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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The EC50 is 12 mg/L (72h; nominal concentration) and the EC10 was 6.9 mg/L (72h; nominal concentration).

Key value for chemical safety assessment

EC50 for freshwater algae:
12 mg/L
EC10 or NOEC for freshwater algae:
6.9 mg/L

Additional information

For this endpoint, one study is available. In this study the effect of the test item to freshwater green algae Pseudokirchneriella subcapitata in a 72 -hour algal growth inhibition test was assessed according to OECD 201 and GLP.

The nominal concentrations tested were 0.32, 1.0, 3.2, 10, 32 and 100 mg/L, in parallel with a control. The test fulfilled the validity criteria.

The stability of the substance was assessed by measuring the actual concentrations tested at the beginning and the end of the experiments.

The measured concentrations did not differ more than 20% except for the lowest concentration tested, indicating the stability of the substance.

The test item had significant inhibitory effect on the growth rate of the algae after 72 hours starting at a concentration of 1.0 mg/L. The algae yield was statistically significantly reduced starting at a test concentration of 3.2 mg/L. The 72-hour NOEC based on the growth rate was determined to be the lowest test concentration, since at this concentration the growth rate of the algae was not significantly lower than in the control.

Microscopic examination of the shape and size of the algal cells at the end of the test showed no difference between the algae growing in the presence of the test substance or in controls up to a nominal concentration of 10 mg/L.

Based on the results of nominal concentrations the ErC50 (72 h) is 12 mg/L and the ErC10 (72 h) was 6.9 mg/L.