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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

After 96 hours, the highest measured concentration at which no mortality had occurred was 2.93 mg/l and the lowest at which there was 100% mortality was 8.51 mg/l. Treatment-related effects were exhibited at 5.33 mg/l and higher concentrations.
Based on these findings the following values have been estimated: 96 hour LC50 value = 4.99 mg/l (95% confidence limits of 2.93 and 8.51 mg/l).

Key value for chemical safety assessment

LC50 for freshwater fish:
4.99 mg/L

Additional information

One reliable proprietary freshwater study, Huntingdon (2004a) is available for the isomer 2-methylbut-2-ene (CAS 513-35-9). Since isoamylene (2-methylbutene, CAS 26760-64-5) is a mixture of the two isomers, 2-methylbut-2-ene (CAS 513-35-9) and 2-methylbut-1-ene (CAS 563-46-2) and in the absence of any reliable data for isoamylene the data for the isomer (CAS 513-35-9) are considered suitable for read-across. After 96 hours, the highest measured concentration at which no mortality had occurred was 2.93 mg/l and the lowest at which there was 100% mortality was 8.51 mg/l. Treatment-related effects were exhibited at 5.33 mg/l and higher concentrations.

Based on these findings the following values have been estimated: 96 hour LC50 value = 4.99 mg/l (95% confidence limits of 2.93 and 8.51 mg/l).