PCB concentrations in fish muscle/liver

	Authors: Anders Bignert, Sara Danielsson, Suzanne Faxneld, Elisabeth Nyberg. The Department of Contaminant Research, Swedish Museum of Natural History

Key message

sPCB concentrations show significant declining trends in the investigated biotic matrices as a result of measures taken to reduce discharges of PCB to the environment. The concentrations are still significantly higher in the Baltic Proper and in the southern Bothnian Sea compared to the Kattegat and the Skagerrak (based on data from the Swedish Monitoring Programme).

Figure 1. Spatial variation in arithmetic mean concentration (2008-2010 in ng/g lipid w.) of CB-153 in herring muscle. The highest concentration (169 ng/g) was found in the northern parts of the Baltic Proper (Lagnö) and the lowest (17 ng/g) was found close to the Bay of Gdansk. The Swedish data originates from the Swedish national monitoring programme and are analysed at the Department of Applied Environmental Science, Stockholm University. Additional data is obtained from ICES database. 

Results and assessments

Relevance of the indicator for describing developments in the environment

PCB concentration in tissues from various species show coherent trends of similar magnitudes from various regions. The investigated species are commonly used for human consumption.

Policy relevance and policy references

The Helsinki Convention (HELCOM) revised 1992 especially names PCB for which special bans and restrictions on transport, trade, handling, use and disposal are imposed. The Minister Declaration from 1988, within HELCOM, calls for a reduction of stable organic substances by 50% by 1995 with 1987 as a base year. The Minister Declaration from 1996, within HELCOM, and the declaration in Esbjerg 1995, calls for measures for toxic, persistent, bioaccumulating substances to have ceased completely in the year 2020.

PCBs are also included in The Stockholm Convention on Persistent Organic Pollutants (POPs), an international agreement, requiring measures for reducing or preventing releases of dangerous substances to the environment.

Assessment

The concentration of sPCB (sum of PCB’s estimated from CB-138 or peak 10 from packed column chromatography) in herring muscle from all herring sites in the Baltic show significant decreasing trends during the time period 1978/80-2010. The rates vary between -5.2 and -8.1% per year. This implies a total decrease of about 85% at Ängskärsklubb and about 70% at Utlängan, of the PCB-concentration in herring muscle, since the end of the seventies. The highest concentration (2008-2010) of PCB-153 in herring muscle (169 ng/g) was found in the northern parts of the Baltic Proper and the lowest concentration (17 ng/g) was observed close to the Bay of Gdansk.

The two cod liver time-series from south east of Gotland in the Baltic Proper and Fladen at the west coast, show significant decreasing trends of sPCB at the rate of about -5% per year (1980-2010).

Figure 2. Temporal trends of sPCB concentration (ug/g lipid w.) in herring muscle (1978/80-2010). Harufjärden (Bothnian Bay), Ängskärsklubb (S. Bothnian Sea), Landsort (N. Baltic Proper), Utlängan (S. Baltic Proper) and Fladen (Kattegat).  The red linear lines presented in the figure are based on a log-linear regression analysis and shows decreasing trends of between -5.2 and -8.1% per year. A red linear line is also presented if there is a significant trend over the last ten years. The non-linear red line (p<0.05) and blue dashed line (0.05<p<0.1) are simple 3-point running mean smoothers fitted to the annual geometric mean values. The horizontal line is the mean concentration over the whole period. A red cross represents a suspected outlier.

Figure 3. Temporal trends of sPCB concentration (ug/g lipid w.) in cod liver (1980-2010) from the southern Baltic Proper (SE Gotland) and from Kattegat (Fladen). The red linear lines presented in the figure are based on a log-linear regression analysis and show decreasing trends of -5.4 and -4.5% per year respectively. The red non-linear lines are simple 3-point running mean smoothers fitted to the annual geometric mean values. The horizontal line is the mean concentration over the whole period. A red cross represents a suspected outlier.

References

Bignert, A., Berger, U., Borg, H., Danielsson S., Eriksson, U., Faxneld, S., Haglund, P., Holm, K., Nyberg, E., Nylund, K. 2012. Comments Concerning the National Swedish Contaminant Monitoring Programme in Marine Biota. Report to the Swedish Environmental Protection Agency, 2012. 228 pp.

Data

Trend (in %) assessed from the annual geometric mean of concentrations of sPCB (mg/g lipid weight) in various matrices and sites during the time period 1978/80-2010 and the estimated mean concentration for the last year (2010). The trend is reported, if p<0.1. The age interval, the total number of analyses and the number of years are also presented. The numbers presented in brackets are the 95% confidence intervals.

* significant trend, p < 0.05

Metadata

Technical information

Data source: The ICES database and results from the National Swedish Monitoring Programme of Contaminants in Biota. Data from the ICES data base has been recalculated from fresh weight basis to lipids weight basis.

For the Swedish data, sampling, sample preparation, storage in specimen bank and evaluation of results are carried out by the Department of Contaminant Research at the Swedish Museum of Natural History, Stockholm. Chemical Analysis is carried out at Institute of Applied Environmental Research at Stockholm University.

Geographical coverage: see data table and map.

Temporal coverage: see data table and figures.

Methodology and frequency of data collection, see Bignert et al, 2012.

Methodology of data manipulation. For a detailed description of statistical methods use, see Bignert et al. 2012.

Quality information

The number of years required to detect an annual change of 10% with a power of 80% varied between 10 to 12 years for the herring time-series. The number of years required to detect an annual change of 10% was 12 and 14 years for the two cod time-series.

For reference purposes, please cite this Baltic Sea Environment Fact Sheets as follows:

[Author’s name(s)], [Year]. [Baltic Sea Environment Fact Sheets title]. HELCOM Baltic Sea Environment Fact Sheets 2012. Online. [Date Viewed], http://www.helcom.fi/environment2/ifs/en_GB/cover/.

Last updated: 2.11.2012