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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Short-term toxicity to aquatic invertebrates

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Administrative data

Link to relevant study record(s)

Description of key information

The 48 hour EC50 value was 3.84 mg/L (95% confidence limits of 3.01 and 4.80 mg/L measured concentration). After 48 hours, the lowest measured concentration resulting in 100% immobility was 6.63 mg/L and the highest measured concentration at which immobilisation was ≤ 10% was 1.74 mg/L (NOEC).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
3.84 mg/L

Additional information

One reliable proprietary freshwater study, Huntingdon (2004c) is available for 2-methylbut-2-ene. The 48 hour EC50 value was 3.84 mg/L (95% confidence limits of 3.01 and 4.80 mg/L measured concentration). After 48 hours, the lowest measured concentration resulting in 100% immobility was 6.63 mg/L and the highest measured concentration at which immobilisation was 10% was 1.74 mg/L (NOEC).

The data were obtained from a reliable proprietary report which was used as the key study in the OECD SIDS (2005) for CAS 513-35-9 where it was given a reliability 1. The EC50 (48 hours) for Daphnia magna (Crustacea) was determined to be 3.84 mg/L for 2-methylbut-2-ene. The EC50 figure indicates that 2-methylbut-2-ene is not toxic, according to the criteria for PBT assessment. However, this endpoint in conjunction with the predicted non-biodegradability of the substance and anincomplete chronic datasetwill result in a classification of a category Aquatic Chronic 2 toxicity to the environment and the hazard statement 'Toxic to aquatic life with long lasting effects'.