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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

 Not readily biodegradable (by OECD criteria).

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

The substance has been tested according OECD 301B with a concentration of the test item exceeding the solubility limit by the factor 16. Practically no indication of biodegradation was observed.

Furthermore, several studies conducted with melamine and cyanuric acid themselves are available.

For the component 108 -78 -1(melamine):

Test results of a MITI test for ready biodegradability, 3 Zahn-Wellens assays for inherent biodegradability and 2 studies on Biochemical Oxygen Demand are reported. The individual results of the studies are consistent: Melamine is not readily biodegradable and also not inherently biodegradable.

With activated sludge taken from an industrial waste water treatment plant as the inoculum, a degradation of DOC of up to 16 % was observed within 20 d (Pagga 1991). A rapid and complete primary degradation of the molecule within 8 h was detected with an activated sludge taken from an industrial waste water treatment plant from a producer of melamine (Fimberger 1997). Addition of glucose, in the absence of NH4+, enables the microorganisms to use melamine as the only nitrogen source (Fimberger 1997). Degradation occurs by hydrolytic deamination to ammeline, ammelide and cyanuric acid, and lastly to CO2 and NH4+ (Fimberger 1997).

For the component 108 -80 -5 (cyanuric acid):

The component is neither readily not inherently biodegradable.