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- Ingri, Johan, et al.
(författare)
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Uptake of alkali and alkaline-earth elements on suspended iron and manganese in the Kalix River, northern Sweden
- 1994
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 58:24, s. 5433-5442
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Tidskriftsartikel (refereegranskat)abstract
- Scavenging of alkali and alkaline-earth elements by suspended Fe and Mn in the Kalix River, northern Sweden, has been studied for a period of seventeen months. More than 95% (by weight) of suspended nondetrital concentrations of Ca, Mg, and Sr are scavenged on suspended nondetrital Fe throughout all seasons. Barium is correlated to suspended Fe during winter, but during the summer a significant fraction of nondetrital Ba is associated with Mn-rich particles. Porewater profiles for Ca, Mg, and Sr are similar to the dissolved Fe profile, suggesting desorption from a Fe-rich carrier phase. Compared with the river water concentration, Ba is enriched twenty-five times in porewater and shows, together with Mn, a post-depositional subsurface maximum in the solid sediment. The alkali elements Na and K show a linear correlation to suspended nondetrital Fe during the winter. However, the summer concentrations cannot be explained by scavenging onto Fe alone, and sediment and porewater data show no clear association with Fe or Mn. The distribution coefficients for the alkaline-earth elements are two orders of magnitude larger than coefficients obtained for model Fe-oxyhydroxides. This suggests that surface complexation occurs via other functional groups and/or the alkaline-earths are more firmly bound to the natural Fe-rich phase.
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| 4. |
- Widerlund, Anders, et al.
(författare)
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Varved sediments in the Kalix River estuary, northern Sweden
- 1994
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Ingår i: Aqua Fennica. - 0356-7133. ; 24:2, s. 163-169
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Tidskriftsartikel (refereegranskat)abstract
- Two virtually undisturbed cores collected by using the crust-freezing technique revealed the occurrence of varved sediments in the Kalix River estuary. Sedimentation rates were determined by super(137)Cs measurements, varve-counting and also by sediment traps. Each varve consists of a grey, predominantly clastic spring flood layer and a brown layer relatively rich in Fe (III) oxides, deposited during the rest of the year. The varve thickness is 5-13 mm, corresponding to a sedimentation rate of 96-227 mg dry sediment/cm super(2)/yr. Fall-out from the Chernobyl accident resulted in a 7-10 fold increase of super(137)Cs in the layer deposited during the summer and autumn of 1986. During the period 1975-1991, one or two major resuspension events occurred in the estuary
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