ALUMINIUM SPECIATION IN DRINKING WATER
Report No FR0192

S J Cowling, A M Gunn and D A Winnard

MAR 1991

SUMMARY

I OBJECTIVES

To investigate the speciation of aluminium in drinking water and to compare bioavailability of aluminium in drinking water with that from other important dietary sources.

II REASONS

Aluminium has been linked with Alzheimer's disease and this has led to concern about levels of aluminium in drinking water. Despite the fact that drinking water constitutes only a minor source of total dietary aluminium intake, recent epidemiological studies have indicated a positive correlation between drinking water aluminium levels and Alzheimer's disease incidence

III RESUME OF CONTENTS

A range of techniques have been employed to survey the chemical forms of aluminium at drinking water treatment works around the country. Samples of both raw and treated waters from the works, and also from the distribution systems, have been examined. The bioavailability of drinking water aluminium relative to the much higher levels present in tea is being investigated by monitoring levels of urinary aluminium excretion. A preliminary study is also underway aimed at determination of concentrations of aluminium in teeth removed for orthodontic reasons from teenage children resident throughout the UK. Levels found in the teeth will be compared with aluminium contents of the relevant drinking water supplies and reported incidence of Alzheimer's.

IV CONCLUSIONS AND RECOMMENDATIONS

The survey of aluminium speciation at drinking water treatment works is now complete and has revealed that aluminium present after treatment tends to exist in highly labile chemical forms. As such they might be expected to exhibit high bioavailability. Results of urinary excretion studies have conflicted with a previous report of increased aluminium excretion after drinking tea; levels found in urine have been low and no significant changes have been observed after consuming either tea or drinking water of high aluminium content. However, further studies will require development of a more sensitive analytical procedure. Interpretation of data on aluminium content of teeth awaits ongoing analyses but early indications are that regional differences may exist.

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