Nickel | Toxic Substances

Source: Nickel is a naturally occurring metal typically found in water or soil (1); nickel typically occurs in nature as oxides, sulfides, and silicates (3). Nickel can also be found in many common foods and drinking water.
Potential for exposure: Occupational exposure is possible but exposure is more probable to occur from manufactured products such as fashion accessories or through diet.
Biotransformation: Nickel is never destroyed in the body; there is only a potential for modification of the metal. Nickel can remain in its original state or transform into the nickel cation Ni2+. (4)

Toxicokinetics:(6)
- Inhalation: 25-30% of inhaled nickel enters the lungs and is distributed into the bloodstream
  - Nickel can be found in urine of workers who experience occupational exposure to nickel with higher nickel concentrations being found in individuals who were exposed to soluble nickel compounds
- Ingestions via drinking water: about 27% of nickel is absorbed into the bloodstream
- Dermal: there is no proof to suggest that nickel is absorbed into the bloodstream following dermal exposure
- Nickel is typically excreted through urine or feces
Carcinogenicity: Nickel is classified as a Group 1 carcinogen. Prolonged nickel exposure resulting in excess inhalation of nickel dust and nickel subsulfide may increase the risk of lung and nasal cancers. (5)
Mechanism of Action: Nickel is said to induce toxic effects primarily through interference of bodily functions related to manganese, zinc, calcium, and magnesium.
Target organs: lung and upper respiratory tract (inhalation exposure), kidneys (oral exposure), skin (dermal exposure) (4)

Signs and symptoms of toxicity: contact dermatitis, dry/itchy/irritated/inflamed skin
Historical or unique exposures: A man died of adult respiratory distress syndrome 13 days after being exposed to a very high concentration of metallic nickel fume; extremely high levels of nickel were detected in his urine at autopsy. (6)
Treatments: Early diagnosis and avoidance of nickel lowers the chances of nickel-induced allergic reactions. Active breakouts can be treated with topical corticosteroids or calcineurin inhibitors. (3)
Biomarkers: Nickel exposure is classically identified by the presence of nickel in the urine, feces, serum, hair, and nasal mucosa (6). There are no alternative biomarkers outside of detecting the original compound.
Nickel deficiency: Nickel deficiency is accompanied by reduced iron absorption and may, in turn, result in anemia. Nickel deficiency may also lead to disruptions in calcium and zinc metabolism (7).

References:

Nickel Poisoning. Environmental Pollution Centers. (n.d.). https://www.environmentalpollutioncenters.org/nickel/.
GlobalData. (n.d.). Philippines’ beleaguered nickel sector boosted by Indonesia’s upcoming nickel export ban. Mining Technology. https://www.mining-technology.com/comment/philippines-beleaguered-nickel-sector-boosted-by-indonesias-upcoming-nickel-export-ban/.
Ahlström, M. G., Thyssen, J. P., Wennervaldt, M., Menné, T., & Johansen, J. D. (2019, July 9). Nickel allergy and allergic contact dermatitis: A clinical review of immunology, epidemiology, exposure, and treatment. Wiley Online Library. https://onlinelibrary.wiley.com/doi/full/10.1111/cod.13327.
The Risk Assessment Information System. (n.d.). https://rais.ornl.gov/tox/profiles/nickel_and_nickel_compounds_f_V1.html#:~:text=The%20primary%20target%20organs%20for,immune%20system%2C%20and%20the%20blood.
The Facts on Nickel. Roadmap on Carcinogens. (2020, November 5). https://roadmaponcarcinogens.eu/nickel.
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES. (2005, August). TOXICOLOGICAL PROFILE FOR NICKEL. https://www.atsdr.cdc.gov/toxprofiles/tp15.pdf
M;, A. M. G. B. K. H. G. (n.d.). Nickel–an essential element. IARC scientific publications. https://pubmed.ncbi.nlm.nih.gov/6398286/#:~:text=Nickel%20deficiency%20is%20accompanied%20by,expression%20in%20disturbed%20zinc%20metabolism.