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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

72 h EC50 = > 100 mg/L, NOEC = 100 mg/L, Scenedesmus subspicatus, OECD 201, EU Method C.3, Thomas 1996c

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

The toxicity of the test material to aquatic plants was investigated in the algae Scenedesmus subspicatus in accordance with standardised guidelines OECD 201 and EU Method C.3. The algal culture was exposed to the test material in at nominal concentrations of 0, 0.1, 1, 10 and 100 mg/L under static conditions. The mean measured concentrations of the test material ranged from 95 to 109 % of the nominal exposure concentrations; the results and conclusions were therefore based on the nominal concentrations. Since the test material was a coloured solution, a modified testing method was used whereby controls shaded by the test solution were used to compare the effects of the reduced light falling on the algae as the concentration of test material increased. Under the conditions of the study, the 72 hour EC50 was determined to be in excess of 100 mg/L based on the specific growth rate and in excess of 100 mg/L based on biomass data. Although the test material was red in colour at 100 mg/L, a method was used to compensate for the absorption of light by the test material so that the assumed toxic effect could be identified.

The study was performed in line with GLP and accepted standardised guidelines with a high standard of reporting. The study was assigned a reliability score of 1 in accordance with the criteria outlined by Klimisch (1997) and considered suitable for assessment as an accurate reflection of the test material.

The available data are considered to be complete and the result determined, 72 h EC50value > 100 mg/L, 72 h NOEC value 100 mg/L, was taken forward for risk assessment.