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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Link to relevant study record(s)

Description of key information

Parent compound butyryl chloride: No data available.
Hydrolysis product butyric acid: 40h EC50 = 329 mg/L

Isobutyric acid: 17h EC10 = 39 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:
57 mg/L
EC10 or NOEC for microorganisms:
39 mg/L

Additional information

Parent compound butyryl chloride

No data are available for butyryl chloride (CAS 141 -75 -3). The substance rapidly decomposes in water and forms HCl (CAS 7647-01-0) and butyric acid (CAS 107-92-6). Therefore, the toxicity to microorganisms is assessed on the basis of data on butyric acid and the structurally similar substance isobutyric acid (CAS 79-31-2).


Hydrolysis product butyric acid (CAS 107-92-6)

Effects of butyric acid on the ciliate Tetrahymena pyriformis were investigated following the method of Schultz (1997). The 40h EC50 was determined to be 329 mg/L (Schultz, 2011).


Isobutyric acid (CAS 79-31-2):

The Pseudomonas putida growth inhibition test with isobutyric acid was performed according to German Industrial Standard Guideline DIN 38412, part 8. The obtained 17h EC10 and 17h EC50 were 39 mg/L and 57 mg/L, respectively (nominal, not neutralized; BASF, 1989).


Taking into account the results of isobutyric acid as a worst-case scenario and based on the available results as well as depending on local conditions and existing concentrations, disturbances in the biodegradation process of activated sludge are possible.