EVALUATION OF RADIATION LEVELS IN NAIROBI’S METROPOLITAN AND THE INDUSTRIAL AREAS

Abstract

Radiation is energy travelling through space. In Kenya, no data exist on radiation levels at various workplaces. Radiation sources are found in a wide range of occupational settings. Uncontrolled levels of radiation within permissible levels can be potentially hazardous especially to the health of the workers. Occupational health and safety is increasingly gaining attention due to advancing technological developments in the world. This may lead to increased exposures to high levels of radiations emanating from these new technologically enhanced instruments and facilities. The objective of this study is to evaluate the variation of radiation levels in the Nairobi Central Business District (CBD) and the Industrial Areas and the possible sources of these radiations. Portable radiometer devices were used to determine the levels of radiation. The collected data was stored for analysis directly on the field by connecting the radiometer devices to an ipad. Soil samples were collected from areas where high levels of radiation were recorded. Soil analysis was carried out qualitatively and quantitatively using gamma spectrometry so as to determine the presence of naturally occurring radioactive materials. Highest dose rates were found in the Industrial Area and Njiru mining site which ranged from 0.999-1.603 mSv/yr. Lowest dose rates were in Mavoko (0.333-1.042 mSv/yr). In most of the places the radiation levels varied between 0.622-1.2439 mSv/yr. From the soil samples the external and internal hazard indexes were 1.241 and 1.501 respectively for Mwiki and 1.739 and 2.170 for the Industrial Area. These values were higher than the standard value (≤1). Radiation dose rates were found to be higher than the permissible exposure limits (1mSv/yr).