Elemental Analysis in Airborne Particulate Matter in Njoro Area of Nakuru County, Kenya

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W. O. Machuka
C. M. Nguta
D. M. Maina
S. M. Ngari


Energy Dispersive X-ray Fluorescence (EXDRF),, heavy metals, vehicular emission


Nakuru County has witnessed notable changes in land use patterns and industrial activities in recent years. These changes have the potential to release heavy metals into the atmosphere through various anthropogenic processes, including industrial emissions, vehicular traffic, and agricultural activities. The presence of heavy metals in the air can lead to a range of environmental problems, such as soil and water contamination, and it can pose health risks to the local population through inhalation exposure. Therefore, the objective of this study was to determine heavy metal in airborne particulate matter in Njoro Area of Nakuru County, Kenya. Sampling was conducted within Njoro Division, Nakuru, in close proximity to the Nakuru-Mau Narok Road, typically within a distance of 1-5 meters from the road's edge. The sampler was positioned at a height of 1.6 meters above ground level. During the sampling period; the average rainfall for the whole period of sampling was measured. The wind direction and speed were also determined using wind vane and wind scope respectively. The daily temperature and humidity readings were also recorded since this also affect the distribution of airborne particulate matter. The elemental composition was determined by Energy Dispersive X-ray Fluorescence (EXDRF) technique. The results revealed fluctuations in pollutant levels over time, and the study also demonstrated that various sources, such as vehicles and agricultural activities, contributed to specific pollutant concentrations. However, there is clear evidence suggesting that vehicles constitute the primary source of emissions. This conclusion is drawn from the detection of Lead (4.13 ± 0.61 ng/m3) and Bromine (0.25 ± 0.08 ng/m3) on 8.0μ and 0.4μ filters, respectively, during both the dry and wet seasons. Nevertheless, it's noteworthy that the concentrations of lead in aerosols and gases in the local ambient air, as determined in this study, were found to be below the recommended levels of 5μg/m3established by the World Health Organization (WHO) in 2006. Other elements detected were Fe: 35.9±2.44, 32.22±2.48; Mn, 3.67±1.15, 2.97±1.12, Cu, 2.24±0.99, 1.05±0.48, Cr, 2.61±1.29, 2.38±1.19 for dry and wet seasons of sampling respectively. The study recommends that there is need to implement a comprehensive and continuous monitoring system for heavy metal concentrations in airborne particulate matter in Nakuru County and promote the adoption of cleaner technologies and emission reduction measures in industries and transportation to minimize the release of heavy metals into the atmosphere. Further, public awareness campaigns should be conducted to educate the local population about the potential health risks associated with exposure to airborne particulate matter and trace elements. This includes disseminating information about protective measures and health advisories.


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