Effects of Food Diet Preparation Techniques on Radionuclide Intake and Its Implications for Individual Ingestion Effective Dose in Abeokuta, Southwestern Nigeria

Abstract

The radioactivity measurements in food crops and their diet derivatives and farm soil samples from Abeokuta, one of the elevated background radiation areas in Nigeria have been carried out in order to determine the concentration levels of natural radionuclides (<sup>40</sup>K, <sup>226</sup>Ra and<sup> 232</sup>Th). The activity concentrations of the natural radionuclides in the samples were determined via gamma-ray spectrometry using a 76 mm × 76 mm NaI(Tl) detector. Different common food crops representing the major sources of dietary requirements to the local population were collected for the measurements. The collected food crops were prepared into their different derivable composite diets using preparation techniques locale to the population. Using available food consumption data and the activity concentrations of the radionuclides, the ingestion effective doses were evaluated for the food crops and diet types per preparation techniques. For the tuberous food crop samples, the annual ingestion effective doses in the raw and different composite diets were 0.02 - 0.04 µSv and cumulatively 0.04 - 0.05 µSv while in the non-tuberous crops the doses were 0.44 - 0.70 µSv and cumulatively greater than 1 µSv respectively. Results of the study indicate that method of diet preparation is seen to play a major role in population ingestion dose reduction especially for tuberous crops than in non-tuberous crops. The study also showed that more ingestion dose could be incurred in diets prepared by roasting techniques. The result of the study will serve as a useful radiometric data for future epidemiological studies in the area and for food safety regulations and policy implementations in the country

Uptake and Distribution of Natural Radionuclides in Cassava Crops from Nigerian Government Farms

“…The transfer factor (TF) is the ratio that depicts the quantity of radionuclide expected to enter the crop from soil [33]. TF for all radioisotopes were calculated using equation 3 and are recorded in Table 3.…”

“…It is pertinent to note that different soil properties and weather conditions affect the accumulation of radioisotopes. The accumulation of 40 K may be affected by several determinants such as cation exchange capacity (CEC), type and pH of the soil [7,33]. The soil type fall under the clay mineral property which usually bear a negative charge.…”

Estimation of Annual Effective Dose Due to Ingestion of Natural Radionuclides in Cattle in Tin Mining Area of Jos Plateau, Nigeria

“…Figures 1, 2 and 3 show the distribution of 40 K, 226 Ra and 232 Th, respectively in the different organs. Radiation dose received due to the intake of food is calculated from the amount of radionuclide deposited on foodstuff, the activity concentration of particular radionuclide in food per unit deposition, the consumption rate of the food products and the dose per unit activity ingested [16]. Annual effective ingestion dose for an adult member of the public due to the intake of radionuclide through ingestion of food can be calculated based on the metabolic models developed by the International Commission of Radiological Protection [17]…”

Radionuclide exposure in animals and the public health implications

“…Food processing is effective in reducing radionuclide concentrations in foods although the retention factor depends on the processing procedure (7). Drying foods, for instance, tends to increase the radionuclide concentration compared with boiling (58). In dairy products, radionuclides are retained less in cream than in other milk products, whereas the concentration of 90 Sr in cheese is 5-10 times higher than that in milk as a result of the precipitation process in cheese production.…”