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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

ErC50 (72 h) = 32.2 mg/L (OECD 201, Desmodesmus subspicatus)
ErC10 (72 h) = 19.9 mg/L (OECD 201, Desmodesmus subspicatus)
EyC50 (72 h) = 22.9 mg/L (OECD 201, Desmodesmus subspicatus)
EyC10 (72 h) = 15.4 mg/L (OECD 201, Desmodesmus subspicatus)

Key value for chemical safety assessment

EC50 for freshwater algae:
32.2 mg/L
EC10 or NOEC for freshwater algae:
19.9 mg/L

Additional information

The toxicity of the test substance to the unicellular freshwater alga Desmodesmus subspicatus was investigated according to the procedures of the OECD Guideline 201. Based on a preliminary range finding test, five nominal concentration levels (6.25, 12.5, 25, 50, 100 mg/L) of a geometrical series (dilution factor: 2) were tested under static conditions. Three replicates were tested for each test concentration and six replicates for the control. The concentrations of the test substance were analytically verified by GC at test start and test end (72 h) for the nominal concentrations of 6.25, 25 and 100 mg/L. The control was only measured at test start. The measured concentrations of the test substance after 72 hours of the exposure were in the range of 60 - 80% of the initial measured values and 44 – 54% of the nominal values, respectively. Based on growth rate an ErC50 (72 h) of 32.2 mg/L (measured) was determined. The corresponding ErC10 (72 h) was 19.9 mg/L (measured).

These results are supported by results of another algae test (72 h-ErC50 = 25.8 mg/L; 72 h-ErC10 = 4.1 mg/L). For this test only a short summary is available without any details on the test design (test system, conditions, measurements, etc.). Therefore, the reliability of the test cannot be assigned (RL4), consequently the results were not used for the assessment of the test substance.