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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

L-Cysteine is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

L-Cysteine was investigated for its ready biodegradability in a "28-Day DOC Die-Away Test" according to the OECD Guideline for Testing of Chemicals, No. 301 A (1992), the Commission Regulation (EC) No 440/2008 C.4-A and the OPPTS 835.3110 (Paragraph (l)).

In the test flasks, containing L-Cysteine and activated sludge (inoculum), the mean concentrations of dissolved organic carbon (DOC) rapidly decreased by 98% of the initial values within the test period of 28 days. The pass level for ready biodegradability (70% removal of DOC in a 10-day window within a 28-day period) was reached (95% removal of DOC within five days of exposure). L-Cysteine is therefore readily biodegradable under the test conditions.