Exposure to soluble barium compounds: an interventional study in arc welders

Area of Science:

• Occupational Health
• Environmental Toxicology
• Industrial Hygiene

Background:

• Soluble barium compounds are known toxicants, primarily through oral ingestion.
• Limited data exists on health effects from inhalative exposure to soluble barium salts in occupational settings.
• Welding processes can generate fumes containing soluble barium.

Purpose of the Study:

• To investigate the health effects of inhalative exposure to soluble barium in welders.
• To assess barium exposure levels during welding with barium-containing electrodes.
• To evaluate the effectiveness of exhaust systems in reducing exposure.

Main Methods:

• An interventional study involving 18 welders over one week.
• Monitoring of welding fume and soluble barium concentrations.
• Measurement of internal exposure through urine and plasma barium levels.
• Assessment of potential health impacts, including hypokalemia.

Main Results:

• Welding fumes contained 31%-37% soluble barium.
• Exceedances of Threshold Limit Values (TLVs) for total welding fumes and soluble barium were observed.
• Median fume concentrations were 13.2 mg/m³ (stick electrode) and 12.3 mg/m³ (flux cored wire).
• Median barium concentrations were 4.4 mg/m³ and 2.0 mg/m³ respectively.
• Integrated exhaust systems were effective for flux cored wire welding.
• Elevated median urine (101.7 µg/l) and plasma (24.7 µg/l) barium levels were found.

Conclusions:

• Inhalative exposure to soluble barium during welding poses a risk, with levels frequently exceeding occupational exposure limits.
• While no definitive health impacts were proven, potential risks such as hypokalemia warrant further investigation.
• Engineering controls, like integrated exhaust systems, can mitigate exposure during specific welding tasks.