Dust Pollution and Its Health Risks among Rock Quarry Workers in Kajiado County, Kenya
Halwenge, Jennifer Atieno
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Dust pollution in quarries pose various health risks to the workers including respiratory ailments, skin and eye problems. Depending on the chemical composition and the concentration of the dust, the workers are exposed to inhalation of silica bearing dust thus being at risk of developing silicosis, a fatal lung disease. Information on the chemical composition of the quarry dust is important as it forms a vital baseline for among others the detection of the undesirable health effects among the quarry workers. The aim of the study was to find out the occupational health risks posed by the dust to the quarry workers in Kajiado County, Kenya. The specific objectives of the study were to find out the chemical composition of the limestone, phonolite and pozzolana quarry dust; concentration of silica, chromium, cadmium and lead in the dust; and to assess the quarry workers awareness of the safety and the health risks in the quarry. Purposive and random sampling was used to get 110 workers for the study and dust samples were collected at 0m, 25m and 50m from the point source of the dust using a dust sampling pump set at 2L/min and run for 120 minutes. The chemical composition of the quarry dust; and the concentration of silica and the heavy metals (chromium, cadmium and lead) were done using standard laboratory procedures. A questionnaire was administered to the workers to find out the occupational safety and health risks and the workers’ awareness levels of the risks. The study revealed that the quarry dust was composed of various chemical compounds and naturally occurring elements at various concentrations, includingSiO2 (3.26% - 35.9%), Cr (9.0-22.18ppm) and Pb (15.5-41.14ppm). The study found that the dust concentration was 86.52mg/m3, SiO2 concentration was 0.62mg/m3, that of Cr was 5.92mg/m3 and of Pb was 9.24mg/m3. The dust concentration showed a negative correlation with distance, r = -0.41227 and p-value of 0.0103. The comparisons of mean dust concentrations forSiO2, Cr and Pb in limestone, phonolite and pozzolana showed p<0.0001, p=0.2071 and p=1460, respectively. The study showed that 60.55%) of the workers exhibited cough, 10% had skin irritation and 2.75%) experienced eye irritation. The study revealed that the quarry workers’ awareness of the safety and health risks was 94.5%, but only 16.51% used protective clothing. The study concluded that the dust concentrations failed to meet the Occupational Safety and Health Administration, (OSHA) standards and therefore exposed the workers to the risk of respiratory, skin and eye health problems. It is recommended that measures should be put in place to mitigate the high dust generation at the quarries and the workers should be sensitized to use protective clothing while at work. Clinical research should be conducted on the quarry workers in order to ascertain any development of silicosis.