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Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Link to relevant study record(s)

Description of key information

72h-EC50 > 0.01 mg/L (average exposure concentration)

Key value for chemical safety assessment

Additional information

A study determining the toxicity of 2-(4-tert-butylphenyl)-6-cyano-5 [bis(ethoxycarbonylmethyl)carbamoyloxy]-1 H-pyrrolo[1 ,2-b][1 ,2,4]triazole-7-carboxylic acid-2,6-di-tert-butyl-4-methyl-cyclohexyl ester (UC-141) to algae is available (Bouwman, 2004). This test was conducted according to OECD Guideline 201 under GLP conditions. Selenastrum capricornutum was exposed for 72 hours to a filtrate of a solution of the test substance prepared at 100 mg/L nominal. Two additional replicates were included in the test set-up at 100 mg/L but without algal presence. Analytical determinations at t=0 and t=24 h in the test vessels containing algae proved that the test concentration after 24 h was already below the limit of detection. However, concentrations in vessels without algae could be still determined at this time point (0.01 mg/L), indicating that adsorption to algae cells might have contributed to the decrease of test concentrations in the standard treatment group. No significant effects regarding biomass or growth rate were observed after 72 hours exposure to the test substance. Therefore, a precise EC50 value could not be determined and it is considered to be > 0.01 mg/L (average exposure concentration).


In conclusion, UC-141 was not acutely toxic to algae under the tested conditions.