Increase in oxidative stress levels following welding fume inhalation: a controlled human exposure study.
Tungsten inert gas (TIG) welding represents one of the most widely used metal joining processes in industry. It has been shown to generate a large majority of particles at the nanoscale and to have low mass emission rates when compared to other types of welding. Despite evidence that TIG fume particles may produce reactive oxygen species (ROS), limited data is available for the time course changes of particle-associated oxidative stress in exposed TIG welders.



Twenty non-smoking male welding apprentices were exposed to TIG welding fumes for 60 min under controlled, well-ventilated settings. Exhaled breathe condensate (EBC), blood and urine were collected before exposure, immediately after exposure, 1 h and 3 h post exposure. Volunteers participated in a control day to account for oxidative stress fluctuations due to circadian rhythm. Biological liquids were assessed for total reducing capacity, hydrogen peroxide (H2O2), malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations at each time point. A linear mixed model was used to assess within day and between day differences.



Significant increases in the measured biomarkers were found at 3 h post exposure. At 3 h post exposure, we found a 24 % increase in plasma-H2O2 concentrations ([95%CI: 4 % to 46 %], p = 0.01); a 91 % increase in urinary-H2O2 ([2 % to 258 %], p = 0.04); a 14 % increase in plasma-8-OHdG ([0 % to 31 %], p = 0.049); and a 45 % increase in urinary-8-OHdG ([3 % to 105 %], p = 0.03). Doubling particle number concentration (PNC) exposure was associated with a 22 % increase of plasma-8-OHdG at 3 h post exposure (p = 0.01).



A 60-min exposure to TIG welding fume in a controlled, well-ventilated setting induced acute oxidative stress at 3 h post exposure in healthy, non-smoking apprentice welders not chronically exposed to welding fumes. As mass concentration of TIG welding fume particles is very low when compared to other types of welding, it is recommended that additional exposure metrics such as PNC are considered for occupational risk assessments. Our findings highlight the importance of increasing awareness of TIG welding fume toxicity, especially given the realities of welding workplaces that may lack ventilation; and beliefs among interviewed welders that TIG represents a cleaner and safer welding process.
Institute for Work and Health, University of Lausanne and Geneva, Lausanne, CH-1066, Switzerland.
Halshka
H
Graczyk
Institute for Work and Health, University of Lausanne and Geneva, Lausanne, CH-1066, Switzerland.|Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, 23284, USA.
Nastassja
N
Lewinski
Institute for Work and Health, University of Lausanne and Geneva, Lausanne, CH-1066, Switzerland.|Department of Environmental Health, Harvard T. H. Chan School of Public Health, Harvard University, 665 Huntington Ave., Boston, MA, 02115, USA.
Jiayuan
J
Zhao
Institute for Work and Health, University of Lausanne and Geneva, Lausanne, CH-1066, Switzerland.
Jean-Jacques
JJ
Sauvain
Institute for Work and Health, University of Lausanne and Geneva, Lausanne, CH-1066, Switzerland.
Guillaume
G
Suarez
Department of Scientific Management, National Institute for Research and Security, INRS, Vandoeuvre, 54500, France.
Pascal
P
Wild
Institute for Work and Health, University of Lausanne and Geneva, Lausanne, CH-1066, Switzerland.
Brigitta
B
Danuser
Institute for Work and Health, University of Lausanne and Geneva, Lausanne, CH-1066, Switzerland. michael.riediker@alumni.ethz.ch.|SAFENANO, IOM Singapore, Singapore, 048622, Singapore. michael.riediker@alumni.ethz.ch.
Michael
0000-0002-5268-864X
M
Riediker
D000293:Adolescent; D000328:Adult; D000395:Air Pollutants, Occupational / Q000633:toxicity*; D015415:Biomarkers / Q000032:analysis / Q000097:blood / Q000652:urine; D001944:Breath Tests; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000032:analysis / Q000097:blood / Q000652:urine; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis / Q000097:blood / Q000652:urine; D019570:Inhalation Exposure / Q000009:adverse effects*; D016014:Linear Models; D008297:Male; D008315:Malondialdehyde / Q000032:analysis / Q000097:blood / Q000652:urine; D016273:Occupational Exposure / Q000009:adverse effects*; D018384:Oxidative Stress / Q000187:drug effects*; D012906:Smoke / Q000009:adverse effects*; D013557:Switzerland; D018675:Toxicity Tests; D014896:Welding; D000078329:Workforce; D055815:Young Adult
D000395:Air Pollutants, Occupational; D015415:Biomarkers; D012906:Smoke; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D003849:Deoxyguanosine
8-OHdG; Apprentice welders; Hydrogen peroxide; Malondialdehyde; Occupational exposure; Oxidative stress; Tungsten Inert Gas (TIG); Welding fume