​​​Thresholds and Status evaluation

The threshold value applied for PBDEs is 0.0085 µg/kg fish wet weight (ww). The threshold value is an Environmental Quality Standard (EQS) for biota, where human health is considered the most critical for PBDEs and therefore is defined for edible parts of fish. The value is a sum of PBDE congeners 28, 47, 99, 100, 153 and 154, mainly representing penta- and octa- but not decaBDE.

Thresholds figure 1.png

Thresholds figure 1: Schematic representation of the threshold value which indicates good status if the concentration is below the threshold value. The threshold value is EQS biota human health 0.0085 µg/kg fish wet weight (ww).

 

Good Environmental Status (GES), defined in accordance with the Marine Strategy Framework Directive 2008/56/EC (MSFD), is "concentrations of contaminants at levels not giving rise to pollution effects" (OJEC No. L164 25.6.2008, 2008). PBDEs are included on the priority list under the Water Framework Directive (2000/60/EC) under which the Quality Standards (QSs) have been developed. All QS are based on ecotoxicological studies and derived to protect freshwater and marine ecosystems from potential adverse effects of chemicals, as well as adverse effects on human health via drinking water and food from aquatic environments. QSs are derived for different protection goals. The most stringent of the QSs for the different protection goals is the base for the EQS (2013/39/EU).

In the case of the PBDEs, the EQS is based on the value derived for human health. The EQS is used as a threshold value although it is debated as being very low, and has not been endorsed by the European Food Safety Authority (EFSA). Thus it is not clear if the value is in accordance with the food safety risk assessments.

The EC Guidance Document No. 32 on biota monitoring (the implementation of EQSbiota) under the Water Framework Directive (EC 2014) was derived for harmonization purposes. This guidance document recommends that for lipid soluble, biomagnifying compounds such as PBDEs the fish assessed for EQS compliance should be at a trophic level of 4.5 for marine environments with a whole body lipid content of 5%. For practical reasons, the guidance opens up for adjustments of results from ongoing monitoring to meet this standard by the use of trophic magnification factors and trophic level. 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.

In cases where it is not possible to evaluate the environmental status using biota-monitoring, a secondary threshold value based on concentration in sediment can be used as a complement. The threshold value for sediment is 310 µg kg-1 dry weight (dw). This value has been suggested by the working group on priority substances for the protection of the benthic community.