Thresholds and Status evaluation

Good status is evaluated for the core indicator 'Polyaromatic hydrocarbons (PAHs) and their metabolites' by comparing the measured concentrations of benzo(a)pyrene in the matrix biota (shellfish soft body) against the EU Environmental Quality Standard (EQS) of 5 µg/kg wet weight (Thresholds figure 1). The threshold value is an EQS derived for the protection goal of human health via consumption of fishery products.

Threwsholds figure.png

Thresholds figure 1. Schematic representation of the threshold value for which the measured concentration of the primary substance benzo(a)pyrene, or the secondary substances fluoranthene and anthracene, should be lower than the threshold value concentration in order for the threshold value to be achieved.


The threshold value for benzo(a)pyrene concentration is matrix sensitive, and only applicable if the concentrations are measured in the appropriate matrix. For historical reasons, the Contracting Parties around the Baltic Sea have differing monitoring strategies and as a pragmatic approach secondary threshold values for secondary substances have also been agreed to be used to evaluate assessment units where no measurements are available for the primary substance and threshold value. The threshold values were agreed at HELCOM HOD 50-2016 (outcome para 4.47).


Thresholds table 1. Threshold value for the primary substance benzo(a)pyrene and the two secondary substances fluoranthene and anthracene.

SubstanceThreshold valueReference
Benzo(a)pyrene5 µg/kg wet weight crustaceans and molluscsEQS biota human health

Secondary substance


30 µg/kg wet weight crustaceans and molluscsEQS biota human health

Secondary substance


24 µg/kg dw sediment (Normalized to 5% TOC)QS


The EU directive on environmental quality standards (2008/105/EC), Article 3, states that also long-term temporal trends should be assessed for substances that accumulate in sediment and/or biota.