Analysis of Radon levels in Water from selected Boreholes and Shallow Wells in Mutomo Area, Kitui County-Kenya

This paper presents In-situ analyses of radon levels in water from Mutomo area located in the southeastern part of Kenya. The region is semi-arid and most resdents depend on water from boreholes and shallow wells for their domestic use. RAD 7 alpha detector was deployed in the In-situ measurements and geographical position of each water source sampled was determined and noted during the radon measurements. An average of 30 ± 1.5 Bq l-1 was determined from the measurements. This value is slightly higher than the maximum contamination levelof 11.1 Bq l-1 prescribed by USEPA but within the UNSCEAR recommended range of 4 – 40 Bq l-1. Ngosini Springs reported the highest radon activity of 120 ± 6 Bq l-1 while Munyoki, Katuuni and Musila shallow wells had no detectable radon activity. Annual effective doses from water averaged 6.0 ± 0.03 µSv y-1 for radiation doses taken through ingestion which is well below the limits of 0.1 mSv y-1 for doses taken via ingestion. The correlational analyses between 222Rn in water and 226Ra in sediments sampled from the proximity of water sources reveal a weak positive correlation suggesting radium mineral has an insignificant influence on the radon level in the water. Based on the findings, water from the sampled wells and boreholes is safe for drinking without remediation measures.