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Scientific Opinion on "Draft Environmental Quality Standards for Priority Substances under the Water Framework Directive" - Silver and its compounds

Final Opinion


WG on Water Framework Directive
SCHEER members: Marian Scott (Chair), Marco Vighi (Rapporteur), Teresa Borges, Raquel Duarte Davidson, Peter Hoet, Pim de Voogt
External experts: Thomas Backhaus, Andrew Johnson, Jan Linders
Contact:SANTE-C2-SCHEERatec [dot] europa [dot] eu (SANTE-C2-SCHEER[at]ec[dot]europa[dot]eu)
On request from: European Commission
Adopted on: 7-8 October 2021

Content of the Opinion:

The dossier on Environmental Quality Standards for “Silver and its compounds” was reviewed by the SCHEER according to the general mandate on EQS dossiers.

The SCHEER endorses the MAC-QSfw,eco = 0.022 μg L-1, derived with a deterministic procedure. The SCHEER agrees with the decision of not performing the probabilistic approach due to the incompleteness of the dataset.

The SCHEER also endorses the deterministic AA-QSeco,fw = 0.01 μg L-1 and agrees with the probabilistic values obtained with different SSD curves (0.012 and 0.016 μg L-1 respectively). As a final AA-QSeco,fw, the rounded value of 0.01 μg.L-1 obtained combining the deterministic one and the two probabilistic values, is endorsed by the SCHEER.

As indicated by the Technical Guidance for Deriving Environmental Quality Standards, freshwater and saltwater data cannot be pooled for metals.

For saltwater, the SCHEER agrees that there are no sufficient data available for the deterministic and probabilistic derivation of the MAC-QSsw,eco and for the probabilistic derivation of the AA-QSsw,eco.

The SCHEER endorses the AA-QSsw eco =0.17 μg.L-1 obtained with the deterministic procedure for the salinity of 30‰. On the contrary, it is the opinion of the SCHEER that the AA-QSsw eco for the salinity of 10‰ is not properly derived and cannot be endorsed.

For sediment ecotoxicity, the SCHEER endorses the AA-QSfreshwater, sed =4.78 μ obtained with the Equilibrium Partitioning method. The SCHEER agrees with the impossibility to derive an AA-QSmarine water, sed due to the lack of a marine Kdsed.

For secondary poisoning, the NOAEL value used to derive the QSbiota refers to silver acetate. Therefore, the tentative QSbiota must be modified by transforming the NOAEL in ionic silver. The same correction must be made for the derivation of the QSbiota,hh food.

Finally, the SCHEER appreciate that antimicrobial resistance is dealt with in the dossier. However, this assessment is not used for the derivation of EQS. The SCHEER recommends that a section on how to deal with antimicrobial resistance should be included in the Technical Guidelines.


pesticides, silver, Water Framework Directive, environmental quality standards

Opinion to be cited as:

SCHEER (Scientific Committee on Health, Environmental and Emerging Risks), Final Opinion on “Draft Environmental Quality Standards for Priority Substances under the Water Framework Directive", silver and its compounds, 7-8 October 2021.


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