Results and Confidence

The core indicator is evaluated against specific threshold values in all assessment units where data is available, with aggregated results calculated for each assessment unit (Results table 1). A full evaluation was possible for 13 out of 17 open sea assessment units, missing only Gdansk Basin (SEA-008), Gulf of Riga (SEA-0011), Gulf of Finland (SEA-0013) and the Quark (SEA-016), and 10 coastal assessment units (Results table 1). To carry out a full assessment, a minimum of three years of data per monitoring station is required, though 'initial' data (data series of 2 or less years or containing 'less-than' values) was also included in the assessment (see section Assessment Protocol). Concentrations are available for the primary substance benzo(a)pyrene in biota for three of the evaluated open sea assessment units and a number of coastal assessment units, and the threshold value was achieved in all but two units. It could furthermore be noted that the secondary substance fluoranthene (in biota) was evaluated in a similar selection of assessment units and that a similar status pattern was observed. The secondary substance anthracene, in sediment, however was assessed across a wider spatial area and 6 of the 13 assessed open sea units (and a number of coastal areas failed to achieve the threshold (i.e. not-good status).

 

It should be noted that in addition to the data that supports a full assessment using the core indicator assessment protocol, there is also initial status assessment data available meaning that measurements are only available for 1-2 years per station (most sediment stations and some mussel stations). In order to achieve a better spatial coverage and include all available monitoring data, the initial status assessment data are also considered using a precautionary statistical approach.

 

Benzo(a)pyrene

The results per station show the details of the underlying assessment data, and includes both the stations for which a full and initial data series were possible, visualising the data on which the aggregated results were produced. Of the assessed units one open sea and three coastal assessment unit failed to achieve the threshold value, and in all cases these were based on few sampling stations with short data series (initial data). In the future longer data series (due to ongoing monitoring) and larger spatial coverage will assist with an even more robust assessment.

 

PAH_trend_BAP.pngPAH_status_BAP.png

Results figure 1. Benzo(a)pyrene concentration status per station (left) and aggregated assessment unit status assessment (right). Green indicates that the threshold value is achieved and red that the threshold value is failed. Small open circles indicate a status assessment based on only 1-2 years of data (initial data), small filled circles indicate that data is not suitable to assess a trend (treated with initial methodology), large filled circles that no detectable concentration trends can be identified during the whole monitoring period (full data), and the filled arrow indicate that there is a statistically defined upward or downward trend during the monitoring period. Click here to access interactive maps at the HELCOM Map and Data Service: PAHs.


PAHs Results figure 2.png 

Results figure 2. Examples of benzo(a)pyrene concentration in blue mussel (soft body) at two stations in the Arkona Basin selected for illustrative purposes, showing a station with full assessment possible (left) and initial status assessment data (right).

 

Fluoranthene

Fluoranthene concentration status in biota, as assessed against the relevant threshold, followed a similar pattern to the primary substance benzo(a)pyrene. The results per station show the details of the underlying assessment data, and includes both the stations for which a full and initial data series were possible, visualising the data on which the aggregated results were produced. Of the assessed units five coastal areas an done open sea area failed to achieve the threshold value and these were in general assessments based on on few sampling stations with short data series (initial data). In the future longer data series (due to ongoing monitoring) and larger spatial coverage will assist with an even more robust assessment (Results figure 3).

 

PAH_trend_FLU.png PAH_status_FLU.png

Results figure 3. Fluoranthene concentration status per station (left) and aggregated assessment unit status assessment (right). Green indicates that the threshold value is achieved and red that the threshold value is failed. Small open circles indicate a status assessment based on only 1-2 years of data (initial data), small filled circles indicate that data is not suitable to assess a trend (treated with initial methodology), large filled circles that no detectable concentration trends can be identified during the whole monitoring period (full data), and the filled arrow indicate that there is a statistically defined upward or downward trend during the monitoring period. Click here to access interactive maps at the HELCOM Map and Data Service: PAHs.

 

Anthracene

Anthracene is monitored in sediments and across a wide spatial area. The sampling strategies for sediments are commonly less frequent that those for biota or water and this data is generally treated with the methodologies applied to 'initial' data (see Assessment Protocol below). The results per station show the details of the underlying assessment data, and includes both the stations for which a full and initial data series were possible, visualising the data on which the aggregated results were produced (Results figure 4). Seven of thirteen open sea assessment units achieved the threshold value (good status) and coastal assessment units, where assessed, generally failed the threshold value (not good status).

 

PAH_trend_ANT.pngPAH_status_ANT.png

Results figure 4. Anthracene concentration status per station (left) and aggregated assessment unit status assessment (right). Green indicates that the threshold value is achieved and red that the threshold value is failed. Small open circles indicate a status assessment based on only 1-2 years of data (initial data), small filled circles indicate that data is not suitable to assess a trend (treated with initial methodology), large filled circles that no detectable concentration trends can be identified during the whole monitoring period (full data), and the filled arrow indicate that there is a statistically defined upward or downward trend during the monitoring period. Click here to access interactive maps at the HELCOM Map and Data Service: PAHs.

 

Confidence of the indicator status evaluation

Confidence in the indictor evaluation for the assessment units where a full assessment was possible is evaluated to be high. Further monitoring data in the future will elongate the data series available and strengthen the confidence further. Certain assessment areas, where relevant, could further benefit from wider spatial monitoring of these substances.

Even if PAH metabolites are not included in the present version of this report it should be noted that they are potentially valuable HELCOM core indicators and could be included in environmental assessment as soon as agreed threshold levels are available. Many countries in Europe including Germany and Poland can provide long term monitoring data on PAH metabolites and this aspect would further strengthen this indicator and status assessment. The analytical methods are quality assured, well documented and PAH metabolites can be turned into a proper environmental assessment as soon as there is agreement on the threshold.

The data used in this assessment are considered to be reliable and the evaluation accurate, indicating a high confidence in the evaluation. The threshold value is based on an EU Environmental Quality Standard (EQS) which is considered to have a high confidence.