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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The toxicity of the water-accommodated fraction of the substance to the green alga Selenastrum capricornutum (now called Pseudokirchneriella subcapitata) was determined in a GLP-compliant study based on OECD and U.S. EPA guidelines.

Key value for chemical safety assessment

EC50 for freshwater algae:
110 mg/L
EC10 or NOEC for freshwater algae:
33 mg/L

Additional information

In the study entitled “Acute Toxicity of the Water Accommodated Fraction (WAF) of OS# 18230U to the Freshwater Alga,Selenastrum capricornutum–Range Finding Test“ (Ward et. al. T.R. Wilbury Laboratory, 1997), exposure of freshwater alga to OS#18230U resulted in a 96 h median effective concentration (EC50) of 110 mg/L (95% confidence interval = 33 to 330 mg/L) when calculated using cells/ml, and an EC50 of 160 mg/L (95% confidence interval = 33 to 330 mg/L) when calculated using average specific growth rate. The 96 h NOEC was determined to be 33 mg/L using both the cells/ml and average specific growth rate. An additional algal toxicity test indicated that the effect of the substance at the highest test concentration of 3,300 mg/L tested was algistatic rather than algicidal.