ACTIVITY CONCENTRATION MEASUREMENT OF NATURAL RADIONUCLIDES IN CATFISH AND THE RADIOLOGICAL IMPACTS ON HUMAN IN IBADAN METROPOLIS, NIGERIA

Abstract

There is extensive contamination of the aquatic environment when rivers and streams flow through areas of high human activities such as industrial cities and major towns. These contaminations may include enhanced background levels of naturally occurring radioactive materials resulting from rapid urbanization and other human activities. The natural radionuclides (40K, 238U and 232Th) contents in farm-raised and wild catfish (Clarias gariepinus ) from five fish farms and three major rivers within Ibadan metropolis have been studied using gamma-ray spectrometry technique. The results shows that the average committed effective dose through the consumption of catfish were 4.68 ± 0.17 and 7.31± 0.21 μSv/y for farm-raised catfish and 11.97 ±0.12 and 21.26±1.7 μSv/y for wild catfish in adult and children of ten (10) years, respectively. The excess lifetime cancer risk due to the consumption of catfish in farm and river was calculated to be 1.5x10-6 and 2.46x10-6 in farm-raised catfish and 1.6x10-6 and 2.6x10-6 due to intake of wild catfish for adult and children of ten (10) years, respectively in the study area which is within the USEPA acceptable limit for excess lifetime cancer risk ranging between 1x10-6 and 1x10-4. It can be concluded that the consumption of catfish poses no significant radiological hazards to the population of the study area.