10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Reducing Toxicity of Welding Fume Particles by Amorphous Silica Encapsulation
RYAN WARD, Trevor Tilly, Sarah Robinson, Arantzazu Eiguren Fernandez, Tara Sabo-Attwood, Chang Yu Wu, University of Florida
Abstract Number: 1342 Working Group: Aerosol Toxicology
Abstract Despite the current safety protocols involved in arc welding, the production of toxic metal fumes as byproducts poses serious health risks to industry workers. According to the Bureau of Labor Statics in 2013, over 575,000 individuals in the United States are involved in the welding industry and of that amount, 31% had experienced metal fume fever at least once in their career. This condition stems from the nanoparticles released by the fumes associated with the welding process and the subsequent reactive metal exposure to the respiratory system of workers, where chronic exposure can be detrimental to human health. The addition of tetramethylsilane (TMS) to the shielding gas of a welder has been shown to coat the surface of these particles in amorphous silica once generated, and because this silica is less toxic to human, the risk associated with inhalation of these fumes is significantly decreased. In previous studies this has been shown, though E. coli was used for toxicity analysis, which cannot be directly correlated to possible adverse health effects in humans. The method employed for toxicity analysis in this study, however, represents a novel procedure wherein human lung cell culture can be exposed immediately to nanoparticles. Welding fume particles were generated, diluted to different concentrations through an air dilution system, and measured by a Scanning Mobility Particle Sizer Spectrometer (SMPS) for their aerosol size distribution. Cell culture were then exposed to the diluted fumes through the DAVID (Dosimetric Aerosol in Vitro Inhalation Device) system, which condensed water vapor onto the welding fume particles to grow particle size and allow for efficient deposition of particles to cell culture at the air-liquid interface, where gaseous phase aerosol are deposited directly into liquid cell culture. This innovative system allowed for a real-time exposure of nanoparticles to cell culture vs. the classical use of filter collection and submerged exposure to liquid cell culture. Both TMS coated welding particles and non-coated particles were exposed to cell culture via this method and a toxicity analysis was performed through a lactate dehydrogenase (LDA) assay, which measured viability of cell cultures post-exposure. Optimization of a TMS infusion system has potential to significantly reduce the health impacts associated with the welding process. Additionally, this demonstrates the functionality of the DAVID system as an alternative to the conventional methods of cell culture exposure analysis that more closely resembles aerosol exchange in that human respiratory system.