1-Ethyl-3-methylimidazolium benzoate

Endpoint summary

Description of key information

Toxicity to aquatic invertebrates:

In an acute immobilization test to Daphnia magna according to OECD guideline 202 (BASF SE, 2018), the 48 hour-EC50 was above 120 mg/L based on the nominal concentration of the test item.

Toxicity to aquatic algae:

In an alga growth inhibition test with Pseudokirchneriella subcapitata according to OECD guideline 201 (BASF SE, 2018), an EC50 of 469 mg/L was determined (EC10 = 144 mg/L).

Toxicity to microorganisms:

The effect of the test substance on oxygen consumption of microorganisms was performed according to OECD guideline 209 (BASF SE, 2017). An EC50 of > 1000 mg/L was determined (EC10 = 220 mg/L). 

Additional information

Toxicity to aquatic invertebrates:

The effects of the test item on aquatic invertebrates were determined in the acute immobilization test with Daphnia magna (STRAUS) according to OECD guideline 202 (BASF SE, 2018). The test item was a clear, yellowish viscous liquid and was miscible with water. The study was performed under static conditions over a period of 48 hours with one concentration of the test item prepared as a limit test item concentration of 120 mg/L. The concentration was visually clear throughout the exposure period.

The measured concentration of the cation of the test item in fresh media at the start of the exposure (0 hours) and at the end of the exposure (48 hours) was 118 % of the nominal concentration. The measured concentration of the anion in fresh media was 108 % of the nominal concentration at the start of the exposure (0 hours) and 88 % of the nominal concentration at the end of the exposure (48 hours). The measured concentrations of the test item components were within ± 20 % of the nominal concentration. This indicates that the test item concentrations were successfully maintained for the duration of the test. Therefore, all effect values given are based on the nominal test item concentrations. The validity criteria of the test guidelines were fulfilled. In the control group, no daphnids were immobilized or showed any signs of disease or stress during the 48-hour test period. The dissolved O2 concentration in the old media at the end of the exposure was > 7.87 mg/L (required: > 3 mg/L at the test end of the exposure) in all test vessels of the limit concentration and the control.

Based on the nominal concentration of the test item, the 48 hour-EC50 for Daphnia magna was > 120 mg/L. The nominal concentration was confirmed by analytical measurement.

Toxicity to aquatic algae:

The toxicity of the test item to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD guideline 201 and Council Regulation (EC) No. 266/2016 method C.3 (BASF SE, 2018). The aim of the study was the determination of EC10-, EC20- and EC50-values of the growth rate over a period of 72 hours.

The test item is yellowish, clear, viscous liquid and miscible with water at room temperature (T = 23 °C) and at T = 20.0 °C ± 0.5 °C in any ratio. The study was conducted under static conditions with an initial cell density of 6839 cells/mL. A stock solution with a nominal concentration of 1000 mg/L was freshly prepared with dilution water and agitated until the solution was visually clear. The stock solution and four dilution levels out of the stock solution were tested in a geometrical series with a dilution factor of √10: 10.0 - 31.6 -100 - 316 - 1000 mg/L. Three replicates were tested for each test item concentration and six replicates for the control. The test media were visually clear throughout the exposure. The environmental conditions were within the acceptable limits. The EC50 -value for inhibition of growth rate after 72 hours was 469 mg/L (EC10 vaule 144 mg/L). The nominal concentrations were confirmed by analytical measurement.

Toxicity to microorganisms:

The influence of the test substance on the respiration inhibition of microorganisms was investigated in a GLP guideline study according to OECD 209 (BASF SE, 2017). Activated sludge from municipal sewage treatment plant, which predominantly receives domestic sewage, was exposed to nominal concentrations of 12.3, 37.0, 111, 333, and 1000 mg/L test substance in a static setting. After 3 hours of exposure an EC50 of > 1000 mg/L (nominal) was determined (EC10 = 220 mg/L).