SCHEER - Scientific Opinion on "Draft Environmental Quality Standards for Priority Substances under the Water Framework Directive" - Triclosan

SCHEER WG on Water Framework Directive
SCHEER members: Marian Scott (Chair), Marco Vighi (Rapporteur), Thomas Backhaus, Teresa Borges, Raquel Duarte Davidson, Peter Hoet, Pim de Voogt, Rodica Mariana Ion
External experts: Andrew Johnson, Jan Linders
Contact: SANTE-SCHEERec [dot] europa [dot] eu (SANTE-SCHEER[at]ec[dot]europa[dot]eu)
On request from: European Commission
Adopted on: 16 January 2023

The dossier on Environmental Quality Standards for “Triclosan” is evaluated by the SCHEER according to the general mandate on EQS dossiers.

The SCHEER endorses the deterministic values for MAC-QS_{fw, eco} of 0.019 μg L^-1 and MAC-QS_{sw, eco} of 0.0019 μg L^-1. The SCHEER does not endorse the SSD-derived values for MAC-QS_{fw, eco} of 0.068 μg L^-1 and MAC-QS_{sw, eco} of 0.0068 μg L^-1 because the pH of several of the tests that formed the basis of the probabilistic derivation has not been mentioned or measured, which is a critical test condition considering the pKa of triclosan. The SCHEER is of the opinion that where the pH of test studies was not available, the test results should not have been used in the probabilistic derivation.

The SCHEER confirms that the QS_sed values have been correctly calculated from the database in the Draft dossier. The SCHEER endorses the resulting AA-QS_fw-sed= 180 μg kg^-1 and AA-QS_sw-sed= 18 μg kg^-1.

The SCHEER does not endorse the QS_{biota, secpois,fw} of 0.89 mg kg^-1_ww for fish and 0.26 mg kg^-1_ww for bivalves and the resulting QS_{fw, biota} for fish (0.79 μg L^-1) and QS_{fw, biota} for bivalves (0.23 μg L-¹) because according to the SCHEER the calculations of DEE and C_{energy normalised} are erroneous and because the SCHEER does not agree with the adequacy of the reference value (RfD) used. Consequently the SCHEER endorses neither the QS_{biota, secpois,sw} obtained after lipid normalisation nor the back-calculations to water (QS_{sw, biota} for fish and bivalves).

The SCHEER does not endorse the proposed QS_{biota hh} and QS_{biota hh food} values, because the SCHEER does not agree with the adequacy of the reference value used as TL_hh.

The most critical EQS (in terms of impact on environment/health) could not be identified by the SCHEER because the overall set of QSs endorsed by the SCHEER is incomplete as a result of the shortcomings mentioned above.

The SCHEER notes that antimicrobial resistance thus far is not considered in the derivation of the QS and recommends that a section on how to deal with AMR be included in the Technical Guidelines.

The SCHEER recommends further investigation of triclosan’s effects on reproduction and on endocrine sensitive endpoints so that these effects can be included in the assessment of the ecotoxicity of Triclosan in the near future.

Keywords:

Triclosan, 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 - triclosan, 16 January 2023.