Distribution of metals between inhalable and respirable fractions of welding fumes generated in gas metal arc welding

Respirable and inhalable fractions of welding fumes were collected in a welding plant, where corrosion resistant steel (X8CrNi1810) was welded with gas metal arc welding (GMAW). Welding fumes were sampled with 'fixed point' sampling technique 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 aerosol fraction. The 'water soluble' and the total concentrations of Fe, Mn, Cr, Ni and Cr(VI) were determined after water extraction and microwave assisted digestion applying inductively coupled plasma quadrupole mass spectrometry (Q-ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and UV visible spectrophotometry. The amounts of 'water soluble' metal components in the respirable aerosol fraction were 60-97% of their amounts in the inhalable fraction. These rates were 64-94% in the case of the total metal concentrations, while the respirable Cr(VI) was 1.6-fold higher than inhalable Cr(VI). These findings suggest that from toxicological point of view the measurements of the chemical composition and size distribution of the particles formed during a welding process have high importance.