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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Weight of evidence approach, one experimental non-GLP study (2000) and one QSAR data point (CATALOGIC Kintetic 301F v.11.14):
78% degradation after 28 days (QSAR data) to 83% degradation after 28 days (experimental study) meeting the 10 day window;
Readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

To assess the biodegradation potential of the registered substance, a weight of evidence approach was used using an experimental non-GLP study (performed in 2000) and a QSAR data.

The non-GLP experimental study (Miffon, 2000) was performed on the registered substance to investigate the ready biodegradability of the substance when exposed to sewage sludge micro-organisms under aerobic conditions during 28 days. The method followed the protocol as described by Birch and Fletcher (Chemosphere, vol. 23, pp. 507-524, 1991). This method is very similar to the ISO Guideline N° 14593 (CO2 headspace test, adopted 1999) and of the OECD Guideline 310 (adopted March 23rd, 2006). The substance, at a concentration of 18.09 mg C/l, was exposed to activated sewage sludge micro-organisms with culture medium in sealed culture vessels in diffused light at 28°C ± 2°C for 28 days. The degradation of the test substance was assessed by the determination of carbon dioxide produced on Days 0, 5, 8, 12, 15, 19, 22 and 29. The test substance attained 83% degradation after 28 days and satisfied the 10-day window validation criterion. Therefore the registered substance can be considered to be readily biodegradable. However, as no reference susbtance was tested during the study the test can only be used as part of a weight of evidence approach.

The QSAR data was performed to support the experimental result. The substance ready biodegradation property was investigated using CATALOGIC Kinetic 301F v.11.14, plug-in from OASIS CATALOGIC v.5.11.15. The registered substance fulfills the general properties requirements (in terms of log Kow, molecular weight and water solubility) and is in the interpolation structural space and in the metabolic domain. 78% biodegradability (BOD) was observed after 28 days.

Since the outcome of the biodegradability prediction of the registered substance converges with the experimental result, it can be concluded that the substance is readily biodegradable.