39 Investigation of Workplace Silica Exposures Using Novel Samplers and Methods

Abstract

Abstract Scientists from the Health and Safety Executive visited a range of workplaces where there was the potential for exposure to silica. The aim of the visits was to determine potential worker exposures to dust and respirable crystalline silica by static air monitoring and exhaled breath condensate (EBC). To evaluate potential airborne exposures low-cost particle monitors were deployed alongside more established scientific equipment.  On site airborne dust concentrations were measured at different locations using two photometers, an optical particle counter (OPC) and a respirable cyclone. The size distribution was measured in real-time using a low-cost OPC and by offline analysis of a polycarbonate membrane filter housed inside an inhalable sampler using a Coulter Counter III. Pre and post shift samples of EBC were taken from 29 workers, with samples analysed by single particle inductively coupled plasma tandem mass spectrometry to measure Si-containing particles.  The real-time air monitoring data showed sustained increased concentrations or peaks corresponding to specific areas or activities, therefore indicating the tasks and/or locations most likely to contribute to worker exposure. The low-cost instruments were also effective in highlighting site locations and tasks most likely to contribute to worker exposure. An approach combining multiple sampling techniques provided a good characterisation of airborne, silica containing dusts. The EBC results consistently showed increased numbers of silicon containing particles post-shift compared with pre-shift.