Registration Dossier
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EC number: 203-383-4 | CAS number: 106-31-0
Short-term toxicity to fish
Administrative data
Link to relevant study record(s)
Description of key information
No valid data could be located regarding the short-term toxicity of butyric acid to fish.
To compensate for this lack of data, information resulting from valeric acid as supporting substance is used as substitute.
Supporting substance valeric acid: in a valid short-term toxicity fish test similar to OECD TG 203, the LC50 of valeric acid was determined to be 77 mg/L (Geiger, 1985).
The LC50 for butyric acid (conversion using the respective molecular weights) is ca. 66.4 mg/L.
Key value for chemical safety assessment
Fresh water fish
Fresh water fish
- Effect concentration:
- 66.4 mg/L
Additional information
The short-term toxicity of butyric acid to fish was investigated in several studies. Exposure period was only 24 or 48 h. This does not comply with recent test guideline requirements, thus reliability of these studies is low. The data con not be used to determine the acute toxicity of butyric acid to fish.
As valid data are not available to assess the short-term toxicity of butyric acid to fish, data for valeric acid as supporting substance will be used based on following reasons.
Valeric acid is closely related to butyric acid. Both compounds are straight chain carboxylic acids differing only in chain length by one carbon atom. Physical properties and chemical reactivity will be quite similar. Main structural feature is the carboxylic acid group, which will have a major impact on the effects of both substances in aquatic systems. Thus, it is justified to use valeric acid as supporting substance in the evaluation of the acute toxicity of butyric acid to fish.
Supporting substance valeric acid
The study was performed similar to OECD TG 202. The test is part of a large series of tests with fathead minnow performed at the Centre for Lake Superior Environmental Studies, University of Wisconsin-Superior, Wisconsin, USA. Reliability is 2.
Geiger 1985
Valeric acid was tested on fathead minnows (Pimephales promelas) in a 96-h flow-through acute study. No specific guideline was reported, but documentation is sufficient to assign validity and good reliability. The test design is similar to OECD TG 203. Five test concentration and 1 control were set up. One test chamber with 20 fish was used per test concentrations. The test concentrations were analytically verified by GLC every day in each test chamber.
Based on mean measured concentrations, the 96-h LC50 of valeric acid was 77 mg/L (Geiger, 1985).
Butyric acid: short-term toxicity to fish
The LC50 value of butyric acid will be calculated on basis of the LC50 for valeric acid (Geiger, 1985) using the respective molecular weights (88.11 and 102.13).
The 96-h LC50 for butyric acid is assessed to be 66.4 mg/L.
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