15 Biomonitoring for Respirable Crystalline Silica: Determination of Si-Containing Particles in Exhaled Breath Condensate Using Single Particle Inductively Coupled Mass Spectrometry

Abstract

Abstract Biological monitoring is a useful way of determining overall exposures to chemical substances; however, in the case of respirable crystalline silica (RCS), this has not been possible in conventional biological matrices.  Previous research at HSE has shown that it was possible to detect silicon-containing particles in exhaled breath condensate (EBC) samples using single particle inductively coupled mass spectrometry (spICPMS) in a small number of quarry workers, and at that time the method had a particle size detection limit of around 300 nm.  In more recent work presented here we will describe the advances in the methodology and the results from exhaled breath condensate samples collected from a range of UK workers with potential RCS exposures.  Control samples were also collected for comparison. Static air/bulk samples were also collected to allow the size distribution and concentration of RCS to be determined in each workplace. The analytical advances include moving to using an ICP tandem MS for better specificity with an improved sample introduction system.  This has increased the size range detection of silicon-containing particles, allowing measurements in the size range of 100-2000 nm, in a one minute acquisition.  We have also standardised the EBC sampling by collecting the same volume of exhaled air (50L) from each volunteer. This improved methodology offers a viable biomonitoring method for a range of workplaces and has the potential to inform information about the efficacy of respiratory protective equipment and control measures in the workplace, complementing occupational hygiene.