Mapping and Assessment of Activity Concentration of 222Rn and its associated Exposures from the Drinking Water Sources of Taraba State, Nigeria

Abstract Radon is a colourless, odourless, and tasteless gas, which emanates from the natural disintegration of radioactive uranium in soils and rocks, dissolves, and accumulates in underground and surface water. 222 Rn is a natural and the most prevalent isotope of radon and poses the largest risk to humans. A Liquid Scintillation Counter (LSC) set-up at the Centre for Energy Research and Training (CERT), Ahmadu Bello University, Zaria, Nigeria, was used to determine the activity concentrations of 222 Rn in water samples from Taraba State. Water samples from Taraba had activity amounts of 222 Rn ranging from BDL to \(11.5Bq/L\) with an average value of \(5.7\pm0.3Bq/L\). This mean value was below the \(10Bq/L\) of WHO and \(11.1Bq/L\) of USEPA recommendations but was higher than \(0.1Bq/L\) acceptable limit for Nigerian Standard for Quality Drinking Water (NSQDW). The iso-concentration map of the state showed that Takum, Ussa, Bali, Sardauna, Gashaka, Yorro, Zing, Lau, Karim Lamido, and Jalingo LGAs of the state are hit with 222 Rn concentrations above \(5.5Bq/L\), while Ardo-Kola, Ibi, Wukari, and Donga LGAs are hit with 222 Rn concentrations below \(5.5Bq/L\). The yearly effective dosage (YED) resulting from ingesting radon-contaminated water in Taraba state were found in the range of \(BDLto112.6\muSv/y\) with a mean value of \(55.7\pm2.8\muSv/y\). The results of the statistical analysis showed a very strong positive correlation between the YED and activity concentration of 222 Rn in the state. An increase in the activity concentration of 222 Rn in the state relates to corresponding \(9.82\text{m}\text{S}\text{v}{y}^{-1}\) increase in YED in the state.