Nickel

Type: Essential Mineral
Periodic Element: (Ni)
RDA: Average daily exposure is not believed to pose a threat to human health.
Importance- To Body:
Toxin at high levels.
Distribution- In Body:
Dietary intake is estimated at 70 to 100 µg/day, with less than 10% absorbed. Most of the nickel ingested every day by humans is removed by the kidneys and passed out of the body through urine or is eliminated through the gastrointestinal tract without being absorbed.
Excess Effects:
The Tolerable Upper Intake Level of dietary nickel is 1000 µg/day as soluble nickel salts.
Deficiency Effects:
Not listed.
Sources Food:
Relatively large amounts of nickel – comparable to the estimated average ingestion above – leach into food cooked in stainless steel. For example, the amount of nickel leached after 10 cooking cycles into one serving of tomato sauce averages 88 µg.
Sources Environmental/Geographic:
Nickel is essential to plants. Nickel-plated faucets may contaminate water and soil; mining and smelting may dump nickel into waste-water; nickel–steel alloy cookware and nickel-pigmented dishes may release nickel into food. The atmosphere may be polluted by nickel ore refining and fossil fuel combustion. Humans may absorb nickel directly from tobacco smoke and skin contact with jewelry, shampoos, detergents, and coins. A less-common form of chronic exposure is through hemodialysis as traces of nickel ions may be absorbed into the plasma from the chelating action of albumin.
Supplemental information:
Nickel released from Siberian Traps volcanic eruptions is suspected of assisting the growth of Methanosarcina, a genus of euryarchaeote archaea that produced methane during the Permian–Triassic extinction event, the biggest extinction event on record
Nickel compounds are classified as human carcinogens based on increased respiratory cancer risks observed in epidemiological studies of sulfidic ore refinery workers. This is supported by the positive results of the NTP bioassays with Ni sub-sulfide and Ni oxide in rats and mice.The human and animal data consistently indicate a lack of carcinogenicity via the oral route of exposure and limit the carcinogenicity of nickel compounds to respiratory tumours after inhalation.