Measurement of the 226Ra, 232Th and 40K activities in corn in the Republic of North Macedonia and resulting annual radiation dose by ingestion

Abstract

Considering the fact that there has been a significant population growth and this increases the need of food, various agricultural activities are increasingly being used, including the use of phosphate fertilizers that can directly affect agricultural crops. Therefore, it is necessary to know the level of present radionuclides, especially in corn, which is very often used for the needs of people and animals. The purpose of this study was focused on comparing the activity concentrations of 226Ra, 232Th, 40K in corn samples, and the calculated results were the basis for the assessment of the external hazard index (Hex), the internal hazard index (Hin), the radium equivalent activity (Raeq), and the annual gonadal dose equivalent (Dgon). The gamma spectrometry technique was used for measurement of the samples, i.e. an instrument - gamma spectrometer (Canbera Packard) with a high purity germanium detector. The obtained spectra from the measurement were analyzed by using the GENIE 2000 program. Based on the performed examinations, the activity concentrations in corn ranged from 0.42 to 0.77 Bq kg - 1 for 226Ra, from 0.06 to 0.87 Bq kg - 1 for 232Th, and from 117.54 to 322.11 Bq kg - 1 for 40K. The mean value of the radiation hazard index, the Heks value is lower than the maximum allowed value which is <1 for Heks. The value of the radium equivalent activity Raeq ranges from 9.01 to 23.16 and is below the maximum recommended limit, i.e. 370 Bq kg-1. The annual gonadal dose equivalent has an average value of 75.62. The research in this study shows that all samples of corn have no biological hazard i.e. it was found that the natural levels of radioactivity are not within the high-risk range and are below the international standards.