Determinación de la concentración de la actividad de Cesio-137 en diez frutas del Ecuador

Abstract

The objective of this work was to determine the concentration of the activity of Cesium-137 in ten fruits of Ecuador (orito, mango, pitahaya, papaya, granadilla, tree tomato, kiwi, passion fruit, physalis and guava) marketed at Mercado Mayorista in Riobamba city, province of Chimborazo, by gamma spectrometry. The concentration of Cesium-137 in the samples of previously treated fruits was measured in a five-phase process: selection, slicing, drying, crushing and screening. Complementary was collected the soil where it was cultivated: physalis, tree tomato and mango, evaluating the percentage of absorption of the activity from the soil to the plant. The samples were analyzed in the Laboratory of Nuclear Techniques at Escuela Superior Politécnica de Chimborazo (ESPOCH), using the Rug 91-2 spectrometer, in a measurement time of 4 hours, with ten repetitions per sample. Additionally, the activity values of Potassium-40 were collected as a reference radioisotope and compared with the levels of Cesium-137 in the samples analyzed. It was obtained that pitahaya absorbs a higher concentration of Cesium-137 (10.96 Bq/Kg), it was concluded that the values obtained are lower than the permissible limit of 100 Bq/Kg established by the International Standards of Mexico, Japan and China in food. Finally, it was evidenced that not all fruits absorb in the same way the activity present in the crop soil; the mango absorbs 98.53% of Cesium-137 and the tree tomato 99% of Potassium-40, evidencing a higher concentration of Potassium-40 than Cesium-137 in the samples. It is recommended to develop research on the quality of crop soils, analyze the Ecuadorian Regulations on the permissible limits of radioisotopes present in food for sale and export for safe consumption.