Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

There are 2 studies for this endpoint which can be considered key studies:
In the Haberlein and Schaefer, 1998 study, the objective of the study was to measure the amount of carbon dioxide produced from the biodegradation of the test substance under the conditions tested. The test contained a blank control group, a reference group, and a treatment group, and each contained three replicate test chambers. The study was conducted according to procedures specified by the OECD Guideline for Testing of Chemicals, Method 301B, ASTM Standard Test Method D 5864-95, and USEPA method 796.3260. The test substance was administered to the treatment group test chambers by direct weight addition at a concentration of 10 mg Carbon per liter. After 28 days the cumulative percent of theoretical carbon dioxide evolved for the test material was 5.9%. The inoculum used in the study was composed of adaptation cultures.
In the O'Leary, 1998 study, the objective of the study was to evaluate the ready biodegradability of the test substance using a respirometry test. The study was conduced according to principles specified in the OECD Ready Biodegradability Test method 301F (Manometric Respirometry Test). A defined medium with low mineral concentration and neutral pH was used to simulate the natural environment where biodegradation can occur. The return sludge from a domestic waste water treatment plant was chosen as the inoculum because of its diverse microbial population and high microbial activities. A measured volume of inoculated mineral medium was prepared containing 100 mg/L of the test substance as the nominal sole source of organic carbon. The mixture was continuously stirred in a closed flask at a constant temperature. The consumption of oxygen was monitored using an electrolytic respirometer system. After 28 days the level of biodegradation achieved for the test material was 4.2%.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Both studies are considered to be key as they are of equal reliability, show similar results and are conducted to different OECD guidelines. The key studies for Biodegradation are considered to have a reliability rating of 1, according to the criteria of Klimisch, 1997.