Zunyi Nickel-molybdenum Mine, Zunyi City Public Dose Estimation And Evaluation

Zunyi nickel-molybdenum mine is a typical associated mine which contains nickel,molybdenum and uranium, and is an important mine which is being exploited activtvely in Guizhou province. Natural radiation nuclides are distributed again following mining, beneficiation and smelting. The nuclides and their progeny are released into the local environment together with three industrial wastes, so as to increase concentration of radionuclide and radiation level.The research data was gained by the site monitoring and reviewing past records of environmental monitoring of radiation of Guizhou province, such as the level of natural radionuclide in soil, air, water and their distribution. The life index of the public was investigated and analyzed. The public was classified with the radiation effect and the dose was estimated. The following conclusions: Uranium is the most important nuclide for soil pollution and is mainly distributed at the shallow soil above 20cm. Radon and its progeny are the main radiation sources in atmosphere. The annual effective dose of worker is 0.68mSv,from external exposure in mine. It exceeds markedly the mean dose of nationwide from natural gamma radiation(about 0.48mSv) and international dose from natural gamma radiation(about 0.54mSv).The total annual effective dose is 0.41～39.31mSv for the public of Zunyi nickel-molybdenum mine and Zunyi city. The results of mine exceed the natural radiation dose of nationwide(1.98mSv) except cosmic rays, also exceed the international value(2.02mSv).The internal radiation dose account for 58.50%～84.94% in the total annual effective dose from radon and its progeny, and mostly exceed international value(62%). It is obvious that the raising of the total annual effective dose is attributed to radon and its progeny.In addition, a series of practical pollution control measures are also proposed according to the investigated and analyzed results in this article.