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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

EC50 > 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

An activated sludge respiration test was performed with the Structural Analogue 01 to evaluate the effect of the test item on microorganisms by measuring the respiration rate. The study was performed in accordance with the OECD Guidelines for Testing of Chemicals (No. 209, 04 April 1984), the Council Regulation (EC) No 440/2008, Part C, C.11, the Product Properties Test Guideline OPPTS 850.6800 of the United States Environment Protection Agency (EPA) and the Principles of Good Laboratory Practice (GLP) and reoprted with a valid GLP certificate. The test concentrations (10, 31, 100, 313 and 1000 mg/L) were chosen to permit the determination of the EC50. In comparison to the inoculum controls the respiration rate of the activated sludge was not inhibited and a slight stimulation of respiration rates (-4.9; -2.9; -2.9 and -1.0%) were observed in the test concentration range of 10-313 mg/L. The respiration rate was inhibited 2.9% at the highest test concentration of 1000 mg/L, which was considered to reflect the biological variability of the test system and not to be a toxic effect on bacteria. Based on measured inhibition rates it can be stated that the 3-hour EC20, EC50 and EC80 were higher than 1000 mg/L. The NOEC was determined to be equal to or greater than 1000 mg/L.

The aquatic toxicity of the Structural Analogue 02 to microbial activity in sewage sludge was tested in a valid GLP activated sludge respiratory inhibition test in accordance with EU Method C.11. Activated sludge from a treatment plant processing predominantly domestic sewage was exposed to the substance for 3 hours under aerated conditions to a series of test concentrations ranging from nominal 10 to 1000 mg/L. The substance had no inhibitory effect (inhibition of <10%) on the sludge activity up to and with the test concentration of 1000 mg/L. The EC50 value for inhibition hence was >1000 mg/L and the NOEC was equal to or greater than 1000 mg/L.