Radioactive contamination of the environment as a result of uranium production: a case study at the abandoned Lincang uranium mine, Yunnan Province, China

The distribution of radioactive pollutants, such as ~(222)Rn, U, Th and ~(226)Ra in the air, sur-face waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studiedThe mechanical, geochemical and biogeochemical processes responsible for the transport andfate of the radioactive elements are discussed based on the monitoring data. The pollutants con-centrations of effluents from the mine tunnels were dependent on pH and SO_4~(2-) which were con-trolled by biochemical oxidation of sulfide in the ore/host rocks. Radon anomalies in air reached 4km from the tailings pile depending on radon release from the site, topography and climate. ~(238)Uand ~(226)Ra abnormities in stream sediments and soil were 40-90 cm deep and 790-800 m awaydownstream. Anomalies of radioactive contaminants of surface watercourses extended 7.5-13km from the discharge of effluents of the site mainly depending on mechanical and chemical proc-esses. There were about 2.86 ha rice fields and 1.59 km stream sediments contaminated. Erosionof tailings and mining debris with little or no containment or control accelerated the contaminationprocesses.