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.