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Environmental fate & pathways

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Description of key information

Due to the fact that the multiconstituent substance reaction mass of potassium aluminium tetrafluoride and tripotassium hexafluoroaluminate is an inorganic substance, only abiotic degradation can be considered. As no information is available on abiotic degradation of this substance, data from its structural analogue cryolite is taken into account (see Annex C.1). In a dissociation and acid/base equilibrium study cryolite was observed to easily dissociate in water into various ions (Dykeman, 1985). Based on the structural analogy it can be expected that the target multiconstituent substance will easily dissociate into various ions in water.

As cryolite dissociates in water and the risks are assumed to be determined by fluoride, it is more appropriate to assess the adsorption behaviour of fluoride. In a column leaching test, Koc values varying from 603 - 6502 were found for fluoride in 4 different soils, tested at cryolite concentrations varying from 5 - 50 ppm (Dykeman, 1985). As the percentage of fluoride in the molar weight in both substances is practically identical, namely 54% for cryolite and 53% for aluminium potassium fluoride, similar Koc values can be expected for aluminium potassium fluoride and it is considered that aluminium potassium fluoride will show a similar behaviour in soil.

Additional information

As cryolite dissociates in water and the risks are assumed to be determined by fluoride, it is more appropriate to assess the adsorption behaviour of fluoride. In a column leaching test, Koc values varying from 603 - 6502 were found for fluoride in 4 different soils, tested at cryolite concentrations varying from 5 - 50 ppm (Dykeman, 1985). As the percentage of fluoride in the molar weight in both substances is practically identical, namely 54% for cryolite and approx. 53% for aluminium potassium fluoride, similar Koc values can be expected for aluminium potassium fluoride and it is considered that aluminium potassium fluoride will show a similar behaviour in soil.