Study On Distribution Characteristics Of ²¹⁰Po And ²¹⁰Pb In The Surrounding Environment Of A Uranium Tailings

With the continuous development of society and increasing demand for resources,it is imperative to exploit more clean and efficient nuclear power.In the process of the development and utilization of nuclear energy and the exploitation of mineral resources,it is inevitably to lead to the diffusion of natural radionuclides in minerals to the soil and water system nearby.These radionuclides have a broad and profound impact on the water and soil in the environment.Among them,two long-lived daughters²¹⁰Pb and210Po in the natural radiation system?4n + 2?are highly toxic radionuclides.They could enter the human body through the migration of drinking water and food chain,which is an important part of the public exposure dose.²¹⁰Po is pure ? emitter.Once ingested or inhaled,it will produce sustained high-energy internal exposure,causing serious harm.At the same time they have an extremely important application in the uranium geological exploration,depositional chronology research,marine geochemical research and many other fields.At present,the monitoring of²¹⁰Po is mainly for water,biological and human content,less involved in ²¹⁰Pb,especially the analysis of ²¹⁰Pb and ²¹⁰Po in soil?sediments?.It is particularly important to examine the radioactivity levels of radionuclides ²¹⁰Pb and ²¹⁰Po in water and soil?sediments?,and to analyze the occurrence forms of the two nuclides in soil?sediments?for understanding whether the environment was polluted by radionuclides and the pollution scope and severity of pollution,as well as their distribution and migration characteristics in the soil.Based on the investigation and comparison of the natural radionuclides ²¹⁰Pb and210Po detection technique,combined with the actual conditions,this paper chose the method of short detection period which is simple to use and not require a tracer to complete²¹⁰Pb,210Po detection by “Constant Temperature Spontaneous Deposition on Cu-foil with Gross ? and ? Counting and Double Samples”.The ²¹⁰Pb and ²¹⁰Po radioactive levels and distribution characteristics of water and soil?sediments?in thesurrounding of a uranium tailings were studied.At the same time,this paper combined the improved “Tessier five-step continuous digestion method” to analyze the occurrence forms of²¹⁰Pb and210Po in soil.The results are as follows:?1?In the water of tailings surrounding,the activity range of ²¹⁰Pb was 0.005Bq/L ¹.976Bq/L,the average was 0.230Bq/L,and the activity range of ²¹⁰Po was 0.003Bq/L ².873Bq/L,the average was 0.275Bq/L.In addition to the tailings dam and the surrounding area of the wastewater treatment station,the rest of the activities are lower than the WHO drinking water quality standards guidance level.?2?A total of two batch of sediments samples were collected in the area In the first sediments samples,the activity range of ²¹⁰Pb was 56.16Bq/kg to 5221.47Bq/kg?2.01E-05?g/g ¹.86E-03?g/g?with an average of 1214.47 Bq/kg?4.34E-04?g/g?;the activity range of ²¹⁰Po was 331.74Bq/kg to 18490.77 Bq/kg?2.00E-06?g/g ¹.11E-04?g/g?with an average of 5627.94 Bq/kg?3.39E-05?g/g?.In the second samples,the activity range of ²¹⁰Pb was 52.34Bq/kg to 23581.19Bq/kg?1.87E-5?g/kg⁸.42E-3?g/kg?with an average of 4921.21Bq/kg?1.76E-3?g/kg?;the activity range of ²¹⁰Po was 243.96Bq/kg to87745.60Bq/kg?1.47E-06?g/kg ⁵.29E-4?g/kg?with an average of 23962.09Bq/kg?1.44E-4?g/kg?.?3?The radionuclide²¹⁰Po was mainly exist in?F5?,and its proportion was as high as86.63% 99.00%.Regardless of the radioactivity of the sample level,this ratio was relatively stable,basically unchanged.The radionuclide ²¹⁰Pb in the tailings reservoir was mainly present in the Organio-Bound Fraction?F4?and the Residual Fraction?F5?.The content of these two forms is approximative,accounting for about 50% of the total activity.In the samples of stream and irrigation canal,it was Fe-Mn Oxides-Bound Fraction?F3?accounted for the largest,about 50% of the total activity,the Residual Fraction?F5?and the Organio-Bound Fraction?F4?followed.