Evaluation of Natural Radioactivity in Fish-feeds and Commercially Cultivated Catfishes in Lapi-Gwari, Niger State

Abstract

This study is focused on the concentration of natural radionuclides in locally produced fish feeds and Catfishes (Clarias gariepinus) obtained from commercial fish ponds from Lapai Gwari in Niger State. Five (5) samples of local fish feed and catfishes were collected from the feed market in Lapai Gwari, Niger State and analyzed for their natural radionuclide contents using NaI (TI) gamma ray detector. The activity concentrations of primordial radionuclides in the samples were determined using the gamma spectrometric technique because of its high efficiency detection with the aim of evaluating the radiological implications attached with the consumption of locally cultivated catfishes in Lapai Gwari. The mean activity concentration in the catfish samples for 40K, 226Ra and 232Th were 41.61, 0.55 and 2.03 Bq/kg respectively; while the mean activity in the fish-feed samples for 40K, 226Ra and 232Th were 30.14, 0.60 and 4.6 Bq/kg respectively. The mean committed effective dose evaluated from the activity concentrations of 40K, 226Ra and 232Th in the catfish samples is 0.0682 μSv/y. The excess lifetime cancer risk was also estimated, having a mean of 0.2387 × 10−6 for the catfishes. The computed mean committed effective dose and excess lifetime cancer risk were found to be lower than the recommended safety limit of 1.0 mSv/y and 2.9 × 10−3 respectively as set by International Commission for Radiological Protection (2007). This shows that the radiation dose incurred from the ingestion of the fresh catfish samples pose no significant health risks to the population from a radiological point of view.