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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Endpoint summary

Administrative data

Description of key information

Additional information

Short-term toxicity to fish:

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).

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


Long-term toxicity to fish:

No experimental data available.

In Annex IX of Regulation (EC) No 1907/2006, it is laid down that chronic tests shall be proposed by the registrant if the chemical safety assessment indicates the need to investigate further the effects on fish. According to Annex I of this regulation, the chemical safety assessment triggers further action when the substance or the preparation meets the criteria for classification as dangerous according to Directive 67/548/EEC or Directive 1272/2008 or is assessed to be a PBT or vPvB. The hazard assessment of the substance reveals neither a need to classify the substance as dangerous to the environment, nor is it a PBT or vPvB substance, nor are there any further indications that the substance may be hazardous to the environment. Therefore, and for reasons of animal welfare a chronic test on fish is not provided.


Short-term toxicity to aquatic invertebrates:

The acute toxicity of 1-methyl-1H-imidazole (CAS 616-47-7) to Daphnia magna was tested in a guideline study according to EU method C2. The EC0 value was determined to be 125 mg/L; the EC50 value was found to be about 267.94 mg/L after 48 h, based on nominal test concentrations (BASF AG, 1989; report no.: 1/0243/2/89-0243/89).

In conclusion, 1-methyl-1H-imidazole (CAS 616-47-7) is considered to be with high probability acutely not harmful to aquatic invertebrates. 


Long-term toxicity to aquatic invertebrates:

A long-term toxicity study is available for aquatic invertebrates. This study was conducted according to OECD Guideline 211 and Daphnia magna was used as a test specie. The following nominal test concentrations were analytically verified: 0 (control), 1.2, 2.5, 5, 7.5 and 10 mg/L. The 21-d EC10 value was determined to be 2.24 mg/L (for reproduction). The NOEC was determined to be >= 1.2 mg/L (BASF SE, 2023).

Overall, it can be concluded that no significant and relevant long-term effects on aquatic invertebrates are to be expected (NOEC > 1 mg/L).


Toxicity to aquatic algae and cyanobacteria:

The acute toxicity of 1-methyl-1H-imidazole (CAS 616-47-7) on the aquatic green algae Desmodesmus subspicatus was investigated in a study conducted according to OECD 201 (BASF AG, 1990; report no.: 2/204389/t72). The results were recalculated using ToxRatPro v3.3.0 (BASF SE, 2021). After 72 h, the ErC10 was found to be 119.4 mg/L based on nominal concentrations; the 72-h ErC50 was determined to be 202.5 mg/L.

1-methyl-1H-imidazole (CAS 616-47-7) is considered to be with high probability acutely not harmful to aquatic algae.


Toxicity to microorganisms:

The of 1-methyl-1H-imidazole (CAS 616-47-7) to microorganisms was investigated in a growth inhibition guideline study performed according to DIN 38412-8, using Pseudomonas putida as test organism. After 7 h of incubation, the EC10 was determined to be 589.6 mg/L (7h EC50 = 1050 mg/L), based on nominal test concentrations.

The inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriate low concentrations.