Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Ready Biodegradability
Not readily biodegradable, OECD 301 D, US EPA OPPTS 835.3110 and EU Test Method C.4-E, Sipos (2015)

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

The ready biodegradability of the test material was investigated in a Closed Bottle Test over a period of 28 days. The study was conducted under GLP conditions and in accordance with the standardised guidelines OECD 301 D, US EPA OPPTS 835.3110 and EU Test Method C.4-E. The study was awarded a reliability score of 1 in accordance with the criteria for assessing data quality as set forth by Klimisch et al. (1997).

The test system was a microbial inoculum of good quality, collected from a sewage plant for domestic sewage. The sludge was washed by centrifugation, filtered through cotton wool and aerated until use. Based on the determined dry weight content, the washed sludge suspension contained 4 g dry material per litre. The applied concentration level of the test material was 6.3 mg/L.

The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As reference material , sodium benzoate was tested simultaneously under the same conditions as the test material, and functioned as a procedure control.

Under the test conditions, the percentage biodegradation of the test material reached a mean of 4.2 % after 28 days based on the measured COD of the test material. Therefore the test material is considered not readily biodegradable.

The reference material was sufficiently degraded to a mean of 93.3 % after 28 days of incubation, confirming the suitability of the activated sludge inoculum.

In the toxicity control containing both the test and the reference material, a mean of 40.5 % biodegradation was noted within 14 days and 41.7 % biodegradation after 28 days of incubation; therefore the test material can be assumed to be not inhibitory.

Under the conditions of this study the test material was determined not to be readily biodegradable.