Developing an integrated preventive framework for construction workers exposed to silica dust and chemical irritants in Zambia.

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Tente, Prisca
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The University of Zambia
Construction industry is key to the world economies in both developed and developing nations. However, construction works could bring hazards such as silica dust and chemical irritants to site personnel. Silica dust and chemical irritants are produced from activities such as demolition, drilling, concrete mixing, brick and concrete block cutting, sawing, tile cutting, painting and grading. Silica dust can cause respiratory diseases such as chronic obstructive pulmonary disease, renal disease, lung cancer and silicosis. Chemicals can cause skin diseases such as dermatitis and eczema. The effects of respiratory and skin diseases are devastating to the workers and in turn affect the cost of projects in terms of medical bills and lost man-hours. The strategies planned by Zambia in its quest to be a middle-income country by 2030 has resulted in an increase in construction projects. There is a high likelihood of an increase in the generation of dust and possible exposure to silica dust and chemical irritants. Several studies have shown a high silica dust and chemical irritant levels and high prevalence of symptoms of respiratory and skin diseases. Nevertheless, construction players are hesitant to adhere to Occupational Safety and Health Laws. Also, it is not known whether silica dust levels experienced by Zambian construction workers were above 0.05mg/m3.Therefore, the staple silica dust and chemical irritant hazards have to be mitigated. The aim of this study was to establish a preventive framework that promotes reduction of exposure to silica dust and chemical irritants. The Case Study- Mixed Method design involving a road construction and a building projects was used. Qualitative and quantitative methods were used simultaneously. Bricklayers, carpenters, batchers, tilers, demolition workers, painters, road construction workers and handymen were purposively sampled. The sample size was established at 10% of the estimated population of 1, 012. A questionnaire survey was conducted on 100 workers among which observations and photographs were randomly done. The Methods of Determination of Hazardous Substances (MDHS14/4) through gravimetric weighing of respirable dust samples and silica dust using MDHS101/2 through X-ray diffraction (XRD) were used for sampling and analysis. Fifteen personal air samples were taken during work activity for 8hr-Time Weighted Average. Quantitative data was analysed using descriptive and inferential statistics. Pearson Chi-square and degree of freedom were used to test the degree of association between the independent and dependent variables. The level of significance of ρ < 0.05 and confidence interval of 95% were considered as statistically significant. Qualitative data was analysed using constant comparative method. Results showed that chemical irritant exposure levels were high and silica dust exposure levels were higher than both local and international Occupational Safety Health Administration Permissible Exposure Limit (0.05mg/m3). There was a high prevalence of symptoms of respiratory and skin diseases. Further, the controls which were used on site were inadequate. Therefore, an integrated preventive framework was developed to reduce exposure to silica dust and chemical irritants and eventually prevent respiratory and skin diseases to protect the workers and safeguard the projects. The study is in line with the Sustainable Development Goal (SDG) number three of achieving good health and well-being by 2023 through reducing the number of deaths and illnesses caused by hazardous chemical and air pollution and contamination. The findings and recommendations would serve as part of the guide policy formulation in Zambia.
Thesis of Doctor of Philosophy in Construction Management.