MEASUREMENT OF GROSS ALPHA AND BETA RADIOACTIVITY IN RIVER KADUNA
ABSTRACT
Thirty samples of river water were taken from the three zones, Farming, Residential/Commercial and Industrial Zones along the course of River Kaduna. The Total dissolved solids (TDS) was determined for the water samples. Also radionuclides present in the water samples were identified using the Exploranium, the identifier. The radionuclides are 238U, 232Th and 40K. The specific activities of the radionuclides in the river water samples were calculated, the average specific activity of 238U was 9.00 Bq/g that of 232Th was 3.93 Bq/g, and for 40K the average specific activity was 199.10 Bq/g. An aliquot of each sample was evaporated to dryness, based on the total dissolved solids (TDS) of the sample, and the residue counted for gross alpha and beta activity using the proportional counter. The results of characterization show that the counter has low background and good plateau, which were all reproducible, for all the channels and for different counting modes. Results also show that the average alpha activity in the Farming Zone is 0.027 0.002x103Bq/m3, average alpha activity in the Residential/Commercial Zone is 0.025 0.001 x 103Bq/m3 and that in the Industrial zone is 0.03 0.003 x 103Bq/m3. The average beta activity in the farming Zone is 0.585 0.007 x 103Bq/m3, that in the Residential/Commercial Zone is 0.411 0.006 x 103Bq/m3 while that in the Industrial Zone is 0.321 0.005 x 103Bq/m3. The overall results show that both alpha activity and beta activity in the three zones are far below the practical screening level of radioactivity in drinking water of 100Bq/m3 for alpha and 1000Bq/ m3 for beta, as recommended by CEC-FAO and WHO.