Pulmonary responses after the inhalation of fumes from resistance spot welding of galvanized zinc-coated steel.
Antonini JM; Afshari A; McKinney W; Meighan TG; Jackson M; Chen BT; Schwegler-Berry D; Marshall NB; Anderson SE; Cumpston A; Cumpston J; Leonard HD; Frazer DG; Zeidler-Erdely PC
Toxicologist 2014 Mar; 138(1):325
Spot welding (SW) of galvanized zinc (Zn)-coated steel is commonly used in the automotive industry where high speed repetitive welding of thin metal sections is needed. SW produces complex aerosols that cause bronchitis and asthma in workers. The goal was to assess the effect of SW fumes on lung responses in an animal model. Male Sprague-Dawley rats were exposed by inhalation to 25 mg/ m3 of SW aerosol for 4 h/d x 8 d. Controls were exposed to filtered air. During exposures, particle size distribution, morphology, and chemical composition of the generated aerosol were determined in the breathing zone of exposed animals. Mass median aerodynamic diameter was determined to be 0.25 um by a MOUDI particle impactor. Particles were arranged as chain-like agglomerates composed of ultrafine primary particles. Large, more spherical particles were observed among the agglomerates. Metal analysis indicated the fumes were 90% Fe, 7% Zn, and 2% Mn. Due to the presence of Zn in the fumes and the possible development of metal fume fever, animal body temperatures were measured before and after each daily exposure. No change in body temperatures was observed throughout the exposure period when comparing the two treatment groups. At 1 and 7 d after the final exposure, bronchoalveolar lavage (BAL) was performed to assess lung toxicity. Lactate dehydrogenase (a marker of lung cell cytotoxicity), total BAL cells, and BAL neutrophils were significantly elevated (p<0.01) 1 d after exposure to the SW fumes compared to controls, indicating the development of acute lung injury and inflammation. However, all markers of lung toxicity returned to control values by 7 d after exposure. Acute inhalation of SW fumes from galvanized Zn-coated steel at an occupationally-relevant concentration caused significant lung toxicity, but not metal fume fever in an animal model. Importantly, the observed lung injury and inflammation subsided after a 7-d post-exposure recovery period.
Toxicology; Respiration; Respiratory-irritants; Respiratory-system-disorders; Pulmonary-system; Pulmonary-system-disorders; Pulmonary-function; Exposure-levels; Humans; Men; Women; Welders; Welders-lung; Welding; Lung; Fumes; Automotive-industry; Aerosols; Laboratory-animals; Animals; Particulates; Chemical-composition; Metal-dusts; Metal-compounds
The Toxicologist. Society of Toxicology 53rd Annual Meeting and ToxExpo, March 23-27, 2014, Phonex, Arizona