Distribution of gamma radiation dose rate related with natural radionuclides in all of Vietnam and radiological risk assessment of the built-up environment

Kazumasa Inoue,Masahiro Fukushi,Tan Van Le,Tan Van Le,Shogo Kasahara,Hiroshi Tsuruoka,Hiroshi Tsuruoka,Veerasamy Nimelan

doi:10.1038/s41598-020-69003-0

Kazumasa Inoue, Masahiro Fukushi + Show 6 more

Open Access

https://doi.org/10.1038/s41598-020-69003-0

Copy DOI

Abstract

A built-up environment utilizes building materials containing natural radionuclides that will change radiological risks. While radiological risks have been estimated from the activity concentrations of natural radionuclides in soil, it is important to evaluate the changes of these risks for the built-up environment using these building materials. Based on the direct measurements of absorbed dose rate in air and calculation of absorbed dose rate in air from activity concentrations in soil for all of Vietnam which has undergone significant economic growth in recent decades, the changes of absorbed dose rate in air and radiological risks before and after construction of many artificial structures were investigated. The results showed that the absorbed dose rates in air were clearly changed by the urbanization, and the difference ratio for all of Vietnam ranged from 0.5 to 2.1, meaning that the artificial structures have been acting as shielding materials to terrestrial gamma-rays or radiation sources. However, changes in annual effective dose in the built-up environment were small, and there was no new radiation risk from the built-up environment for Vietnam.

Highlights

A built-up environment utilizes building materials containing natural radionuclides that will change radiological risks
A way to investigate this impact is offered by the direct measurement of absorbed dose r ates[6] in air 1 m above the ground surface from terrestrial gamma-rays and artificial structures, followed by a comparison of the estimated absorbed dose rates in air 1 m above the ground surface based on activity concentrations of 238U, 232Th and 40K in soil samples
External effective dose and the external hazard index were calculated using data obtained from direct measurements of absorbed dose rate in air and from activity concentrations in soil samples collected at 426 locations

Summary

Introduction

A built-up environment utilizes building materials containing natural radionuclides that will change radiological risks. It is well known that construction materials of concrete, brick, sandstone, granite and other natural stones contain these natural sources Depending on their amounts, these sources may cause changes in radiation level of the built-up environment which means the environment made by the natural environment, artificial structures (i.e., roads, buildings and bridges) and human activities; as a consequence, the radiological risks from such natural radioactivity will be changed[9,10]. An impact can be assumed on the radiation level from natural radionuclides contained within the materials of newly constructed artificial structures, especially roads and high-rise buildings, resulting in changed radiation level and hazard risks related with them. This study is the first large-scale attempt in Vietnam to assess changes of radiological risk on the built-up environment in relation to economic growth

Methods

Results

Conclusion