摘要：
Radon in the household water (especially groundwater) which is an important source of indoor radon, has become a potential health hazard to residents. In this study, radon concentrations in groundwater sampled from five villages near Dongpo W-polymetallic metallogenic region were measured using RAD-7 detector with RAD H2O accessory, and the effect of regional geology and mineralization on radon concentration in groundwater was studied. In addition, we also estimated the radiation doses received by people via ingestion of radon in water and inhalation of the radon from the indoor air while using water. The results show that the radon concentration in groundwater samples varies from 1.29 Bq L(-1) to 31.31 Bq L(-1) with 10.47 Bq L(-1) on average, and about 31.3% of the groundwater samples analyzed have a higher radon concentration than the maximum contaminant level of 11.1 Bq L(-1) recommended by United States Environmental Protection Agency (USEPA). The relatively high radon level in groundwater can be attributed to a relatively high uranium background produced by the magmatic activity and magmatic-hydrothermal system. The values of annual effective dose (AEDing) due to ingestion of radon in groundwater range from 0.002mSv y(-1) to 0.055mSv y(-1), 0.005mSv y(-1) to 0.11mSv y(-1) and 0.008mSv y(-1) to 0.188mSv y(-1) for adult, child and infant respectively. The values of annual effective dose due to the inhalation of radon released from water are 63.6, 15.4 and 3.8 times of those through the ingestion of radon in groundwater by the adults, children and infants, respectively. In addition, the values of estimated total annual effective doses are 0.020-0.480mSv y(-1), 0.017-0.406mSv y(-1) and 0.020-0.484mSv y(-1) for adult, child and infant, respectively. These values are much lower than the reference dose level of 1mSv y(-1) recommended by World Health Organization (WHO) and United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR).
摘要：
土壤氡浓度分布具有双分形特征,其分维值分别为 D 1=0.079 4和 D 2=1.465 4,分形临界值为2 167.7 Bq/m 3.低于临界值的分形其分维值 D 1很小,代表了区域背景分布,其背景值为1 088.16 Bq/m 3.高于临界值的分形其分维值 D 2显著增大,反映该区发生了较强的成矿作用的叠加.分形临界值可以作为异常下限值.金狮岭地区土壤氡浓度异常区分布范围较大,表明具有较好的成矿远景.
作者机构：
[Yi, Zheng-ji] Hengyang Normal Univ, Key Lab Funct Organometall Mat, Sch Chem & Mat Sci, Coll Hunan Prov, Hengyang 421008, Peoples R China.;[Tan, Kai-xuan] Univ South China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Peoples R China.
会议名称：
2nd International Workshop on Renewable Energy and Development (IWRED)
会议时间：
APR 20-22, 2018
会议地点：
Guilin, PEOPLES R CHINA
会议主办单位：
[Yi, Zheng-ji] Hengyang Normal Univ, Key Lab Funct Organometall Mat, Sch Chem & Mat Sci, Coll Hunan Prov, Hengyang 421008, Peoples R China.^[Tan, Kai-xuan] Univ South China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Peoples R China.
会议论文集名称：
IOP Conference Series-Earth and Environmental Science
摘要：
The Xiangxi gold mine was taken as an example to illustrate the application of the finite element and updated Lagrangian approach in the simulation and prediction of the quality of tailings effluents. The numerical modeling results suggest that tailings-water interaction at the early stage leads to the acidification and release of heavy metals which are responsible for the persistent pollution to the environment for 30 years. Tailings pore water can be gradually neutralized and contents of polluted species tend to decline markedly with time. The gangue dissolution and organic matter reaction can stimulate acid neutralization and decrease the diffusion rate of oxygen in tailings impoundments. The contents of pore-water species in upper tailings are significantly higher than in lower part and change severely at 6 m depth. Therefore, the hydrological zoning phenomenon in tailings impoundments accounts for geochemical zonation. This model has the potential to predict drainage quality of sulfide mine tailing impoundments.
作者机构：
[谭凯旋; 李春光; 谭婉玉] School of Nuclear Resources Engineering, University of South China, Hengyang, 421001, China;[夏良树] School of Nuclear Science and Technology, University of South China, Hengyang, 421001, China;[刘振中] School of Environmental Protection and Safety Engineering, University of South China, Hengyang, 421001, China
通讯机构：
School of Nuclear Resources Engineering, University of South China, Hengyang, China
作者机构：
[Xia, Yiqun; Zheng, Weina; Li, Reirei; Xia, Liangshu] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Xia, Yiqun] China Inst Atom Energy, Dept Radiochem, POB 275-26, Beijing 102413, Peoples R China.;[Tans, Kaixuan] Univ South China, Sch Nucl Resource & Nucl Fuel Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Xia, Liangshu] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.
摘要：
Basic aspects of uranium adsorption by rice husk have been investigated. The influences of various experimental parameters such as pH, time, adsorbent dosage, rice husk size, temperature and various concentrations of uranium on uptake were evaluated. The thermodynamics and kinetics of adsorption were analyzed by FT-IR and SEM. The adsorption capacity for uranium on rice husk increased upon increasing initial concentration of uranium and temperature, while decreased with the increase of the amount of rice husk. Maximum uranium adsorption was observed at pH = 3 and particle size between 120 μm and 150 μm. Adsorption equilibrium was achieved within 60 min. At 25 °C, the saturated adsorption capacity qmax was up to 15.14 mg/g when the initial concentration of uranium ranged from 10 to 400 mg/dm3. The adsorption of uranium followed Langmuir adsorption isotherm and according to quasi-second order kinetic equation. The calculated values of δHo, δS0, and δGo indicated that the biosorption process was endothermic and spontaneous. Based on FT-IR spectra it may be concluded that hydroxyl, carbonyl, P-O and Si=O groups are the main active sites.
通讯机构：
[Tan, Kaixuan] U;Univ South China, Sch Nucl Resources Engn, Hengyang 421001, Hunan, Peoples R China.
关键词：
diffusion;radon;soil;uranium
摘要：
Radon diffusion and transport through different media is a complex process affected by many factors. In this study, the fractal theories and field covering experiments were used to study the fractal characteristics of particle size distribution (PSD) of six kinds of geotechnical materials (e.g., waste rock, sand, laterite, kaolin, mixture of sand and laterite, and mixture of waste rock and laterite) and their effects on radon diffusion. In addition, the radon diffusion coefficient and diffusion length were calculated. Moreover, new formulas for estimating diffusion coefficient and diffusion length functional of fractal dimension d of PSD were proposed. These results demonstrate the following points: (1) the fractal dimension d of the PSD can be used to characterize the property of soils and rocks in the studies of radon diffusion behavior; (2) the diffusion coefficient and diffusion length decrease with increasing fractal dimension of PSD; and (3) the effectiveness of final covers in reducing radon exhalation of uranium tailings impoundments can be evaluated on the basis of the fractal dimension of PSD of materials.
