Last updated 21 December 2020

Capelin (Mallotus villosus) is an important species in the ecosystem of the Barents Sea and pollutants in capelin would rapidly be transferred upwards in the food chain. Capelin contain low levels of pollutants. There has been little change over time, with the exception of PBDE, which has declined.

Capelin stock in the Barents Sea
Photo: Institute of Marine Research

What is being monitored?

POPs in capelin

The levels of HCB, dieldrin and chlordane in 2013-2018 were generally lower than the maximum levels applying to animal feedin EC and Norway. Partly because of changed analytical methods, it is not possible to assess whether there has been any real change in the level of pesticides in capelin over time. HCB levels are well below the environmental quality standard (EQS) for HCB, which is 10 μg/kg wet weight.
(Cite these data: National Institute of Nutrition and Seafood Research (NIFES), Institute of Marine Research (2022). HCB, dieldrin and cis-chlordane in capelin. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL:

The data set shows levels of PBDE7 measured in capelin in the Barents Sea. PBDE levels in capelin are well above the environmental quality standard for PBDE6, which is 0.0085 μg/kg wet weight.
(Cite these data: National Institute of Nutrition and Seafood Research (NIFES), Institute of Marine Research (2022). PBDE7 in capelin. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL:

The cadmium level has been relatively stable since 2007, with concentrations well below the maximum level for animal feed (2 mg/kg feed product with 12 per cent water). In 2019, the mean cadmium concentration was around the mean for the entire period.
(Cite these data: National Institute of Nutrition and Seafood Research (NIFES) (2022). Cadmium in capelin. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL:

Details on these data

Last updated21 December 2020
Update intervalEvery 3rd year
Next updateDecember 2023
Commissioning organizationMinistry of Trade, Industry and Fisheries
Executive organizationInstitute of Marine Research
Contact personsSylvia Frantzen


The sampling is mostly performed by one of the vessels from the Institute of Marine Research.  

Aggregated samples of minimum 25 individuals or 1-2 kg capelin are analysed from each position. Homogenised samples are freeze dried prior to analysis.

To determine dioxins (PCDD), furans (PCDF), dioxin-like PCB (DL-PCB; non-ortho and mono-ortho PCB), non-dioxin-like PCB (NDL-PCB) and polybrominated diphenyl ether (PBDE), freeze-dried samples were mixed with Hydromatrix and added to the internal standard for PCDD/F, PCB and PBDE. The samples were extracted using hexane with Accelerated solvent Extractor-300 (ASE®). The fat was broken down on-line using sulphuric acid-impregnated silica gel in the cells. The extract was further cleansed chromatographically on columns packed with silver nitrate-silica gel, sulphuric acid-silica gel, carbon and alumina respectively using a GO-HT system. Two fractions were collected.

  • Fraction 1 contained mono-ortho PCB, NDL-PCB and PBDE.
  • Fraction 2 contained dioxins, furanes and non-ortho PCBs.

PCDD, PCDF and non-ortho PCB are analysed using HRGC/HRMS. Mono-ortho PCB, NDL-PCB and PBDE were analysed using GC-MSMS. All compounds are quantified using the isotope dilution/internal standard method. 

NDL-PCB comprised PCB 28, 52, 101, 138, 153 and 180, and PCB7 is the sum of these, plus PCB 118. Sum 7 PBDE (PBDE7) is the sum of PBDE 28, 47, 99, 100, 153, 154 and 183. For each of the 29 congeners of PCDD/F and DL-PCB, a toxic equivalent value (TE) was calculated by multiplying the concentration by the congener’s toxic equivalent factor (TEF) (2005-TEF, Van den Berg et al., 2006). The upper bound of the sum of the TE values was then calculated, with concentrations below the limit of quantification (LOQ) being set as equal to LOQ.

To determine per- and polyfluorinated alkyl substances (PFAS), the following method was used: The weighted sample quantity was added to the mass-marked internal standard and methanol, and extracted in an ultrasonic bath. Following centrifuging, the supernatant was filtered through a 0.45 μm nylon filter, before cleansing on ASPEC®. The extract from ASPEC was further cleansed by filtering through a 3K ultrafilter. Finally, the samples were analysed using LC-MS/MS and quantified using the internal standard. This method is accredited for various matrices such as fat and lean fish muscle and liver, but not for whole fish.

A single method was used which determines a number of chlorinated pesticides, and the analyses were carried out at Eurofins GfA Lab Service GmbH using their method no. GFB53. The analysis was performed using GC-HRMS based on an accredited method.

Hexabromocyclododecane (α, β, γ-HBCD) and tetrabromobisphenol A (TBBP-A) were analysed by Eurofins GfA Lab Service GmbH using method nos. GFB71-2 and GFB86-2. The determinations were carried out using LC-MS/MS based on a accredited method.

A series of metals/elements (e.g. arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), zinc (Zn), selenium (Se)) were determined by weighing the freeze-dried sample, adding nitric acid, and heating in a microwave oven in order to completely break down organic matter. The determination of the elements was carried out using an inductively coupled mass spectrometer (ICPMS), and element concentrations were calculated using an external standard curve. Rhodium, germanium, indium or thulium were used as internal standards, and gold was added to stabilise the mercury ions.

To determine polyaromatic hydrocarbons (PAH), the sample material was mixed with Hydromatrix and added to the internal standard, before being extracted using dichloromethane:cyclohexane (1:3) with ASE®. Fat was partially removed using silica gel in the ASE cell, and the extracts evaporated in Turbovap® and further cleansed in ASPEC®. The solvent was switched to isooctane and the samples were concentrated before being added to the recycling standard and analysed using GC-MSMS. A calibration curve was used for quantification.   


Analyse av samleprøver gir manglende informasjon om variasjon mellom fisk fanget ved hver posisjon og begrenser muligheten for statistisk behandling.

  • For practical reasons, the samples were taken from capelin in different locations in the Barents Sea, and sometimes at different times of the year. The results are therefore representative of the whole of the Barents Sea, but seasonal variations in particular can cause substantial variations in pollutant concentrations. This means that it will be difficult to detect any changes over time, and that differences between years cannot be interpreted as time series for changes in levels.
  • Nedre kvantifiseringsgrense (Level of Quantification – LOQ) og måleusikkerhet for enkeltparametere i analysemetodene er gitt i tabellen under. Når det er flere kongenere i gruppen gjelder kvantifiseringsgrense og måleusikkerhet for enkeltparametere.
  • For pesticidene (DDT, klordaner, dieldrin, HCH, HCB og toksafen) har det vært brukt ulike metoder i perioden overvåkningen har foregått. Nedre kvantifiseringsgrense har endret seg mye fra år til år. Grensene som er oppgitt her er de som benyttes i dag (per november 2020).
ParameterLOQMåleusikkerhet %Akkreditert?
ndl-PCB (28, 52, 101, 138, 153, 180)0,05 – 0,08 ng/g30Ja
Dioksiner, furaner og dl-PCB0,04 – 0,40 pg/g20 – 35Ja
PBDE (28, 47, 99, 100, 153, 154, 183)0,005 – 0,04 ng/g30 – 50Ja
PFAS0,5 – 10 ng/g30 – 80Nei*
DDT og metabolitter0,25 ng/g50Ja
Klordan (cis-, trans-, oksy-) og nonaklor (trans-)0,13 – 0,75 ng/g50Ja
Dieldrin0,38 ng/g50Ja
HCH (α, β, δ, γ)0,25 ng/g50Ja
HCB1 ng/g50Ja
Toksafen (26, 50, 62)1 ng/g50Ja
Heptaklor og heptaklorepoksid (cis-, trans-)0,25 – 1 ng/g50Ja
Endosulfan (αβ) og endosulfan-sulfat1 ng/g50Ja
HBCD (α, β, γ)0,006 pg/g40Ja
TBBP-A0,04 ng/g40Ja
PAH (16 EFSA PAH1)0,15 (0,752) ng30 (602)Ja (Nei2)
Cd0,005 µg/g30 – 403Ja
Hg0,005 µg/25 – 703Ja
Pb, As, Cu, Zn, Se0,01 – 0,5 µg/g30 – 403Ja
*This method is accredited for various matrices such as fish muscle and liver, but not for whole fish.

1Benz(a)anthracen, benzo(a)pyren, benzo(b)fluoranthen, benzo(c)fluoren, benzo(g,h,i)perylen, benzo(j)fluoranthen, benzo(k)fluoranthen, chrysen, cyclopenta(c,d)pyren, dibenz(ah)anthracen, dibenzo(a,e)pyren, dibenzo(a,h)pyren, dibenzo(a,i)pyren, dibenzo(a,l)pyren, indeno(1,2,3,-c,d)pyren, 5-methylchrysen.

2A higher LOQ and greater measurement uncertainty for dibenzo(a,e)pyrene, dibenzo(a,h)pyrene, dibenzo(a,i)pyre and dibenzo(a,l)pyrene. These analytes are not accredited.

3Depending on the concentration range, the measurement uncertainty is greater at concentrations close to the LOQ (<10 x LOQ) than at higher concentrations.

Reference level and action level

Reference values for the unaffected state of substances not found in the natural environment, like persistent organic pollutants, will be zero (really the detection limit). Since these are in practice widespread, it will be natural to compare the levels in capelin with those measured in other comparable species.

Action levels

Increase in the level of pollutants over a certain number of years, or a sudden increase from one sample to the next in the same area.

Should capelin be used directly for human consumption, it will be relevant to compare with the maximum levels applying to products intended for human consumption in the EU and Norway (EU 2006 and FOR 2002-09-27 no. 1028, see the reference list). There are three persistent organic pollutants on this list, sum of dioxins, sum of dioxins and dioxin-like PCBs and sum of six non-dioxin-like PCBs.

The maximum levels set for food and feedstuffs for fish, however, cannot be applied directly to the levels in the fish. This is because the fish undergoes an industrial process en route to fish meal and fish oil, and thence to feed, which can change the content of contaminants from the raw material. It is only when the Norwegian Food Safety Authority takes samples from ingredients like fish meal and fish oil or the finished feed product that the maximum levels are applicable and measures can be taken if the concentrations are too high.

Status and trend

Capelin from the Barents Sea generally have low levels of environmental contaminants. Cadmium levels have been relatively stable since 2007, with concentrations well below the limit for fish feed (2 mg/kg feed product with 12 per cent water). In 2019, the mean cadmium concentration was around the mean for the whole period.

Levels of dioxins and dioxin-like PCBs, such as PCB6 and brominated flame retardant (PBDE), were low during 2019, as in previous years.

There do not appear to have been any changes in the levels of dioxins and PCBs since monitoring began in 2007, while the level of PBDE has been lower since 2010. Nevertheless, PBDE levels in capelin are well above the environmental quality standard for PBDE6, which is 0.0085 μg/kg wet weight.

In 2017 and 2019, the levels of the brominated flame retardants HBCD and TBBP-A were also measured in capelin. Levels of α-HBCD were approximately equal to the level of total PBDE7, while TBBP-A was below the measurable level.
Levels of HCB, dieldrin, toxaphene, chlordane and α-HCH in 2013-2018 were generally lower than the limits set for the sale of feed. The exception was one sample in 2013 that had a toxaphene level of 7.2 µg/kg wet weight, while the limit converted to wet weight is 5.7 µg/kg. However, these limits only apply to capelin used as a raw material for the feed industry, without being first processed into fish meal and fish oil.

Levels of HCB were also well below the environmental quality standard of 10 μg/kg wet weight set for this substance. Other chlorinated pesticides for which there are environmental quality standards are endosulfan, heptachlor and heptachlor epoxide, as well as total DDT. Levels of heptachlor and heptachlor oxide are above the environmental quality standard, while the other substances are well below it.

Partly because different methods of analysis have been used, for some pesticides it is not possible to assess whether there have been any real changes in pesticide concentrations in capelin over time. For cis-Chlordane, the levels in capelin from 2014 onwards have been lower than previously.

Levels of all measured PFAS compounds were below the respective detection limits. This means that all samples are well within the environmental quality standard set for PFOA of 91.3 μg/kg wet weight.

During the period 2013-2019, PAH compounds in capelin were also analysed. Only a few of the substances showed measurable, but low, levels.

Causal factors

Capelin may have consumed contaminants which have originated locally or been transported to the Barents Sea via atmospheric and ocean currents. Some environmental contaminants may occur naturally rather than being caused by pollution. This applies for example to cadmium.

The levels of contaminants in capelin are affected by the levels in what the capelin eat, which are medium sized zooplankton. Capelin are thus at a relatively low level in the food chain. Together with a short lifespan, this contributes to the level of contaminants in general being relatively low in capelin.

The quantities of pollutants in capelin affect the level of pollutants in species which feed on the species, such as herring, cod, marine mammals and sea birds, as well as species higher up the food chain.


Capelin contain relatively low levels of environmental contaminants. There is no evidence of any increases in the pollutants which were analysed.

Levels of PBDE, heptachlor and heptachlor epoxide are consistently above the environmental quality standards for these substances. These are man-made substances which should not have been present in the environment at all. Environmental quality standards are set at a low level in order to protect the most vulnerable species at the top of the food chain, such as seabirds and marine mammals.

EU legislation:

Norwegian legislation:

About the monitoring

The indicator describes the level of pollutants in capelin and how this level changes over time.

Concentrations of pollutants in capelin from the Barents Sea were first analysed in 2000, and has been monitored by the Institute of Marine Research (HI) every year since 2007 (before 2018; National Institute of Nutrition and Seafood Research, NIFES).
The sampling is primarily carried out on the Institute of Marine Research’s winter expedition in January/February. In general, testing is performed at three different positions, often in different areas from year to year.

Places and areas

Data are collected to give a representative presentation of the situation for capelin in the Barents Sea, hence samples are taken at different positions every time. Each year, samples of capelin are taken at three  locations  in the Barents Sea.

Relations to other monitoring

Monitoring programme

International environmental agreements

  • None

Voluntary international cooperation

  • None

Related monitoring

Further reading



  1. Arneberg, P., van der Meeren, G., Frantzen, S., & Vee, I. (red.) (2020). Status for miljøet i Barentshavet – Rapport fra Overvåkingsgruppen 2020. Rapport fra Havforskningen 2020-13.
  2. Julshamn, K., Måge, A., Norli Skaar, H., Grobecker, K., Jorheim, L., & Fecher, P. (2007). Determination of arsenic, cadmium, mercury, and lead by inductively coupled plasma/mass spectrometry in foods after pressure digestion: NMKL Interlaboratory Study. Journal of Aoac International 90, 844–456.
  3. Van den Berg, M., Birnbaum, L. S., Denison, M., De Vito, M., Farland, W., Feeley, M., … & Peterson, R. E. (2006). The 2005 World Health Organization reevaluation of human and mammalian toxic equivalency factors for dioxins and dioxin-like compounds. Toxicological sciences93(2), 223-241.