Investigation And Evaluation Of Radioactive Environment In REE Mining Areas, Mianning County,Sichuan Province

REE mining in Mianning, Sichuan Province, is highly developed, but disorder exploration for the REE ore in the districts in recently years has caused radioactive pollution to some degree. This thesis studied on:1) investigating the distribution characteristics of radioactive element in the soil, water and air and ground y radiation absorbed dose rate;2) assessing the environmental contamination status quality; and3) suggesting pollution prevention measures.The main results obtained are:(1) Radioactive level in the studied areas is a little higher than that in normal environment. Radioactive level in Mianning REE mining district (Maoniu ping-MaoniuVillage-Baozi Village), Maoniu Mountain and Baizhang ditch in Haha Village-Sancha River-Wadu Ditch, Chengxiang Town Stone ladder-Diao Tengzi are higher than the level required by the National Standard. Chengxiang Town Beishan Dam(County), Huiping Village, Wuli Village in Senrong, Caocucun, AnGuCun and Fuxing Town(West), Hongmo Village(Northwest), and Heli Village(North) are all on normal radioactive level.(2) Water in the Waweiai river, the Gawu river and the South river, where Mianning Mining areas is located has suffered radioactive pollution to some degree for the mineral process waste water and tailing from factory go directly into the stream.(3) γ radiation annual effective equivalent dose in Mianning Mining district is0.765mSv/a. Among the inhabited towns in the district, y radiation annual effective equivalent dose in Senrong Town Maoniu Ping-Maoniu Village-Baozi Village is the highest, coming to1.189mSv/a, above the standard GB18871-2002requested public accept limit1mSv/a. y radiation annual effective equivalent dose in Hahaxiangweiqiluo-Caoxile area is0.970mSv/a, close to requested public accept limit. In the Peripheral towns of rare earth mining district, y radiation annual effective equivalent dose is between0.399mSv/a and0.673mSv/a, not above the requested limit. The collective y radiation annual effective equivalent dose in the whole district is53.340Sv/a。...