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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

Parent compound: With high probability acutely not harmful to fish.
Hydrolysis product: With high probability acutely not harmful to fish.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
146.6 mg/L

Additional information

Parent compound isobutyryl chloride:

The toxicity of isobutyryl chloride (CAS 79 -30 -1) to the test organism Danio rerio (reported as Brachydanio rerio) was tested according to OECD 203 (Fish, acute Toxicity Test). The 96 -h LC50 was determined to be 280.7 mg/L [(measured, not neutralized) BASF 1999 17F0505/965151].

Based on the reported test results the substance is with high probability acutely not harmful to fish.

Hydrolysis product isobutyric acid:

In three individual short term (96 h) tests, the toxicity of isobutyric acid to three fish species was tested. All tests were performed using the same method (similar to OECD TG 203). Although there are some restrictions (test substance concentration not measured, only four concentrations tested) the studies are assessed as acceptable.


There was no adjustment of pH. In two tests (Hoechst AG), pH-values were measured after addition of the test substance to the dilution water. Values in the test medium declined in a concentration dependent manner within 24 hours to a pH as low as 4.6.


The 96 -h LC50 for golden orfe (Leuciscus idus) was 146.6 mg/L(BASF AG, 1989).

The 96-h LC50 for rainbow trout (Oncorhynchus mykiss) was 286 mg/L(Hoechst AG, 1979).

The 96-h LC 50 for pumpkinseed (Lepomis gibbosus) was 435 mg/L(Hoechst AG, 1979).


Sublethal effects were discouloration, imbalance, uncoordinated movements, and dorsal and lateral position. Fish of the three highest dose groups were narcotized. In sacrificed pumpkinseed (dose group 315 and 500 mg/L), light discoloration of livers were observed.


For high test substance concentrations, the observed toxicity may have been influenced by the acidic conditions of the test medium.

Hydrolysis product hydrochloric acid (HCl):

HCl was tested in a semi-static acute toxicity test according to OECD 203 with Cyprinus carpio. The 96-h LC50 was 4.92 mg/L (acid equivalent to pH 4.3; OECD, 2002).