB’s.
  • a number of pesticides: including DDT and its metabolites, HCB, HCH, chlordane and toxaphene
  • per- and polyfluorinated alkyl compound (PFAS) (some years)

Quality

The laboratory at the National Institute of Nutrition and Seafood Research (NIFES) is accredited in accordance with ISO 17025, but not all the methods are accredited yet.

Reference level and action level

The maximum level in the EU and Norway for trade in fish for human consumption is 0.5mg/kg wet weight (EU 2006 and FOR 2002-09-27 no. 1028).

The maximum level in the EU and Norway for feed manufactured from fish or other marine animals is 0.5mg/kg (EU 2002 and FOR 2002-07-07 no. 1290).

Status and trend

The level of cadmium in whole polar cod varies considerably, and was above the EU and Norwegian maximum level for food safety during the period 2012-2016. The last two years, in 2017 and 2018, the levels were again lower and below the maximum level. Cadmium mainly accumulates in the internal organs, and much less in muscle. This can explain why levels are high when whole fish have been analysed. Maximum levels set for food safety will apply to whole fish if whole fish is to be consumed.

The levels of lead and mercury were low in 2017 and 2018, as they were in earlier years. For most of the years from which we have data, the levels have been either close to or below the quantifying limits. Mean mercury levels were most years below the EQS of 0.02 mg/kg.

The level of arsenic in polar cod has varied since 2006, with the highest level in 2009 and 2011 and lowest in 2007-2008 and 2012-2013.

The level of persistent organic pollutants in samples taken of whole polar cod were very low from 2006 to 2018. None of the compounds were above the maximum levels for food. There were no observable increasing or decreasing trends during the period, with the possible exception of brominated flame retardants (PBDEs), which have shown a decreasing trend since monitoring started in 2006. In 2018, the total level of sum PBDE7 was less than a third of the level in 2006. The level of PBDE in Polar cod is however clearly above the EQS for PBDE6 at 0.0085 µg/kg wet weight. The level of PCB7 was above the EQS of 1 µg/kg wet weight in 2015 and 2016, but not in 2017 or 2018.

The samples of polar cod have had quantifiable levels of HCB, dieldrin and DDT during the entire 2006-2018 period (not analysed during 2010 and 2017). In 2018, the level of HCB was higher than earlier, averaging 1.9 µg/kg, which still is well below the EQS. The levels of HCH have been below or just above the quantification limit. The levels of chlordane and toxaphene have varied from below the quantification limit up to 2.8 and 3.4 µg/kg wet weight, respectively. However, due to the fact that the analytical methods have varied between years, direct interannual comparisons of levels of pesticides in polar cod are not possible.

The levels of PFAS in whole polar cod were below or just above quantifiable levels during the entire period through 2017, while two samples from 2017 had detectable, but low, levels.

polar cod were analysed for PAH compounds from 2014 on. Most of the years there were no measurable levels of the compounds, however one composite sample in 2018 had measurable, but low, levels of several PAH compounds.

Causal factors

polar cod may have consumed pollutants originated from local pollution or transported to the Barents Sea via atmospheric and ocean currents. Some compounds, such as cadmium, can occur naturally in the environment, and measured levels in biota thus may not necessarily stem from pollution.

The amount of contaminants in the polar cod is influenced by the amount of contaminants in the food it consumes. The polar cod consumes moderately large zooplankton, and is therefore at a relatively low level of the food chain. Together with a short lifespan, this contributes to the amount of polluting substances in general being fairly low in Polar cod.

The levels of persistent organic polluatants in polar cod were very low during the whole period from 2006 to 2018. With regard to brominated flame retardants (PBDE) levels appear to have decreased since monitoring started in 2006 until 2016. A possible reason for this may be a reduced usage of these compounds following a prohibition issued by the EU from 2004.

Consequences

The levels of cadmium and arsenic in polar cod have varied since 2006. The levels of cadmium in polar cod were above the EU and Norwegian maximum levels for food safety during the period 2012-2016, but not in 2017 and 2018. The maximum level only applies to the edible parts of the fish, but it applies to while fish if whole fish is to be consumed. At present there are no Polar cod fisheries, neither by Norwegian nor Russian vessels.

The levels of contaminants are therefore so low that it is of no concern for food safety. But contaminants in polar cod will be transferred to and can affect species that feed on it, such as cod, marine mammals and sea birds, as well las species even higher in the food chain. Of the substances that have been measured in quantifiable amounts, only PBDEs exceed the EQS, which has been set particularly low for PBDE.

About the monitoring

The indicator describes the levels of environmental contaminants in polar cod and how these change over time.

Contaminants in polar cod has been monitored annually since 2006 by the Norwegian Institute of Marine Research (previously the National Institute of Nutrition and Seafood Research).

Sampling is primarily made during the Institute of Marine Research ecosystem cruises in the Barents Sea during late winter and autumn. In general, sampling is performed at two or three different positions, often in different areas from year to year.

Places and areas

  • Barents Sea
    During one year, samples of polar cod are taken from 2-3 positions at different locations in the Barents Sea. As it was difficult to obtain samples the first two years, polar cod were taken from only one position then.

Relations to other monitoring

Monitoring programme

International environmental agreements

Voluntary international cooperation

  • None

Related monitoring

  • None

Further reading