N-methylaniline

Biodegradation in water: screening tests

Description of key information

Comparing the various biodegradation tests with test substance, the extent and rate of degradation differs significantly from readily to inherently biodegradable. Considering the increased degradation observed after acclimation, degradation of test substance in a STP depends on the extent of adaptation of the micro-organisms in the active sludge to this substance.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

Evaluation of the results of the various studies:

In a 21-day biodegradation using an acclimated activated sludge inoculum, 82% mineralization and 99.9% primary degradation was obtained. It was found that degradation was faster when acclimation was performed in a single flask, rather than by an enrichment procedure.

Results of standard aerobic biodegradability tests for test substance include:

92% Dissolved organic carbon (DOC) in 8 days in the Zahn-Wellens test;

29 and 67% DOC removal after 28 and 42 days, in the French AFNOR test;

46% CO2 produced and 92% DOC removed in 28 days after 14 days acclimation (Sturm test);

17% DOC removal after 19 days in the OECD Screening test;

38% of the ThOD was obtained in a 5-day BOD test;

18-20% of the ThODwas expended after 5-8 days in a respiratory test using 500 ppm of the test substance;

0% of the ThOD in 30 days with a drop of sewage as an inoculum;

3% of the ThOD in 14 days in the MITI test;

8% mineralization to CO2 occurred in a 21-day test using an activated sludge as an inoculum.