Comparison of different sampling heads applied for investigation of welding fume

Welding fume samples were collected in two Hungarian welding plants, where different types of steels were welded with metal active gas (MAG) welding. Welding fumes were sampled with “fixed point” and personal sampling techniques applying different sampling heads: Institute of Occupational Medicine (IOM) sampler and conical inhalable sampler (CIS) for the inhalable aerosol fraction and the Higgins-Dewell (HD) cyclone for the respirable fraction. When sampled, the welding fume samples were digested with the mixture of nitric acid and hydrogen peroxide in a closed vessel microwave digestion system. The Cr, Mn, Ni and Co contents of the solutions were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Iron was analysed only by the ICP-AES method. Metal concentrations of the workplace air were calculated for the three samplers, and the results were compared to each other. The differences of the metal concentrations determined by the different inhalable sampling heads, which were paired during the sampling, proved not to be significant. Therefore, the IOM and CIS heads can be equally used for the sampling of welding fume. Finally, the distributions of metals were determined between the inhalable and respirable fractions. Metal concentrations in the respirable aerosol fraction were 57-98% of the concentrations in the inhalable fraction. These high rates of metals in the respirable aerosol call the attention to the increased health risk of the welding fume.