Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Biodegradation in water = 75 %, based on O2 consumption (96 % based on DOC removal)

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

The biodegradability of the test substance exposed to microorganisms derived from activated sludge of a municipal sewage treatment plant was investigated under aerobic static exposure conditions, following the OECD guideline 301 F. Both the biodegradation over the course of the test (based on O2consumption compared to the theoretical oxygen demand ThOD) and the total elimination at the end of the test (based on the determination of the dissolved organic carbon, DOC) were assessed.

Based on O2consumption the biodegradation of the test substance was calculated to be 75% of the ThOD after 28 days and reached 68% at the end of the 10-d window (i.e. within 10 days after attainment of 10% degradation).

The procedure control with sodium benzoate reached a biodegradation of 82% after 14 days, thus confirming suitability of inoculum and test conditions.

Based on the determination of the DOC at the end of the test the total elimination was calculated to be 96% for the test substance and 99% for sodium benzoate. These data are in line with the degradation calculated based on O2consumption.

The test item reached the pass level of 60 % biodegradation in the Manometric Respirometry Test within the 10-day window and, therefore, can be termed as readily biodegradable. All validity criteria were fulfilled.