​​​​​​​​Results and confidence

Overall the status of polybrominated diphenyl ethers (PBDEs) fail the threshold value (Results figure 1). Data is available across a wide spatial area and shows that the concentrations of PBDEs are above the threshold value in biota throughout the Baltic Sea..


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Results figure 1. Aggregated mean concentrations in biota per scale 4 HELCOM assessment unit. The bars represent the upper 95% confidence interval. The threshold value is exceeded (failed) in all areas. 


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Results figure 2. PBDE biota measurements per station in the Baltic Sea (right) and resulting status assessment (left). Red colour indicates that the upper 95 % confidence interval for PBDE concentrations are above the threshold value. Small open circles indicate a status assessment based on only 1-2 years of data, small filled circles indicate that there is not enough data to assess a statistical trend, large filled symbols indicate statistical trends assigned with circles indicating no detectable trend in concentration during the whole monitoring period and the filled arrows indicating significant upward or downward trend in concentration during the monitoring period. Click here to access interactive maps at the HELCOM Map and Data Service: PBDEs.


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Results figure 3. Temporal trends of PBDEs concentration (ng/g wet weight – 5% lipid normalized) in herring muscle from stations Fladen Kattegat, Gdansk Basin, Bothnian Sea and  north Baltic Proper, (grey colour- confidence level 95% range (see Assessment protocol)). 


Confidence of the indicator status evaluation

The confidence of the status evaluation is considered high. Data is available from several regions covering a time period of several years.

 

Evaluation of secondary matrices

Concentrations of PBDEs has also been measured in sediments. The threshold value for sediment is 310 µg kg-1 dry weight (dw). This threshold value is high compared to the threshold value in biota. When these results are assessed against the QS for sediment all assessment units with data show a good status (Results figure 4).


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Results figure 4. Status assessment results (left) and assessment per station in the Baltic Sea (right) based on the evaluation of the indicator Polybrominated diphenyl ethers (PBDEs) in sediments. Green colour indicates that the upper 95 % confidence interval for PBDE concentrations are below the threshold value. Small open circles indicate a status assessment based on only 1-2 years of data. The assessment is carried out using Scale 4 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). Click here to access interactive maps at the HELCOM Map and Data Service: PBDEs.