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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The 3-hour NOEC of FAT 60'253/A to activated sludge microorganisms is at least at the limit of water solubility of FAT 60'253/A under the present test conditions, or at least nominal 1000 mg/l. 

Key value for chemical safety assessment

EC50 or LC50 for microorganisms:
1 000 mg/L
EC10, LC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

In a key study, the inhibitory effect of the test item FAT 60'253/A on the respiration rate of aerobic wastewater microorganisms of activated sludge was investigated in a 3-hour respiration inhibition test according to the Commission Directive 87/302/EEC, and the OECD Guideline

for Testing of Chemicals, No. 209.

The following nominal concentrations of FAT 60'253/A were tested: 10, 32, 100, 320 and 1000 mg/l. Concentrations in excess of nominal 1000 mg/l were not tested.

In addition, two controls and three different concentrations of the reference item 3,5-dichlorophenol (5, 16 and 50 mg/l) were tested in parallel. The results of these treatments confirmed suitability of the activated sludge and the method used.

Up to and including the highest concentration of nominal 1000 mg/l the test item FAT 60'253/A had no significant inhibitory effect (<15%) on the respiration rate of activated sludge after the incubation period of three hours. Based on the physical appearance of the test suspensions, the saturation concentration (equilibrium) under the present test conditions was reached and resulted in less than 15% inhibition after three hours contact time. Thus, the 3-hour EC50 is clearly higher than the limit of water solubility of FAT 60'253/A under the present test conditions, or higher than nominal 1000 mg/l. The 3-hour NOEC of FAT 60'253/A to activated sludge microorganisms is at least at the limit of water solubility of FAT 60'253/A under the present test conditions, or at least nominal 1000 mg/l. This value might be even higher, but concentrations in excess of nominal 1000 mg/l were not tested. The 3-hour EC20 and EC80 could not be calculated, but are clearly higher than the limit of water solubility of FAT 60'253/A, or higher than nominal 1000 mg/l.