Aluminium tris(dihydrogen phosphate)

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Additional information

Aluminium tris(dihydrogen phosphate) (CAS 13530-50-2) dissociates to dihydrogen phosphate and aluminium ions in aqueous and biological systems. Aluminium and phosphorus are naturally abundant elements. They are naturally released to the environment from the weathering of rocks and volcanic activity. Aluminium and phosphorus concentrations in surface waters originating from man-made applications cannot be distinguished from concentrations released from natural sources during weathering of aluminium and phosphorus bearing minerals. 

The transport and partitioning of aluminium in the environment are determined by its chemical properties, as well as the characteristics of the environmental matrix that affects its solubility. In acidic aquatic systems, aluminium exists in natural waters in a number of species, including dissolved and particulate forms. This again depends on many factors, especially pH, alkalinity, temperature, dissolved organic carbon, dissolved inorganic carbon and anion concentration. Furthermore, hydrolysis of aluminium ions has two possible “directions” towards a neutral pH, i.e. base hydrolysis and acid hydrolysis. Both acid and base hydrolysis of aluminium rapidly results in precipitation of aluminium hydroxide, which can adsorb to suspended particles or become immobilised in sediment. A direct release of aluminium tris(dihydrogen phosphate)  to the terrestrial environment is negligible. If emitted to soil, depending on the buffer capacity of the soil, the substance will be neutralised and decomposes to stable aluminium hydroxide or oxide (gibbsite) and will be immobilised in soil. Nevertheless, as a result of this dynamic chemistry, the amount of aluminium associated with suspended particles is dependent on the chemical conditions. Known factors affecting aluminium speciation, such as pH and DOC, are also known to affect adsorption and desorption from particle surfaces.

The global phosphorus cycle involves only aquatic and soil compartments. As a basic constituent of nucleic acids, phospholipids and numerous phosphorylated compounds, phosphorus is one of the nutrients of major importance to biological systems, where the phosphorus adsorption by organisms in aquatic and soil compartment has significant impact on the phosphorus cycle. 

The air compartment is considered not relevant for aluminium tris(dihydrogen phosphate). Since these aluminium phosphates are usually not emitted to air, the amount of aluminium present in air that is related to the aluminium being considered here would be negligible compared with the amount coming from natural erosion of soil (Environment Canada Health Canada, 2008).

 

References

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