Registration Dossier

Administrative data

Endpoint:
mode of degradation in actual use
Type of information:
other: summary
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: This is the lowest score of any of the summarized studies.

Data source

Materials and methods

Principles of method if other than guideline:
The relevant results of the studies Fimberger 1997 (Chapter 5.2.1), Pagga 1991 (Chapter 5.2.1), Hauck 1964 (Chapter 5.2.3), Jutzi 1982 (Chapter 6.5) , Bollag 1991 (Chapter 6.5) are repeated here, see in the executive summary.

Test material

Reference
Name:
Unnamed
Type:
Constituent

Results and discussion

Applicant's summary and conclusion

Executive summary:

With activated sludge taken from an industrial waste water treatment plant as the inoculum, a degradation 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 only nitrogen source (Fimberger 1997).

Nitrification was investigated in soil (Hauck 1964): Nitrification of melamine from powders was slightly greater than from solutions and considerably greater than from granules of these materials. Up to ca. 18 % of the nitrogen in the molecule are converted to nitrate within 24 weeks.

The deamination of melamine -> ammeline -> ammelide -> cyanuric acid is described for Pseudomonas sp. (Jutzi 1982). Melamine was converted stoichiometrically into equimolar amounts of ammeline and NH4+. The bacterium converted 0.4 mM melamine anaerobically into 2.3 mM NH4+. The degradative pathway of melamine appears to be hydrolytic and proceeds by three successive deaminations to cyanuric acid, which is further metabolized. Two other Pseudomonas and two strains of Klebsiella pneumoniae were also examined, with similar results.

Bollag 1991: Melamine is subjected to degradation by microorganisms under anaerobic conditions. Melamine is thought to be deaminated to cyanuric acid, followed by cleavage of the triazine ring, before ultimate conversion to ammonium and carbon dioxide occurs (as has been shown for Pseudomonas sp. and Klebsiella pneumoniae, which are facultative anerobes).