Measurement and spatial distribution pattern of natural radioactivity in a uranium tailings pond in Northwest China

Abstract

Numbers of radioactive tailings were produced in the process of uranium mining and milling.In this study,radiation environment monitoring was carried out on a decommissioned uranium mining and milling tailings pond in northwest China, and the governance effect and operation status of the tailings pond was investigated. The soil radionuclide activity concentration and ambient dose equivalent rate (H * (10)) were measured, and soil surface radon exhalation rate was calculated. The results shown that in the tailings pond and its surrounding area, the average soil radionuclide activity concentration was respectively 238 U: 42.64±11.17 Bq•kg -1 , 226 Ra: 45.47±13.56 Bq•kg -1 , 232 Th: 33.30±7.33 Bq•kg -1 , 40 K: 631.33±72.05 Bq•kg -1 , the average H * (10) was 63.32±6.46 nSv•h -1 , and the average radon exhalation rate was 40.46±11.29 mBq•m -2 •s -1 .Radionuclide activity concentration, H * (10) and radon exhalation rate were within the range of world natural background. Spatial distribution of radioactivity was analyzed by OK interpolation based on the investigated data. According to the measured results and spatial interpolation analysis,the decommissioning governance effect of the uranium tailings reservoir is good, the operation is normal, and there is no migration or diffusion situation of radionuclides in the pond has been found.

Heavy Metals/Metalloids in Soil of a Uranium Tailings Pond in Northwest China: Distribution and Relationship with Soil Physicochemical Properties and Radionuclides

“…For example, the excessive rate of As in rice planted around some uranium mining areas has reached 97.73% [18]. In addition, the extraction and recovery of radionuclides and heavy metals/metalloids from waste materials are also facing several constraints such as technic-economic, environmental, and social aspects [19]. Thus, a large number of uranium tailings ponds are built to bury the waste materials to prevent radionuclide and heavy metal/metalloid migration and diffusion to the surrounding environment media and maintain long-term stabilization [20][21][22].…”

“…Thus, a large number of uranium tailings ponds are built to bury the waste materials to prevent radionuclide and heavy metal/metalloid migration and diffusion to the surrounding environment media and maintain long-term stabilization [20][21][22]. Nevertheless, with the increasing number of service years of the tailings ponds and the existence of some adverse conditions such as natural or anthropogenic factors, the treated radionuclides and heavy metals/metalloids in the tailings pond still have potential risk of migration and diffusion to the adjacent environment and transfer to the food chain, affecting human health [5,19,23]. Therefore, in view of the characteristics of radionuclides and heavy metals/metalloids in the ecological environment, uranium tailings ponds have attracted extensive attention of researchers and governments all over the world [11,19,20,[23][24][25].…”

Estimation of 238U and 232Th in soil and water of prominent fault region of Mizoram

“…As mentioned above approximately after the 1970s onwards (after intensified mining era) most radon and uranium studies were found to concentrate on reporting radiological background, risk estimation and their correlation [18][19][20][21][22][23][24][25][26]. Several relevant papers estimating radon and uranium concentrations of a particular region or site were reported till date [27][28][29][30][31][32][33][34][35][36]. Recent reporters like Bezuidenhout [27] performed mapping and estimation of radon risk in South Africa while Novikov et al [28] reports radon and uranium content in groundwater of the Zaeltsovsky-Mochishch zone of Novosibirsk in Russia.…”

“…Wang et al [29] directly measure uranium content in order to map radon hazard region in Norway. Authors like Liu et al in southern China [30], Fuhrmann et al [31] in the USA and Yong et al [32] in northwest China measured radon exhalation rate and fluxes from uranium tailing pond to determine whether it lies within world natural background. All other papers [33][34][35][36] mainly focus on reporting radon and uranium concentrations in soil, water and air.…”

“…Approximately all recent studies on radon and uranium measurement focused on assessing their background radiation, health risk and comparison with the reported global average. Although extensive work has been done; radon monitoring and especially estimating its parent nuclei still has uncertainties reflected as well in the above recent reports [27][28][29][30][31][32][33][34][35][36]. The main problem is that the radon exhalation process was influenced by several external factors such as physicochemical features of the soil (such as grain size, density, porosity, permeability etc), geophysical factors (morphology and movement of groundwater and nature of aquifers) and meteorological factors (temperature, pressure, humidity, rainfall and wind speed) [16,17,[37][38][39].…”