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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

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Description of key information

Isobutyric acid inhibited the cell growth of Tetrahyma pyriformis test cultures by 50 %  at a concentration of 2.15 mg/mL.

Key value for chemical safety assessment

EC50 for microorganisms:
2.15 mg/L

Additional information

Hydrolysis studies show that isobutyric anhydride added to water rapidly converts to isobutyric acid. Thererfore, isobutyric acid data is being used by read across for most environmental fate and ecotox endpoints.

From three tests identified, only one test is valid (Schulz, 1997). The documentation of the other two (BASF AG, 1989; Hoechst AG 1979) is insufficient for assessment.

Schulz 1997

In a valid 40 hour growth inhibition study, test cultures of the cilliate Tetrahymena pyriformis were exposed to isobutyric acid at five graduate concentrations under static conditions (individual concentrations not reported). The assay was performed in three independent replicate runs on the basis of a preceding range finding test.

The IC50 value based on cell density was determined to be 2.15 mg/L indicating low to moderate toxicity of isobutyric acid to aqueous microorganisms (cilliates) (Schultz, 2006).