Study of radon exhalation from soil to ascertain the elevated levels of background radiation of Bangladesh
Study of radon exhalation from soil to ascertain the elevated levels of background radiation of Bangladesh
复制标题
研究土壤中的氡析出以确定孟加拉国本底辐射水平升高
DOI：
10.1051/radiopro/2002061
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Alam
中科院分区：
文献类型：
--
作者：
M. I. Chowdhury;M. R. Chowdhury;M. Alam
利用P-y辐射测量仪对孟加拉国正常地区进行了全国范围的本底辐射测量，结果表明，孟加拉国正常地区的室外环境本底辐射水平在110 ~ 445 nGy·h ~（-1）之间。联合国原子辐射影响问题科学委员会（UNSCIOF）在1988年向联合国大会提交的报告中指出，占世界人口一半的23个国家的室外平均环境空气本底辐射水平在24 - 85 nGy·h-1之间，平均值为55 nGy·h-1，是孟加拉国Jevel辐射剂量的四分之一。在本研究中，镭和氡放射性核素的活度浓度测量在该国的土壤样品，并测量其氡射气系数，氡质量析出率和氡面积析出率，目的是评估孟加拉国的高背景辐射水平的原因。结果表明，大部分土壤样品中226 Ra的浓度高于世界平均值，其中U2 Th系列子体^Ra的浓度比世界平均值高出两倍多。大部分样品的40 K活度高于正常值和世界平均值。m Rn射气系数、~（222）Rn质量和面积射气率的计算结果都很有意义。发现若干地点土壤样品的氡射气系数值超过世界平均值。发现m Rn散发系数在3.10 - 44.68%的范围内，发现质量呼气率在2.50 - 27.84 mBq·m·sec·s·uBq.kg由于土壤中镭和钾的浓度高以及氡的析出率高，外部和内部剂量也较高。土壤中的总外照射剂量高于世界上大多数国家报告的结果。这一结果将有助于评估人类、动物和植物的辐射暴露以及与辐射相关的癌症风险。
The outdoor environmental background radiation level in normal area of Bangladesh ranged between 110 and 445 nGy.h"1 was observed in a countrywide background radiation survey using P-y radiation survey meter. The United Nation Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reported to the united Nations General Assembly in its 1988 report that the outdoor country averaged environmental background radiation level in air in 23 countries representing about one half of the world population were found to range between 24 and 85 nGy.h"1, with a mean value of 55 nGy.h'1, which is one fourth of the radiation dose Jevel of Bangladesh. In the present study, activity concentration of radium and radon radionuclides was measured in the soil samples of the country and measured their radon emanation coefficient, and radon mass exhalation and radon area exhalation rates with an aim to evaluate the cause of high background radiation level in Bangladesh. The result shows that the concentration of 226 Ra in most of the soil samples was higher than that of world average value, and the concentration of ^Ra, a daughter of U2 Th-series, is more than two times higher than the world average value. The activity of 40K was found higher than both the range and average world value in most of the samples. The results of m Rn emanation coefficients, 222 Rn mass and area exhalation rates are very significant. Values of radon emanation coefficients for the soil samples in a number of locations were found in excess of world average value. The m Rn emanation coefficients was found in the range 3.10 - 44.68%, the mass exhalation rates was found in the range 2.50 - 27.84 uBq.kg"'.sec"', and the area exhalation rates was found in the range 3.15 - 38.15 mBq.m"J.sec"'. Due to high concentrations of radium and potassium in soil and the high radon exhalation rate the external and internal doses are also higher. The total external dose from soil was found higher than the reported results of most of the countries of the World. This result would be helpful to assess the radiation exposure to human, animal and plants, and radiation related cancer risk.