Bismuth Trioxide Toxicology

Introduction

Bismuth trioxide occurs in nature as the mineral bismite.

I-Product Identification

Synonyms

• Bismuth oxide
• bismuth yellow
• bismuthous oxide
• dibismuth trioxide.

CAS No.: 1304-76-3
Molecular weight: 465.96
Chemical formula: Bi2O₃

II-Uses and Sources of Emission

It is used in

• disinfectants;
• magnets;
• glass;
• ceramics;
• rubber vulcanization;
• fireproofing of papers and polymers;
• catalysts.

It is also an astringent.

Toxicology

I-General Information

Few environmental measurements of bismuth have been reported, in general ambient concentration of bismuth appears to be low; less than 1µg/m³ in rural air and about 1 mg/kg in soil.

The daily intake of bismuth from food and water was estimated to range from 5 to 20 µg. Bismuth and its compounds are considered to be the least toxic of the heavy metals but they are not without important human toxicity. Previously, salts of bismuth (e.g. salicylate) were given parenterally to humans in an attempt to treat syphilis; and more recently, bismuth compounds have been used as an over-the-counter drug against certain gastrointestinal symptoms and disorders. Severe side effects, including gingivostomatitis and toxicity to the liver, kidney, and the central nervous system, have been recorded. Most severe is the encephalopathy, which, during the 1970s in France and Australia, was associated with long-term per os treatment with high daily doses of bismuth subnitrate and subgallate; it is considered to be totally reversible in almost all cases if exposure to bismuth ceases.

If occupational toxicity has occurred, reports are not found in the pertaining literature.

II-Bismuth Trioxide Toxicity

A-Inhalation

Not expected to be a health hazard.

B-Ingestion

Low toxicity. Bismuth salts are poorly absorbed. Should absorption occur, symptoms may include loss of appetite, headache, skin rashes, kidney damage, and rarely mild jaundice.

C-Skin Contact

Not expected to be a health hazard from skin exposure.

D-Eye Contact

Not expected to be a health hazard.

E-Chronic Exposure

Repeated or prolonged ingestion may cause a "bismuth line", black spots on the gums, foul breath, and salivation.

F-Aggravation of Pre-existing Conditions

No information found.

Thermal Decomposition

When heated to decomposition bismuth oxide emits toxic vapors of Bi.

First Aid Measures

I-Inhalation

Remove to fresh air. Get medical attention for any breathing difficulty.

II-Ingestion

Give several glasses of water to drink to dilute. If large amounts were swallowed, get medical advice.

III-Skin Contact

Remove any contaminated clothing. Wash skin with soap or mild detergent and water for at least 15 minutes. Get medical attention if irritation develops or persists.

IV-Eye Contact

In case of contact, immediately flush eyes with plenty of water for at least 15 minutes, lifting upper and lower eyelids occasionally. Call a physician if irritation persists.

Fire Fighting Measures

I-Fire

Not considered to be a fire hazard.

II-Explosion

Not considered to be an explosion hazard.

III-Fire Extinguishing Media

Use any means suitable for extinguishing surrounding fire.

IV-Special Information

Use protective clothing and breathing equipment appropriate for the surrounding fire.

Accidental Release Measures

Ventilate area of leak or spill. Wear appropriate personal protective equipment. Spills: Sweep up and containerize for reclamation or disposal. Vacuuming or wet sweeping may be used to avoid dust dispersal.

Handling and Storage

Keep in a tightly closed container, stored in a cool, dry, ventilated area. Protect against physical damage. Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product.

Exposure Controls/Personal Protection

I-USA-Airborne Exposure Limits

A- OSHA Permissible Exposure Limit (PEL)

15 mg/m3 total dust, 5 mg/m3 respirable fraction for nuisance dusts.

B- ACGIH Threshold Limit Value (TLV)

for Particulates (insoluble or poorly soluble) Not Otherwise Specified (PNOS) 3 mg/m3 respirable particles and 10 mg/m3 inhalable particles.

II-Ventilation System

A system of local and/or general exhaust is recommended to keep employee exposures below the Airborne Exposure Limits. Local exhaust ventilation is generally preferred because it can control the emissions of the contaminant at its source, preventing dispersion of it into the general work area.

Personal protection

I-Personal Respirators

Wear an appropriate respirator according to the severity of exposure.

II-Skin Protection

Wear protective gloves and clean body-covering clothing.

III-Eye Protection

Use chemical safety goggles. Maintain eye wash fountain and quick-drench facilities in work area

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
6. Mallinckrodt Baker, MSDS, Bismuth Trioxide, May 2003.

By Edouard Bastarache

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