Abstract：
Terrestrial gamma radiation is one of the major outdoor radiation exposures to the general public that varies substantially based on the type and geological properties of the soil. The objective of this study is to evaluate the naturally occurring radioactive materials (NORMs) distribution and assess the hazard parameters in the riverbank soil within various industrial zones in the densely populated Dhaka and Chattogram cities of Bangladesh. The mean activities of 226Ra (37 ± 3), 232Th (58 ± 4), and 40K (1129 ± 18) Bqkg-1 in the assessed soil samples were found to be slightly higher than the world average values 32, 35, and 420 Bqkg-1, respectively. The mean radium equivalent activity (207.49 Bqkg-1) and the external and internal hazard indices were within the recommended limits of 370 Bqkg-1 and <1, respectively. The mean absorbed dose rate (99.47 nGyhr-1), annual effective dose (0.12 mSva-1), ELCR (4.27 × 10-4), and gamma level index (1.58) exceeded the world average values 59 nGyhr-1, 0.07 mSva-1, 2.9 × 10-4, and 1 respectively. However, the studied areas are safe from a radiological viewpoint with no radiation health hazard to the people. The results of this study can be utilized to produce factual baseline data for future studies.
摘要：
地面伽马辐射是对公众的主要户外辐射之一，根据土壤的类型和地质特性而变化很大。这项研究的目的是评估自然存在的放射性物质（NORM）分布，并评估孟加拉国人口稠密的达卡和Chattogram城市各个工业区内河岸土壤中的危害参数。226Ra的平均活性(37±3)，232Th(58±4),发现评估土壤样品中的40K（1129±18）Bqkg-1分别略高于世界平均值32、35和420Bqkg-1。平均镭当量活性（207.49Bqkg-1）以及外部和内部危害指数分别在370Bqkg-1和<1的建议范围内。平均吸收剂量率（99.47nGyhr-1），年有效剂量（0.12mSva-1），ELCR(4.27×10-4),和伽马水平指数（1.58）分别超过世界平均值59nGyhr-1、0.07mSva-1、2.9×10-4和1。然而,从放射学的角度来看，研究区域是安全的，对人们没有辐射健康危害。这项研究的结果可用于产生未来研究的事实基线数据。
