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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

As the parent compound hydrolyses in water within 10 minutes the assessment of the biodegradability relates to isovaleric acid and its structurally similar substances isobutyric acid and valeric acid. The hydrolysis product turned out to be readily biodegradable by the use of a weight-of-evidence approach.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Parent compound isovaleryl chloride and hydrolysis product isovaleric acid:

No experimental data are available for isovaleryl chloride (CAS 108 -12 -3). The substance rapidly decomposes in water and forms HCl (CAS 7647 -01 -0) and isovaleric acid (CAS 503 -74 -2). Therefore, the biodegradability is assessed on the basis of data on isovaleric acid and the structurally similar substance valeric acid (CAS 109 -52 -4).

Isovaleric acid is readily biodegradable based on the findings by Dias & Alexander (1971) who tested the substance in Warburg respirometers following standard techniques which are similar to nowadays OECD TG 310 D. Valeric acid was found to be readily biodegradable in a BOD test according to EU Method C.5 (ECHA, 2011).

The results named above are supported by three QSAR models performed with isovaleric acid.

- EPI Suite v4.10: BIOWIN v4.10: Overall conclusion on ready biodegradability: readily biodegradable

- CATALOGIC v5.10.8: BOD 28 days MITI [OECD 301C] v3.04: ca. 61.9% after 28 d (domain similarity: 100%) - (readily) biodegradable

- CATALOGIC v5.10.8: BOD Kinetic [OECD 301F] beta v06.07: ca. 60.8% after 28 d (domain similarity: 100%) - readily biodegradable, but failing

10 -day window

In a weight-of-evidence approach based on the results summmarised above, isovaleryl chloride hydrolyses rapidly in aqueous systems. Its hydrolysis product isovaleric acid is expected to be readily biodegradable.