Background: Nuclear radiation emission by radionuclides causes the diseases, such as cancer or genetic anomalies. Therefore, the study of radioactivity in soil and food as well as calculating the risk of cancer seems essential for foods consumption.

Materials and Methods: In this research, nine different varieties of beans containing the grain of beans, areal part and their soil cultivated were collected. The specific activity of ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs was determined for each sample employing gamma ray spectrometry method using high purity germanium detector with 30% relative efficiency.

Results: The absorbed dose rate in the air in one meter above the ground surface varied from 77.23 to 112.78 in nGy/h. The annual effective dose rate absorbed by adult person from the beans consumption in Iran is in the range of 122.14 to 905.86 in μSv/y. The cancer risk for the different varieties of beans varied from of 1.87 × 10^-5 to 1.59 ×10^-4 which is less than acceptable value as 10^-3.

Conclusion: The specific activities of radionuclides in soils samples are more than average of world wide range. The absorbed dose rate from bean consumption for the most of Varieties is more than of world average. Cancer risk resulted from bean consumption is less than acceptable value and consumption of bean has no risk for population health.

Abstract

Background: Amount of natural background   ionizing radiations in environment depends on kind of soil, stones and geographical conditions. Hot springs of Mahallat facilities are annually visited by many tourists. Determination of environmental radioactivity and excess lifetime cancer risk is very important.

Materials and Methods: In this research, twenty four samples of igneous and travertine rocks from a region (300 hectares) and four water samples of Mahallat hot springs were collected. The specific activities of radionuclides were determined for all samples by using gamma ray spectrometry method and employing high purity germanium detector with 30% relative efficiency.

Results: External and internal hazard indices for igneous rocks, water and two travertine samples varied from 0.00 to 0.71 and for two another travertine samples obtained from 8.17 to 22.50.  The average of annual gonadal dose equivalent (AGDE) was determined as 0.36 and 0.20 mSv/y and also the average of excess lifetime cancer risk (ELCR) was calculated as 0.23 × 10^-3 and 0.12×10^-3 for igneous and travertine rocks, respectively. Maximum acceptable value and world wide average of ELCR are 10^-3 and 0.29×10^-3, respectively.

Conclusion: The results of this research show that the hazard indices and ELCR for magma region are less than unity and world wide average respectively. Therefore; there is no consequence for people health. So, the radioactivity only around the orifice of hot springs where radium compositions are deposited, is more than maximum acceptable value.