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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

Under the conditions of the study, the 48-hour EC50 value was determined to be 73.4 mg/L LR WAF and the corresponding No Observed Effect Concentration (NOEC) was considered to be 46 mg/L LR WAF based on nominal concentrations.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
73.4 mg/L

Additional information

The toxicity of the test material to the freshwater invertebrate, Daphnia magna, was investigated in a study which was conducted under GLP conditions and in accordance with the standardised guideline OECD 202. The study was assigned a reliability score of 1 in accordance with the criteria for assessing data quality set forth by Klimisch et al. (1997).

Based on the results of a range-finding test, an initial experiment was conducted with a test concentration of 100 mg/L LR WAF (loading rate water accommodated fraction), a control group was also included. The test was conducted under semi-static test conditions with media preparation at 0 and 24 hours. However due to 30 % immobility observed the in the test concentration the test was repeated with a full range of 5 concentrations.

Based on the results of a range-finding test and an initial experiment, for which the key results only have been reported, a definitive test was conducted at test concentrations of 4.4, 9.6, 21, 46 and 100 mg/L LR WAF, a control group was also included. The test was conducted under semi-static test conditions with media preparation at 0 and 24 hours.

At the start of the test, five juvenile Daphnia magna were added to each test vessel. The Daphnia magna in each test vessel were observed at 24 and 48 hours. The Daphnia magna were not fed during the test. Analytical chemistry was not performed during the definitive phase due to issues seen during media trial work and range-finder phases of the study. Following extensive evaluation, it was determined that chemical analysis would not be appropriate (based on preliminary testing) or result in reliable numbers for hazard assessment (not reliable or repeatable).

As chemistry analysis was not performed during the definitive phase, results were based on mg/L LR WAF. However, Smithers study number 3201220 found the water solubility of the test material to be < 0.05 µg/mL.

The validity criteria for control immobility (=10 %) and dissolved oxygen (=3 mg/L) were both satisfied. The test is therefore considered valid.

Under the conditions of the study, the 48-hour EC50 value was determined to be 73.4 mg/L LR WAF and the corresponding No Observed Effect Concentration (NOEC) was considered to be 46 mg/L LR WAF based on nominal concentrations.