Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Under the conditions of the performed Activated Sludge Respiration Inhibition Test, the following EC values were determined: 
EC10 = 270 mg/L, EC20 = 930 mg/L, EC50 > 1000 mg/L and EC80 > 1000 mg/L.

Key value for chemical safety assessment

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

Additional information

An activated sludge respiration inhibition test with the test item was performed according to OECD guideline 209. The purpose of the 3-hour test was to evaluate the influence of the test item on the activity of the activated sludge by measuring the respiration rate under defined conditions. The test substance was added in the required amounts to the test concentrations (62.5, 125, 250, 500 and 100 mg/L) directly to the test vessels contained deionized water. Afterwards synthetic medium was added to each test vessel. After addition of 250 mL of inoculum suspension (3 g/L dry weight) the incubation was started by aeration of the test vessels with pressured air. The consumption rate of each test concentration, the reference substance (3,5-dichlorophenol) and the blank controls were determined after 3 hours of exposure for a period of 8 – 10 min. The consumption rates were used to calculate the inhibition effects.

The EC50 of the reference substance 3,5-dichlorophenol was in the range of 2-25 mg/L in 3 hours. An EC10 = 270 mg/L, EC20 = 930 mg/L, EC50 >1000 mg/L, EC80 >1000 mg/L were found in the activated sludge respiration inhibition test with 3 hour residence time for the test substance.