Aluminium sulphate

Endpoint summary

Additional information

As the third most abundant element, constituting approximately 8% of the earth's crust, aluminium is ubiquitous in soils, water and air. In addition to its natural occurrence, and as a result ofits inherent chemical and physical properties, aluminium finds usein a wide varietyof applications including packaging materials,various containers and kitchen utensils, automobile bodies and components, airplanes and building materials. Aluminium compounds are also used in, for example, paint pigment, insulating materials,water treatment, drugs, cosmetics as well as food additives.

 

The general population is exposed to aluminium from air, water and food. Aluminium levels in unpolluted air are generally below100 ng/m3 and resultant intakes would be less than 2 μg/day(0.002 mg/day). However, in industrial areas where aluminium levels as high as 6200 ng/m3 have been reported, intakes could reach124 μg/day (0.124 mg/day) (Ministry of Agriculture, Fisheries and Food,1985; Havas & Jaworski, 1986; Bowen, 1979).

 

Aluminium concentrations in fresh (untreated) water are generally low i.e. less than 0.001 to 1 mg/l, although values ashigh as 26 mg/l have been found in certain regions. In manyinstances, elevated levels have been associated with pH values lessthan 5.5 or water rich in organics. Although the use of aluminiumbased coagulants in processing drinking water supplies can increasealuminium levels above natural background content, most potablewaters surveyed recently in Europe were generally below the EECstandard of 0.2 mg/l aluminium. The intake of aluminium fromdrinking 1.5 to 2.0 l water daily containing an estimated meanlevel of 0.1 mg/l ranges from 0.15 to 0.20 mg/day. While suchintakes would be representative of most individuals, it is apparentfrom the levels noted above, that aluminium intakes from watercould reach as high as 5 mg/day for certain persons (Ministry ofAgriculture, Fisheries and Food, 1985; Havas & Jaworski, 1986).

 

Aluminium in food can derive from that which is presentnaturally, that which results from aluminium-containing foodadditives, and that arising from contact with Al used in foodcontainers, cookware, utensils and wrappings. Based on results frommore recent surveys of foods, tea, some spices and herbs (e.g.thyme, cayenne powder), contain naturally high aluminiumconcentrations. Other products, such as processed cheese, grainproducts and baking powder may be high in aluminium if they containaluminium-based food additives. Although aluminium-containingcookware, utensils and wrappings can increase amounts of thissubstance in foods, particularly if the foods are acidic, basic orsalty, studies to date have shown that aluminium contamination fromthis avenue is generally too small to be of practical importance.

 

Nevertheless, such studies have highlighted that adverse impact ofaluminium on the vitamin C content of foods cooked in aluminiumsaucepans (Ministry of Agriculture, Fisheries and Food, 1985; Havas& Jaworski, 1986; Sorenson et al., 1974).

 

Daily dietary aluminium intakes have more recently beenestimated to range from about 2 to 6 mg/day for children and fromabout 6 to 14 mg/day for teenagers and adults. The majorcontributors to these dietary aluminium intakes are grains andgrain products, dairy products (i.e. milk, cheese and yoghurt),desserts and beverages. Consumption of other foods containingelevated aluminium levels (e.g. spices and herbs, pickledcucumbers) can also dramatically increase dietary aluminium intakes(Ministry of Agriculture, Fisheries and Food, 1985; Havas &Jaworski, 1986; Sorenson et al., 1974).

 

Finally it is important to recognize that use of certainaluminium-containing non prescription drugs (e.g. Antacids) canincrease daily aluminium intakes by a factor of 10 to 100 (Havas &Jaworski, 1986).

 In summary, the intake of aluminium from air, even inindustrial areas, is minor relative to that from food. Although water does not contribute significantly to the total aluminium intake from all sources for most individuals, elevated aluminium levels have been found in certain areas and resultant aluminiumintakes can be as high as the dietary contribution. Aluminium intake from foods, particularly those containing aluminium compounds used as food additives, represents the major route of aluminium exposure by the general public excluding persons who regularly ingest aluminium-containing drug.