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Environmental fate & pathways

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Experimental data on the transport of diphosphoric acid, compound with 1,3,5-triamine (1:2) are not available. Based on the experimentally determined low log Pow of the substance (log Pow -1.24 at 20 °C, OECD 107) a low adsorption potential of the substance is expected.

The substance is not stable in the environment. In aqueous solution the substance will dissociate forming melamine and pyrophosphate ions.

An available QSAR calculation for the component melamine (CAS 108-78-1) resulted in a log Koc of 1.13 indicating a low adsorption potential. The mobility of phosphate depends on the number of phosphate units. The adsorption potential of polyphosphates increases with increasing length (Busman, 1984). Precipitation-dissolution and sorption-desorption processes control the concentration of phosphate ions in solution. Phosphorus ions are mainly immobilised in soils by adsorption to solid matter or by reaction with aluminium or iron to aluminium- and iron phosphates (Cornforth 2008). Sato et al. (2009) observed that phosphorus released from calciumphosphate was adsorbed to aluminium and iron-oxyhydroxides. Basically, phosphate adsorption dominates in mineral soil with a low pH.

Reference

Busman, Lowell Marion, (1984)."Behavior of polyphosphates in soils " Retrospective Theses and Dissertations. Paper 8979.

Cornforth I.S. (2008) The fate of phosphate fertilizers in soil. New Zealand Institute of Chemistry. II-Chemicals and Soils-D-Phosphate-2 (with reference to: Dahal 1977; McLaren and Cameron 1990; Syers and Cornforth 1983)

Sato et al. (2009) Biogenic calcium phosphate transformation in soils over millennial time scales. Journal of Soils Sediments (2009) 9:194–205