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| 2. |
- Fältmarsch, Rasmus, et al.
(författare)
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Metal concentrations in oats (Avena sativa L.) grown on acid sulphate soils
- 2009
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Ingår i: Agricultural and Food Science. - 1459-6067 .- 1795-1895. ; 18:1, s. 45-56
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to investigate the impact of soil chemistry on the concentrations of Co, Ni, Zn, Mn, Cu and Fe in oats (Avena saliva L. cv. Fiia) grown on Finnish acid sulphate (AS) soils with varying geochemical characteristics. Twenty two soil profiles, which were sampled to a depth of 1 m (five 20 cm section splits), and 26 composite oat grain samples were collected on a total of five fields. The concentrations of Co, Ni, Zn and Mn in the grains were correlated with the NH(4)Ac-EDTA-extractable concentrations in the soils. However, as these four chalcophilic metals are in general easily lost to drains and not retained as a large pool in the soil in easily-extractable form, also the concentrations in the oats were not in general elevated as compared with average values on other soils. On one of the fields, however, the Co and Ni concentrations in the soil, and thus also in the oats, were clearly elevated. Copper and Fe displayed no correlation between the soil and oat concentrations, indicating that the plant-uptake mechanisms are much more important than variations in geochemistry. It was suggested that the NH(4)Ac-EDTA solution was not efficient in extracting Fe and Cu, which shows that these metals are bound in relatively immobile oxyhydroxides.
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| 3. |
- Gustafsson, Peter, et al.
(författare)
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Macroeconomic effects of a decline in housing prices in Sweden
- 2016
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Ingår i: Journal of Policy Modeling. - : Elsevier. - 0161-8938 .- 1873-8060. ; 38:2, s. 242-255
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Tidskriftsartikel (refereegranskat)abstract
- Real housing prices in Sweden have roughly doubled the last 15 years. The rise in housing prices has coincided with a rise in household debt, sparking debate about both the presence of financial imbalances in the Swedish economy and the macroeconomic effects that a correction of these imbalances would have. In this paper, we conduct a quantitative assessment of the macroeconomic effects of a considerable decline inhousing prices using a Bayesian VAR model. Results show that a 20% drop in housing prices would lead to a recession-like impact on household consumption and unemployment. The impact would be even greater if falling housing prices coincided with a global economic downturn. This information should be useful to policymakers. If a fall in housing prices were to materialize, more expansionary stabilization policies would be motivated in order to dampen the effects on the real economy.
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| 4. |
- Hogfors-Ronnholm, Eva, et al.
(författare)
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Gallionella and Sulfuricella populations are dominant during the transition of boreal potential to actual acid sulfate soils
- 2022
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Ingår i: Communications Earth & Environment. - : Springer Nature. - 2662-4435. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Acid sulfate soils release metal laden, acidic waters that affect the environment, buildings, and human health. In this study, 16S rRNA gene amplicons, metagenomes, and metatranscriptomes all demonstrated distinct microbial communities and activities in the unoxidized potential acid sulfate soil, the overlying transition zone, and uppermost oxidized actual acid sulfate soil. Assembled genomes and mRNA transcripts also suggested abundant oxidized acid sulfate soil populations that aligned within the Gammaproteobacteria and Terracidiphilus. In contrast, potentially acid tolerant or moderately acidophilic iron oxidizing Gallionella and sulfur metabolizing Sulfuricella dominated the transition zone during catalysis of metal sulfide oxidation to form acid sulfate soil. Finally, anaerobic oxidation of methane coupled to nitrate, sulfate, and ferric reduction were suggested to occur in the reduced parent sediments. In conclusion, despite comparable metal sulfide dissolution processes e.g., biomining, Gallionella and Sulfuricella dominated the community and activities during conversion of potential to actual acid sulfate soils.
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| 5. |
- Högfors-Rönnholm, Eva, et al.
(författare)
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Chemical and microbiological evaluation of novel chemical treatment methods for acid sulfate soils
- 2018
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 625, s. 39-49
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Tidskriftsartikel (refereegranskat)abstract
- Naturally occurring sulfide rich deposits are common along the northern Baltic Sea coast thatwhen exposed to air, release large amounts of acid and metals into receiving water bodies. This causes severe environmental implications for agriculture, forestry, and building of infrastructure. In this study, we investigated the efficiency of ultrafine-grained calcium carbonate and peat (both separately and in combination) to mitigate acid and metal release. The experiments were carried out aerobically that mimicked summer conditions when the groundwater level is low and acid sulfate soils are exposed to oxygen, and anaerobically that is similar to autumn to spring conditions. The ultrafine-grained calcium carbonate dissipated well in the soil and its effect alone and when mixed with peat raised the pH and reduced pyrite dissolution while peat alone was similar to the controls and did not halt metal and acid release. High throughput 16S rRNA gene sequencing identified populations most similar to characterized acidophiles in the control and peat treated incubations while the acidophilic like populations were altered in the calcium carbonate alone and calcium carbonate plus peat treated acid sulfate soils. Coupled with the geochemistry data, it was suggested that the acidophiles were inactivated by the high pH in the presence of calcium carbonate but catalyzed pyrite dissolution in the controls and peat incubations. In conclusion, the anaerobic conditions during winter would likely be sufficient to mitigate acid production and metal release from acid sulfate soils and in the summer, treatment with calcium carbonate was the best mitigation method. (c) 2017 Elsevier B.V. All rights reserved.
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| 6. |
- Högfors-Rönnholm, Eva, et al.
(författare)
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Targeting oxidation sites on boreal acid sulfate soil macropore surfaces mitigates acid and metal release to recipient water streams
- 2023
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Ingår i: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 158
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Tidskriftsartikel (refereegranskat)abstract
- When reduced sulfidic parent sediments are oxidized, they become acid sulfate soils and discharge metal laden acidic solutions that can damage the environment, infrastructure, and human health. Consequently, methods to mitigate the effect of acid sulfate soils are a priority in affected areas. In this study, acid sulfate soil core samples, consisting of a natural network of preferential-flow soil macropores with defined macropore surfaces and inner cores of denser clay, were characterized and subjected to treatments with calcium carbonate and peat suspensions, or combinations thereof. The effects on the geochemistry and microbial communities were examined on both macropore surfaces and in inner cores. Although transport of treatment substances into the inner cores was demonstrated, no substantial effects were found on the geochemistry and microbial community that consisted of bacterial taxa commonly identified in acid mine drainage. In contrast, positive treatment effects were clearly detected on macropore surfaces and the most promising mitigation effects were detected for treatments combining calcium carbonate and peat suspensions. These treatments increased the pH of the macropore surfaces, added an electron donor in the form of peat, and significantly decreased the relative abundance of acidophilic bacterial populations while shifting the microbial community towards species typically growing at circumneutral pH values. These new environmental conditions were favorable for iron reduction that resulted in a positive effect on permeate quality. The study presents novel data regarding the important differences between acid sulfate soil macropore surfaces and inner cores, as well as their diverse biogeochemical characteristics. It further establishes that the major oxidation-reduction processes occur at the macropore surfaces, and that the combination treatment was the most effective at mitigating the negative environmental effects.
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| 7. |
- Johnson, Anders, et al.
(författare)
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Dredging and deposition of metal sulfide rich river sediments results in rapid conversion to acid sulfate soil materials
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 813
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Tidskriftsartikel (refereegranskat)abstract
- Sediments along the Baltic Sea coast can contain considerable amounts of metal sulfides that if dredged and the spoils deposited such that they are exposed to air, can release high concentrations of acid and toxic metals into recipient water bodies. Two river estuaries in western Finland were dredged from 2013 to 2018 and the dredge spoils were deposited on land previously covered with agricultural limestone to buffer the pH and mitigate acid and metal release. In this study, the geochemistry and 16S rRNA gene amplicon based bacterial communities were investigated over time to explore whether the application of lime prevented a conversion of the dredge spoils into acid producing and metal releasing soil. The pH of the dredge spoils decreased with time indicating metal sulfide oxidation and resulted in elevated sulfate concentrations along with a concomitant release of metals. However, calculations indicated only approximately 5% of the added lime had been dissolved. The bacterial communities decreased in diversity with the lowering of the pH as taxa most similar to extremely acidophilic sulfur, and in some cases iron, oxidizing Acidithiobacillus species became the dominant characterized genus in the deposited dredge spoils as the oxidation front moved deeper. In addition, other taxa characterized as involved in oxidation of iron or sulfur were identified including Gallionella, Sulfuricurvum, and Sulfurimonas. These data suggest there was a rapid conversion of the dredge spoils to severely acidic soil similar to actual acid sulfate soil and that the lime placed on the land prior to deposition of the spoils, and later ploughed into the dry dredge spoils, was insufficient to halt this process. Hence, future dredging and deposition of dredge spoils containing metal sulfides should not only take into account the amount of lime used for buffering but also its grain size and mixing into the soil.
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| 8. |
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| 9. |
- Nordmyr, Linda, et al.
(författare)
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The influence of metal leakage from acid sulphate soils on estuarine sediments in western Finland.
- 2006
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Konferensbidrag (refereegranskat)abstract
- Acid sulphate soils (AS soils) release large amounts of acidity and chemical elements into the rivers in western Finland. A recent study by our research group showed that AS soils liberate more toxic metals into water courses than the whole Finnish industry together. The elevated concentrations of metals are transported to the estuary, where they are deposited as a result of higher salinity and pH, and slower water currents. The bottom sediments are therefore excellent tools to evaluate changes in element discharge into the environment over both temporal and spatial scales. The objective of this study was to track changes in sediment elemental distribution as a result of leakage from AS soil landscapes and to quantify the impact of AS soils from the drainage area to the sea. The Vörå River is one of the most strongly AS soil affected rivers in Finland. It has a low pH (occasionally down to 4.0) and carries high amounts of many metals, which as a result of increasing pH and salinity, are precipitated and deposited in the bottom sediments in the estuary. The coastal area adjacent to this river was therefore selected for a bottom sediment and suspended particulate matter study. This study comprises sampling of four sediment cores and collection of particular matter with sediment traps, in a profile extending from the river mouth out to the open sea. A selective chemical extraction procedure was used in order to identify the chemical speciation within the sediment.The results show that an appreciable amount of elements (e.g. Al, Cd, Co, Cu, La, Mn, Ni and Zn) are elevated in the surface and sub-surface of the sampled bottom sediments compared to the deeper sediment background levels. These elements are all known to be leached from AS soils. At a site, approximately 4 km from the river outlet the sediments had 5-100 times higher concentrations of Cd, Co, Mn, Ni and Zn compared to the background levels. These elevated concentrations are much higher than the corresponding concentrations in the sediment cores situated closer to the river mouth. The reason for this deposition pattern is that some elements like for example Al and Cu are pH sensitive, and are therefore deposited closer to the river mouth, while other elements like Cd, Co, Mn, Ni and Zn are transported further out in the estuary and are not deposited until the impact of sea water increases. In contrast, elements that are not abundantly leached from Finnish AS soils (e.g. Cr, Pb, Ti and V) display a consistent concentration pattern in all sediment cores. This leads to the conclusion that the elevated element concentrations in the surface layers are a result of leakage from AS soils.The elevated concentrations of Cd, Co, Mn, Ni and Zn pose a significant environmental problem since: 1) episodic pH declines in the shallow estuary, caused by strong runoff from the river, might cause sudden release and relocation of the metals; and 2) as a result of the isostatic land uplift of the region (0.9 cm/year), these bottom sediments are going to be new land in a near future and will then consist of metal-contaminated land. The elevated concentrations of these metals at such a distance from AS soil environments suggest that the environmental impact of metal leakage extends far beyond the geographically adjacent environment. This poses a significant issue for land management.
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| 10. |
- Nystrand, Miriam I., et al.
(författare)
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Distribution and speciation of metals, phosphorus, sulfate and organic material in brackish estuary water affected by acid sulfate soils
- 2016
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Ingår i: Applied Geochemistry. - : Elsevier BV. - 0883-2927 .- 1872-9134. ; 66, s. 264-274
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Tidskriftsartikel (refereegranskat)abstract
- Dissolved (<1 kDa) and colloidal (1 kDa-0.45 mu m) size fractions of sulfate, organic carbon (OC), phosphate and 17 metals/metalloids were investigated in the acidic Vora River and its estuary in Western Finland. In addition, geochemical modelling was used to predict the formation of free ions and complexes in these waters. The sampling was carried out during high-water flow in autumn and in spring when the abundantly occurring acid sulfate (AS) soils in the catchment area are extensively flushed. Based on the high concentrations of sulfate, acidity and several metals, it is clear that the Vora River and its estuary is strongly affected by AS soils. The high dissolved form of metals limits also the existence of fish and other organisms in this estuary, and certainly also in other similar shallow brackish estuaries elsewhere in the Gulf of Bothnia. However, generally already <20% saline sea water reduces the concentration for OC and several elements (Al, Cu, Cr, Fe, Pb, PO4 and U) by half and c. 20-30% saline sea water is needed to halve concentrations of Cd, Co, Mn, Ni and Zn. Consequently, these elements as well as organic matters were rapidly precipitated in the estuary, even after mixing with fairly small amounts of the alkaline brackish sea water. Aluminium, Cu, Fe and U most likely precipitate together with organic matter closest to the river mouth. Manganese is relatively persistent in solution and, thus, precipitates further down the estuary as Mn oxides, which concomitantly capture Ba, Cd, Co, Cu, Ni and Zn. In the inner estuary, the high contents of Al is as important than Fe in removing PO4 and, thus, also reducing the risk of algae blooms in near coastal areas influenced by AS soils in the Gulf of Bothnia. Moreover, the dispersion of metals far out in the estuary is dependent on hydrological conditions, i.e. with high flows the plume of metal-rich water will spread further out in the estuary. Furthermore, the extensive drainage of the catchment and subsequent artificial enlargement of the river channel during recent decades has not only enabled oxidation of sulfidic sediments, but strongly increased flow peaks that reach further out in the estuary. (C) 2016 Elsevier Ltd. All rights reserved.
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