Workers occupational exposure to Free Crystal Silica of respirable particles in a cement factory in Khorasan Razavi province

There are many chemicals in Portland cement including crystalline Silica. Workers’ exposure to cement airborne particles containing Free Crystal Silica may cause some serious diseases. This study was carried out to evaluate Free Crystal Silica particle concentration in the workers’ breathing zone in a cement factory in the Khorasan Razavi province.

The concentration of free Crystal Silica of respirable cement particles was evaluated on 42 sample of workers in different sections of a cement factory in the Khorasan Razavi province in 2018. Sampling of respirable particles was conducted based on standard method of MDHS101/2 recommended by NIOSH, using a personal sampling pump, a cyclone and a filter. Filters were weighed using an accurate microbalance with one microgram precision. Filter was analyzed by XRD method for determination of free crystalline silica.

The mean workers’ exposure to cement respirable particles was 3.75±4.09 mg/m3 and the average concentration of free silica in cement respirable particles was 0.12±0.3 mg/m3 in all studied sections. On average, 69 percent of workers were exposed to free silica higher than OEL. Maximum average of exposure to free silica (0.54 mg/m3) was observed in stone crushing section and the minimum average exposure was observed in Raw mill section (0.03 mg/m3).

Workers exposure to respirable cement particles and free crystalline silica in respirable particles were higher than national and international exposure limits. There is a relationship between temperature and respirable particle concentration. Regarding high exposure of workers to free crystalline silica respirable particle concentration.