Abstract: The uranium (U) concentrations and isotopic composition of waters and sediment cores were used to investigate the transport and accumulation of U in a water system (tailings pond, two lakes, and the Kalix River) receiving mine waters from the Kiruna mine. Concentrations of dissolved U decrease two orders of magnitude between the inflow of mine waters and in the Kalix River, while the concentration of the element bound to particulate matter increases, most likely due to sorption on iron‑manganese hydroxides and organic matter. The vertical distribution of U in the water column differs between two polluted lakes with a potential indication of dissolved U supply from sediment’s pore waters at anoxic conditions. Since the beginning of exposure in the 1950s, U concentrations in lake sediments have increased \textgreater20-fold, reaching concentrations above 50 μg g-1. The distribution of anthropogenic U between the lakes does not follow the distribution of other mine water contaminants, with a higher relative proportion of U accumulating in the sediments of the second lake. Concentrations of redox-sensitive elements in the sediment core as well as Fe isotopic composition were used to re-construct past redox-conditions potentially controlling early diagenesis of U in surface sediments. Two analytical techniques (ICP-SFMS and MC-ICP-MS) were used for the determination of U isotopic composition, providing an extra dimension in the understanding of processes in the system. The (234 U)/(238 U) activity ratio (AR) is rather uniform in the tailings pond but varies considerably in water and lake sediments providing a potential tracer for U transport from the Kiruna mine through the water system, and U immobilization in sediments. The U mass balance in the Rakkurijoki system as well as the amount of anthropogenic U accumulated in lake sediments were evaluated, indicating the immobilization in the two lakes of 170 kg and 285 kg U, respectively.

Abstract: Vietnam is a country with a long coastline and a high population density residing in the coastal plains. The largest dry area in Vietnam, the coastal plain of Ninh Thuan province, always lacks water in the first dry months of the year (Jan., Feb., Mar., and Apr.). Groundwater is an extremely valuable resource for supplies at this time. Therefore, the objective of this study is to establish a comprehensive approach to sustainable groundwater management in this semi-arid region. This approach is not only mitigating the negative impacts of factors such as climate change, sea level rise, and socio-economic development but also suggesting measures for management of aquifer recharge. A groundwater model for a 3-layer system with variable density flow SEAWAT is built to predict the impacts of climate change and sea level rise without a change in groundwater abstraction. This model helps to understand the trend of salt intrusion and lowering groundwater level in the study area. Afterwards, scenarios with different ground water abstraction and groundwater development such as ground dam, infiltration basin have been set up to meet the demands of socio-economic development in the future. Predicted results will show the impacts of the groundwater systems in the area such as groundwater level change, and saltwater intrusion. Controlled groundwater abstraction and some measures of groundwater development such as infiltration basin, underground dam would allow for an increase of up to 50000m3/day in the year 2050 without negative impacts on the aquifer system.

Abstract: Whether a nuclear installation has radiological impact and, in that case, its extension, are the questions behind any environmental analysis of the installation along its operational life. This analysis is based on the detailed establishment of the radiological background of the area. Accordingly, the dismantling and decommissioning process (D&D) of a nuclear power plant starts with a radiological monitoring plan, which includes the radiological characterization of the area and of its surroundings. At the completion of the D&D, unrestricted use for the site will be permitted strictly in accordance with results of the radiological survey within the limits established by the local authorities. Groundwater quality is typically included in any radiological analysis since, among other reasons, a significant part of it is highly likely to end up being extracted for domestic use and hence, human consumption. While there is no regulation containing maximum activity concentration or radionuclide guidance values for water that may be destined for uses other than public consumption, if groundwater is considered a “part” of the land, dose criteria for site release can be applied. Therefore, together with the guidance levels to be established for the different radionuclides expected in the groundwater, the detection limits to be employed when performing routine radio analytical characterization procedures in the laboratory should also be provided. In this paper, we first propose a relation of the potential radionuclides to be analyzed in groundwater, together with their detection limits to be achieved when the determinations are performed in a laboratory, and subsequently, we discuss the most suitable analytical methodologies and resources that would be necessary to undertake radiological characterization plans from a practical point of view.