Aluminium in drinking water: An overview

Abstract

Aluminium (Al) is one of the trace inorganic metals present in drinking water. In addition to the naturally occurring Alin raw waters, use of Al-based coagulants especially Al 2(SO4)3 (alum) often leads to an increase in treated water Al concentrations. A high (3.6 to 6 mg/ l) concentration of Al may precipitate as aluminium hydroxide giving rise to consumer complaints. Al is also a suspected causative agent of neurological disorders such as Alzheimer’s disease and presenile dementia. During conventional water treatment processes, Al undergoes various transformations (also called ‘speciation’ of Al) which are influenced by factors such as pH, turbidity, temperature of water source, and the organic and inorganic ligands present in water. Chemical precipitation, reverse osmosis, electrodialysis and cation exchange methods are efficient in Al removal from water. This paper gives an overview of the presence of Alin drinking water with reference to its speciation, removal (treatment methods), water supply and health problems, and the regulation of its levels in drinking water.

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