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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

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Administrative data

Link to relevant study record(s)

Description of key information

With high probability acutely not harmful to fish.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Dose descriptor:
Effect concentration:
> 100 - < 215 mg/L

Additional information

The LC50 value of 1-methyl-1H-imidazole (CAS 616-47-7) on Leuciscus idus was determined to be >= 100 mg/L to <= 215 mg/L (nominal, no analytics) in a guideline study according to DIN 38 412 (BASF AG 10F0073/885186, 1989).

Even though no analytical verification of the test substance concentration was assessed, the test item can be considered as stable under test and storage conditions according to results of biodegradation and adsorption as well as physico-chemical properties such as water solubility and volatility: 1-methylimidazole is considered not readily biodegradable (according to OECD criteria), and only inherently biodegradable after a prolonged test duration (60 days, BASF, 2011, 29G0492/11G077). Additionally, adsorption of 1-methylimidazole to the solid soil phase is not expected (BASF, 2021, Franco&Trapp 2008/2009/2010; BASF, 2018, KOCWIN v2.00). Furthermore, the substance is completely miscible at 20°C (1000g/L; see Ch. 4.7) and has a low vapour pressure of 0.3514 hPa at 20 °C and 0.5166 hPa at 25 °C (see IUCLID Chapter 4.6).

Therefore, the substance can be regarded as stable during the 72h test period and tested concentrations can be regarded as nominal test concentrations.


In conclusion, the substance is considered to be with high probability acutely not harmful to fish.