Assessment and health effects of radon and its relation with some parameters in groundwater sources from shallow aquifers in granitic terrains, southeastern axis of Ibadan, Nigeria

Abstract

Assessing the level of radon concentrations in water for domestic purposes is important because it will reveal if the consumption and uses of such water is safe. This study was conceived with the aim to ascertain the integrity of water being consumed and used for other activities as well as to determine the source of radon concentrations in shallow aquifers within the granitic rocks of Amuloko and Olorunsogo areas in Ibadan, Nigeria. Concentrations and health effects of radon in 40 groundwater samples were analyzed using RAD7 detector. In Amuloko area, the radon concentrations and the total annual effective dose received in groundwater varied from 3.00 to 24.50 Bql−1 and 29.49 to 240.61 μSvy−1. The mean and the standard deviation (SD) of radon concentrations and the total annual effective doses received in groundwater by adults in Amuloko area are 13.45 ± 6.58 Bq l−1 and 132.06 ± 64.62 μSv y−1. In Olorunsogo (control points), the radon concentrations and the total annual effective dose received in groundwater varied from 3.18 to 20.00 Bql−1 and 31.18 to 196.42 μSvy−1. The mean and the SD of radon concentrations and the total annual effective doses received in groundwater by adults at the control points are 12.06 ± 4.74 Bq l−1 and 118.47 ± 46.57 μSv y−1, in sequence. The mean radon concentrations and the mean total annual effective dose received in groundwater were higher than the threshold limits of 11.10 Bql−1 and 100.00 μSvy−1 by factors of 1.21 and 1.32 (in Amuloko), and 1.09 and 1.19 (in Olorunsogo), respectively. It is established that no significant variation exists between the sources of radon concentrations in the shallow aquifers from the two settlements. This suggests that the elevated concentrations of radon at the two settlements are due to the geological contributions of faults.