SPECIATION AND BIOAVAILABILITY OF ALUMINUM IN DRINKING-WATER

The form of aluminium in water abstracted for potable supply, in water after treatment, and in water delivered to consumers' taps, has been examined using techniques based on size and chemical reactivity. Speciation in water is compared with that in tea. Although the concentration of the metal in tea is an order of magnitude larger than that in water, its relative contribution to dietary intake depends on the degree of absorption. Bioavailability is examined, using human subjects, via the determination of aluminium concentrations in both serum and urine, after the ingestion of various test drinks. Aluminium in water after treatment was found to be in a more chemically labile form than the metal present in most raw waters. Speciation in tea is dominated by high molecular weight, organically complexed forms. A slight increase in urinary aluminium concentrations was observed after consumption of both a spiked mineral water and tea. This increase was small with respect to the quantity of aluminium ingested, suggesting relatively low bioavailability from both sources.