The Environment Pollution And Evaluation Of The Water Surrounding One Southern Uranium Mine Tailing

With the exploiting of the Uranium mines,a large number of acidic waste water and waste residue which had a lot of heavy metals, radionuclides, fluoride and other toxic substances would be produced by the Uranium mines. Then this toxic substances would cased vary serious pollution of the surface water and shallow groundwater surrounding the tailings reservoir. In this paper,the surface water and shallow groundwater surrounding the tailings reservoir was selected to study the chemical properties, the distribution and contents of heavy metals and radionuclides in the water. Then we use the field sampling and indoor test to get the results. The main achievements are as followings:（1）The type of water chemistry in the tailings reservoir is Ca SO₄ water and the shallow groundwater is Ca-Na-SO₄ type, so the chemical types of the shallow groundwater may be influenced by the tailings reservoir in the study area. In the study area, the p H of the shallow groundwater was 5.75-6.70, the p H of the discharge water was 4.65-7.40, and the p H of the percolating water was 4.50-8.70. The TDS of the shallow groundwater mainly be influenced by Ca2+ and F-, and had a positive correlation with Na+ and Mg2+, a weak positive correlation with SO₄2- and Cl-, a negatively correlated with HCO3-.（2）The correlation coefficient of Cr and Cd is 0.714, and the correlation coefficient of and Cd reached 0.619, the correlation coefficient of Pb and Cr reached 0.625, and the correlation coefficient of Pb and reached 0.05. In surface water, the correlation coefficient of Cd and Pb reached 0.725, and the correlation coefficient of Cr and Cu was 0.05, and the correlation coefficient was 0.595.（3）The content of fluoride in the drain of the tailings reservoir did not reach the emission requirements; but the water in the shallow groundwater is polluted seriously by the fluoride. The main reason is the exploiting of the Uranium mines which produced a lot of fluoride, then the fluoride would be released into the water. The p H, TDS and climatic conditions had great influence of the content of fluoride in water system, and the HCO3- and the other cations may had certain effect on fluoride content.（4）The migration of ²²⁶Ra in groundwater may be influenced by many factors, such as the nature of rock, the biological adsorption, temperature, water chemical characteristics, water dynamic conditions and so on. The highest concentration of ²²⁶Ra in the discharge of the tailings reservoir may be the main pollution source in the surface water and groundwater in the tailings reservoir.（5）Using single index evaluation method, we got that the shallow groundwater which are not directly drinking only after special treatment are all V class water of the study area. 80% of the surface water are V class water and the other is IV class water of the study area. The pollution of U and NO₂^- in the shallow groundwater in the study area is the most serious, the exceeding standard rate is 100%, the highest ratio of U pollution is reached 112. Fluoride exceeded the rate of 85.71%, Pb exceeded the standard rate of 14.29%. Similarly, the pollution of U, NO₂^- and fluoride in the study area is the most serious, and the standard rate of the study area is 100%, the highest ratio of U pollution reached 219.3. NO3- exceed the standard rate of 20%.