Nickel (Ni) is a dietary requirement for many organisms, but may be toxic in larger doses. Metallic nickel and some other nickel compounds are teratogenic and carcinogenic to mammals. Nickel may be found in slate, sandstone, clay minerals and basalt, however; nickel is not commonly found in nature as a pure metal. Nickel is often used in electroplating, stainless steel and alloy products. Nickel is directly emitted from various industries through discharge on surface waters. It generally gets into water from mining and refining operations. Nickel compounds are also applied in agriculture. Phosphate fertilizers contain traces of nickel. The absorption of dietary nickel from the gastrointestinal tract appears to be quite low, with the majority of nickel passed through the body.
The recommended method of treatment for nickel is Reverse Osmosis or Distillation.