Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Area under the growth curve (measured concentrations);
EbC50 (72h): 10.5 mg/L (95% confidence limits, 9.55 & 11.7 mg/L)
EbC50 (96h): 10.1 mg/l (95% confidence limits, 9.21 & 11.1 mg/L)
No observed effect concentration (NOEC): 3.61 mg/L
Average specific growth rate (measured concentrations):
ErC50 (0-72h): 12.0 mg/L (95% confidence limits, 7.22 & 21.1 mg/L)
ErC50 (0-96h): 13.2 mg/L (95% confidence limits, 12.2 & 14.3 mg/L)
No observed effect concentration (NOEC): 7.22 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:
12 mg/L
EC10 or NOEC for freshwater algae:
7.22 mg/L

Additional information

One reliable proprietary freshwater study, Huntingdon (2004d) 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.

These results show that using area under average specific growth rate (measured concentrations); ErC50 (0-72h): 12.0 mg/L (95% confidence limits, 7.22 & 21.1 mg/L), ErC50 (0-96h): 13.2 mg/L (95% confidence limits, 12.2 & 14.3 mg/L), no observed effect concentration (NOEC): 7.22 mg/L.