Zeidler-Erdely-PC; Afshari-AA; Meighan-TG; McKinney-W; Chen-BT; Schwegler-Berry-D; Jackson-M; Cumpston-A; Cumpston-JL; Leonard-DH; Erdely-A; Frazer-DG; Antonini-JM
Toxicologist 2012 Mar; 126(Suppl 1):226-227
Resistance spot welding (RSW) is commonly used in the automotive and aircraft industries where high speed, repetitive welding is needed and relatively thin metal sections are welded. Epoxy adhesives are applied as sealers to the seams of the metals that are joined. RSW produces complex aerosols composed of both metals and volatile compounds which have caused respiratory symptoms, including bronchitis and asthma, in exposed workers. The goals of the study were to develop a RSW generation and inhalation system, characterize the generated aerosols, and expose laboratory animals to determine the potential mechanisms that may be involved with the development of lung toxicity. RSW was configured so that two aerosols were generated and compared: (1) high metal (HM) fume and (2) low metal (LM) fume (mostly volatiles). Male Sprague-Dawley rats were exposed to 20-50 mg/m3 of the aerosols for 4 hr/d x 3 d. Control animals were exposed to filtered air. Bronchoalveolar lavage (BAL) was performed at 1 and 7 d after exposure, and lung injury and inflammation parameters were measured in the recovered lavage fluid (BALF). Mass median aerodynamic diameter was determined by a Micro-Orifice Uniform Deposit Impactor and found to be 0.77 and 0.93 microm for the HM and mostly volatile LM fume, respectively. The HM fume was composed of greater than 90 % Fe, whereas little to no metal was present in the LM fume. Volatiles present in the LM fume included benzene, toluene, 2-propen-1-ol, acetone, and others. An increase in lung injury parameters (albumin and lactate dehydrogenase) in the BALF was observed at 1 d after exposure to the HM fume that had resolved by 7 d, whereas exposure to the LM fume had no effect on lung injury and inflammation. Initial findings of this pilot study indicate that the metal, and not the volatile, component of RSW aerosol may influence the development of lung injury. Additional inhalation studies are ongoing to determine if either of these components alters lung function.
Laboratory-animals; Laboratory-techniques; Laboratory-testing; Exposure-assessment; Exposure-methods; Exposure-levels; Lung; Pulmonary-system; Immune-reaction; Dose-response; Particulates; Inhalants; Inhalation-studies; Fumes; Welding; Adhesive-bonding; Adhesives; Epoxy-resins; Metals; Sealing-compounds
The Toxicologist. Society of Toxicology 51st Annual Meeting and ToxExpo, San Francisco, California, March 11-15, 2012