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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

The 48-hour EC50 was determined to be > 0.10 mg/L. Correspondingly the No Observed Effect Concentration was ≥ 0.10 mg/L.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
0.1 mg/L

Additional information

Methods

A study was performed to assess the acute toxicity of the test material to Daphnia magna. The method followed that described in the OECD Guidelines for Testing of Chemicals No. 202, "Daphnia sp, Acute Immobilisation Test and Reproduction Test", referenced as Method C.2 of Commission Directive 92/69/EEC.

Procedures

Following a preliminary range-finding study, 40 daphnids (4 replicates of 10 animals) were exposed to an aqueous dispersion of the test material at a concentration of 0.1 0 mg/L for 48 hours under static test conditions. lmmobilisation and any adverse reactions to exposure were recorded after 24 and 48 hours.

 

Results

The 48-Hour EC50 for the test material to Daphnia magna based on nominal test concentrations was > 0.10 mg/L and correspondingly the No Observed Effect Concentration was ≥ 0.10 mg/L.

The test concentration of 0.10 mg/L was the highest attainable test concentration due to the limited solubility of the test material in water and auxiliary solvent, and having due regard for the amount of auxiliary solvent permitted in the test under the OECD Guidelines.

Analysis of the freshly prepared test solutions at 0 hours showed the measured concentrations for the 0.10 mg/L test concentration to be 77 % (replicates R1- R2pooled) and 80 % (replicates R3- R4pooled) of nominal. These low results were considered to be due to sampling and/or analytical variation given that analysis of duplicate frozen samples gave measured concentrations of 84 % and 84 % of nominal respectively. At 48 hours, measured concentrations in excess of the required 80 % of nominal test concentrations were observed. It was therefore considered justifiable to estimate the EC50 values based on nominal test concentrations only.