International Journal of Research and Scientific Innovation (IJRSI) | Volume IX, Issue VIII, August 2022 | ISSN 2321–2705
A.K Mutambu1*, J. M. Linturi1, J.M. Kebwaro2, S.M. Matsitsi1
1Department of Physical Sciences, South Eastern Kenya University, P.O BOX 170-90200 Kitui, Kenya
2School of Pure and Applied sciences, Karatina University, P.O BOX 1957-10101 Karatina, Kenya
*Corresponding Author
Abstract: 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.
Keywords: Radon gas, RAD 7 detector, Mutomo area, Groundwater, Exposure.
I. INTRODUCTION
Radon a tasteless, odourless, colourless gas that is chemically inert and radioactive is considered one of the major contributors to human exposure to ionizing radiation in the terrestrial environment. The gas has a half-life of 3.86 days and is normally present in various natural sources such as; air, water and sediments of geological origin. [1, 2]
Radon decays contribute to over 42 % of the total radiation dose from various sources [3]. Radon gas enters the human biological systems through various pathways where it may decay with the emission of alpha particles that damage the body. Studies on radon levels in water and associated radiation doses have reported a wide range of data from below detection limits to elevated levels where remediation measures have been recommended [4].