The radionuclide concentrations in all water samples were measured using gamma spectroscopy method. The purpose of this study was to evaluate background radionuclides in groundwater sources in the communities, which border the Tano Basin for the radiological risk assessment. The average values of 226Ra, 228Ra and 40K obtained are in the range of 0.14±0.01 to 1.38±0.22 Bq/L, 0.18±0.01 to 1.41±0.18 Bq/L and 0.46±0.02 to 5.92±0.10 Bq/L respectively. The committed effective dose and excess lifetime cancer risk were calculated for four age brackets. The average total annual effective dose for adults that take groundwater ranged from 1.20E-04 ± 8.70E-06 to 9.50E-04 ± 1.52E-04 mSv/y and that for teenagers, children and babies ranged from 9.04E-04 ± 6.07E-05 to 7.04E-03 ± 1.10E-03 mSv/y, 2.74E-04 ± 1.13E-05 to 2.06E-03 ± 2.13E-04 mSv/y and 1.17E-03 ± 7.21E-05 to 8.84E-03 ± 1.35E-03 mSv/y respectively. The excess lifetime cancer risk in adults ranged from 4.21E-04 ± 3.05E-05 to 3.32E-03 ± 5.32E-04. That for teenagers, children and babies ranged from 7.68E-04 ± 5.16E-05 to 5.98E-03 ± 9.37E-04, 1.65E-04 ± 6.79E-06 to 1.24E-03 ± 1.28E-04 and 5.85E-05 ± 3.61E-06 to 4.42E-04 ± 6.76E-05 respectively. Other parameters of the water samples are in the ranges of pH: 4.4 – 7.2, Temperature/OC: 29.1 – 32.9, Conductivity/μScm-1:51.4 – 420, Salinity: 0.0 – 0.1 and Total Dissolved Solids (TDS)/mg/L: 31 – 252.
Keywords: Excess Lifetime Cancer Risk, Gamma radiation, Health Hazard, Radioactivity
