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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Readily biodegradable (according to OECD criteria) in freshwater.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

In a study according to OECD guideline 301 A, the test substance was determined to be readily biodegradable according to OECD criteria in freshwater systems (BASF AG, 1993; Report no. 93/1749/21/1). Activated sludge from a laboratory wastewater treatment system using municipal sewage was used as inoculum. The substance was degraded to 96% after 18 d. The 10 -d window was kept. This study was selected as key study.

The biodegradability is supported by further studies:

- BASF AG (1988). Report no. 01.0273/88: Zahn-Wellens test (OECD 302B), industrial activated sludge: 95% after 14 d: easily eliminated from water/inherently biodegradable

- BASF AG (1994). Report no. 94/0989/29/1: CO2/DOC Combination test (ultimate aerobic biodegradability, ISO 9439), industrial activated sludge: > 95% after 15 d: inherently biodegradable

In a ready biodegradability test according to OECD 301 C, the substance was not readily biodegradable (25% after 28 d; JETOC, 2005).

While the substance is readily biodegradable in freshwater systems, it is not readily biodegradable in seawater as concluded from an OECD 306 study (BASF SE, 2011; Report no. 00G0087/01x018). The maximum biodegradation of 15% was reached on day 63, the final day of the study. This result is supported by the published result from Eide-Haugmo et al. (2009), who determined that the substance is poorly degradable in seawater in an OECD 306 test (< 10% BOD of ThOD after 28 d).