Sampling and Monitoring of Particles in Metal Inert Gas (MIG) Welding Fumes
Abstract No:
1737
Abstract Type:
Student Poster
Authors:
K Prasad1, J Park2
Institutions:
1none, Cary, NC, 2Purdue University, West Lafayette, IN
Presenter:
Kaushal Arvind Prasad
none
none
Faculty Advisor:
Dr. Jae Park, Ph.D./CIH
Purdue University
Purdue University
Description:
Welding fumes are a mixture of metal oxide particles and gases containing hazardous metals such as Manganese and Chromium. These metals produce chronic and acute adverse health effects such as metal fume fever, cardiopulmonary issues, lung diseases, etc. The size of the welding fumes particles ranges from 0.005-20 µm, where a large proportion is fine (<2.0 µm) and nano- (<100 nm) particles. A metal inert gas (MIG) welding is widely used in manufacturing processes and heats a welding consumable electrode at a temperature higher than 2000℃. Vaporized metals from the welding electrode form nanoparticles. In this project, the respirable particles were sampled from MIG welding and non-welding locations and their size distributions were monitored for eight hours.
Situation/Problem:
Metal nanoparticles are deposited within the respiratory tract following the occupational inhalation of fumes produced during welding, smelting, soldering, and laser cutting operations. This may result in a variety of potential cardiopulmonary health effects, including pneumonia, asthma, fibrosis, and lung cancer. A substantial portion of the emitted nanoparticles from MIG welding consists of metal nanoparticles. More importantly, the toxicity of metal nanoparticles is frequently greater than that of larger particles of the same composition due to the finer particle's ability to translocate to other organs. Characterizing particles in welding fumes is the first step to assess the exposure and protect workers' health.
Methods:
The respirable particles were collected and monitored from a trailer manufacturing facility in Indiana. One location that exclusively conducted MIG welding (location A) and another location that worked on a non-welding process (location B) within the facility were chosen for sampling. At each location, both personal and area samplings were performed. For the sampling, a respirable sampler consisting of an aluminum respirable cyclone and a sampling cassette (25 mm) holding a mixed cellulose ester (MCE) filter (diameter of 25 mm, a pore size of 0.8 µm) was used. A sampling flow rate of 2.5 L/min was used. Gravimetric analysis was conducted after sampling and the mass concentration was calculated from the total sampling volume and mass of particles collected on the filters. For area monitoring, the particle size distributions were measured by a scanning mobility particle sizer and optical particle sizer for every minute at the location approximately 5 meters away from the MIG welder. The welding wire was analyzed using an X-ray fluorescence before sampling.
Results / Conclusions:
The mass concentrations of the respirable particle for the personal sampling at locations A and B yielded 4.190 mg/m^3 and 0.113 mg/m^3, respectively. The mean concentration of the respirable particle for the area sampling at locations A and B yielded 0.299 mg/m^3 and 0.118 mg/m^3, respectively. The total number concentration collected from location A was 5.1×10^4 particles/cm^3 and location B was 2.0×10^4 particles/cm^3. The geometric mean diameters of the particles at locations A and B were 0.045 µm and 0.070 µm, respectively. Metal nanoparticles can nucleate, coagulate, and condense to form larger particles above 100 nm. A greater concentrate of metal vapor released during MIG welding resulted in larger particles (>100nm) emitted from location A. Also, the higher concentrations of the finer metal particles in location A have a higher probability of depositing into the lungs, which allows them to translocate to other organs in the body. Additionally, smaller sized particles will occupy a larger surface area in the lungs. The current United States occupational exposure limit, set by OSHA, is 5 mg/m^3 for respirable dust and is based on the mass of the entire sample, not just one specific metal. As per the results collected, the mass concentrations were below the exposure limit.
Primary Topic:
Sampling and Analysis
Secondary Topics:
Aerosols
Nanotechnology
Co-Authors
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Acknowledgements and References
List any additional people who worked on the project or provided guidance and support along with details on the role they played in the research. (Please include first name, last name, organization, city, state and country).
Hansen et al., Welding fumes and chromium compounds in cell transformation assays, Journal of Applied Toxicology, Vol. 5(5), 306–314, 1985.
Yu et al., Pattern of deposition of stainless-steel welding fume particles inhaled into the respiratory systems of Sprague–Dawley rats exposed to a novel welding fume generating system, Toxicology Letters, Vol. 116, 103–111, 2000.