1,4-bis[(2,6-diethyl-4-methylphenyl)amino]anthraquinone

Endpoint summary

Description of key information

One testing proposal is requested on the source substance, Reinblau RLW (CAS No 41611-76-1), to cover the terrestrial toxicity endpoint of the present Annex IX tonnage band registered subtance, Reinblau BLW (CAS No 32724-62-2).

As explained in the category approach document (see attached justification document in section 13), the category consists of substances all having the diamino-anthraquinone structure as a common moiety which is linked to phenyl groups via the amino groups. Differences within the category are described by various alkyl groups bound to the phenyl groups. All substances included in the category approach are poorly water soluble with high adsorption coefficient (log Koc>6), high partition coefficient (logKow>8) and not readily biodegradable. These properties lead to a reduced bioavailability for organisms.

The terrestrial toxicity should be assessed for Annex IX/X dossiers. In the category approach, only two substances are Annex IX tonnage band substances: the registered substance (Reinblau BLW) and Reinblau RLW. 

According to Chapter R.7c of the ECHA Guidance on information requirements and chemical safety assessment (version 3.0, June 2017), both substances should be classed as a soil hazard category 3 (log Kow > 5; no aquatic toxicity). Therefore, the Equilibrium Partitioning Method (EPM) has to be used as a screening assessment, for assessing the hazard to terrestrial organisms. However, as no aquatic toxicity were observed or estimated up to the highest attainable limit of solubility of the substances in acute and chronic exposure, it is not possible, neither required, to derive a PNEC aqua, and therefore not possible to derive a PNEC soil based on EPM. Nevertheless, in the context of an Integrated Testing Strategy for soil toxicity, a confirmatory long-term soil toxicity testing is requested. Normally, the choice of test (invertebrate / plant / micro-organisms) should be based on aquatic toxicity data to select the most sensitive organisms group. For both substances, due to lack of toxicity, the most sensitive organism group in aquatic toxicity cannot be determined, so the invertebrates earthworm species is proposed. Hence, a testing proposal is included in the Reinblau RLW dossier to conduct an earthworm reproduction test, according to OECD Test Guideline 222. This source substance, Reinblau RLW, has been chosen for the testing proposal and will be used as a read-across study for the registered substance, Reinblau BLW. 

All other terrestrial studies (terrestrial arthropods / plant / micro-organisms) were waived based on the new requested soil toxicity test, and an exposure consideration. Direct or indirect exposure of the soil compartment can be excluded. A direct exposure of soil can be excluded as the substance is not applied on soil. Furthermore, all relevant surfaces are sealed to prevent any exposure. In addition, physicochemical data indicate that the substance is not bioaccumulative (experimental BCF value comprised between 2 and 5) and the results of aquatic studies clearly indicate no harmful effects.

The terrestrial toxicity strategy could be revised depending on the results of the new requested aquatic and terrestrial studies on some substances of the category approach.