Radiological Risks Assessment of Ogun State Drinking Water

Abstract

The presence of radionuclides in water constitute health risk to man. The consumption of such water increases the likelihood of incurring cancer. Analysis will enhance the detection of significant radionuclides causing harm to the populace and stimulate remediation. This inferred the radioactivity measurements of twenty (20) well water samples from three industrial cities of Ogun State using Hyper Pure Germanium detector (HPGe). The pH and other physiochemical parameters were also determined. The result showed that the mean activity concentrations of ⁴⁰K, ²¹⁰Pb, ²²⁴Ra, ²³²Th and ²³⁸U were found to be 1.86±1.70 Bql^-1; 7.93±2.40 Bql^-1; 3.60±1.25 Bql^-1; 8.48±2.10 Bql^-1; and 2.28±0.57 Bql^-1 respectively. The corresponding mean total annual effective dose for ages 0-1 y; 1-2 y; 2-7 y; 7-12 y; 12-17 y and > 17 y are: 9.14 mSv y^-1; 9.58 mSv y^-1; 6.87 mSv y^-1; 6.86 mSv y^-1; 11.91 mSv y^-1; and 5.68 mSv y^-1 respectively. The mean cancer mortality and morbidity risks respectively are: {(3.16 and 5.00)10^-5} for ⁴⁰K; {(575.74 and 759.67)10^-5} for ²¹⁰Pb; {(43.25 and 71.05)10^-5} for ²²⁴Ra; {(63.37 and 96.03)10^-5} for ²³²Th; and {(10.70 and 16.40)10^-5} for ²³⁸U. The activity concentrations of ²¹⁰Pb, ²²⁴Ra and ²³²Th exceeded the World Health Organization (WHO) guidance level in all samples but one. The corresponding total annual effective dose for all the six age groups exceeded the recommended WHO standard of 0.1 mSv y^-1 in all samples. More importantly, there is high radiation risk in drinking the water from these wells and ²¹⁰Pb contribution to risk was the highest.