TY  - JOUR
AU  - Pontér, S.
AU  - Rodushkin, I.
AU  - Engström, E.
AU  - Rodushkina, K.
AU  - Paulukat, C.
AU  - Peinerud, E.
AU  - Widerlund, A.
PY  - 2021//
TI  - Early diagenesis of anthropogenic uranium in lakes receiving deep groundwater from the Kiruna mine, northern Sweden
JO  - Science of The Total Environment
SP  - 148441
VL  - 793
KW  - Isotope ratios
KW  - Mine water
KW  - Sediments
KW  - Uranium
N2  - 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.
SN  - 0048-9697
UR  - https://www.sciencedirect.com/science/article/pii/S0048969721035130
N1  - exported from refbase (http://www.uhydro.de/base/show.php?record=154), last updated on Fri, 26 Jan 2024 13:19:04 +0100
ID  - Ponter_etal2021
ER  -