Aluminium tris(dihydrogen phosphate)

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Additional information

Aluminium tris(dihydrogen phosphate) (CAS 13530-50-2) will be hydrolytically transformed in the ionic forms in water (Al3+ and PO43- ions) which will further associate with the ionic forms of H2O. Therefore a separate assessment of the toxicity of Al3+ ions and the PO43- ions is considered justified.

Aluminium is the most abundant metallic element in the Earth’s crust, with a proportion of around 8% by weight, and the third most abundant of all elements. Due to its reactive nature it does not exist in nature as free elemental metal, rather it occurs in a variety of minerals, usually combined with elements such as silicon, oxygen, phosphates, fluorine, and hydroxides, for example (Lide 1991, as cited in WHO 1997). Based on its ubiquitous occurrence existing data clearly demonstrate that the present natural background concentration far outweighs anthropogenic contributions of aluminium to the terrestrial environment (Environment Canada and Health Canada, 2008). Exposure of soil dwelling organisms and plants to aluminium of geogenic and anthropogenic origin is expected to be high (cited in WHO, 1997). However, the relative contributions of anthropogenic aluminium to the existing natural pools of aluminium in soils and sediments is very small, and therefore, not relevant either in terms of added amounts or in terms of toxicity.

There is no direct release of the substance to the terrestrial environment. If emitted to soil, depending on the buffer capacity of the soil, aluminium will be neutralised and decomposes to aluminium hydroxide or oxide (gibbsite). Both are stable forms that will be immobilised in soil. Nevertheless, the fate of aluminium in the terrestrial environment is dependent on local conditions. As for the aquatic environment the acidification of soils will lead to increased solubility of aluminium (WHO, 1997)

Phosphate is applied to soil as a fertilizer for a variety of crops. Phosphate has low potential for adsorption to solid particles (as it will be rapidly transformed in water into its dissociated forms). Phosphate is an essential nutrient for terrestrial organisms. Therefore bioaccumulation and toxicity are considered not relevant for phosphate.

Aluminium tris(dihydrogen phosphate) is considered not acutely toxic to aquatic organisms. Toxic effects on terrestrial organisms are therefore not expected.

Based on the available data terrestrial toxicity testing is also not deemed necessary.

 

Reference:

WHO (World Health Organization) 1997. Environmental Health Criteria 194. Aluminum. International Programme on Chemical Safety (IPCS). Geneva ISBN 92 4 157194 2.

Environment Canada Health Canada, 2008, Canadian Environmental Protection Act, 1999, PRIORITY SUBSTANCES LIST STATE OF THE SCIENCE REPORT; FOLLOW-UP TO THE STATE OF SCIENCE REPORT, 2000, Aluminum Chloride, Aluminum Nitrate, Aluminum Sulphate, November 2008