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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

ErC50 (72h) > 100 mg/l (nominal)
ErC10 (72h) > 100 mg/l (nominal)
NOEC (growth rate, 72h) ≥ 100 mg/l (nominal)

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

The toxicity potential of the substance to green algae was evaluated after 2 hours of exposure to different concentrations of the substance (ranging from 40 -1800 mg/l). Fluorescence parameters were measured on 2 ml algal suspension after 1 and 2 h of exposure. The ΕC50 (2h) was determined to be 1098.1 ± 13.7 mg/l.


 


A second study is performed.


This study evaluated the toxicity of the test item towards Desmodesmus subspicatus according to the OECD 201 and EU Method C.3 and under GLP conditions. This freshwater green alga is chosen as a typical species of phytoplankton. The test concentrations for the main study were chosen based on the results of the range finding test. Algae were exposed to 0 -1 -10 -100 mg/l of the substance and the cells were counted at 24, 48 and 72 hours. The growth rate and yield inhibition percentage were determined at 72 hours. No inhibition of growth rate or yield was observed at any of the tested concentrations. The EC50 at 72 h from the dose range finding test is therefore > 100 mg/l, while the NOEC at 72 h could be ≥ 100 mg/l.


In the main study algae were exposed to the substance under static conditions for 72 hours at 4.6, 10, 22, 46 and 100 mg/L nominal. The test concentrations were measured at the beginning and at the end of the study.  A positive control was tested in parallel. The cell concentrations were tested every 24 hours with an electronic particle counter. The pH value in treatments and blank control was measured at the beginning and start of the test. At the end of the test, the treatments were examined microscopically in order to assess the appearance of the algae and detect abnormalities (e.g. caused by the exposure to the test item).


The measured concentrations lay between 92 % and 95 % of the nominal concentrations at the beginning of the test and between 81 % and 102 % of the nominal concentrations at the end of the test. Normal and Healthy Appearance of the Algae was noted.


No inhibition of the growth was noted in any of the test solutions and control.


ErC50 (72h) > 100 mg/l (nominal)
ErC10 (72h) > 100 mg/l (nominal)
NOEC (growth rate, 72h) ≥ 100 mg/l (nominal)

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