Exposure to cobalt in the welding process with stellite

Area of Science:

• Occupational Health and Safety
• Environmental Monitoring
• Toxicology

Background:

• Cobalt alloys like stellite are used in ceramic tile mould production.
• Workers in small factories may be exposed to cobalt during welding processes.
• Understanding cobalt exposure pathways and monitoring methods is crucial for worker protection.

Purpose of the Study:

• To assess environmental and biological cobalt exposure in workers using gas-shielded arc (MAG) and oxy-acetylene welding.
• To evaluate the correlation between environmental cobalt levels and urinary cobalt concentrations (CoU).
• To investigate the utility of CoU as a real-time indicator of occupational cobalt exposure.

Main Methods:

• Conducted environmental and biological monitoring for eight workers in stellite alloy production.
• Measured cobalt exposure during MAG and oxy-acetylene welding processes.
• Analyzed urinary cobalt concentrations (CoU) at the end of working shifts for two MAG welders over two weeks.

Main Results:

• Oxy-acetylene braze-welding showed very low cobalt exposure and urinary cobalt levels.
• MAG welding processes resulted in cobalt exposure levels that could exceed Threshold Limit Value-Time-Weighted Average (TLV-TWA) limits.
• Urinary cobalt concentrations correlated well with MAG welding exposure, but past exposure influenced current CoU levels.

Conclusions:

• MAG welding poses a higher risk of cobalt exposure compared to oxy-acetylene braze-welding in this setting.
• Urinary cobalt levels reflect exposure, but historical exposure significantly impacts current readings.
• Further research is needed to validate urinary cobalt as a reliable indicator for real-time occupational exposure monitoring.