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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Diurea 8 is not considered readily biodegradable.

Key value for chemical safety assessment

Additional information

A study was performed to assess the ready biodegradability of isolated Diurea 8 in an aerobic aqueous medium (Harlan 2012). The method followed was designed to be compatible with the OECD guidelines 301B, "Ready Biodegradability; CO2 Evolution Test". Diurea 8, at a concentration of 10 mg carbon/L, was exposed to activated sewage sludge micro-organisms with culture medium in sealed culture vessels in the dark at approximately 21°C for 28 days.The concentration of inoculum in the test system was 30 mg suspended solids/L. The study determined, as far as possible, the absence of inhibition of micro-organisms by Diurea 8. Diurea 8 attained 17% degradation after 28 days and therefore is not considered readily biodegradable according to the strict terms and conditions of OECD guideline 301B.

The BIOWIN v4.10 QSAR estimates for biodegradability indicate that none of the 18 components of Diurea 8 modelled are expected to be readily biodegradable (US EPA 2009). The ultimate biodegradation timeframe prediction was weeks (one component), weeks-months (12 components) or months (five components).