Abstract

Twenty eight samples of water fourteen each from hand-dug wells and boreholes in some parts of Chikun and Kaduna south LGAs were selected using a stratified random sampling. Twenty (20mils) of concentrated nitric acid were added to each two liters of the sampled water for preservation. The samples were then evaporated and counted for Gross Alpha and Beta activity using MPC-2000-DP model gas free proportional counter at Centre for Energy Research and Training (CERT), Ahmadu Bello University, Zaria. The results showed that the range of alpha activity varied from (0.008-0.276)Bq/L with a geometric mean of 0.048 Bq/l for borehole samples and (0.001-0.413) Bq/L with a geometric mean of 0.124 Bq/l for well water samples. The range of beta activity varied from (0.009-0.338) Bq/l with a geometric mean of 0.099 Bq/l for borehole water samples and (0.003-0.808) Bq/L with the geometric mean of 0.183 Bq/l for well water samples. The overall results show that, the alpha and beta activity have their values below WHO recommended practical screening level of 0.5 Bq/L for alpha and 1.0 Bq/L for beta radioactivity for drinking water. The mean values of CED due to intake of borehole water for alpha activity are 0.019mSv/yr, 0.039mSv/yr and 0.078mSv/yr for infants, children and adult respectively. For beta activity the values are 0.032mSv/yr, 0.063 mSv/yr. and 0.127 mSv/yr. In the well water samples, the mean CED value for alpha activity are 0.048 mSv/yr, 0.095 mSv/yr. and o.146 mSv/yr for infants, children and adults respectively and for beta activity the mean values are 0.081 mSv/yr., 0.147mSv/yr. and 0.294 mSv/yr respectively. The results showed elevated values in few of the location above the ICRP acceptable standard of 0.1mSv/yr. These values show that the general public in few of the locations are committed to higher dose above the standard values and long term exposure could pose health threat.

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