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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

NOEC of Everzol Orange ED-G Crude was at 1000 mg/l. The EC50 exceeded 1000 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L
EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

The influence of Everzol Orange ED-G Crude on the respiration rate of activated sludge was investigated after a contact time of 3 hours.

Concentrations of 10, 100 and 1000 mg/l were tested. The result showed no inhibition, 5% and 13% inhibition of the respiration rate at 10, 100 and 1000 mg/I, respectively. The respiration inhibition rate of the sludge at 1000 mg/l was not significant based on the statistics in the Appendix 3 in the experimental report (Two samples t-Test: α =0.05). Thus, the EC50 was above the highest concentration rate tested (1000 mg/l).

There was no oxygen uptake from abiotic processes. The results at 1000 mg/l with a nitrification inhibitor showed that the heterotrophic inhibition of the respiration rate was comparable to the total inhibition.

The batch of activated sludge was checked for sensitivity by testing the reference substance 3,5 -dichlorophenol, which showed normal sensitivity.

In conclusion, Everzol Orange ED-G Crude was not toxic to waste water (activated sludge) bacteria at a concentration of 1000 mg/l (NOEC). The EC50 exceeded 1000 mg/l.