145. Aluminium and aluminium

Abstract

Aluminium (Al) is silvery, light, malleable and ductile, and the most abundant metal in the earth’s crust. Al is used primarily for metallurgical purposes, especially to produce Al-based alloy castings and wrought Al. Al compounds are found in consumer products such as antacids, astringents, buffered aspirin, food additives and antiperspirants. Powdered Al metal is often used in explosives and fireworks. No human data were available on respiratory tract and eye irritation following acute/single exposure to Al or Al compounds. Despite the wide use of Al, the small number of reports on effects indicates that Al is not harmful to the skin. Occupational high-level inhalatory exposure to Al can cause lung disorders such as impaired lung function and pulmonary fibrosis. In the most relevant repeated animal inhalation study, rats and guinea pigs were exposed to 0.25, 2.5 or 25 mg/m3 Al chlorohydrate for 6 months. All animals in the two higher dose groups had multifocal granulomatomous pneumonia and microgranulomas in the peribronchial lymph nodes. At the lowest dose, these effects were regarded as minimal. Thus, 0.25 mg/m3 (0.061 mg Al/m3) is probably close to the no-effect level. Some field studies suggest that Al induce subclinical neurotoxic effects, but no exposure-response relationships could be established and co-exposure to other compounds may have played a role. Al compounds are neurotoxic in orally exposed animals at high doses. There are no animal inhalation neurotoxicity studies. Available data indicate that Al is not mutagenic, but that especially the watersoluble sulphate may cause chromosomal damage. Human and experimental animal data do not allow firm conclusions on the potential carcinogenicity of Al or its compounds. Increased cancer mortality rates in workers in the Al production industry especially for lung and urinary bladder is generally considered to be caused by co-exposure to carcinogenic compounds such as polycyclic aromatic hydrocarbons. No studies were found on the effects of occupational exposure to Al or Al compounds on reproductive capacity, pregnancy outcome or postnatal development. In animals, there are studies in which Al compounds were administered in the diet or drinking water. Water-soluble Al compounds have induced postnatal development effects. No effects on prenatal development were reported. Overall, the data are insufficient to identify a critical effect level except for Al chlorohydrate for which minimal pulmonary effects were seen in an animal study at 0.061 mg Al/m3. Keywords: aluminium, fibrosis, lung function, neurotoxicity, occupational exposure limit, pulmonary, review, risk assessment, toxicity