Aluminium is the third most common element on earth and is used in many forms...
    

The metal is light and strong, has good thermal and electric conductivity and can readily be shaped by casting, welding, extruding and machining. Its strength can be increased, and other properties modified by adding small amounts of other metals to it (zinc, tin, copper). Although aluminium is relatively soft and chemically very reactive, it can be used for cooking pots and kitchenware (and other purposes) because it quickly becomes covered with a layer of aluminium oxide which is hard and chemically inert under most conditions. The oxide layer also readily absorbs colours. This makes it possible to print on it, as in drink cans.

Aluminium is also used in its compound forms. Aluminium sulphate is used in water purification; and alum, a mixed potassium aluminium sulphate, is used in some pickles, in tanning, and to stem the flow of blood from a razor cut and also has been used for water purification. Other aluminium salts are used in antiperspirants, in antacid powders and in some baking powders.

Health effects
There has long been controversy about the harm that can be done by an excessive intake of aluminium. There is no doubt that unusually high aluminium concentrations are found in the brains of people with Alzheimer's disease (senile dementia), but it is uncertain whether this is the cause of the disease or a side effect of it. When aluminium pots are used to cook acid fruit or vegetables or even boil salty water, they become pitted because some of the metal has been dissolved. The level of aluminium measured in tomatoes, fruit and some other foods when they were cooked in aluminium saucepans was found to be much higher than when stainless steel saucepans were used. While about 85 per cent of the aluminium taken in with food is not absorbed in the gut, its absorption may be increased in the presence of citric acid from fruit.

There have been suggestions that aluminium may interfere with calcium and iron metabolism in the body, and thus may affect the bones and the bone marrow, but this is also controversial. There may be enough evidence to make one hesitate to cook acidic food in aluminium saucepans or to store fruit drinks in aluminium containers.

Environmental effects
In the manufacture of aluminium a large amount of electric energy is used which is mostly produced from fossil fuels and thus contributes to the greenhouse effect. Recycling saves up to 95 per cent of the energy used to make aluminium from the ore-and cuts the air pollution by 95 per cent. Aluminium smelters can damage the vegetation in their immediate environment by the emission of fluoride from their smokestacks. They also produce a very persistent, solid toxic waste containing fluoride and cyanide which requires special disposal methods to keep it from polluting the environment.

The aluminium contained in the soil can be leached out by acid rain which results from the burning of fossil fuels. This dissolved aluminium is taken up by roots of trees and is thought to be one of the causes of the extensive dieback of forests in many heavily industrialised countries. Fish are also very sensitive to aluminium and when it is leached by acid rain into watercourses, it is thought to be the cause of fish dying in lakes (as in Sweden).

Alternatives
Stainless steel or enamelled steel saucepans and cast-iron skillets are good alternatives to aluminium ware. Put out your used drink cans for recycling wherever possible. Using waxed paper instead of aluminium foil helps to conserve resources.