The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from...The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from 0.01 to 0.09 Bq/（m^2· d）, with an average of 0.04 Bq/（m^2 · d）. The seasonal pattern showed elevated polonium-210 fluxes in summer and autumn rather than in winter. Atmospheric depositional fluxes of polonium-210 showed a good correlation with beryllium-7 （r^2 =0. 85） and lead-210 fluxes （r^2 =0.71 ）, indicating their similar removal mechanism from atmosphere. The relationship between the polonium-210 depositional fluxes and the precipitation amount demonstrated that the precipitation dominates the polonium-210 removal from the atmosphere. The observed high activity ratios of polonium-210 to lead-210 indicated the occurrence of excess polonium-210 in coastal atmosphere, which may originate from marine surface waters either by indirect （foam）, or mare likely, direct （ air - sea exchange） input of marine bingenic material into the atmosphere. This source is even more important than the in situ decay of lead-210.展开更多
Distribution of Cu, Zn, Pb, Cr, Ni, Mn concentrations and the activity of polonium-210 in the surrounding area of a phosphate fertilizer industry located on the eastern coast of the Mediterranean Sea has been determin...Distribution of Cu, Zn, Pb, Cr, Ni, Mn concentrations and the activity of polonium-210 in the surrounding area of a phosphate fertilizer industry located on the eastern coast of the Mediterranean Sea has been determined. Nineteen sampling sites were distributed around the industrial zone on a surface area of about 100,000 m^2. Atomic absorption spectroscopy and Alpha spectroscopy were used to quantify the heavy elements and polonium-210, respectively. Investigation on a particle scale was conducted by TEM and SEM coupled to EDX and X-ray cartography to determine the nature of heavy elements carriers and their distribution. Heavy elements were mainly concentrated inside the particle size fraction 〈 50 μm. Their levels decreased with distance increasing from the industry. According to the reference soil, enrichment factors were about 10, 15, 32 and 100 times for Zn, Pb, Cu, and Cr, respectively inside the particle size fraction 〈 50 μm on the closest sites to the industry. The main contaminant sources were transport and storage of row materials and the free release of phosphogypsum waste. Heavy elements were entrapped inside agglomerates of sulfates, phosphates and iron oxihydroxides in a diffused shape. Polonium-210 with an enrichment factor of about 56, showed the same behavior of the spatial distribution of the trace elements.展开更多
The polonium-210 activity in raw material targets which was used to make the start neutron source rods of Qinshan Nuclear Power Station was determined in calorimetry. The calorimeter used is a twin-cup isothermal one....The polonium-210 activity in raw material targets which was used to make the start neutron source rods of Qinshan Nuclear Power Station was determined in calorimetry. The calorimeter used is a twin-cup isothermal one. It works at room temperature and does not need any device of constant temperature. The instruments used for calorimetry are simple and have good properties. The background is from -1μV to + 2 μ V when the room temperature changs between 16℃ and 28 ℃. The data gotten in calorimetry are in correspondence within ±3.4 % with those from liquid scintillation method after the targets were dissolved, additionally in correspondence within ±1.7% with the data given by Amersham Laboratories for 241Am determination.展开更多
采用α能谱示踪法进行了大气气溶胶中的210Po分析方法研究。气溶胶滤膜样品经剪碎后加入209Po示踪剂,在硝酸-硫酸-高氯酸体系中湿式消化,用0.5 mol/L盐酸反复浸取,在高温高速搅拌的水浴中置入银片自沉积,样品源银片在α能谱仪上测量。...采用α能谱示踪法进行了大气气溶胶中的210Po分析方法研究。气溶胶滤膜样品经剪碎后加入209Po示踪剂,在硝酸-硫酸-高氯酸体系中湿式消化,用0.5 mol/L盐酸反复浸取,在高温高速搅拌的水浴中置入银片自沉积,样品源银片在α能谱仪上测量。建立的分析测量方法,对于采样体积大于500m3的气溶胶样品,探测下限可达0.01 m Bq/m3,回收率接近95%。本方法经多项质量控制措施验证,现已在国家辐射监控点大气气溶胶测量和铀矿污染源监测项目中得到应用。展开更多
基金This research was supported by the National Natural Science Foundation of China under contract No.90411016the National Key Basic Research Special Foundation Program of China under contract No.2005CB422305China 0cean Mineral Resources Research and Development Association Foundation under contract Nos DY105-02-04 and DY105-02-01.
文摘The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from 0.01 to 0.09 Bq/（m^2· d）, with an average of 0.04 Bq/（m^2 · d）. The seasonal pattern showed elevated polonium-210 fluxes in summer and autumn rather than in winter. Atmospheric depositional fluxes of polonium-210 showed a good correlation with beryllium-7 （r^2 =0. 85） and lead-210 fluxes （r^2 =0.71 ）, indicating their similar removal mechanism from atmosphere. The relationship between the polonium-210 depositional fluxes and the precipitation amount demonstrated that the precipitation dominates the polonium-210 removal from the atmosphere. The observed high activity ratios of polonium-210 to lead-210 indicated the occurrence of excess polonium-210 in coastal atmosphere, which may originate from marine surface waters either by indirect （foam）, or mare likely, direct （ air - sea exchange） input of marine bingenic material into the atmosphere. This source is even more important than the in situ decay of lead-210.
基金supported by the research grants program of the Lebanese Council for Scientific Research
文摘Distribution of Cu, Zn, Pb, Cr, Ni, Mn concentrations and the activity of polonium-210 in the surrounding area of a phosphate fertilizer industry located on the eastern coast of the Mediterranean Sea has been determined. Nineteen sampling sites were distributed around the industrial zone on a surface area of about 100,000 m^2. Atomic absorption spectroscopy and Alpha spectroscopy were used to quantify the heavy elements and polonium-210, respectively. Investigation on a particle scale was conducted by TEM and SEM coupled to EDX and X-ray cartography to determine the nature of heavy elements carriers and their distribution. Heavy elements were mainly concentrated inside the particle size fraction 〈 50 μm. Their levels decreased with distance increasing from the industry. According to the reference soil, enrichment factors were about 10, 15, 32 and 100 times for Zn, Pb, Cu, and Cr, respectively inside the particle size fraction 〈 50 μm on the closest sites to the industry. The main contaminant sources were transport and storage of row materials and the free release of phosphogypsum waste. Heavy elements were entrapped inside agglomerates of sulfates, phosphates and iron oxihydroxides in a diffused shape. Polonium-210 with an enrichment factor of about 56, showed the same behavior of the spatial distribution of the trace elements.
文摘The polonium-210 activity in raw material targets which was used to make the start neutron source rods of Qinshan Nuclear Power Station was determined in calorimetry. The calorimeter used is a twin-cup isothermal one. It works at room temperature and does not need any device of constant temperature. The instruments used for calorimetry are simple and have good properties. The background is from -1μV to + 2 μ V when the room temperature changs between 16℃ and 28 ℃. The data gotten in calorimetry are in correspondence within ±3.4 % with those from liquid scintillation method after the targets were dissolved, additionally in correspondence within ±1.7% with the data given by Amersham Laboratories for 241Am determination.
文摘采用α能谱示踪法进行了大气气溶胶中的210Po分析方法研究。气溶胶滤膜样品经剪碎后加入209Po示踪剂,在硝酸-硫酸-高氯酸体系中湿式消化,用0.5 mol/L盐酸反复浸取,在高温高速搅拌的水浴中置入银片自沉积,样品源银片在α能谱仪上测量。建立的分析测量方法,对于采样体积大于500m3的气溶胶样品,探测下限可达0.01 m Bq/m3,回收率接近95%。本方法经多项质量控制措施验证,现已在国家辐射监控点大气气溶胶测量和铀矿污染源监测项目中得到应用。
