Niobium
Classification:
Niobium is a chemical element.
Cas:
7440-03-1
Synonyms/Trade Names:
None.
Chemistry/Composition:
Nb.
Structure:
Cubic face centered.
Crystallographic Constants:
3.3066 3.3066 3.3066 90.000 90.000 90.000.
Crystal Group:
Cubic.
Color:
Pale-gray.
Optical Properties:
Opaque.
Pleochroism:
None.
Powder Diagram:
2.379 1.3499 1.6532 1.1688 (5-789).
Natural Sources:
Mined in Norway.
Medical Importance:
Key Hazards:
Possibly carcinogenic.
Involved Organs:
Lung, upper respiratory tract.
Exposure/Epidemiology:
Exposure may occur in mining or in usage in metallurgy or magnetoceramics. World production was 75×103 tons in 1978.
Thresholds: |
TWA |
|
mg/m3 |
| Denmark | 5 |
| Germany | 6 |
Etiology/Pathophysiology:
Detailed data are not known.
Lung Diseases:
Niobium mining may be associated with an increased risk of lung cancer (dose dependent); for further information see under the heading mining.
Clinical Presentation:
Symptoms are nonspecific and the same as those seen in lung cancer.
Radiology:
Associated specific findings are not known.
Lung Function:
Usually normal, or related to size and location of lung cancer.
Bronchoalveolar Lavage:
Associated specific findings are not known.
Pathology:
Gross:
The lungs are of normal color and consistency until the development of lung cancer.
Histology:
Usually normal findings until the development of lung cancer.
Prognosis:
Fair, as exposed persons have an increased risk of lung and nasal cancer.
Additional Diseases:
Nose:
Carcinoma of the nose.
References:
search Pubmed for Niobium
IARC: Cancer: causes, occurrence and control. IARC Sci Publ 100 (1990)
Solli HM, Andersen A, Stranden E, Langard S: Cancer incidence among workers exposed to radon and thoron daughters at a niobium mine. Scand J Work Environ Health 11 (1985) 9-13