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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

The tested multiconstituent substance belongs to a category of substances consisting of similar composition. Starting substance for all group members is Propylidynetrimethanol which is ethoxylated and/or propoxylated to different magnitudes and - for some of the substances - gets modified with an amine compound. A more detailed description of the group is attached to section 13 of this dossier.

The biodegradation of the test substance after a test duration of 28 days was measured to be 60 to 70% based on oxygen-consumption in a GLP guideline study according to OECD 301F (BASF AG 26G0333/023024, 2007). However, the 10d window was failed in this experiment. In the Revised introduction to the OECD guidelines for the testing of chemicals, section 3, Part 1: Principles and strategies related to the testing of degradation of organic chemicals, Introduction, paragraph 43 (adopted 23 March 2006), it is stated that "if a test on the mixture is performed and it is anticipated that a sequential biodegradation of the individual structures is taking place, then the 10-day window should not be applied to interpret the results of the test." Furthermore, section 4.1.2.9.5.(a) of Commission Regulation (EU) No 286/2011 of 10 March 2011 is saying "These levels of biodegradation must be achieved within 10 days ... unless the substance is identified as an UVCB or as a complex, multi-constituent substance with structurally similar constituents. In this case, and where there is sufficient justification, the 10-day window condition may be waived and the pass level applied at 28 days". The components of the tested multiconstituent substance are analogous molecules, differing mainly by the degree of ethoxylation and/or propoxylation, respectively. Based on this close structural similarity, the final degradation degree exceeding 60% after 28d and the application of the rules laid out in the documents cited above, the submission item is considered to be readily biodegradable.