Analysis of Radon-222 in Surface and Groundwater Sources in Kajiado County, Kenya

This study entailed measurement of the concentration of ²²²Rn in surface and subsurface water sources from Kajiado Municipality in Kenya. Kajiado County receives minimal rainfall and is not well covered by the municipal treated water network. The residents of the area mainly rely on subsurface water sources for their domestic consumption. Twenty-seven surface and groundwater samples were collected, and ²²²Rn concentrations were measured using a RAD7 alpha detector. It was observed that the radon activity in groundwater ranged from 0.62 to 13 mBq/L while the radon activity in surface water ranged between 0.06 and 1.53 mBq/L. The mean values obtained were 6.01 ± 1 mBq/L for the groundwater and 0.45 ± 0.11 mBq/L for the surface water. These values are within the US Environmental Protection Agency (USEPA) standard limit of 148 mBq/L and the World Health Organization (WHO) global average of 100 mBq/L. The water is generally safe for domestic consumption.