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Short-term toxicity to aquatic invertebrates

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Under the conditions of the present study 1-ETHYL-3-METHYL IMIDAZOLIUM ETHYLSULFATE did not induce acute immobilisation of Daphnia magna at 100 mg/L after 48 hours of exposure (NOEC). The 48h-EC50 was > 100 mg/L based on analytically confirmed nominal concentrations.

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Additional information

Acute Toxicity Study in Daphnia magna with 1-ETHYL-3-METHYL IMIDAZOLIUM ETHYLSULFATE.

The study procedures described in this report were based on the ISO International Standard 6341, 1996. In addition, the procedures were designed to meet the test methods and validity criteria of the EEC directive 92/69, Part C.2, 1992 and the OECD guideline No. 202 Part I, 1984.

The batch of 1-ETHYL-3-METHYL IMIDAZOLIUM ETHYLSULFATE tested was a light yellow viscous liquid with a purity of 99.0% and completely soluble in test medium at the concentrations tested. Preparation of test solutions started with a stock solution of 100 mg/L applying 15-20 minutes of magnetic stirring to accelerate the dissolving of the test substance in the test medium. The lower test concentrations for the range-finding test were prepared by subsequent dilutions of the stock in test medium. The final test solutions were all clear and colourless. The study started with a range-finding test, exposing ten daphnids per concentration (in duplicate, 5 per vessel) to a range of 0.1 to 100 mg/L increasing by a factor of 10 and to a blank control. No immobility was observed in any of the test solutions during the test period. The analytical results showed a mean measured concentration of 102 mg/L at a nominal concentration of 100 mg/L at the start of the test. Further, this mean measured concentration proved to be stable under test conditions for at least 48 hours. Based on these results, the expected 48h-EC50 was above a concentration of 100 mg/L. The study was continued with a limit test, exposing twenty daphnids per concentration (in quadruplicate, 5 per vessel) to a blank-control and a nominal concentration of 100 mg/L. The total test period was 48 hours and samples for analytical confirmation of actual test concentrations were taken from the blank-control and the limit concentration at the start and the end of the test period. Analysis of the samples taken at the start of the limit test showed that the mean actual test concentration was in agreement with nominal (99%) and remained stable during the 48-hour test period (i.e. 98% of initial). Based on these results, the NOEC and the EC50 were based on nominal concentrations. The study met the acceptability criteria prescribed by the protocol and was considered valid. 1-ETHYL-3-METHYL IMIDAZOLIUM ETHYLSULFATE did not induce acute immobilisation of Daphnia magna at 100 mg/L after 48 hours of exposure (NOEC). The 48h-EC50 was > 100 mg/L based on analytically confirmed nominal concentrations.