Thresholds and Status evaluation

The core indicator evaluates whether an area reflects good status by comparing the concentration to a threshold value which should not be exceeded (Thresholds figure 1).

thresholds figure 1.png

Thresholds figure 1. Schematic representation of the threshold value which indicates good status when the measured concentration is below the threshold value.


Thresholds table 1. Threshold value for the core indicator 'PCBs, dioxins and furans'. The secondary threshold value for the dl-PCB CB-118  is not yet fully agreed in HELCOM and therefore not used in the assessment and marked *.

 Primary threshold valuereferenceSecondary threshold value*reference
Dioxin and dioxin-like compounds

Sum of PCDDs, PCDFs, dl-PCBs 

0.0065 TEQ/kg ww fish, crustaceans or molluscs

EQS biota human health



CB-118 24 μg/kg lw fish liver or muscle EAC
Non-dioxin like PCBssum of congeners (28, 52, 101, 138, 153, 180) 75 μg/kg ww fish muscle EC 1881/2006 and 1259/2011  


The threshold value is defined based on Ecological Quality Standards (EQS) derived for the purposes of the EU Water Framework Directive, and where EQS values are not available on Environmental Assessment Criteria (EAC) values developed in the OSPAR framework.

The threshold value 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. As a pragmatic approach, a threshold value is defined in this indicator (based on 2013/39/EU GES boundary), however if suitable monitoring data is not available in a region the secondary threshold value can be used for the evaluation.

The threshold value for PCB is defined for the Sum of 6 congeners (non-dioxin like) (Good Environmental status Table 1). Other congeners included in current monitoring programmes can be included when suitable boundary values become available. For dioxins, the threshold value is defined as the EQS-value for human consumption. However, this EQS value stems from the foodstuff legislation and is derived taking into consideration information beyond the environmental parameters, such as typical levels of contaminants in different foodstuff. The aim of the target value is to identify and prevent contaminated foodstuff from being placed on the market. Thus, the foodstuff threshold values do not cover all combinations of matrices and contaminants relevant for an environmental assessment of the marine environment. Because of this, a full equivalence between EQSs based on foodstuff threshold values and EQS based on toxicological evaluations should not be expected.

The EU directive on environmental quality standards (2008/105/EC and 2013/39/EU), Article 3, states that also long-term temporal trends should be assessed for substances that accumulate in sediment and/or biota.