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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The substance has been shown to be not readily biodegradable according to the test method described in the OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Ready biodegradability was tested according to the test (OECD 301 C) and in compliance with GLP. Nominal initial test substance concentrations 100 mg/L. The test was performed with inoculum prepared as follows to maintain its uniformity: The mixed filtrate (5 L) of the supernatant of the sludge collected at sampling sites was mixed with the filtrate (5 L) of the supernatant of the activated sludge previously cultivated for about 3 months. The mixed filtrate (10 L) was aerated after the pH value of the mixture was adjusted to 7.0 ±1.0. The test substance at 100 mg/L achieved mean degradations of 11 % by day 28. The viability of the inoculum and validity of the test were supported by the results of the reference substance, aniline, which degraded approximately 76% by the end of the test, and achieved greater than 70% biodegradation by day 14.  Some of the test item was converted into acrylic acid, 2-(perfluorohexyl)ethanol and 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanoic acid under the test conditions of this study. It was considered that some of acrylic acid transferred from the test solution to the absorbent for carbon dioxide attached to the test vessel and that the other was biodegraded by microorganisms. The rest of the test item, 2-(perfluorohexyl)ethanol and 3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluorooctanoic acid remained in the test solution.