Silver EQS under the Water Framework Directive

The Water Framework Directive (WFD) is the EU’s primary legislation for the protection of inland surface waters and groundwater. Its objective is to ensure that European waters achieve ‘good chemical status’, meaning they comply with EU-wide standards for chemical pollutants. To achieve this, the EU identifies and regulates Priority Substances, chemicals that pose a significant risk to or via the aquatic environment. For these Priority Substances, Environmental Quality Standards (EQS) are set. 

Silver as a Priority Substance

IIn 2022, the European Commission proposed revising the list of priority substances and introduced silver (Ag) as a new entry, together with proposed EQS for silver in freshwater: 

• Annual average EQS (AA-EQS) of 0.01 μg/L 

• Maximum allowable concentration EQS (MAC-EQS) of 0.022 μg/L 

The WFD review still needs to be formally voted on and official adoption is expected early 2026. 

Silver’s inclusion significantly impacts the sector, as silver release may occur from the manufacturing, processing, and use of silver-containing substances and articles. Currently, no other precious metals are under consideration for EQS development at EU level. 

EPMF position: silver does not pose an EU-wide risk

The EPMF believes that the correct assessment of precious metals in water is essential for the protection of the environment. According to the WFD, only substances that pose a ‘significant risk’ should be designated as Priority Substances. However, EU monitoring data do not indicate an EU-wide risk from silver (Arijs et al. 2022). Furthermore, the highly conservative EQS of 10 ng/L is not supported by the weight of evidence (Arijs et al. 2021); the EPMF’s scientifically derived value is 46 ng/L.  The more detailed EPMF position with scientific findings can be found here. 

Scientific engagement and the Silver BLM Project

To ensure robust science underpins regulatory decision-making, the EPMF is supporting extensive research. This includes a four-year collaborative project (started in 2023) with Ghent University, ARCHE Consulting and the UK Centre for Ecology & Hydrology (CEH).  

The project aims to develop a chronic Biotic Ligand Model (BLM) for silver to better understand how water chemistry influences silver speciation and toxicity in freshwater. This will enable future EQS to be expressed in terms of bioavailable silver, improving both scientific accuracy and practical implementation.