Biomedical aspects of aluminium.

About 2.5 mg of aluminium is absorbed daily with food; it then undergoes minimal absorption via the gastrointestinal tract (0.1%) and total excretion of the absorbed dose via the kidneys. The concentrations of aluminium in blood of non-exposed subjects with normal renal function are extremely low (1-3 micrograms/L). Until the beginning of the 1970's aluminium was considered to be of little toxicological interest, but in 1972 a neurological syndrome due to aluminium intoxication was described in dialysis patients in the UK and in 1973 Canadian research workers speculated on the role of aluminium in Alzheimer's disease (senile or presenile dementia), even though this does not at present have wide support. Al intoxication in dialysis patients can be prevented if the Al concentration in the dialysis solution is kept below 10 micrograms/L. No cases have been reported of systemic intoxication due to aluminium in occupationally exposed subjects. Al in plasma values of 5-15 micrograms/L have been reported in exposed workers, which are 10 times lower than the values observed in dialysis patients with encephalopathic symptoms. However, rare cases of occupational pulmonary fibrosis have been reported where an etiopathological role of aluminium was suspected. Nevertheless, it has been demonstrated that the alumina used in primary aluminium production lacks any fibrogenic potential.