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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The EbC50, ErC50 and EyC50 for the green algae Pseudokirchneriella subcapitata of the read-across substance bisamide (UVCB) were > 100 mg/L (nominal loading rate). The no observed effect loading rate (NOELR) for the area under the growth curve, growth rate and yield was 100 mg/L and no toxicity was observed at the limit of solubility of the test substance.

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC50 for marine water algae:
100 mg/L

Additional information

A study was performed to assess the acute toxicity of the read-across substance bisamide (UVCB) to the unicellular green alga Pseudokirchneriella subcapitata under non-axenic conditions according to OECD Guideline 201 and EU Method C.3 in compliance with GLP. Triplicate algal cultures, with an initial cell density of ca. 1 x 104/mL, were exposed to WAFs of the test substance prepared from an aqueous mixture with initial nominal loading rates of 6.25, 12.5, 25.0, 50.0 and 100 mg/L. At each concentration, the test substance was added to medium, stirred for approximately 24 h in the dark and then left to stand for another 24 h in the dark before the aqueous phase was removed and filtered (0.2 μm pore size cellulose nitrate). The resultant WAF was used in the test. Cell numbers were counted daily to monitor growth. The test results were expressed in terms of the area under the growth curve, growth rate and yield. Concentrations were not verified analytically because of the high insolubility of the substance. Under the test conditions, the EbC50, ErC50 and EyC50 were greater than the maximum concentration tested of 100 mg/L (nominal loading rate). The no observed effect loading rate (NOELR) for the area under the growth curve, growth rate and yield was 100 mg/l and no toxicity was observed at the limit of solubility of the test substance.