Millions of workers worldwide are exposed to welding aerosols daily. Health effects in welders have included, metal fume fever, decreased lung function, and chronic bronchitis. Resistance spot welding (RSW) using adhesives is common in the automotive, aircraft, and appliance industries for fabricating with sheet metal where high speed, repetitive welding is needed and relatively thin section sizes are welded. Preliminary air sampling in an automotive plant during RSW detected numerous volatile organic compounds (VOCs) such as methyl methacrylate, toluene, benzene, that were also found in adhesives used in the process. The goals of this study were to develop an automated RSW generation and inhalation system for laboratory animals and to physically and chemically identify and characterize the aerosols formed. The system is divided into three different areas: (1) enclosed control room, (2) spot welder, and (3) animal exposure chamber and aerosol characterization equipment. RSW is performed on low carbon and galvanized steel (1/32" thick, up to 1-1/2" wide) conveyed from a pair of spools at a controlled rate using an automated welder equipped with two copper alloy electrodes. Adhesives commonly used during RSW are evenly dispensed at a controlled rate between the strips of metal to be welded. Welding aerosols are transported via a flexible trunk to the animal exposure chamber. Airborne emissions in the animal breathing zone are collected onto desorption tubes for identification and measurement of VOCs. Fume morphology, composition, and size are determined by electron microscopy, atomic emission spectroscopy, and particle impactors, respectively. With the development of this novel system, it is possible to investigate in an animal model the pulmonary effects of welding fume generated from RSW on metal coated with adhesives.
Fumes; Lung; Lung-cells; Lung-disorders; Lung-irritants; Inhalation-studies; Pulmonary-disorders; Pulmonary-system-disorders; Laboratory-animals; Respiratory-infections; Respiratory-system-disorders; Vapors; Welders-lung; Welding; Aerosols; Aerosol-particles; Airborne-dusts; Airborne-particles; Respiratory-gas-analysis; Respiratory-irritants; Respiratory-system-disorders; Respiratory-hypersensitivity; Exposure-chambers
The Toxicologist. Society of Toxicology 47th Annual Meeting and ToxExpo, March 16-20, 2008, Seattle, Washington