Aluminium contents in drinking water from public water supplies of Galicia (northwest Spain)

Aluminium (Al) salts are used extensively as coagulants in drinking water treatment. Since several research works have linked Al levels in drinking water to elevated risks of Alzheimers disease, we have studied the Al content in drinking water from populations in Galicia (NW Spain). Drinking water from 35 cities and villages in Galicia were analysed for dissolved Al and other relevant parameters (pH, turbidity, sulphate, fluoride and DOM) for the period 1997-2003. The results obtained showed an average aluminium content of 126 mu g L-1, but the variability was high, with Al levels ranging from 8 to 650 mu g L-1. Of the waters studied, 19% and 34% contained Al above 0.2 and 0.1 mg L-1, respectively. Speciation studies performed using the WHAM computer model showed that most dissolved Al was DOM-complexed, although some waters contained significant amounts of labile Al, mainly as hydroxo and fluoride complexes.