Abstract
Background: South Africa’s (SA) has been recorded as the largest producer of platinum (Pt) in the world. Pt mining categories include underground and opencast. However, opencast mining leads to increased rates of air pollution, triggering health risks due to the exposure of workers to coarse and fine dust particles. The purpose of this study was to assess the risk of exposure of workers to inhalable and respirable dust fractions, and then compare this to national and international occupational exposure limits (OELs). Methods: A quantitative, descriptive cross-sectional study was conducted at two pre-selected Pt mine waste rock crusher plants (named, Facility A and B) in Fetakgomo-Greater Tubatse Local Municipality. A walk-through survey was conducted to create a basis for the quantitative assessment and better analysis of results. A total of 34 self-administered questionnaires were used to obtain permanent workers’ demographic and occupational information and analysed using SPSS version 25 software. A total of 18 static dust samples, (inhalable (n = 9)) and respirable (n = 9)), were collected using a multi-fraction sampler from 9 work stations (Screen A and B, Crusher A and B, Feeder A and B, Excavator A and B, and FEL A). The dust samples were analysed according to NIOSH 7602 and MDHS 14/4, over the recommended 8-hours’ time-weighted average (TWA) shift. Results and discussion: The highest numbers of workers were found at the cleaning (20.6%) and crushing (17.6%) activity groups. The participants’ average age of 37 years was deemed not vulnerable to dust exposure as guided by the British Medical Association. The reviewed literature showed that the 8.8% of the workers with >10 years of service were at high risk due to cumulative dose exposure. The results show no association between age and length of employment but an association existed between gender and the length of employment. About 79% of the participants use their respiratory protective equipment’s (RPE), with the remaining 21% of the workers indicating lack of compliance. The Pt mine’s inhalable TWA dust concentrations (range, 0.1 mg/m3 - 2.2 mg/m3 ) were higher than respirable TWA dust (< 5% crystalline silica) concentrations (range, 0.022 mg/m3 - 0.904 mg/m3 ) at all work stations, indicating a high proportion of large particles which do not affect the vi deep lung. There was a significant difference in the mean TWA dust concentrations between Facility A and B (t8.118= -0.619, p <0.026). The mean TWA dust concentrations for Facility B were 0.2 times higher than the mean TWA dust concentrations for Facility A. The exposure assessment data enabled the risk classification of work stations, with the highest risk level areas at 11% (feeder A and crusher B), indicating the need for improvements in the bid to prevent future health risks. The moderate risk level areas were found at 39%, low risk level at 22%, and lastly screen B, excavator A and B were found at tolerable risk level and account for 28%. About 65% of individuals were exposed to over the recommended 8-hours work shift.
M.A. (Public Health)