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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The toxicity of melamine to 3 different microorganisms is low.

Key value for chemical safety assessment

Additional information

As the substance is a salt of phosphate, effects can be read-across from the cation, which is likely to have the more important effects. Inbiological systems, phosphate is an abundant in cells and body fluids. In ecological terms, because of its important role in biological systems, phosphate is a highly sought-after resource. Thus, read-across from component CAS Reg.-No. 108-78-1, melamine, is justified. All effect values are minimum values as the molar ratio anion:cation equals 1.74.

Three old and/or insufficiently reported studies on the toxicity of melamine to different microorganisms are available. A weight of evidence approach is applied.

Pagga 1979: Inhibition of respiration of activated sludge: EC20 >1992 mg/L.

Hockenbury 1977: Inhibition of nitrification by Nitrosomonas sp.: EC0, 2h >100 mg/L.

Tillmann 1990: Inhibition of respiration of Pseudomonas putida: EC0 >10000 mg/L.

Each of the studies with different endpoints and microorganisms indicates a low toxicity of melamine. The study of Hockenbury 1977 is the relatively best reported one and was therefore selected as the lead study in the weight of evidence approach.