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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

EC50/LC50 for freshwater invertebrates:
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'.