Titanium Dioxide
By 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 and Carcinogenic Effects
No data are available regarding human genetic effects.
Evaluation by the IARC : The agent (the mixture) is possibly carcinogenic to humans Evaluation by the NIOSH and OSHA : Potential human carcinogen.
Note it is not classified as a confirmed carcinogen to man by these organisms.
Evaluation by the ACGIH: Substance not classifiable as a carcinogen to man (A4 group).
Limits of exposure :
The limits of exposure proposed in the USA and Quebec do not mention this carcinogenic potential, and the limit is in relation with its irritating power.
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.
References :
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
Edouard Bastarache M.D.
Occupational & Environmental Medicine
Author of "Substitutions for Raw Ceramic Materials"
Tracy, Québec, CANADA
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
Out Bound Links
In Bound Links
| 
The future of ceramic recipe, material and physical testing record keeping is here.
Maintain your recipe database on-line
- Login to a private account or work with others in a group account (e.g. university).
- Nothing to install (access it using your web browser). It is always the latest version.
- Easy to import your existing data.
- As many side-by-side recipes as you want.
- Many ways to search and classify glaze and body recipes.
- Glaze and body recipes are robust, with units-of-measure, unlimited pictures with individual titles and descriptions.
- Add variations to a recipe; each with its own pictures, descriptions and name/code-number extensions.
- Recipes can link to typecodes, projects and firing schedules (all managed in their own areas).
- Standard reports and mix ticket reports with last-minute-totalling; variations report as if they are a complete recipe.
- Video tutorials, help system, contact form on every page, dedicated messaging and support ticket systems.
- It is an industrial-strength database system (unlimited capacity, fast, reliable, scalable).
Imports many file formats
- Glaze recipe formats supported: HyperGlaze, GlazeGhem, GlazeMaster, Matrix, INSIGHT XML recipes (single and multiple), INSIGHT SQLite DB files.
- Assign a batch number to imports, and later search by batch.
- Assign multiple typecodes to imported glaze and body batches (to classify) and search on these later.
- Prepend character sequences to glaze recipe names during import.
- Import the pictures and pair them to their corresponding records automatically.
- One click to automatically export the database to an SQLite DB database file and download it (for use with desktop INSIGHT or just as a backup).
- Export and import individual glaze recipes as text or XML.
Perfect for Education
- Ceramic study programs can now accumulate material, recipe and testing data year-after-year, students can login and together build a valuable ceramic glaze and body knowledge resource.
- Students already have internet connected devices, computers are not even needed in the class.
- The Reference Manager gives you quick access to the Digitalfire Ceramic Reference Database.
Learn more..
|
