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Titanium Dioxide
Article courtesy of Edouard Bastarache
Titanium is one of the most common components of the earth's crust, ninth in abundance. It occurs naturally as ilmenite (iron titanate) and rutile (titanium dioxide).
Titanium forms four distinct oxides: titanium monoxide (TiO), dititanium trioxide (Ti2O3), titanium dioxide (TiO2) and titanium trioxide (TiO3).
Occupational and Environmental Exposure Sources:
Titanium is frequently used as a white pigment for a wide range of paints, paper, inks, plastics, and the like. Exposure results from breathing titanium dioxide dust. Possible exposure to intermediate products in titanium dioxide production may also occur. Exposure may then occur at any stage in the mining of ores, in the preparation of titanium dioxide, and in any of the industries in which the powder is stored and used.
Clinical Toxicology:
I- Routes of exposure:
Titanium dioxide inhalation is the most common route of exposure. Ingestion is certainly possible when some dust accumulates on mucosal surfaces of the oropharynx and nasopharynx.
II-Distribution, Metabolism and Elimination:
Titanium dioxide is found in the lymphatics and regional nodes that drain the lungs, indicating a slow removal by this process. No data are available regarding oral absorption of titanium. Titanium is excreted by the kidneys.
III-Signs, Symptoms and Syndromes:
A-Acute Toxicity:
Titanium dioxide is an irritant to the upper airway, as are other nuisance dusts. No evidence indicates that it induces an acute inflammatory reaction at commonly seen exposure concentrations. In workers with preexisting chronic obstructive airway disease, titanium dioxide may exacerbate symptoms.
B-Chronic Toxicity:
Titanium dioxide is retained in the lungs. Particles of this dust are found also in the regional nodes draining the lungs, suggesting that these particles are slowly cleared by the lymphatics. Little evidence indicates that titanium dioxide promotes a chronic inflammatory reaction in the lungs. Titanium dioxide dust currently is considered to be merely a nuisance dust that results only in upper airway irritation.
IV-Genetic Effects:
No data are available regarding human genetic effects, and very limited epidemiologic data about carcinogenicity are available. Recent animal data support the conclusion that titanium dioxide is a nuisance dust and does not produce any inceased incidence of cancer rates.
V-Management of Toxicity or Exposure:
Titanium dioxide is an irritant dust, therefore, management of exposure is supportive. Exposed workers should be removed from the environment, and supportive pulmonary care should be provided.
A-Medical and Biological Monitoring:
Most laboratory tests are not helpful. Assessement of serum and urinary titanium levels help to identify recent exposure.
B-Occupational and Environmental Regulations:
Acute upper airway irritation may be reduced by keeping exposure to titanium at low limits.
Quebec's exposure limit:
VEMP (Valeur d'Exposition Moyenne Pondéré) = 10 mg/m3 as total dust.
C-Exposure Controls:
Good industrial hygiene and monitoring of the environment should limit employee exposure to titanium dust. If employees must work in an environment with high titanium dioxide dust levels and poor ventilation,respirators should be used.
Edouard Bastarache M.D. (Occupational & Environmental Medicine)
Author of " Substitutions for raw ceramic materials "
1-Occupational Medicine,Carl Zenz, last edition.
2-Clinical Environmental Health and Toxic Exposures, Sullivan & Krieger; last edition.
3-Sax's Dangerous Properties of Industrial Materials, Lewis C., last edition.
4-Toxicologie Industrielle et Intoxications Professionnelles, Lauwerys R.R. last edition.
5-Chemical Hazards of the Workplace, Proctor & Hughes, 4th edition

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