| 1. |
- Åström, Mats E., et al.
(författare)
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Lanthanoid behaviour in an acidic landscape
- 2010
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 74:3, s. 829-845
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Tidskriftsartikel (refereegranskat)abstract
- Lanthanoids were studied in a boreal landscape where an abundance of acid sulfate soils and Histosols provide a unique opportunity to increase the understanding of flow these metals behave in acidic soils and waters and interact with soil and aqueous organic matter. In the acid sulfate soils lanthanoids are mobile as reflected in high to very high concentrations in soil water and runoff (typically a few mg 1(-1) but Lip to 12 mg 1(-1)) and abundant release by several relatively weak extractants (ammonium acetate EDTA, sodium pyrophosphate, hydroxylamine hydrochloride) applied on bulk soil. Normalisation with the lanthanoid pool in the underlying parent materials (sulphide-bearing sediments deposited in brackish-water) and soil water showed that the extensive release/retention in the acidic soil was accompanied by large, and variable, fractionation trends across the lanthanoid series. In low-order streams draining these soils, the lanthanoid concentrations were high and, as indicated by frontal ultrafiltration and geochemical modelling, largely dissolved (<1 kDa) in the form of the species LnSO(4)(+) and Ln(3+). In other moderately acidic stream waters (pH 4.3-4.6), organic complexation was predicted to be important in the <1 kDa fraction (especially for the heavy lanthanoids) and strongly dominating in the colloidal phase (1 kDa-0.45 mu m). Along the main stem of a stream in focus (catchment area of 223 km(2)), lanthanoid concentrations increased downstream, in particular during high flows, caused by a downstream increase in the proportion of acid sulfate soils which are extensively flushed during wet periods. The geochemical models applied to the colloidal Ln-organic phase were not successful in predicting the measured fractionation patterns.
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| 2. |
- Augustsson, Anna, et al.
(författare)
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Trace metal and geochemical variability during 5,500 years in the sediment of Lake Lehmilampi, Finland
- 2010
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Ingår i: Journal of Paleolimnology. - : Springer Science and Business Media LLC. - 0921-2728 .- 1573-0417. ; 44:4, s. 1025-1038
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Tidskriftsartikel (refereegranskat)abstract
- A high-resolution geochemical profilefrom a 5,500-year-old sediment core of Lake Lehmilampiin eastern Finland was analyzed to study longtermtrends and variability in element concentrationsand accumulation rates. The accumulation rates of allstudied elements followed the same trend, respondingto changes in the total sedimentation rate. Concentrationprofiles differed among elements and showedconsiderable variation over time. Principal componentsanalysis (PCA) was used on the concentrationdata to identify groups of elements that have similargeochemical controls. The first principal componentwas influenced by changes in mineral matter accumulation,and it incorporated elements that areassociated with stable allochthonous minerals (suchas Mg, K, Cs, Rb, Li, Ti and Ga), as well as elementsin forms that become diluted when mineral matterincreases (e.g., S, Fe and Mn). The second and thirdprincipal components showed that a large proportionof the variance was accounted for by elements withcontinuously increasing or decreasing concentrationsrelated to pedogenetical development of the catchmentsoil. In the case of Hg, Pb and Cd, however,accumulation rates increased faster at the surface thanis simply accounted for by changes in total sedimentationrates. For Cu, Cr, Ni and Zn, concentrationsincreased over the past 150 years, but there were noindications of a significant addition due to atmosphericdeposition. These elements had more variableconcentrations before the mid nineteenth century thanafter, as did elements that are often used fornormalization. These findings suggest that lakesediments may not properly reflect the history of atmospheric metal deposition in remote areas.
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| 3. |
- Brun, Christian, et al.
(författare)
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Spatial distribution of major, trace and ultra trace elements in three Norway spruce (Picea abies) stands in boreal forests, Forsmark, Sweden
- 2010
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Ingår i: Geoderma. - : Elsevier BV. - 0016-7061 .- 1872-6259. ; 159:3-4, s. 252-261
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Tidskriftsartikel (refereegranskat)abstract
- The spatial distribution of 49 major, trace and ultra trace elements within a Norway spruce system was examined in three sites within the Forsmark area in central Sweden. The system included stemwood, roots, fresh green shoots, litterbags, humus, mineral soil, rhizosphere soil and moss. Based on Principal Component Analysis and manual plots the elements were grouped according to their distribution within the different compartments. One large group of elements occurring abundantly in the soil, and in much lower concentrations in the biota and litter was distinguished, containing mainly elements typically associated with soil minerals. A similar pattern was found for a second group of elements, but with higher concentrations in the biological samples and/or litter. In contrast, there was also one group of elements with high concentrations in biological samples and/or litter and low content in soil. This was mainly nutrients, but also the highly toxic Cd, Hg and Sb. This study is part of the site investigation programme, carried out by the Swedish Nuclear Fuel and Waste Management Company (SKB), in order to locate a suitable area for a deep repository for nuclear fuel waste.
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| 4. |
- Peltola, Pasi, et al.
(författare)
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Urban geochemistry : a multimedia and multielement survey of a northern small-town urban area
- 2003
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Ingår i: Environmental Geochemistry and Health. - 0269-4042. ; 25:4, s. 397-419
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations and distributions of chemical elements (Ag, Al, As, Au, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K, La,Mg,Mn,Mo, Na,Ni, P, Pb, S, Sb, Sc, Se, Sr, Te, Th, Ti, Tl,U, V, Wand Zn) were studied in till, humus and urban soil in Jakobstad, a small town (20,000 inhabitants)in W. Finland. The analyses were performed with ICP-MS after aqua regia leaching of till (n = 37), urban topsoil (n = 32) and subsoil (n = 32), and HNO3 leaching of humus (n = 37). The till and humus samples, collected at the same sites, were divided into urban and rural samples. The urban till was not significantly enriched in metals. In contrast, a majority of the elements occurred in higher concentrations in the urban than the rural humus samples. Statistical and spatial interpretations of the humus data revealed that traffic (Pb, V and Ni), metal industry (Pb, Zn, Bi, Sb and Cr), an abandoned shooting range (Pb and Sb) and other sources contribute to higher metal levels in the urban humus. The urban soil samples were collected at parks, yards, abandoned industrial sites, roadsides, etc. The topsoil samples were enriched in most elements, also by elements not enriched in the urban humus (e.g. Cd). At several sites, the concentrations far exceeded the limit concentrations for contaminatedsoils in Finland. A large variety of sources were identified or indicated.
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| 5. |
- Peltola, Pasi, et al.
(författare)
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Can boron isotopes be used as a sedimentary marker for fire events? : a case study from a historic urban fire event in W Finland
- 2006
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Ingår i: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 21:6, s. 941-948
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to seek the origin of a B peak found in two sediment profiles from a small lake close to a small-sized town in Finland. The peak was found by chance when an environmental multielement study was performed. Altogether 51 chemical elements were determined with ICP-MS, after aqua regia digestion. None of the other determined elements were enriched or depleted in the B rich layer, including elements derived from sea-salt inclusions (Na and Sr) and anthropogenic sources (Pb, Cu, Cd, Hg, etc.). Boron stable isotopes, dating of the sediment cores, and the B concentrations found in possible source materials suggest that the B rich layer is the result of leaching of wood ash produced in a fire that destroyed half of the nearby wooden town in the early 19th century. The results imply that the concentrations and isotopic signatures of B in lacustrine environments (sediments) can be used to detect historic fires
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| 6. |
- Peltola, Pasi, et al.
(författare)
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Concentations and leachability of chemical elements in estuarine sulfur-rich sediments, W. Finland
- 2002
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 284:1-3, s. 109-122
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Tidskriftsartikel (refereegranskat)abstract
- Concentrations, distributions and mobility of chemical elements were investigated in reduced sulfur-rich estuarine sediments located in western Finland. The main objective was to determine the possible extent of metal leaching when dredged masses of these sulfur-rich sediments are dumped on the land and thus exposed to air. When dredged, the reduced sulfur in the sediments oxidises resulting in a lowering of pH, which in turn is expected to leach metals. The study area is an artificial lake claimed from the Botnian sea in 1962. In this lake, several mass-kills of fish have occurred, believed partly to be due to dredging. Two sediment samples (0–50 and 50–100 cm) were taken from 39 sampling points in the lake. These samples were leached in aqua regia (2:2:2 HNO3/HCl/H2O) and analysed for Fe, Al, Mg, Ca, K, P, Na, Mn, Zn, Ba, V, Sr, Cr, Ni, Cu, Co, As, Pb, B, Mo and Cd with ICP-AES. Sulfur and organic carbon were analysed with Leco. In a controlled laboratory experiment, the sediments were allowed to oxidise for 1 year while moisturised with deionised water every month. The pH and conductivity were determined in the beginning of the experiment (reduced state) and in the end (oxidised state). In the supernatants in the oxidised states the amount of leached metals (Na, Al, Mn, Zn, Sr, Co, Ni, Cu, Cd, Cr, Pb, U, Li, Rb and As) were determined with ICP-MS. The sediments were found to contain low levels of toxic metals but, as expected, high concentrations of sulfur. In the experiment, pH was lowered (down to 3.0) and the conductivity increased in all samples due to oxidation and release of metal ions. The extent of leaching varied between 0.03% for As and 12.3% for Na. Critical pH values, at which high amounts of metals begin to leach, were obtained graphically. These values varied between 4.8 (Ni) and 3.3 (Cr). Not all elements were controlled by pH, e.g. Mn correlated well with its aqua regia leachable concentration. In a planned dredging operation in the area some 23 300 t (10 500 m3) (dry wt.) of sediments will be dredged. The amounts of metals likely to be leached, according to the results from this study, are as follows (kg): Al (1710), Mn (1230), Zn (59), Sr (39), Co (13), Ni (12), Cu (2) and less than 1 kg of Cd–Cr–As–Pb.
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| 7. |
- Peltola, Pasi, et al.
(författare)
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Lead and Cu in contaminated urban soils : Extraction with chemical reagents and bioluminescent bacteria and yeast
- 2005
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Ingår i: Science of the Total Environment. - Amsterdam : Elsevier. - 0048-9697 .- 1879-1026. ; 350:1-3, s. 194-203
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Tidskriftsartikel (refereegranskat)abstract
- Twenty urban soil samples, with a wide range of Pb (14–5323 mg/kg) and Cu (8–12987 mg/kg), were used to compare the operational speciation of a five-step sequential leach with the bioavailability determined with bioluminescent Pb (RN4220(pTOO24)) and Cu (MC1061(pSLcueR/pDNPcopAluc)) specific bacterial biosensors and a Cu specific yeast sensor. The bioavailable Pb concentrations were all similar or lower than the first sequential leach step (1M NaOAc). In contrast, in some samples the bioavailable concentrations of Cu clearly exceeded even the second sequential leach step (0.1 M Na4P2O7). With the yeast sensor 12/20 samples were below detection, however, the yeast sensor was capable of detecting all high Cu concentrations. The biosensors used in this study are not capable of detecting the natural soil concentrations of Pb and Cu in the studied area.
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| 8. |
- Peltola, Pasi
(författare)
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Multielement Urban Geochemistry : Exporing the Expected, the Unexpected and the Unknown
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Urban areas are hot-spots for the human use of most elements. These elements are the building blocks of our various goods and chemicals and are used both purposely and in a more unaware fashion. There are many ways in which the elements get dispersed from the human use. Commonly acknowledged and evident processes of dispersion are point sources (e.g. industrial pollution), diffuse sources (e.g. traffic) and the past historic use of various chemicals. In fact everything ever produced is going to end up somewhere - it is just a matter of time. Soils and sediments are the main sinks for elements dispersed from the above and other sources. The importance of recognising the dispersion of elements lies in the well-known fact that many elements are toxic or potentially toxic. Due to the multitude of chemicals used in urban areas during time periods up to even thousand of years it can not be known exactly which elements are enriched at specific sites or in specific samples. Moreover, if the presence of a specific element is "unexpected" then it can lead to the element not being searched for (determined) at all. Due to this it is important that as many elements as possible are determined from samples with urban environmental concern. In this thesis multielement chemical analyses (mainly ICP-MS) are used to study the past, present and potential future dispersion of chemical elements, mainly in and around the small town of Jakobstad (Pietarsaari), Finland. The materials studied were till, boreal forest humus, various urban soils, street dust, lake sediments and sediment leachates. The results first of all show that multielement analytical methods are useful, if not totally necessary, in order to grasp the presence and dispersion of various elements from both natural and anthropogenic sources. This is especially important when dealing with the dispersion of toxic elements. The most important specific findings of this thesis are: the presence of reduced sulphur in natural lake sediments can lead to considerable leakage of many elements if the sediments are dredged and allowed to oxidise; that boreal forest humus can be used to track the past urban dispersion of various chemical elements; boron can be used to track wood fires from sedimentary profiles; that the use of red lead has caused extreme lead concentration in the topsoil from small-scale usage. This lead can be "invisible" and highly bioavailable to certain bacteria and most likely also to other organisms; that tungsten carbide is enriched in the urban humus and dust and dispersed to the environment from the studded tyres as < 0.1 -1.4 um particles.
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| 9. |
- Peltola, Pasi, et al.
(författare)
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Tyre stud derived tungsten carbide particles in urban street dust
- 2006
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Ingår i: Boreal environment research. - Helsinki : Finnish Environment Institute. - 1239-6095 .- 1797-2469. ; 11:3, s. 161-168
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Tidskriftsartikel (refereegranskat)abstract
- In countries where studded winter tyres are used they contribute to the generation of street dust by grinding the road surface and traction sand into finer particles. At the same time the hard metal tips of the studs, made out of tungsten carbide (WC), wear to finer particles dispersed into the environment. Elevated tungsten concentrations in different sampling media, probably caused by the use of studded tyres, have also been reported. In this study three size fractions of street dust sampled in Turku, Finland, were investigated. Tungsten and various other element concentrations were determined with ICP-MS after total dissolution, pseudo total concentration (aqua regia) and a weaker extraction (1M NH4Ac). A visual analysis was made with a SEM-EDX to study the presence and size fraction of WC particles, which has not been studied before. The total concentrations (median values) of tungsten in the fractions were 9.2 µg g–1 (100 µm–2 mm), 21 µg g–1 (45 µm–100 µm) and 39 µg g–1 (< 45 µm). As expected, tungsten showed a tendency to accumulate into the finer size fractions. However, more surprising was the result that out of all elements determined, tungsten had the greatest (median values) relative enrichment in the fine fraction. In the SEM-EDX analysis particles consisting of tungsten were identified and ruled out to be WC abraded from tyre studs. The WC particles occurred either separately or in clusters with size range of 0.1–1.4 µm.
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| 10. |
- Åström, Mats E., et al.
(författare)
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Attenuation of rare earth elements in a boreal estuary
- 2012
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 96, s. 105-119
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity < 6 parts per thousand). Surface water was collected in a transect from the creek mouth to the outer estuary, and settling (particulate) material in sediment traps moored at selected locations in the estuary. Ultrafiltration, high-resolution ICP-MS and modeling were applied on the waters, and a variety of chemical reagents were used to extract metals from the settling material. Aluminium, Fe and REE transported by the acidic creek were extensively removed in the inner/central estuary where the acidic water was neutralised, whereas Mn was relatively persistent in solution and thus redistributed to particles and deposited further down the estuary. The REE removal was caused by several contemporary mechanisms: co-precipitation with oxyhydroxides (mainly Al but also Fe), complexation with flocculating humic substances and sorption to suspended particles. Down estuary the dissolved REE pool, remaining after removal, was fractionated: the < 1 kDa pool became depleted in the middle REE and the colloidal (0.45 mu m-1 kDa) pool depleted in the middle and heavy REE. This fractionation was controlled by the removal process, such that those REE with highest affinity for the settling particles became most depleted in the remaining dissolved pool. Modeling, based on Visual MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (< 0.45 mu m) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.
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