Nickel

Nickel (Ni) is an essential element in many species. In humans, there is some evidence to suggest an essential role in haematopoesis alongside vitamin B12, though only trace amounts are needed, and no known condition is associated with nickel deficiency. The element is essential at levels as low as <1µg/kg/day.

Nickel is found in inexpensive jewellery and is the most common cause of hypersensitivity dermatitis (‘nickel dermatitis’). This condition can also arise through chronic industrial exposure to nickel compounds. Nickel tetracarbonyl, used as an intermediate in the nickel refining industry and in alloy manufacture, is a volatile liquid. It is lipid soluble, and has been shown to cause pulmonary oedema, airway irritation and CNS effects with chronic exposure.

Inorganic nickel salts (primarily present in the oxidation state, Ni2+) are used in the steel industry, as a catalyst, and in the manufacture of jewellery, heat exchangers, Ni-Cd batteries and also to colour ceramics. Occupational exposure is thus feasible through air particulates or through poor work system/hygiene. Ingestion of nickel salts causes gastrointestinal symptoms (nausea, diarrhoea), neurological symptoms (headache, lassitude) and mild nephrotoxicity. It also increases the risk of cancer of the respiratory system.