Design, construction, and characterization of a novel robotic welding fume generator and inhalation exposure system for laboratory animals.
Respiratory effects observed in welders have included lung function changes, metal fume fever, bronchitis, and a possible increase in the incidence of lung cancer. Many questions remain unanswered regarding the causality and possible underlying mechanisms associated with the potential toxic effects of welding fume inhalation. The objective of the present study was to construct a completely automated, computer-controlled welding fume generation and inhalation exposure system to simulate real workplace exposures. The system comprised a programmable six-axis robotic welding arm, a water-cooled arc welding torch, and a wire feeder that supplied the wire to the torch at a programmed rate. For the initial studies, gas metal arc welding was performed using a stainless steel electrode. A flexible trunk was attached to the robotic arm of the welder and was used to collect and transport fume from the vicinity of the arc to the animal exposure chamber. Undiluted fume concentrations consistently ranged from 90-150 mg/m(3) in the animal chamber during welding. Temperature and humidity remained constant in the chamber during the welding operation. The welding particles were composed of (from highest to lowest concentration) iron, chromium, manganese, and nickel as measured by inductively coupled plasma atomic emission spectroscopy. Size distribution analysis indicated the mass median aerodynamic diameter of the generated particles to be approximately 0.24 microm with a geometric standard deviation (sigma(g)) of 1.39. As determined by transmission and scanning electron microscopy, the generated aerosols were mostly arranged as chain-like agglomerates of primary particles. Characterization of the laboratory-generated welding aerosol has indicated that particle morphology, size, and chemical composition are comparable to stainless steel welding fume generated in other studies. With the development of this novel system, it will be possible to establish an animal model using controlled welding exposures from automated gas metal arc and flux-cored arc welding processes to investigate how welding fumes affect health.
Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA. jga6@cdc.gov
James M
JM
Antonini
Aliakbar A
AA
Afshari
Sam
S
Stone
Bean
B
Chen
Diane
D
Schwegler-Berry
W Gary
WG
Fletcher
W Travis
WT
Goldsmith
Kurt H
KH
Vandestouwe
Walter
W
McKinney
Vincent
V
Castranova
David G
DG
Frazer
D000336:Aerosols; D000818:Animals; D000830:Animals, Laboratory; D001331:Automation; D004195:Disease Models, Animal; D004867:Equipment Design; D019570:Inhalation Exposure; D016273:Occupational Exposure; D012371:Robotics; D014896:Welding; D017132:Workplace
D000336:Aerosols