Clinical Information

Nickel (Ni), a silvery white metal widely distributed in the earth's crust, is essential for the catalytic activity of some plant and bacterial enzymes but its role in humans has not been defined. Elemental Ni may be essential for life at very low concentrations and is virtually nontoxic.

Ni is commonly used in industry. It is a pigment in glass, ceramics and fabric dyes. It is converted in the Mond process to nickel carbonyl, Ni(CO)(4), and used as a catalyst in petroleum refining and in the plastics industry, is frequently employed in the production of metal alloys (which are popular for their anticorrosive and hardness properties) in Ni-cadmium rechargeable batteries, and is used as a catalyst in hydrogenation of oils. Ni(CO)(4) is very toxic.

Ni(CO)(4), a liquid with low vapor pressure, is one of the most toxic chemicals known to man. Ni(CO)(4) is absorbed after inhalation, readily crosses all biological membranes, and noncompetitively inhibits ATP-ase and RNA polymerase. Ni(CO)(4) binds avidly to hemoglobin with resultant inability to take up oxygen. The affinity for hemoglobin is higher than carbon monoxide. The binding to hemoglobin is the main transport mechanism for spreading Ni(CO)(4) throughout the body. Urine is the specimen of choice for the determination of Ni exposure via inhalation.

Patients undergoing dialysis are exposed to Ni and accumulate Ni in blood and other organs; there appear to be no adverse health affects from this exposure. Hypernickelemia has been observed in patients undergoing renal dialysis. At the present time, this is considered to be an incidental finding as no correlation with toxic events has been identified. Routine monitoring of patients undergoing dialysis is currently not recommended.

Breathing dust high in Ni content has been associated with development of neoplasms of the respiratory system and nasal sinuses. Most reactions to Ni are localized skin sensitivity and allergic skin disorders that occur on contact with Ni-containing alloys. These reactions do not correlate to urine concentrations; patients experiencing skin sensitivity reactions to Ni are likely to have normal Ni excretion.