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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

5.2.1 Biodegradation in water:

The study conducted in accordance with the Method C.4-D “Manometric Respirometry Test“(2008) (similar to OECD Guideline 301 F) measured a degradation rate of 0 % of C.I Solvent Green 28 within 28 days (Neuhahn, 2017). C.I Solvent Green 28 is considered to be "Not Readily Biodegradable". 

Based on the mineralization data, C.I Solvent Green 28 is not inherently biodegradable under the conditions of the OECD guideline no. 302 (Haener, 2003), since less than 20 % degradation (mineralization) was attained after 28 days of contact time. However, based on DOC measurements C.I Solvent Green 28 was completely eliminated.

5.2.2 Biodegradation in water and sediment:

Simulation testing on ultimate degradation in surface water is not considered as scientifically relevant. Depending on the outcome of the soil assessment, sediment simulation (OECD TG 308) testing would be considered at a later stage. Further simulation test would not be conducted if the substance is classified as persistent in soil.

5.2.3 Biodegradation in soil:

It is proposed to start simulation testing in soil compartment with an OECD Test Guideline 307 on the target/registered substance, C.I Solvent Green 28 (CAS n°4851-50-7)(OECD-TG 307 Testing Proposal, 2022).



Additional information

Category approach:

LANXESS Deutschland GmbH has registered five mono-constituent anthraquinone dyes of similar chemical structure using a category approach: Solvent Violet 36 (CAS No 82-16-6), Solvent Green 28 (CAS No 4851-50-7), Reinblau RLW (CAS No 41611-76-1), Reinblau BLW (CAS No 32724-62-2) and Solvent Green 3 (CAS No 128-80-3). Additional data were taken from another registered anthraquinone dye, Solvent Blue 104 (CAS 116 -75 -6), leading to a category consisting of six members (see attached justification in IUCLID chapter 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.

To cover all the members of the category, soil simulation tests will be performed on 2 members of the category: 

- Reinblau RLW (CAS n°41611-76-1): this substance is registered as Annex IX and simulation tests are required for this tonnage band. This substance is considered as the low limit of the boundary (exp log Kow of 8.2; exp Log Koc of 6.2) of the category group. This substance share the same metabolic profile from EAWAG model with other substances of the category (Reinblau BLW, Violet 36 and Green 3)(see category approach document). Indeed, it seems they have a similar pathway predicted for biodegradation model.

- Solvent Green 28 (CAS n°4851-50-7): this substance has been chosen as the high limit of the boundary (exp log Kow of 10.7; Log Koc of 8 - 8.2 (QSAR)) of the category group. This study on C.I Solvent Green 28 will be used to support the category approach as a worst-case.