| 1. |
- Abrahamsson, Christina, et al.
(author)
-
DeltaT50 - a new method to assess temporal ventricular repolarization variability
- 2011
-
In: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 44:4
-
Journal article (peer-reviewed)abstract
- Background Increased beat-to-beat variability in cardiac repolarization time is a tentative risk marker of drug-induced torsades de pointes. We developed a new, automatic method based on the temporal variability of the T-wave down slope to assess this variability. Method and Results Leads V1 to V6 of resting electrocardiograms were recorded in 42 healthy subjects (18-68 years, 22 men). The temporal variability at 50% of the T-wave down slope, deltaT50 (1.5 ± 0.41 milliseconds; range, 0.86-2.66 milliseconds), was measured with an accuracy of 1 millisecond on at least 9 pairs of electrocardiogram complexes with a signal-to-noise ratio more than 10 and changes in the R-R interval less than 150 milliseconds. The correlation between repeated measurements of deltaT50 was high. DeltaT50 was measured without corrections for age, sex, heart rate, T-wave amplitude, signal-to-noise ratio, R-R variability, and QTcF because none of these factors explained more than 4% of the within-subject deltaT50 variability. Conclusion The beat-to-beat repolarization variability was measured with high fidelity with the deltaT50 method and was a robust measure in healthy volunteers.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Düker, Anders, 1966-
(author)
-
Natural aquatic colloidal matter : Characteristics and impact on the mobility of trace metals and organics
- 1998
-
Doctoral thesis (other academic/artistic)abstract
- Natural colloidal (< 1.0 µm) matter plays an important role for tbe transport and redistribution of water-borne substances. The aim of this work was to characterise colloidal matter from surface waters and groundwaters, and to improve on the understanding on the role of natural colloidal matter in the redistribution and mobility of trace metals. Laboratory studies of tbe stability (coagulation rate) of model colloids showed that the stability was dependent on the electrolyte composition, pH and the presence of fulvic acid. The uptake of Zn(II) and Pb(II) on colloidal AI, Fe, and Si (hydr)oxides was studied at high and low concentrations of reactants. The concentration of fulvic acid, pH, and thecomposition of the solid phase had a strong influence on the interaction between the metal ions and the solid surfaces. Photon correlation spectroscopy was used for measurements of particle size distributions in surface water and groundwater, and was also found to be suitable for on-line measurements in samples sensitive to changes in the partial pressure of atmospheric gases. The intensity of the scattered light was found to be useful for simultaneous estimates of tbe colloidal particle concentration. A calibration of the light intensity with material from one sample site showed that the spatial variation in sensitivity within a small catchment was relatively large, and there was also a variation in time. The mechanisms behind the concentration and composition of colloids were complex, but were to some extent related to input of organic carbon, pH aluminium and iron. Studies of colloidal matter in an estuary and a saline groundwater demonstrated the coagulating effect of high ionic strength and the presence of divalent ions. The major part of manganese and organic carbon was not bound in colloidal particles in the freshwater and estuarine samples, in contrast to aluminium and iron.
|
|
| 6. |
- Elgh-Dalgren, Kristin, et al.
(author)
-
Anaerobic bioremediation of a soil with mixed contaminants : Explosives degradation and influence on heavy metal distribution, monitored as changes in concentration and toxicity
- 2009
-
In: Water, Air and Soil Pollution. - Dordrecht : Springer Netherlands. - 0049-6979 .- 1573-2932. ; 202:1-4, s. 301-313
-
Journal article (peer-reviewed)abstract
- Two soils with explosives and metals were evaluated for the degradation efficiency of explosives by native microorganisms under anaerobic conditions. The commercially available method Daramend®, amended with zero-valent iron (ZVI), was compared with a horse-manure amended compost and a treatment with ZVI alone. In a moderately contaminated soil, Daramend® and ZVI treatment gave significantly higher removal rates compared to compost and control treatments (Tukey’s test, P<0.05). The largest overall decrease in ecotoxicity, measured with bioluminescent bacteria (Vibrio fischeri), was achieved with ZVI-treatment. In a more contaminated soil no degradation of contaminants and no decline in soil toxicity could be distinguished after the same time period. Problems with establishment of anaerobic conditions during parts of the remediation process and low microbial activity due to acute toxicity of contaminants are plausible explanations. Redistribution that could potentially lead to mobilization of the co-contaminant Pb was not observed in either of the soils during the biological treatments.
|
|
| 7. |
- Elgh-Dalgren, Kristin, et al.
(author)
-
Re-cycling of remediated soil : evaluation of leaching tests as tools for characterization
- 2011
-
In: Waste Management. - : Pergamon Press. - 0956-053X .- 1879-2456. ; 31:2, s. 215-224
-
Journal article (peer-reviewed)abstract
- In Sweden, leaching tests with deionized water (D.W.) are frequently utilized in risk assessment, but implementation of these results to evaluate the risk of spreading in the environment is difficult. One problem is that most leaching procedures only consider heavy metals release, whereas organic pollutants are left out. The aim of the present study was to assess the possible pollutant mitigation in four remediated soils, three with heavy metals and one with polycyclic aromatic hydrocarbons (PAH), utilizing three different leaching solutions: D.W., a weak ionic solution (0.001 M CaCl2) and an artificially made soil water (ASW). In general, batch leaching implied larger contaminant removal than column leaching, possibly due to the more rough treatment of the soil particles, and guidelines would at times be exceeded by batch leaching but not column leaching. Utilization of CaCl2 was found to release much less heavy metal than D.W., whereas the metals mobilized by ASW were removed from solution by the filtration of soil leachates. Low molecular weight PAH was most efficiently mobilized by CaCl2, while D.W. worked better for high molecular weight PAH. Despite very low initial PAH-concentrations, tap- and groundwater criteria were exceeded by all leaching solutions.
|
|
| 8. |
- Elgh-Dalgren, Kristin, 1980-, et al.
(author)
-
Simultaneous remediation of explosives and lead from contaminated soil by pH-adjustment
-
Other publication (other academic/artistic)abstract
- Soil washing with pH-adjusted water was evaluated in two soils containing different concentrations of heavy metals and explosives. Overall, the most efficient treatment was with water adjusted to pH 12 by NaOH. For explosives, pH 12 removed significantly higher amounts (P<0.05) of RDX and TNT compared to pH 4 (adjusted with HNO3) and distilled water in a moderately contaminated soil (230 mg HMX/kg, 1340 mg RDX/kg, 450 mg TNT/kg). In a more highly contaminated soil (6080 mg HMX/kg, 28740 mg RDX/kg, 3120 mg TNT/kg), the pH 12-treatment was the most efficient for removal of TNT and 2,4-DNT. Explosives removal increased with treatment time, probably due to the kinetically slow processes underlying the explosives degradation. Mobilization of heavy metals was strongly dependent on pH, with pH 12 mobilizing more than pH 3. In addition, the change in distribution coefficient (Kd) was more pronounced for local contaminants Pb and Cd in comparison with Cu and Zn, which were present in background concentrations.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
- Grahn, Evastina, et al.
(author)
-
Historical pollution of seldom monitored trace elements in Sweden : Part B: sediment analysis of silver, antimony, thallium and indium
- 2006
-
In: Journal of Environmental Monitoring. - 1464-0325 .- 1464-0333. ; 8:7, s. 732-744
-
Journal article (peer-reviewed)abstract
- Sediment cores from four boreal and remote lakes in a south to north transect in central Sweden were analysed for acid leachable silver, antimony, thallium and indium in the solid sediment phase and the corresponding porewater. Dating of the cores was made by their content of acid leachable lead and the 206Pb/207Pb ratio, in one lake also by 210Pb. The impact of diagenesis on element redistribution in the sediments was included and found to be minor except for thallium. The results show lowered concentrations towards the north and most intense accumulation after the Second World War, which is taken as evidence for atmospheric deposition being the primary source. Indium has declining concentrations in recent strata while silver and antimony increase. Thallium has lowered acid-leachable concentrations in recent strata. For all metals the impact of domestic industrialisation as well as the early industrialisation of central Europe is discernible. Only thallium appears to reach a geological background at depths that correspond to the late 18th century. For the other metals elevated levels are concluded.
|
|
| 12. |
- Grahn, Evastina, 1968-
(author)
-
Lake sediment as environmental archive : natural and anthropogenic influence on the chronology of trace elements
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- The focus of this thesis is the historical pollution of some seldom-monitored trace elements (SMTEs; Ag, Be, Ga, In, Sb and Tl) that have been involuntarily released for several thousands of years but whose usage have increased during the industrial era. Sediment cores from four rural lakes in a south to north transect in central Sweden, and two urban lakes have been used as environmental archives for chronological studies. The historical development of the SMTEs is put in perspective of frequently monitored elements (Cd, Cu, Pb and Zn) that serve as a well-known anthropogenic signal. Dating of the sediments is made with 210Pb, 137Cs and 239,240Pu as well as acid leachable lead and the 206Pb/207Pb ratio. The impact of diagenetic redistribution is included, when necessary. The results show that site-specific reference concentrations are required in order to estimate the present pollution as well as its historical development. Atmospheric deposition is the principal pathway of transport in rural lakes and the concentrations are lowered towards the north. It is not possible from this material, however, to separate the direct deposition on the lake surfaces from the contribution from their catchments. From 21Pb, acid-leachable Pb and the 206Pb/207Pb ratio a minimum of four periods of pollution can be discerned. For the SMTEs the quantitatively most important period of pollution took place from the Second World War until present. The growth of the domestic industrialisation as well as the early industrialisation of central Europe and the British Isles are also distinguishable. The pollution history of Ag, In and Sb goes back for several centuries as a result of metal processing whereas the levels of thallium mainly increase as a result of industrialisation. For Ag and Tl in-sediment diagenetic redistribution limits the precision of the historical estimate. The preliminary interpretation of 137Cs and 239,240Pu indicates that they are less suitable as chronological markers in the system studied. The urban impact on the trace metal sediment content in the urban lakes was lower than expected, except for Au. There is a large impact from hydrological conditions on the studied system why further investigations are recommended.
|
|
| 13. |
- Grahn, Evastina, et al.
(author)
-
Sediment reference concentrations of seldom monitored trace elements (Ag, Be, In, Ga, Sb, Tl) in four Swedish boreal lakes : comparison with commonly monitored elements
- 2006
-
In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 367:2-3, s. 778-790
-
Journal article (peer-reviewed)abstract
- This paper presents reference and recent acid-leachable concentrations of some seldom monitored trace elements (SMTE; Ag, Be, Ga, In, Sb and Tl) in sediments from four boreal oligotrophic lakes in a south to north transect in Sweden. For comparison commonly monitored trace elements (As, Cd, Co, Cr, Cu, Ni, Pb and Zn) are included as well as those of relevance for redistribution processes (Al, Ca, Fe, Mg and Mn). Pore water pH and the corresponding solid/solution distribution coefficients (Kd) indicated that redistribution of the elements due to acidification is minor. The depth of impact was defined as the level in the sediment where the mean values became constant on successive exclusion of metal concentrations in overlying strata. Reference concentrations were calculated below the depth of impact. The present concentration changes are estimated by the ratio between the average concentration above the depth of impact and the reference concentration. Reference concentration ranges for the SMT-elements are (mg/kg, dry wt.): Ag 0.16–0.66; Be 1.6–3.7; Ga 2.0–5.1; In 0.05–0.22; Sb 0.05–0.11 and Tl 0.17–0.70. The concentration ratios for these elements ranged in the two most southern lakes from 1.5 to 4.5 and in the two northern ones from 0.6 to 1.6. A high correlation between Kd for the SMT-elements, and iron, except for Sb and Tl, infer that the biogeochemistry of iron is quantitatively important for the accumulation of these elements. The reference concentration ranges for the commonly monitored trace elements are (mg/kg, dry wt.): As 7.0–29.6; Cd 0.33–0.98; Co 5.7–23.8; Cr 15.2–26.1; Cu 27.6–58.4; Ni 5.4–20.8; Pb 44–96. The corresponding concentration ratios were 1.2–18 (second highest 3.9) in the two most southern lakes and 0.8–1.6 in the two northern ones. Declining ratios were found from south to north, most obvious for cobalt and zinc. The copper ratios did not show a regional pattern, partly because of the impact from old mine waste. Increased concentrations of Ag, Be, Ga, In, Sb and Tl in recent sediments up to 4.5 times the reference levels in combination with the geographical pattern infer an elevated loading of these elements.
|
|
| 14. |
|
|
| 15. |
- Greis, Christina, 1975-, et al.
(author)
-
Determination of plutonium in environmental samples with quadrupole ICP-MS
- 2008
-
In: Journal of Radioanalytical and Nuclear Chemistry. - Berlin : Springer. - 0236-5731 .- 1588-2780. ; 275:1, s. 55-70
-
Journal article (peer-reviewed)abstract
- A method for rapid determination of plutonium isotopes in environmental samples with ultrasonic nebulisation and quadrupole ICP-MS detection was established. Techniques for sample dissolution, pre-concentration and chemical separation were evaluated and the optimal scheme outlined. Comparisons with α-spectrometry and high resolution ICP-MS confirmed the suitability of the method when applied to different environmental matrices within the global fallout concentration range in the northern hemisphere as well as more contaminated sites. Operational detection limits were 0.5–1.5 fg/l for fresh waters and 0.03–0.1 ng/kg for lake sediments and saline marsh sediments.
|
|
| 16. |
- Greis, Christina, 1975-, et al.
(author)
-
Plutonium remobilization in a humic-rich lake
- 2007
-
In: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 277:1, s. 265-268
-
Journal article (peer-reviewed)abstract
- Fresh water from Lake Svartsjön, Sweden, was collected and four fractions were prepared: (1) adsorption on DEAE, (2) flocculation with Ca2+, (3) co-precipitation with Fe hydrous oxide and (4) co-precipitation with Mn hydrous oxide. The plutonium level in the lake is 65 fg/l (222 μBq/l), measured by ICP-QMS and ICP-SFMS. Pronounced accumulation in fractions (1) (34%) and (2) (66%), combined with observed levels of organic matter indicate that plutonium is predominantly associated with organic matter. Measurements of isotopic ratios indicate that 77% of the plutonium originates from weapons testing and the remaining appears to originate from the Chernobyl accident.
|
|
| 17. |
- Greis, Christina, 1975-
(author)
-
Rapid analysis of actinide isotopes using quadrupole ICP-MS for emergency preparedness and environmental monitoring
- 2007
-
Doctoral thesis (other academic/artistic)abstract
- Transuranium elements in the environment are mainly derived from nuclear weapons testing and the nuclear fuel cycle. Of growing concern are illicit nuclear trafficking and the threat of terror acts. The development of rational methods, for environmental monitoring and for tracing sources of nuclear and radioactive materials in the environment, is constantly required. Traditionally, the actinides have been determined by radiometric techniques. These analyses can be time consuming for elements at low concentrations and with long half-lives. This thesis addresses the determination of actinides, especially plutonium, in environmental samples with ICP-QMS (inductively coupled plasma quadrupole mass spectrometry). The ICP-QMS instrument was equipped with an USN (ultrasonic nebuliser), which proved to be a successful combination for the determination of plutonium at low concentrations in acidified solutions after separation with anion exchange. The detection limit for plutonium was in the range 10-30 pg/l with a RSD of 1-10%. The suitability of chemical separation was evaluated for anion exchange, liquid-liquid-extraction and extraction chromatography. The outlined procedure, including sample dissolution, chemical separation and analysis, for determination of actinides in environmental matrices proved to be accurate and reliable. Quality assurance of the procedure was performed during an intercomparison exercise and with reference materials. The detection accuracy has also been validated with α-spectrometry and ICP-SFMS. The procedure has been applied to saline sediments and fresh water sediments as well as several fresh water matrices.
|
|
| 18. |
|
|
| 19. |
- Hagberg, Jessika
(author)
-
Capillary zone electrophoresis for the analysis of low molecular weight organic acids in environmental systems
- 2003
-
Doctoral thesis (other academic/artistic)abstract
- Capillary zone electrophoretic (CZE) methods were developed to identify and quantify low molecular weight (LMW) organic acids in environmental samples. Sensitivity and selectivity were optimised by adapting the background electrolyte to the characteristics of analytes, and by using different modes of detection and injection. Electrokinetic injection mode in combination with an isotachophoretic state increased the sensitivity remarkably for LMW organic acids using UV detection. Calcium ions were added to the background electrolyte, inducing an on-column complexation between acids and calcium ions, which gave good separation of the acids. Mass spectrometric detection (compared to UV detection) increased the sensitivity when using hydrodynamic injection mode during analysis, and selectivity was improved by mass identification. A CZE method for determination of the dissociation constants of LMW organic acids in the pKa range of 3.54.5 was also developed. The developed procedures were applied to different areas where LMW organic acids play an important environmental role: Low molecular weight organic acids were analysed in rainwater and soil water in the low μg/l range, within ten minutes after sampling. Rapid analysis and high sensitivity are essential when studying samples with rapid turnover due to microbial activity and photodegradation. The use of CZE-ESI-MS proved to be a robust analytical tool for determining LMW organic acids in samples rich in interfering ions. Organic acids excreted by soil fungi as response to metal exposure was easily and rapidly quantified with CZE-ESI-MS compared to HPLC and CZE-UV analysis. Dissociation constants for isosaccharinic acid (ISA) and gluconic acid were determined by CZE to 3.87 and 3.64, respectively. The ability to make the determinations in the presence of impurities as well as not having to know the exact concentration of analyte were identified as the major benefits of CZE. Isosaccharinic acid was identified as the main degradation product from alkaline degradation of cellulose by CZE analysis. Long-term predictions on both cellulose degradation and ISA production were made based on three years of sampling data. A control sampling after seven years indicated that the degradation of cellulose and the production of ISA were lower than predicted.
|
|
| 20. |
- Karlsson, Stefan, et al.
(author)
-
Historical pollution of seldom monitored trace elements in Sweden - Part A : sediment properties and chronological indicators
- 2006
-
In: Journal of Environmental Monitoring. - 1464-0325 .- 1464-0333. ; 8:7, s. 721-731
-
Journal article (peer-reviewed)abstract
- Sediment cores from four small oligotrophic boreal lakes, with minor acidification, in remote regions of central Sweden were used for historical interpretation of their metal content, with focus on Cu, Cd, Pb and Zn in Lake Stensjön, which has the longest sediment record (at least two centuries according to 210Pb dating). Comparison is made with the other three lakes. Major and trace elements in lake water, porewater and the acid-leached (HNO3) solid sediment phase was analysed with ICP-MS. In addition, general lake water chemistry, TOC and principal anions were measured in the aqueous phases. Redistribution processes were interpreted from geochemical modelling. The solid/solution distribution of pe/pH sensitive elements, indicates a minor diagenetic redistribution and the concentration profiles are therefore suitable for chronological evaluation. The ratios of Al, Ti, Sc and V, indicated a qualitative shift of sedimenting material a century ago, which did not have any impact on the retention of trace elements. Lead had a concentration profile, supported by the 206Pb/207Pb ratio, where it was possible to distinguish preindustrial conditions, early industrialisation in Europe, industrialisation in Sweden, and the use of leaded petrol after the Second World War. Cadmium showed a similar concentration pattern. The zinc profile resembled that of cadmium, but with less enrichment. Local lithogenic sources are believed to be quantitatively important. The solid/solution distribution (Kd) was independent of depth for all four elements. The sediment concentrations of copper and zinc are not related to early industrialisation but its concentration has doubled since the Second World War.
|
|
| 21. |
- Karlsson, Stefan, et al.
(author)
-
Sediment chronologies of As, Bi, and Ga in Sweden - impact of industrialisation
- 2007
-
In: Journal of Environmental Science and Health. Part A. - : Informa UK Limited. - 1093-4529 .- 1532-4117. ; 42:2, s. 155-164
-
Journal article (peer-reviewed)abstract
- The acid-leachable amount and pore water concentration of As, Bi and Ga in sediment cores from four remote lakes in a south to north transect in Sweden were used to recapitulate the pollution history of the elements. The diagenetic impact on the element distribution was elucidated from their solid/solution partition and relationships to elements indicative for diagenesis. Dating was made by their acid-leachable lead content in combination with the Pb-206/Pb-207 ratio. In one of the lakes this approach was validated against dating with Pb-210. The impact of diagenesis on the sediment distribution of theses elements was found to be low enough for a chronological interpretation of the sediment profiles, as evidenced by their ratios to elements indicative of the geological background. A closer examination of the diagenetic impact would however be required if a more detailed chronology is desired. This study has demonstrated that atmospheric deposition of arsenic, bismuth and gallium contributes to the sediment inventory of these elements. The major part of the deposition of arsenic and bismuth took place after the Second World War. For gallium no concentrations exceeding background were detected before circa 1930. Increased levels of arsenic are traceable to circa 1850. For bismuth increased levels are concluded to extend before 1790, i.e., background concentrations were not reached in the present cores. For all elements the atmospheric deposition has been lower towards the north.
|
|
| 22. |
|
|
| 23. |
- Karlsson, Ulrika, 1976-
(author)
-
Environmental levels of thallium : influence of redox properties and anthropogenic sources
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- Thallium is a highly toxic element that humans are exposed to mainly by consumption of drinking water and vegetables grown in soil with high thallium content but also through inhalation of particles in the air. Thallium is also present in fossil fuels, alloys, and in electronic utilities. The increasing use of the element and emissions from notably energy production has lead to a higher load on the surface of the Earth. This study aims at increasing the knowledge about the behaviour of thallium in aquatic environments. Focus has been on the redox chemistry of thallium in relation to its mobility, which is of great importance because Tl(I) and Tl(III) have very different properties in this respect. The relationship between Tl(I) and Tl(III) in surface waters from contaminated and uncontaminated environments was examined by ion chromatography connected on line to ICP-MS (inductively coupled plasma mass spectrometry). It was found in controlled systems that even though Tl(III) is thermodynamically unstable under fresh water conditions Tl(I) was oxidised in the presence of light and iron(III). This was also confirmed in field studies. When lake water samples were exposed to light, Tl(I) was oxidised and thallium was lost from the solution. The most likely explanation for this was adsorption of thallium to particle surfaces. The concentration of thallium in Swedish lakes and soil were measured. In unpolluted lakes the concentration ranges between 4.5-12 ng/l, the sediment concentration was 0.07-1.46 mg/kg. The anthropogenic load was found to have increased since the end of the Second World War although concentrations above background were found since the early industrialisation. In contaminated areas the concentration in soil ranges from 0.64-88 mg/kg, high concentrations were found in systems with alum shale and in soil exposed to runoff from a lead and zinc enrichment plant. The mobilisation of thallium from solid phases in contaminated areas was dependent on pH and about 50% of the leachable content was mobilised already at pH 5-6. Once it had been released to water it was highly mobile. These conditions suggest that in a large part of the Swedish environment a high mobility of thallium can be expected.
|
|
| 24. |
- Karlsson, Ulrika, et al.
(author)
-
Separation and quantification of Tl(I) and Tl(III) in fresh water samples
- 2006
-
In: Journal of Environmental Science and Health. Part A. - : Informa UK Limited. - 1093-4529 .- 1532-4117. ; 41:7, s. 1155-1167
-
Journal article (peer-reviewed)abstract
- The two oxidation states of thallium, Tl(I) and Tl(III), were quantified by IC-ICP-MS using complexation of Tl3+ with DTPA (penta-carboxymethyl-diethylenetriamine) and separation on a cation exchange column according to a modification of the method devised by Coetzee et al. In order to avoid successively lowered separation efficiency and loss of resolution during a run, a gradient elution was made using HCl instead of HNO3. With an ultrasonic nebuliser instead of a V-groove nebuliser the limit of detection for Tl(I) and Tl(III) could be lowered from 25 ng/L and 3.0 ng/L to 9.0 ng/L and 0.7 ng/L, respectively, which is adequate for many fresh water systems. The stability of Tl(III) in acidic solutions was found to be concentration dependent, with an initially high reduction rate of Tl(III). Exposure of the sample to light further increased the reduction rate. Addition of DTPA (0.01 mM) and acid (HNO3, 1%) to a sample with 1 μg/L Tl(III) stabilised the Tl(III) content for at least 48 h. Analysis of field samples showed that only acidification is inadequate to maintain the original distribution of Tl(I) and Tl(III). Internal calibration (standard addition) and correction of the analytical signal (205Tl) with a non-ionic internal standard (11B) yielded almost quantitative recoveries of both Tl(I) and Tl(III). A scheme for field sample preparation is proposed, including sampling, storage and pre-analysis treatment.
|
|
| 25. |
- Karlsson, Ulrika, et al.
(author)
-
The effect of light and iron(II)/iron(III) on the distribution of Tl(I)/Tl(III) in fresh water systems
- 2006
-
In: Journal of Environmental Monitoring. - 1464-0325 .- 1464-0333. ; 8:6, s. 634-640
-
Journal article (peer-reviewed)abstract
- The distribution of aqueous Tl(I)/Tl(III) as a function of light exposure and solution properties was studied by quantifying the oxidation states after separation with ion chromatography and on-line detection with ICP-MS. Ultraviolet irradiation of aqueous solutions containing 1 μg l−1 Tl(III) and in equilibrium with the atmosphere increases the reduction rate. In systems with photoreduction of Fe(III)(aq) a quantitative oxidation of Tl(I)(aq) was observed, notably at low pH. The process is reversible, as indicated by formation of Tl(I) when the irradiated systems were kept in the dark. In systems with colloidal silica-stabilised ferrihydrite, UV irradiation also leads to oxidation of Tl(I)(aq), but not quantitatively. It is suggested that adsorption of thallium to the ferrihydrite determines the rate of oxidation. Detectable, but not quantitative, oxidation of Tl(I)(aq) took place when natural water samples with 1 μg l−1 Tl(I)(aq) were exposed to either sunlight or UV-light. For these samples, the reduction was not quantitative when they were kept in the dark for 24 h. The results suggest that the light dependent iron cycle in fresh water systems strongly influences the redox state of thallium.
|
|
| 26. |
- Löfgren, Stefan, et al.
(author)
-
Trender i surhetstillstånd i skogs-, myr- och fjällbäckar i Dalarna : Resultat från den regionala miljöövervakningen
- 2015
-
Reports (other academic/artistic)abstract
- Försurningen av sjöar och vattendrag har generellt minskat i Sverige och det är följaktligen intressant att följa upp och söka förklara utvecklingen i Dalarnas vattendrag. Länsstyrelsen har därför initierat en vattenkemisk utvärdering av de regionalt övervakade vattendragen. Syftet med utvärderingen är att utvärdera surhetstillståndets utveckling med tiden samt att söka förklara orsakerna till eventuella trender i Hyttingsån, Acktjärnsbäcken, Göljån och Skidbågsbäcken (SK1 och SK2). Utvärderingen omfattar hela mätperioden t.o.m. 2012. Om man undantar den kalkade Skidbågsbäcken SK2, var samtliga bäckar jonsvaga med en medelkonduktivitet i intervallet 1,2-2,5 mS/m. I samtliga bäckar förutom Skidbågsbäcken SK1 var Ca2+ den dominerande baskatjonen (BC) följt av Na+, Mg2+ och K+. I Skidbågsbäcken SK1 dominerade Na+. BC-halterna balanserades primärt av RCOO- och HCO3-. Båda dessa anjoner bildas vid nedbrytning av organiskt material respektive vid koldioxidvittring av olika silikatmineral och utgjorde mellan 57-84% av anjonerna i de okalkade bäckarna. Andelen SO42- varierade mellan 8-25% med de högsta värdena i Hyttingsån och Göljån. Det är därför troligt att mänskligt betingad försurning bidrog med maximalt 8-25% i de studerade vattendragen och att denna påverkan var som störst i Hyttingsån och Göljån. I den kalkade Skidbågsbäcken SK2 var Ca2+ extremt dominerande och balanserat av HCO3-, båda med ursprung i den kalk som spridits. Buffertsystemet i Skidbågsbäcken SK1 dominerades helt av svaga organiska syror, vilket gav ett lågt medel-pH (4,5), medan buffertsystemen i Acktjärnsbäcken och Göljån dominerades av kolsyrasystemet och därför hade betydligt högre pH (6,1 respektive 6,4 i medeltal). Hyttingsån uppvisade en mix av de båda buffertsystemen och hade därför ett något lägre medel-pH (5,8) betingat av högre halter organiska syror. Den kalkade Skidbågsbäcken SK2 hade pH≈6,5. Med undantag av Hyttingsån, som inte uppvisar någon statistiskt signifikant trend (p>0,05), har pH ökat med ca 0,15, 0,3 och 0,45 pH-enheter under de ca 15 år som övervakningen pågått i Skidbågsbäcken SK1, Göljån respektive Acktjärnsbäcken. pH-ökningen sammanfaller med minskande SO42- -halter, vilket indikerar minskande påverkan från svavelnedfall. Hyttingsån uppvisar den största minskningen i SO42- -halter (2,8 µekv/l, år), men pH har inte förändrats. En förklaring är att de minskade SO42- -halterna i hög grad kompenserats av att baskatjonen Ca2+ minskat samtidigt som halterna organiska syror ökat. För samtliga bäckar förutom Hyttingsån indikerar BDM-resultaten att försurningstrycket var som högst i början på tidsserierna och endast Göljån uppvisade 1995 ett pH-värde som indikerar försurning. I Hyttingsån indikerar resultaten försurat tillstånd under vårarna 1996, 1999, 2001 och 2008. Någon generell trend går inte att spåra i Hyttingsån, vilket gör det angeläget att fortsätta mätningarna där. Efter 2008 bedöms samtliga vattendrag som icke-försurade med BDM-modellen.
|
|
| 27. |
|
|
| 28. |
- Svensson, Margareta, et al.
(author)
-
Formation of cinnabar : estimation of favourable conditions in a proposed Swedish repository
- 2006
-
In: Journal of Hazardous Materials. - Amsterdam : Elsevier. - 0304-3894 .- 1873-3336. ; 136:3, s. 830-836
-
Journal article (peer-reviewed)abstract
- A deep repository for permanent storage of mercury will be designed and built in Sweden. The preferred chemical state for mercury in such a repository would be the sulphide HgS (cinnabar), which is a highly insoluble and the dominating natural mercury mineral. The possible formation of HgS from HgO or Hg(0) by reaction with a sulphur source (S, FeS or FeS2) is discussed from thermodynamic considerations, and pe–pH-diagrams are constructed by using the computer code MEDUSA to illustrate under which conditions HgS would dominate. Calculations of the speciation (PHREEQE) under varying conditions (S/Hg-ratios, presence of chloride) are given. Long-term laboratory experiments are performed, where the formation of HgS from the basic components is demonstrated (after mixing under various conditions and storage at room temperature for up to 3 years). The feasibility of HgS-formation with time in a geologic repository under conditions representative of deep granitic bedrock (calcium-bicarbonate buffered to pH 7–8.5) is discussed, as well as effects of alkaline conditions (concrete environment, pH 10.5–12.5). Formation of soluble polysulphides is not expected as long as the S/Hg mole ratio is within 1–1.3 and pH is below 10.5–11. Concrete should be used with caution. Suitable ballast materials could be introduced that would reduce porewater-pH that otherwise would be above 12.
|
|
| 29. |
- Svensson, Margareta, et al.
(author)
-
Formation of HgS : mixing HgO or elemental Hg with S, FeS or FeS2
- 2006
-
In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 368:1, s. 418-423
-
Journal article (peer-reviewed)abstract
- The aim of this study is to assess the feasibility for generation of the sparingly soluble solid HgS from HgO or elemental Hg by mixing with a suitable sulphur source under various conditions (dry, wet at different pH, and room temperature). The formation of mercury sulphide was confirmed in 14 of the 36 combinations of Hg and S sources. Mercury sulphide was generally formed under alkaline conditions. Almost 100% HgS was obtained in anaerobic systems at high pH in the presence of elemental sulphur after about two years. Thus, it is feasible to create an environment at room temperature that, with time, leads to the generation of HgS from elemental Hg or HgO. This is relevant for the design of a repository for permanent geologic disposal of mercury. Choosing wrong components and conditions can however lead to a reduction of Hg(II) to elemental mercury.
|
|
| 30. |
- Svensson, Margareta, 1967-
(author)
-
Mercury immobilization : a requirement for permanent disposal of mercury waste in Sweden
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- The Swedish Government states that mercury in the Swedish industry and private use shall be collected and waste containing more than 1% of mercury shall be conditioned for permanent storage in proposed groundwater-saturated repository in deep bedrock. The owners of mercury waste in Sweden are responsible for finding ways to the conversion of the mercury waste to insoluble forms. The aim of this thesis was to investigate different low-cost immobilization methods for mercury. Choice of treatment method depends on the nature of the waste, such as the mercury concentration and matrix constituents. High-contaminated waste would be suitable to transform to chemically insoluble mercury forms, while low-contaminated wastes would be suitable to treat with an encapsulation method. The investigations assessed conditions favourable for the formation of HgS at room temperature from elemental mercury as well as from mercury oxide. Elemental sulphur in an alkaline anaerobic environment gave a yield of close to 100% mercury sulphide within two years. The stabilization/solidification (S/S) method was estimated as a suitable treatment method for low contaminated mercury waste (below 5%w/w). The lowest leaching rate was observed from slag monoliths with elemental sulphur as sulphur source. After one year the accumulated leaching amount was 0.008-0.013%w/w of the total mercury content of the monolith (1% of the monolith mass). This is about 100-150 times more than from monoliths that initially contained black meta-cinnabar. Apparent diffusion coefficients for Hg(II)(aq) were determined in cement monoliths with different constituents (10-14-10-15 m2/s), for a barrier of Standard Portland concrete (10-14 m2/s) and in quartz sand (10-13 m2/s). After some 60 d in the leaching test, the apparent diffusion coefficient was of the order 10-17-10-21 m2/s, which was indicative of a slow release rate of the remaining mercury that could represent the dissolution/transformation of HgS, which gradually was formed during curing of the cement (aged for one year). The apparent diffusion coefficient for Hg(0) could not be measured since the mercury species oxidizes in aerobic systems.
|
|
| 31. |
|
|
| 32. |
|
|
| 33. |
|
|
| 34. |
- Temnerud, Johan, 1969-, et al.
(author)
-
Landscape scale patterns in the character of natural organic matter in a Swedish boreal stream network
- 2009
-
In: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 13:9, s. 1567-1582
-
Journal article (peer-reviewed)abstract
- This paper defines landscape-scale patterns in the character of natural organic matter (NOM) and tests for relationships to catchment soil, vegetation and topography. The drainage network of a boreal catchment, subcatchment size 0.12-78 km(2), in Northern Sweden was sampled in August 2002 during a period of stable low water flow. The NOM was characterized with UV/Vis spectroscopy, fluorescence, XAD-8 fractionation (%humic substances), gel permeation chromatography (apparent molecular weight), and elemental composition (C:N). The largest spatial variation was found for C: N, absorbance ratio, and specific visible absorptivity. The lowest variation was in fluorescence index, %humic substances and molecular retention time. The variation in total organic carbon (TOC), iron and aluminium concentration was more than twice that of C: N. Between headwater and downstream sites no significant changes were distinguished in the NOM character. At stream reaches, junctions and lakes little change (<10%) in NOM character was observed. Common factor analysis and partial least squares regression (PLS) revealed that the spatial variation in surface coverage of lakes and mires could explain some of the variation of TOC and NOM character. Our suggestion is that the mosaic of landscape elements (different amounts of water from lakes, forest soil and mires) delivers NOM with varying characteristics to a channel network that mixes conservatively downstream, with possible small changes at some stream reaches, junctions and lakes.
|
|
| 35. |
- Temnerud, Johan, et al.
(author)
-
Spatial patterns of some trace elements in four Swedish stream networks
- 2013
-
In: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 10, s. 1407-1423
-
Journal article (peer-reviewed)abstract
- Four river basins in southern Sweden, with catchment sizes from 0.3 to 127 km(2) (median 1.9), were sampled in October 2007. The 243 samples were analysed for 26 trace elements (Ag, As, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Ga, Ge, In, La, Li, Mo, Ni, Pb, Sb, Se, Sn, Tl, Ti, U, V and Zn) to identify spatial patterns within drainage networks. The range and median of each element were defined for different stream orders, and relationships to catchment characteristics, including deposition history, were explored. The sampling design made it possible to compare the differences along 40 stream reaches, above and below 53 stream junctions with 107 tributaries and between the 77 inlets and outlets of 36 lakes. The largest concentration differences (at reaches, junctions and lakes) were observed for lakes, with outlets usually having lower concentration compared to the inlets for As, Ba, Be, Bi, Cd, Co, Cr, Ga, Ge, Ni, Pb, Sn, Ti, Tl, U, V and Zn. Significantly lower concentrations were observed for Cd and Co when comparing headwaters with downstream sites in each catchment. Common factor analysis (FA) revealed that As, Bi, Cr, Ga, Ge, Tl and V co-vary positively with Al, Fe and total organic carbon (TOC) and negatively with La, Li and pH. The strong removal of a large number of trace elements when passing through lakes is evident though in the FA, where lake surface coverage plots opposite to many of those elements. Forest volume does not respond in a similar systematic fashion and, surprisingly, the amount of wetland does not relate strongly to either Fe or TOC at any of the rivers. A better understanding of the quantitative removal of organic carbon and iron will aid in understanding trace element fluxes from landscapes rich in organic matter and iron.
|
|
| 36. |
- Wallman, Karin, et al.
(author)
-
Metallanalys i vatten från Bottenhavet och Bottenviken
- 2020
-
Reports (other academic/artistic)abstract
- På uppdrag av Naturvårdsverket har vattenkemiska laboratoriet vid Institutionen för vatten och miljö, SLU tagit fram en metod för analys av metaller i brackvatten och analyserat prover från Bottenhavet och Bottenviken. Halterna av arsenik, kobolt och nickel ökade i sydlig riktning, liksom för vanadin och zink ehuru trenden var mindre tydlig för dem. För bly, kadmium och krom kunde inga spatiala skillnader ses eftersom analysresultaten låg under rapporteringsgränsen. För koppar var halterna vid de nordligaste stationerna RA1 och RA2 lite lägre än vid övriga stationer men längre söderut syntes ingen skillnad.För kadmium, krom, koppar, nickel och bly var medelhalterna vid respektive station i denna studie lägre än gränsvärdena i Havs- och Vattenmyndighetens föreskrifter HVMFS 2019:25. Enligt dessa föreskrifter ska hänsyn tas till den naturliga bakgrunden vid jämförelse med gränsvärden för arsenik och zink, men dessa bakgrundshalter är inte kända i Bottenviken och Bottenhavet. Om den regionala bakgrundshalten som Herbert et.al. tog fram för zink i Östersjön används istället så låg medelhalterna vid alla provpunkter i Bottenhavet utom utsjöstationen C3 över gränsvärdet. Vid stationerna i Bottenviken och C3 i Bottenhavet låg medelhalterna under gränsvärdet men det kan inte uteslutas att anledningen till detta kan vara att halterna på dessa stationer korrigerats för mycket genom att den regionala bakgrundshalten använts istället för den naturliga bakgrundshalten. För arsenik låg medelhalterna i de nordligaste stationerna RA1, RA2 och A5 under gränsvärdet även utan att värdena korrigerats för bakgrundshalterna. För övriga stationer låg medelhalterna över gränsvärdet för arsenik men i och med att ingen korrigering av bakgrundshalt hade gjorts kan ingen slutsats dras av detta.
|
|
