Zinc probably came in to use around 500 BC. It has commonly been used as roofing material and later to galvanize steel to provide corrosion resistance. It is also used as a pigment in paint and as a poison against mould in impregnation treatments, and is a constituent in brass alloys. Extraction of zinc causes the release of small amounts of heavy metals including cadmium. Zinc is susceptible to aggressive atmospheres. In ordinary air conditions, one can assume a lifespan of 100 years for normal coating; but only a few years near the sea air, in damp city air or industrial air. There are very limited reserves of zinc. When zinc is broken down, the zinc particles are absorbed in earth and water. In higher concentrations, zinc is considered toxic to organisms living in water. It can be recycled.

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