目的了解四川省地表水体中^(226)Ra的放射性水平并对其健康风险进行评估。方法于2016年至2021年间检测了四川省主要地表水系23个监测断面的^(226)Ra放射性水平,应用剂量转换系数计算待积有效剂量,应用健康风险模型评估对居民的健康风险...目的了解四川省地表水体中^(226)Ra的放射性水平并对其健康风险进行评估。方法于2016年至2021年间检测了四川省主要地表水系23个监测断面的^(226)Ra放射性水平,应用剂量转换系数计算待积有效剂量,应用健康风险模型评估对居民的健康风险。结果四川省地表水体中^(226)Ra的放射性水平为1.9 m Bq/L~20.0m Bq/L,所有地表水体中^(226)Ra的放射性水平均合格;不同年度、不同地表水体的^(226)Ra放射性水平间比较,差异均无统计学意义(P>0.05);平水期地表水体的^(226)Ra放射性水平高于枯水期,差异有统计学意义(P<0.05)。通过饮水、水体浸没途径摄入^(226)Ra而所致年均待积有效剂量在各年龄组均低于0.1 m Sv,对各年龄段居民所致的总致癌风险处于9.50×10^(-9)/a~1.004×10^(-7)/a,均低于WHO和ICRP发布的限值(10^(-6)/a和5×10^(-5)/a)。结论四川省主要地表水系中^(226)Ra的放射性水平均未超标,经直接饮水途径、水体浸没途径摄入^(226)Ra所致健康风险处于可接受水平;全省主要地表水体中^(226)Ra的放射性水平对各年龄组都是安全的。展开更多
Radium isotopes 226Ra and 228Ra in seawater of the western Yellow Sea were measured by using the Mn-fiber adsorption - HPGe 7 spectrum method. The distribution features of the two isotopes have been studied. The activ...Radium isotopes 226Ra and 228Ra in seawater of the western Yellow Sea were measured by using the Mn-fiber adsorption - HPGe 7 spectrum method. The distribution features of the two isotopes have been studied. The activities of 226Ra and 228Ra are 2.72-5.57 Bq m^-3 and 7.51-34.3 Bq m^-3 respectively. The activities of 226Ra and 228Ra from surface to bottom for each depth profile station are comparable within the experimental error, but the mean activities decrease with distance from the shore. From the distribution data of 228Ra, the horizontal eddy diffusion coefficient was estimated at 29 × 10^6 cm^2 s^- 1.展开更多
The ^226Ra and ^228Ra activities of Qinghai Lake surface water, groundwater, river water, suspended particles, and bottom sediments were measured in a gamma-ray spectrometer. The sources of ^226Ra and ^228Ra were disc...The ^226Ra and ^228Ra activities of Qinghai Lake surface water, groundwater, river water, suspended particles, and bottom sediments were measured in a gamma-ray spectrometer. The sources of ^226Ra and ^228Ra were discussed according to their distribution characteristics. ^226Ra and ^228Ra activities （dpm/（100 L）） ranged from 14.13±0.22 to 19.22±0.42 and 17.724-0.66 to 30.96：kl.47 in the surface water of the North Bay, respectively, and from 7.88±0.24 to 33.80±0.47 and 15.73±0.74 to 57.31±1.44, respectively, in the South Bay. The surface water near the estuary had a lower salinity and had a higher concentration of radium isotopes than the samples collected further away. The farther offshore the sample, the higher the salinity was, and the lower the radium isotope activity. The distribution of radium activities in the western part of Qinghai Lake is controlled by several factors, including Buha River runoff, desorption from suspended particles derived from the river, groundwater discharge, and a small amount of diffusion from the sediment.展开更多
Material fluxes （e.g., nutrients） from coastal waters to offshore areas play an important role in controlling the water quality of the adjacent sea areas not only by increasing nutrient concentration hut also by cha...Material fluxes （e.g., nutrients） from coastal waters to offshore areas play an important role in controlling the water quality of the adjacent sea areas not only by increasing nutrient concentration hut also by changing nutrient structures. In this study, naturally occurring isotopes, ^226Ra and ^228Ra, were measured with the alpha spectrometry in the Wenjiao-Wenchang and Wanquan estuaries and adjacent sea areas along the east coast of Hainan Island. The excess ^226Ra and ^228Ra activities were observed by comparison with the values derived from the conservative mixing of freshwater and seawater end-members in both estuaries. Using a one-dimensional diffusion model, the horizontal eddy diffusion coefficient of 3.1 6 × 10^5 cm^2/s, for nutrients diffusing from their sources, was derived from 228Ra activities. Consequently, the corresponding nutrient fluxes flowing into the coastal waters were assessed. The results can provide useful information for the study of the mixing and exchange processes of coastal waters as well as dissoluble pollutant transport in this sea area.展开更多
文摘目的了解四川省地表水体中^(226)Ra的放射性水平并对其健康风险进行评估。方法于2016年至2021年间检测了四川省主要地表水系23个监测断面的^(226)Ra放射性水平,应用剂量转换系数计算待积有效剂量,应用健康风险模型评估对居民的健康风险。结果四川省地表水体中^(226)Ra的放射性水平为1.9 m Bq/L~20.0m Bq/L,所有地表水体中^(226)Ra的放射性水平均合格;不同年度、不同地表水体的^(226)Ra放射性水平间比较,差异均无统计学意义(P>0.05);平水期地表水体的^(226)Ra放射性水平高于枯水期,差异有统计学意义(P<0.05)。通过饮水、水体浸没途径摄入^(226)Ra而所致年均待积有效剂量在各年龄组均低于0.1 m Sv,对各年龄段居民所致的总致癌风险处于9.50×10^(-9)/a~1.004×10^(-7)/a,均低于WHO和ICRP发布的限值(10^(-6)/a和5×10^(-5)/a)。结论四川省主要地表水系中^(226)Ra的放射性水平均未超标,经直接饮水途径、水体浸没途径摄入^(226)Ra所致健康风险处于可接受水平;全省主要地表水体中^(226)Ra的放射性水平对各年龄组都是安全的。
文摘Radium isotopes 226Ra and 228Ra in seawater of the western Yellow Sea were measured by using the Mn-fiber adsorption - HPGe 7 spectrum method. The distribution features of the two isotopes have been studied. The activities of 226Ra and 228Ra are 2.72-5.57 Bq m^-3 and 7.51-34.3 Bq m^-3 respectively. The activities of 226Ra and 228Ra from surface to bottom for each depth profile station are comparable within the experimental error, but the mean activities decrease with distance from the shore. From the distribution data of 228Ra, the horizontal eddy diffusion coefficient was estimated at 29 × 10^6 cm^2 s^- 1.
基金Supported by the"One Hundred Plan"Project of Chinese Academy of Sciences:Groundwater Discharge and Geochemical Processes of Plateau Inland Lakes(No.Y210101028)the Tracer of Groundwater Discharge by Radioactive Isotope(No.Y360051010)
文摘The ^226Ra and ^228Ra activities of Qinghai Lake surface water, groundwater, river water, suspended particles, and bottom sediments were measured in a gamma-ray spectrometer. The sources of ^226Ra and ^228Ra were discussed according to their distribution characteristics. ^226Ra and ^228Ra activities （dpm/（100 L）） ranged from 14.13±0.22 to 19.22±0.42 and 17.724-0.66 to 30.96：kl.47 in the surface water of the North Bay, respectively, and from 7.88±0.24 to 33.80±0.47 and 15.73±0.74 to 57.31±1.44, respectively, in the South Bay. The surface water near the estuary had a lower salinity and had a higher concentration of radium isotopes than the samples collected further away. The farther offshore the sample, the higher the salinity was, and the lower the radium isotope activity. The distribution of radium activities in the western part of Qinghai Lake is controlled by several factors, including Buha River runoff, desorption from suspended particles derived from the river, groundwater discharge, and a small amount of diffusion from the sediment.
基金supported by the Natural Science Foundation of China (Grant No.41021064)the Sino-German Cooperation Project of Ministry of Science and Technology of China (Grant No.2007DFB20380)the Ph. D. Program Scholarship Fund of East China Normal University (Grant No.2010047)
文摘Material fluxes （e.g., nutrients） from coastal waters to offshore areas play an important role in controlling the water quality of the adjacent sea areas not only by increasing nutrient concentration hut also by changing nutrient structures. In this study, naturally occurring isotopes, ^226Ra and ^228Ra, were measured with the alpha spectrometry in the Wenjiao-Wenchang and Wanquan estuaries and adjacent sea areas along the east coast of Hainan Island. The excess ^226Ra and ^228Ra activities were observed by comparison with the values derived from the conservative mixing of freshwater and seawater end-members in both estuaries. Using a one-dimensional diffusion model, the horizontal eddy diffusion coefficient of 3.1 6 × 10^5 cm^2/s, for nutrients diffusing from their sources, was derived from 228Ra activities. Consequently, the corresponding nutrient fluxes flowing into the coastal waters were assessed. The results can provide useful information for the study of the mixing and exchange processes of coastal waters as well as dissoluble pollutant transport in this sea area.
