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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Experimental result

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Biodegradation in water:
under test conditions no biodegradation observed

Additional information

The ready biodegradability of the submission item was studied under GLP in a modified MITI test in accordance with OECD TG 301C. The degradation was studied in parallel in three bottles by adding 30 mg test substance and 10 mL activated sludge (3000 mg suspended matter/L, diluted to 900 mg/L by addition of basal medium) to 290 mL basal medium. In addition, an inoculum control (1 bottle), a positive control (1 bottle with aniline and activated sludge) and an inorganic control (1 bottle with test item and purified water) were run. The test was performed during 28 days at a temperature of 25 ± 1 °C in a closed system oxygen consumption measuring apparatus. The biodegradability of the substance was surveyed by regularly checking the oxygen consumption in the testing bottles. No oxygen consumption over that of the inoculum control was observed during the testing period of 28 days in the three testing bottles containing the test item showing that no biodegradation had occurred. This finding was confirmed by analysis of dissolved organic carbon and by analysis of the four components of the submission item by means of gas chromatography. No decline in the concentrations of dissolved organic carbon or test material was observed over the period of 28 days confirming the stability of the test item in the testing system. The positive control substance aniline was degraded by 59 % within 7 days, which showed the appropriateness and normal activity of the applied activated sludge. It was concluded that the submission item was not biodegradable under the conditions of this modified MITI test.