Gross Alpha and Beta Activity Concentrations in Surface Water Supplies from Mining Areas of Plateau State, Nigeria and Estimation of Infants and Adults Annual Committed Effective Dose

A radiological characteristic of surface waters of the mining areas of Plateau State, Nigeria covered by the Naraguta Topographical sheet 168 was carried out in the month of March 2012. For this purpose forty – eight (48) surface water samples were collected from 25 mine ponds and 23 streams. Analysis included gross alpha and gross beta activities using MPC – 2000 – DP and estimation of committed effective Dose to the different age groups of the general public. The results obtained showed that the gross alpha activities ranged from (0.047±0.010 – 6.640±0.032)Bq/l with a geometric mean of 0.410±0.016Bq/l for mine ponds samples while the gross beta activities for mine ponds ranged from (0.001±0.009-6.680±0.039)Bq/l with a geometric mean of 0.125±0.010Bq/l. Also the gross alpha activities for stream water samples ranged from (0.140±0.011 – 4.310±0.013)Bq/l with a geometric mean of 0.642 ±0.015Bq/l and the gross beta activities for stream samples ranged from (0.040±0.001 – 1.170±0.018)Bq/l with a geometric mean of 0.250±0.008Bq/l. The annual committed effective dose for all age groups was calculated and they showed elevated values above the ICRP acceptable standard of 0.1mSv/yr. This implies that infants and children who are more susceptible to radiation dose through water ingestion may be exposed to high radiation health risk.