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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The substance is not readily biodegradable. 

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable

Additional information

In two RBT, based on oxygen consumption (according to OECD 301 F) or on evolved CO2 (according to OECD 301 B) the degree of mineralisation, in 28 days, has been resp. 29 and 23 %, i.e. below the threshold of 60 % for ready biodegradability. It is assumed to be inherently biodegradable, although it is difficult to assess globally the potential for biodegradability for a mixture of about 13 different molecules.

In a second tier, applying the scheme described in the guidance, in Figure R.11-1, other evidence indicating non persistence have been investigated.

The 13 molecules identified in the mixture have been studied through BIOWIN from US-EPA's EPISuite. BIOWIN runs 7 models and gives an overall estimation of ready biodegradability from the results of Biowin 3 and Biowin 5. The guidance R.11 recommends to base the conclusion on a combination of Biowin 2 and 3 or Biowin 6 and 3. Whatever prediction system is used, the conclusion is the same: 12 out of the 13 molecules identified in the mixture are predicted to be readily biodegradable. The only one predicted not to be readily biodegradable accounts for 0.76 % by weight of the mixture. Finally, it can be assumed, according to BIOWIN, that the complete substance is readily biodegradable.