Determination of Percentage Concentration of Alpha and Beta Radioactivities in Drinking Water from Mubi-North Metropolis, Adamawa State, Nigeria
Ahmadu Ibrahim, Sani Bello.
Increasing levels of radioactivity in drinking-water are a growing public-health concern because ingestion of radionuclides can produce both shortand long-term adverse effects. Routine screening for gross alpha and gross beta activity provides a rapid means to identify water sources that may require more detailed radiochemical and dose-assessment investigations. To determine the relative contributions (percentage concentrations) of gross alpha and gross beta radioactivity in drinking-water from selected locations within Mubi North metropolis and to evaluate whether further radiological assessment is warranted. Five drinking-water samples were collected by convenience sampling from five distinct locations in Mubi North metropolis. Samples were analyzed at the Centre for Energy Research and Training (CERT), Zaria, using the MPC2000D-Phosphate system to quantify gross alpha and gross beta activities. Results are reported as the percentage of total detected radioactivity attributable to alpha and beta emissions at each sampling location. Gross alpha contributions ranged from 0.13% to 10.43% across the five sampling locations, while gross beta contributions ranged from 89.57% to 99.87%. Location B exhibited the lowest proportion of alpha activity and the highest proportion of beta activity; conversely, Location D had the highest alpha fraction and the lowest beta fraction. The data indicate that beta-emitting radionuclides dominate the measured radioactivity in these samples. The low percentage contribution of gross alpha activity suggests a relatively minor role for alpha-emitting radionuclides in the total radioactivity budget of the sampled waters. However, the predominance of beta activity warrants further investigation. Specifically, we recommend: (1) quantifying absolute activity concentrations (e.g., Bq·L−1) for gross alpha and gross beta and comparing them with national and international guideline values; (2) performing radionuclide-specific analyses (e.g., for 40K, 90Sr, 137Cs, uranium isotopes and radium isotopes) to identify the primary beta emitters; and (3) expanding the sampling program using systematic, representative sampling to better characterize spatial variability and potential exposure pathways. These follow-up actions are necessary to determine whether the observed beta activity poses a radiological health risk and to inform any remedial or public-health measures.
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