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).
