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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The concentrations of test item causing a 50 % and 10% reduction in growth rate were estimated:
72h-EC50 = 50.0 µg/L (47.8-52.3)
72h-EC10 = 26.2 µg/L (23.9-28.5)

Key value for chemical safety assessment

EC50 for freshwater algae:
50 µg/L
EC10 or NOEC for freshwater algae:
26.2 µg/L

Additional information

The determination of the growth inhibition of the freshwater algae Pseudokirchneriella subcapitata exposed to the test item for 72 hours was assessed according to the OECD Guideline 201.

Algae were exposed to serial dilutions of a saturated solution of the test item prepared with slow-stirring conditions due to the characteristics of the substance.

The test item concentrations were not maintained over the 72h test period (i.e. deviation > 20%) only in the samples with algae. Therefore, it can be assumed that the test substance adsorbed onto algae; as a consequence the analysis of the results was based on the initial measured concentrations (all results are µg/L):

Growth rate (data determined from cytomer)

72h-EC10 = 26.2 µg/L (23.9-28.5)

72h-EC50 = 50.0 µg/L (47.8-52.3)

Biomass (data determined from cytomer)

72h-EC10 = 19.1 µg/L (17.7-20.4)

72h-EC50 = 31.2 µg/L (30.4-32.1)

Growth rate (data determined from counter)

72h-EC10 = 28.4 µg/L (26.7-30.2)

72h-EC50 = 52.0 µg/L (50.4-53.7)

Biomass (data determined from counter)

72h-EC10 = 21.8 µg/L (N.D.)

72h-EC50 = 34.1 µg/L (N.D.)