TCDD-equivalents in herring muscle and guillemot egg 

	Anders Bignert, Elisabeth Nyberg, Sara Danielsson Contaminant Research Group, Swedish Museum of Natural History

Key message

The concentrations of TCDD-equivalents in guillemot eggs show an overall significant decreasing trend. However, the concentrations of TCDD-equivalents have not continued to decrease significantly during the recent 15 years. No significant changes can be seen for TCDD-equivalents in herring muscle from 1990-2005, which coincides with the results for guillemot eggs during this time period.

The concentrations of TCDD-equivalents are higher in the Bothnian Bay and Baltic Proper compared to Kattegat. 

Figure 1. Spatial variation in mean concentration (pg/g lipid weight) of TCDD-equivalents in herring muscle (2003-2005). The highest concentration (around 38 pg/g) was found in the northern Bothnian Bay, the lowest (around 8,4 pg/g) in Kattegat. Data originates from the Swedish national monitoring programme and are analysed at the Department of Chemistry, University in Umeå. 

Results and assessments

Relevance of the indicator for describing developments in the environment

Analyses of contaminants in biotic samples, in contrast to abiotic matrices, exhibit the bioavaliable part of the contaminants. The lipid content of both herring muscle tissue and guillemot eggs is high, about 2-4% and 11-13% respectively, and thus appropriate for analysis of fat-soluble contaminants as dioxins. Herring are also commonly used for human consumption.

Policy relevance and policy references

Dioxines are comprised by the objective of HELCOM’s strategy for hazardous substances, that is to continuously reduce discharges, emissions and losses of hazardous substances, with a goal of their eventual cessation by the year 2020. The ultimate aim is to achieve concentrations in the environment near background values for naturally occurring substances and close to zero for man-made synthetic substances. This objective was adopted in 1998 and dioxin has been selected as one of the priority substances for immediate action.

The Stockholm Convention on Persistent Organic Pollutants (POPs) is an international agreement, requiring measures for reducing or preventing releases of dioxins to the environment.

Assessment

In guillemot eggs an overall significant decreasing trends are observed for TCDD-equivalents. However, the concentrations of TCDD-equivalents have not continued to decrease significantly during the recent 15 years. The number of years required to detect an annual change of 5% varied between 14 and 19 years for the last ten years in herring and guillemot.

No significant changes can be seen in herring muscle. The number of years required to detect an annual change of 5% varied between 17-20 years for these time series.

TCDD-equivalents show declining trends due to measures taken to reduce emissions between 1969 and 1985 but after that, this decline has ceased, contrary to e.g. PCBs.
 

Figure 2. Temporal trends of TCDD-equivalent concentration (pg/g lipid weight) in herring muscle from three different sampling sites (1990-2005). Harufjärden (Bothnian Bay), Utlängan (S. Baltic Proper), Fladen (Kattegatt). 

Figure 3. Temporal trends of TCDD-equivalent concentration (ng/g lipid weight) in guillemot egg (1969-2005)

References

Bignert, A., Nyberg E., Asplund L., Eriksson U., Wilander A. Haglund P. 2007. Comments Concerning the National Swedish Contaminant Monitoring Programme in Marine Biota. Report to the Swedish Environmental Protection Agency, 2007. 128 pp.  

Data

Estimated geometric mean concentrations of TCDD-eqv. (pg (herring) ng (guillemot egg)/g lipid weight) for the last sampled year in various matrices and sites during the investigated time period. The trend is reported, if p<0.1. The total number of analyses and the number of years of the various time-series are also presented.

Metadata

Technical information

Data source: The National Swedish Monitoring Program of Contaminants in Biota

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 the Department of chemistry at University of Umeå.

Geographical coverage: see data table and map.

Temporal coverage: see data table and figures.

Methodology and frequency of data collection, see Bignert et al, 2007

Methodology of data manipulation. For a detailed description of statistical methods use, see Bignert et al. 2007.

The number of years required to detect an annual change of 5% with a power of 80% varied between 17 to 19 years for the herring time-series. The number of years required to detect an annual change of 5% was 14 years for the guillemot egg time-series.

For reference purposes, please cite this indicator fact sheet as follows:

[Author’s name(s)], [Year]. [Indicator Fact Sheet title]. HELCOM Indicator Fact Sheets 2007. Online. [Date Viewed], http://www.helcom.fi/environment2/ifs/en_GB/cover/.

Last updated: 29.10.2007