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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

There is a high probability that the product is not acutely harmful to aquatic algae. 
Based on long-term (chronic) toxicity study data, the product is very likely not harmful to aquatic algae.

Key value for chemical safety assessment

Additional information

To assess the growth inhibition potential of the test substance on aquatic algae, a study was conducted according to the algal growth inhibition test guideline described in 87/302/EEC. Green Algae (Scenedesmus subspicatus) were used in an initial cell density of 10300 cells/mL. Tween 20 was used as a vehicle. The tested concentrations were 1.23, 3.7, 11, 33 and 100 mg test substance/L (nominal). Each test concentration was tested in 3 replicates, the blank control in 6. The duration of the test was 72 hours, cell densities were counted after 24, 48 and 72 hours. The mean cell densities at the end of the exposure time (72 hours) were 355000 cells/mL for the blank control and 284000 for the vehicle control. For the test concentrations, the following cell densities were determined: test conc. 1.23 mg/L: 418000 cells/mL, test conc. 37000 mg/L: 409000 cells/mL, test conc. 11 mg/L: 249000 cells/mL, test conc. 33 mg/L: 309000 cells/mL and test conc. 100 mg/L: 98000 cells/mL. As a result, the EbC50 value was determined to be 62 mg/L and the NOEbC was determined to be 3.7 mg/L. No values based on growth rate were availble.

As supporting information a study with CAS 65140-91-2 was conducted. In a 72 hour acute toxicity study, the green algae Scenedesmus subspicatus was exposed to the test item at nominal concentrations of 1.23, 3.7, 11, 33, 100 mg/L under static conditions in accordance with the EEC guideline 302/87 (1987). The NOEbC and EbC50 values based on cell number were both above 100 mg/L. The detailed read across justification is attached to the endpoint study record.

In conclusion, there is a high probability that the product is not acutely harmful to aquatic algae. Based on long-term (chronic) toxicity study data, the product is very likely not harmful to aquatic algae.