Assessment of Radionuclides Uptake by Melon (Cucumeropsis mannii) Seeds from Selected Farms in Akwa Ibom State, Nigeria

Abstract

Plants and animals (including humans) are vulnerable to ionizing radiation in many ways. One of these ways is through the food chain. This research aimed at assessing the radionuclide uptake by melon seeds from soil, and the effect of ionizing radiation in humans due to melon. The activity concentrations of natural radionuclides in soil and melon seed samples from twenty locations in the study area was conducted using a Gamma ray spectrometric system coupled with a NaI(Tl). The soil samples were quartered and put in the oven at 50 − 70°C for 1440 minutes in order to obtain a constant weight. The melon seeds were ground, dried and weighed. The samples were packaged into labeled nylon bags before being moved to the laboratory for analysis. The average activity concentrations of ⁴⁰K, ²³⁸U and ²³²Th in soil samples were 397.56±7.61 Bq.kg^-1, 17.37±0.29 Bq.kg^-1 and 62.98±1.02 Bq.kg^-1 respectively. The average activity concentrations of ⁴⁰K, ²³⁸U and ²³²Th in melon samples were 521.49±8.47 Bq.kg^-1, 15.50±1.67 Bq.kg^-1 and 28.753±0.69 Bq.kg^-1 respectively. The average values of absorbed dose rate, external and internal hazard indices, radium equivalent, annual effective dose rate and representative level index were 46.40 Bq.kg^-1, 0.26 and 0.30 Bq.kg^-1, 93.12 Bq.kg^-1, 0.057 mSv.y^-1 and 0.730 Bq.kg^-1 respectively, for melon samples, while for soil samples, were 63.65 Bq.kg^-1, 0.37 and 0.42 Bq.kg^-1, 138.04 Bq.kg^-1, 0.078 mSv.y^-1 and 1.01 Bq.kg^-1 respectively. The average values of the transfer factors of ⁴⁰K, ²³⁸U and ²³²Th were 1.3693 (49%), 1.0041 (36%) and 0.4721 (15%) respectively. The regression analysis indicated nonlinearity between radionuclide concentrations in soil and that of melon seeds. Hence, the radionuclide concentrations in soil and melon seeds are not proportional.