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

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.