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Expert opinion

Groundwater quality standards for proposed additional pollutants in the annexes to the Groundwater Directive (2006/118/EC)

Final Opinion


SCHEER WG on Water Framework Directive
SCHEER members: Marian Scott (Chair), Thomas Backhaus, Teresa Borges, Peter Hoet, Marco Vighi, Pim de Voogt (Rapporteur)
External experts: Andrew Johnson, Jan Linders
Aknowledgements: Rodica Mariana Ion
Contact:SANTE-C2-SCHEERatec [dot] europa [dot] eu (SANTE-C2-SCHEER[at]ec[dot]europa[dot]eu)
On request from: European Commission
Adopted on: 18 July 2022

The SCHEER was asked to evaluate groundwater quality standards proposed for additional pollutants, including pollutant groups, in the annexes to the Groundwater Directive. These included per- and polyfluorinated alkyl substances (PFAS), pharmaceuticals, in particular carbamazepine and sulfamethoxazole, and non-relevant metabolites of plant protection products. The SCHEER is of the opinion that uniform EU-wide quality standards should be set for the groundwater body for chemicals with no natural background concentrations. The SCHEER is aware of the Guidance document by the European Medicines Agency (EMA, 2018) that requests to use an additional assessment factor of 10 for the protection of groundwater organisms. The SCHEER supports such a precautionary approach, although it considers the size of such an assessment factor as still being uncertain, especially for non-pharmaceuticals.

The SCHEER endorses the relative potency approach for PFAS and suggests using a quality standard for groundwater of 4.4 ng L-1 for PFOA equivalents. The SCHEER does not agree with a group QS of 0.50 μg L-1 for total PFAS.

The SCHEER concludes that the groundwater QSs for carbamazepine (0.5 μg.L-1) and sulfamethoxazole (0.1 μg.L-1) may not be sufficiently protective, in view of the additional assessment factor required for the protection of groundwater organisms. A general standard of 0.5 μg L-1 for all pharmaceuticals would also not be sufficiently protective.

The SCHEER does not support a group total quality standard for non-relevant metabolites of pesticides of 10 μg.L-1. Although a quality standard of 0.75 μg L-1 for all non-relevant metabolites will protect human health (unless additional relevant toxicological information becomes available, e.g., ED effects), the SCHEER recommends using a quality standard of not more than 0.1 μg.L-1 in groundwater to protect the groundwater ecosystem, human health and against the development of antibiotic resistance.

The SCHEER does not see any scientific reason to consider moving PFAS, pharmaceuticals or non-relevant metabolites of pesticides as a group to Annex II.


PFAS, carbamazepine, sulfamethoxazole, pharmaceuticals, non-relevant metabolites, pesticides, plant protection products

Opinion to be cited as:

SCHEER (Scientific Committee on Health, Environmental and Emerging Risks), Final opinion on groundwater quality standards for proposed additional pollutants in the annexes to the Groundwater Directive (2006/118/EC). 18 July 2022.


11 JANUARY 2022