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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

In this study the test item was found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 hours with the following effect values (geometric mean measured test item concentrations). The NOEC-values for inhibition of growth rate and inhibition of yield after 72 hours were 52.3 mg/L and 14.6 mg/L, respectively. The LOEC-values for inhibition of growth rate and inhibition of yield after 72 hours were 93.5 mg/L and 31.0 mg/L, respectively. The EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) with 95 % confidence intervals after 72 hours were 60.9 (53.5 – 79.2) and 59.5 (53.8 - 80.2) mg/L, respectively. The effects were caused by the low pH-values. This was confirmed by the pH-neutralized concentration level of 98.9 mg/L (geometric mean measured) which caused no effects on the algae growth. Based on the pH-neutralized concentration the NOEC-values for both the inhibition of the growth rate and the inhibition of the yield after 72 hours were 98.9 mg/L. The EC50-values for both inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 98.9 mg/L. All effect levels are given based on geometric mean measured concentrations of the test item.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:
98.9 mg/L

Additional information

In this study the test item was found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 hours with the following effect values (geometric mean measured test item concentrations). The NOEC-values for inhibition of growth rate and inhibition of yield after 72 hours were 52.3 mg/L and 14.6 mg/L, respectively. The LOEC-values for inhibition of growth rate and inhibition of yield after 72 hours were 93.5 mg/L and 31.0 mg/L, respectively. The EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) with 95 % confidence intervals after 72 hours were 60.9 (53.5 – 79.2) and 59.5 (53.8 - 80.2) mg/L, respectively. The effects were caused by the low pH-values. This was confirmed by the pH-neutralized concentration level of 98.9 mg/L (geometric mean measured) which caused no effects on the algae growth. Based on the pH-neutralized concentration the NOEC-values for both the inhibition of the growth rate and the inhibition of the yield after 72 hours were 98.9 mg/L. The EC50-values for both inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 98.9 mg/L. All effect levels are given based on geometric mean measured concentrations of the test item.