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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Key study, OECD 301B and EU Method C.4-C, GLP, reliability 1:
100% biodegradation after 28 days, 10-day window was met.
Readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

One valid key study is available to assess the readily biodegradability of the substance. This study was performed according to EU Method C.4 -C and OECD Guideline 301B with GLP statement, in an aerobic aqueous medium with microbial activity introduced by inoculation of activated sludge.

The substance was tested in duplicate at c.a 37 mg per 2 liters, corresponding to ca. 12 mg TOC/L. The organic carbon content was based on the molecular formula. Two inoculum blank bottles (with only inoculum), one positive control bottle (with reference substance (sodium acetate, TOC = 12 mg/L) and inoculum) and one toxicity control bottle (with reference substance, test substance and inoculum) were performed. The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05M standardized HCl.

The theoretical CO2 production (ThCO2) of the substance was calculated to be 2.44 mg CO2/mg. The relative degradation values calculated from the measurements performed during the test period revealed complete degradation of the substance. Furthermore, biodegradation of the substance of at least 60% was reached within 10 days of biodegradation exceeding 10%. Thus the criterion for ready biodegradability was met. In the toxicity control, the substance was found to be not inhibitory.

In conclusion, the substance was considered readily biodegradable under the conditions of the modified Sturm test.