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Toxicity to microorganisms

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Description of key information

EC50: 87 mg/L after 30 min incubation

Key value for chemical safety assessment

EC50 for microorganisms:
87 mg/L
EC10 or NOEC for microorganisms:
10 mg/L

Additional information

The results of this study show that the sample tested, Yoracryl Yellow RL Liquid 100, caused a significant inhibitory effect on the respiration rate of activated sludge after a contact period of 30 minutes. The estimated EC50 value for the sample was 87 mg/L. Dilution of the test solution from 1000 mg/L to 10 mg/L had a significant effect on the degree of inhibition. Dilution of the sample resulted in the inhibition rate of the activated sludge respiration to decrease from 90.8 % to 4.5 % over this range of test sample concentrations.

The Test Procedures state that the controls are run before and after the test concentrations. However, the controls reported for the reference test were both run after the test concentrations. The Study Director considered this deviation from the procedures to be acceptable and to have no significant effect on the results presented in this report.