某区放射性环境地质评价研究

在某区拟建隧洞沿线的条带状区域进行了放射性环境地质调查。共采集和分析岩土(芯)放射性核素镭、钍、钾样品111组,地下水和地表水样品5组;现场测定岩土放射性样品392组。结果表明,在该区域内,某煤矿巷道中煤层和砂岩接触带煤、砂岩中镭-226比活度出现高值异常,相应的内照射指数和外照射指数也超过相关标准中规定的放射性核素限量,该异常带环境辐射剂量率也较高。镭-226的富集可能源于煤中有机质对放射性核素的吸附和解吸过程。建议在隧道选线过程中尽力避让这一地段。

A SURVEY AND ASSESSMENT OF RADIOACTIVE ENVIRONMENTAL GEOLOGY

The survey and assessment were conducted at an area where a long tunnel was planned to construct.The work aimed at gaining radioactive geology information needed for the selection of the tunnel site and feasibility study.Radioactivity was measured in-situ over 392 rock and soil samples.A total of 111 groups of rock and soil samples and 5 groups of water samples were collected for radioactive nuclide analysis(Ra,Tu and ~(40)K).The results show that specific activity of ~(226)Ra is anomalously higher at the connective belts of coal seams and sandstone of Jurassic age at a coal mine and their internal and external exposure indices exceed the national standard.The enrichment of ~(226)Ra may be resulted from the organismal adsorption/desorption of radioactive nuclides at the coal seams.Therefore,it is recommended that tunnel should be rerouted to avoid those sites,and the environmental terrestrial radiation and radon emanation should be monitored during the tunnel's construction.