OCCURRENCE AND DOSE FROM INTAKE OF RADON IN DRINKING GROUNDWATER IN OGUN STATE, NIGERIA.

Abstract

Radon-222 concentrations in groundwater from 10 local government areas (LGAs) of Ogun State were measured using AlphaGUARD radon detector and AquaKIT. The mean activity concentration of radon ranged from 1.23±0.21 to 12.68±18.11Bq.l-1 corresponding to geometric means (GMs) of 1.22- 6.39Bq.l-1. The radon concentrations of all the samples were below the World Health Organization and European Commission guidance level of 100Bq.l-1, with 17% higher than 11.1Bq.l-1, recommended by the United States Environmental Protection Agency. Mean annual effective dose due to ingestion ranged from 0.020±0.004 to 0.254±0.353mSv.y-1 (adults), 0.041±0.007 to 0.509±0.705mSv.y-1 (children) and 0.024±0.004 to 0.297±0.411mSv.y-1 (infants). That of inhalation varied from 0.303±0.053 to 3.108±4.440μSv.y-1. The mean annual effective doses of some of the LGAs were higher than the International Commission for Radiological Protection recommended reference dose level of committed effective dose of 0.1mSv from 1-year consumption of drinking water.