Absorption - Inhalation Nickel (Ni)

 Oral      Dermal

  • Nickel and its inorganic compounds can be absorbed from the respiratory tract. The quantity of Ni absorbed is dependent on the quantity, physical and chemical properties of the Ni compounds. Smaller particles (1-5 μm) enter the trachea and bronchiolar region. The smallest particles (< 1 μm) enter the alveolar region, where less intense airflow and system geometry enhance sedimentation, diffusion, and electrostatic particle precipitation (Czerczak and Gromiec, 2001).

  • Solubility is also an important factor. Soluble Ni salts readily dissociate in aqueous medium releasing Ni ions that can penetrate cellular membranes. The solubility of Ni compounds appears to be the most reliable indicator of the rate that Ni-containing dust in the alveoli is absorbed into the blood. This rate is higher for soluble Ni salts, such as Ni chloride and sulfate, and lower for less soluble species, such as Ni sulfide and forms generally considered insoluble, such as the subsulfide, Ni oxide dusts and metallic Ni. Nickel carbonyl is absorbed to a high degree; 26% of the inhaled amount had been excreted in urine in 4 days (Sunderman and Selin, 1968). Since exhalation may have cleared the same amount or more, at least 50% of the inhaled dose is estimated to have been absorbed. A least 75% of intratracheally deposited Ni chloride was absorbed within 72 hours in rats (Clary, 1975) whereas 80% of inhaled Ni oxide aerosol remained in hamster lung 10 days later (Wehner et al., 1972). There was evidence of Ni subsulfide, but not Ni oxide, absorption. The half-lives of Ni in rat lung following inhalation of Ni sulfate, Ni subsulfide and nickelous oxide were ~ 30 hours, 4 to 6 days and 120 days, respectively (Hirano et al., 1994; Czerczak and Gromiec, 2001). Ni solubility relates to its carcinogenicity; insoluble forms are carcinogenic, soluble forms are much less so or not.

  • Nickel detected in the urine of workers exposed to soluble Ni compounds (Ni chloride and Ni sulfate) was higher than in workers exposed to insoluble species (Ni oxide, Ni subsulfide), indicating soluble Ni species were more quickly absorbed from the respiratory system (Angerer and Lehnert, 1990; Baranowska-Dutkiewicz et al., 1992).

 

Link to Absorption Periodic Table         

Link to Nickel (Ni) Index

Link to Database Index

 

Comments to Robert Yokel, Ph.D., Last Modified: November 17, 2008
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