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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The 72-h ErC50 and ErC10 values are 74 mg/L and 25 mg/L, respectively in freshwater green algae (P. subcapitata)

Key value for chemical safety assessment

EC50 for freshwater algae:
74 mg/L
EC10 or NOEC for freshwater algae:
25 mg/L

Additional information

The toxicity towards freshwater algae was determined in a study according to OECD guideline No 201 and in compliance with GLP criteria.

In this study, exponentially growing freshwater algae (Pseudokirchneriella subcapitata) at an initial cell concentration of ca. 5E+03 per mL, were exposed to nominal test substance concentrations of 0 (control), 6.25, 12.5, 25, 50, and 100 mg/L for 96 hours under static conditions. The test was performed in 3 replicates per test concentration. Test concentrations were analytically verified and remained well within ± 20% of nominal throughout the test. After 24, 48, 72, and 96 hours, the algae were scored for the number of cells and for microscopic abnormalities.

After 72 hours exposure a significant inhibition of growth rate was observed at test concentrations of 25 mg/L (7%), 50 mg/L (34%) and 100 mg/L (64%). Inhibition of yield was also significant at 25 mg/L (28%), 50 mg/L (81%) and 100 mg/L (96%). Based on these findings the 72-h ErC50 and 72-h EyC50 values were determined at 74 mg/L and 32 mg/L, respectively. The 72-h ErC10 and 72-h EyC10 values were 25 mg/L and 15 mg/L, respectively. The NOEC for both endpoints was 12.5 mg/L.