Ben Byju S, Koya P K M, Sahoo B K, Jojo P J, Chougaonkar M P, Mayya Y S
Department of Physics, Fatima Mata National College, Kollam, Kerala 691001, India.
Radiat Prot Dosimetry. 2012 Nov;152(1-3):154-8. doi: 10.1093/rpd/ncs213. Epub 2012 Sep 7.
The observational evidence for radiation-induced health effects in humans comes largely from the exposures to high doses received over short periods of time. The rate of induction of any health risk at low doses and dose rates is estimated by extrapolation from observations at high doses. Effects of low dose/low dose rate could be done by the study of populations that have been exposed to slightly above-average natural radiation doses. Southwest coastal line of the Kerala state in India is one such region known to have elevated levels of background radioactivity mainly due to the mineral-rich sand available with high abundance of thorium. In the present work, a study was conducted to investigate the inhalation and external radiation doses to human beings in the high background radiation area along the southwest coast of Kerala. Five hundred dwellings were selected for the study. All the selected houses were at least 10 y old with similar construction. Long-term integrated indoor measurements of the external gamma dose using thermoluminescent dosemeters (TLDs) and the inhalation dose with the SSNTD-based twin-cup dosemeters were carried out in the dwellings simultaneously. Ambient gamma dose measurements were also made with a GM tube-based survey meter while deploying and retrieving the dosemeters. The data show a high degree of heterogeneity. The inhalation dose was found to vary from 0.1 to 3.53 mSv y(-1) and the external dose rates had a range of 383-11419 µGy y(-1). The external doses measured by the survey meter and TLDs showed an excellent correlation.
关于辐射对人类健康影响的观察证据主要来自于短时间内接受高剂量辐射的情况。低剂量和低剂量率下任何健康风险的诱发率是通过从高剂量观察结果进行外推来估计的。低剂量/低剂量率的影响可以通过对暴露于略高于平均自然辐射剂量的人群进行研究来确定。印度喀拉拉邦的西南海岸线就是这样一个已知背景放射性水平升高的地区，主要是由于富含矿物质的沙子中钍含量很高。在本研究中，对喀拉拉邦西南海岸高本底辐射地区人类的吸入剂量和外照射剂量进行了调查。选择了500所住宅进行研究。所有选定的房屋至少有10年历史，建筑结构相似。在这些住宅中同时使用热释光剂量计（TLD）进行长期室内外伽马剂量测量，并使用基于固体核径迹探测器的双杯剂量计测量吸入剂量。在部署和回收剂量计的同时，还使用基于盖革计数器的测量仪进行环境伽马剂量测量。数据显示出高度的异质性。发现吸入剂量在0.1至3.53 mSv y(-1)之间变化，外照射剂量率范围为383 - 11419 µGy y(-1)。测量仪和TLD测量的外照射剂量显示出极好的相关性。
