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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The substance showed 8.8 % respiration inhibition of activated sludge at the highest test item concentration of 1000 mg/L. After 3 hrs an EC10 and an EC50 of >1000 mg/l were obtained. (Caspers 2010).

Key value for chemical safety assessment

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

Additional information

"Should read: > 1000 mg/L"

In order to test the toxicity to microorganisms of the substance activated sludge from predominantly domestic sewage plant was exposed to the test solution of three nominal concentrations (10, 100 and 1000 mg/L), blank control solution and solution with positive reference substance were applied for a period of 3 hours. The method used was the EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test) which is equivalent to OECD Guideline for Testing of Chemicals No. 201. Dissolved oxygen was recorded and respiration rates were calculated. No physico-chemical oxygen consumption was observed at the highest concentration of test substance. No respiration inhibition was observed at 10, 100 and 1000 mg/L. The effect value relates to nominal concentration, since no analytical monitoring was performed.

This toxicity study is classified as acceptable and satisfies the guideline requirements for the toxicity study to microorganisms.