| 1. |
- Regnell, Olof, et al.
(författare)
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Linking Cellulose Fiber Sediment Methyl Mercury Levels to Organic Matter Decay and Major Element Composition.
- 2014
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Ingår i: Ambio: a Journal of Human Environment. - : Springer Science and Business Media LLC. - 0044-7447. ; 43:7, s. 878-890
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Tidskriftsartikel (refereegranskat)abstract
- Methylation of mercury (Hg) to highly toxic methyl Hg (MeHg), a process known to occur when organic matter (OM) decomposition leads to anoxia, is considered a worldwide threat to aquatic ecosystems and human health. We measured temporal and spatial variations in sediment MeHg, total Hg (THg), and major elements in a freshwater lagoon in Sweden polluted with Hg-laden cellulose fibers. Fiber decomposition, confined to a narrow surface layer, resulted in loss of carbon (C), uptake of nitrogen (N), phosphorus (P), and sulfur (S), and increased MeHg levels. Notably, fiber decomposition and subsequent erosion of fiber residues will cause buried contaminants to gradually come closer to the sediment-water interface. At an adjacent site where decomposed fiber accumulated, there was a gain in C and a loss of S when MeHg increased. As evidenced by correlation patterns and vertical chemical profiles, reduced S may have fueled C-fixation and Hg methylation at this site.
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| 2. |
- Christenson, Nina, 1975-
(författare)
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Knowledge, Value and Personal experience : Upper secondary students' resources of supporting reasons when arguing socioscientific issues
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on upper secondary students’ use of resources in their supporting reasons when arguing socioscientific issues (SSIs). The skills of argumentation have been emphasized in science education during the past decades and SSIs are proven a good context for learners to enhance skills of argumentation and achieve the goal of scientific literacy. Research has shown that supporting reasons from various resources are embedded in students’ argumentation on SSIs, and also that multi-perspective involvement in reasoning is important for the quality of argumentation. To explore the reasons used by students in arguing about SSIs in this thesis, the SEE-SEP model was adopted as an analytical framework. The SEE-SEP model covers the six subject areas of sociology/culture, economy, environment/ecology, science, ethics/morality and policy, which are connected to the three aspects of knowledge, value and personal experience. Two studies covering four SSIs (global warming, GMO, nuclear power and consumption) explore how students construct arguments on one SSI topic chosen by them. In paper I, I investigated students’ use of resources in their informal argumentation and to what extent students made use of knowledge. The results showed that students used value to a larger extent (67%) than knowledge (27%). I also found that the distribution of supporting reasons generated by students varied from the different SSIs. In paper II, I explored students’ use of resources in relation to students’ study background (science majors and social-science majors) and gender. The results showed that social-science majors and females generated more numbers of reasons and also showed a larger amount of multi-disciplinary resources in their supporting reasons. From the findings of this thesis, the SEE-SEP model was established as a suitable model used to analyze students’ resources of supporting reasons while arguing about SSIs. Furthermore, the potential for applying the SEE-SEP model in teachers’ SSI-teaching and students’ SSI-learning is suggested. The implications to research and teaching are also discussed.
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| 3. |
- Elert, Mark, et al.
(författare)
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Laktester för riskbedömning av förorenade områden : Huvudrapport och underlagsrapport 1a
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Två centrala moment i riskbedömningar av förorenade områden är dels att bedöma hälsorisker vid vistelse på området dels att uppskatta risken för utlakning och spridning av föroreningar. I många fall baseras bedömningarna på mätningar av totalinnehållet av föroreningar i marken, vanligen i kombination med analyser av grundvatten och ytvatten. Det är dock väl känt att det för både oorganiska och organiska ämnen endast är en del av det totala innehållet som är tillgängligt för snabb utlakning eller för upptag i kroppen. Under de senaste 15 åren har laktester utvecklats och standardiserats för oorganiska ämnen med syfte att bedöma riskerna för lakning till grund- och ytvatten. Dessa laktester har etablerats som en metod för att bedöma olika typer av avfallsmaterial. Det har även utvecklats laktester för att bedöma föroreningarnas farlighet för människor vid intag av jord (biotillgänglighetstester). Användning av laktester vid riskbedömning av förorenad mark har blivit allt vanligare på senare år, dock finns det ingen standard för vilka tester som bör användas eller hur resultaten skall användas i riskbedömningen. Denna rapport redovisar ett förslag till metodik för val och utförande av tester samt tolkning av lak- och biotillgänglighetstester som verktyg i miljö- och hälsoriskbedömningar för förorenade områden. I rapporten beskrivs olika typer av laktester och rekommendationer ges på hur tolkning av testerna kan göras i riskbedömningssammanhang. Vidare diskuteras hur resultaten kan utnyttjas som indata till riktvärdes- och spridningsmodeller samt osäkerheter och känsliga antaganden. Dataunderlaget är störst för oorganiska ämnen, men även laktester för organiska ämnen diskuteras. Metodiken baseras på en sammanställning, utvärdering samt modellering av resultat från laktester på förorenad jord från olika svenska och danska efterbehandlingsobjekt. Utvärderingen visar att det finns osäkerheter i hur resultat från dagens standardiserade laktester skall användas och tolkas i riskbedömningar av förorenad mark.För att kunna utveckla den metodik som föreslås i denna rapport till mer handgripliga råd i en mer detaljerad vägledning krävs fler utredningar kring laktester på förorenad jord och hur dessa kan tolkas och utvärderas vid riskbedömning av förorenade områden. Hur biotillgänglighetstester kan inkluderas i riskbedömningen bör också utredas vidare. Kompletterande utredningar föreslås i rapporten.
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| 4. |
- Fanger, Gabriella, et al.
(författare)
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Laktester för riskbedömning av förorenade områden : – Underlagsrapport 3:Sammanställning av underlagsdata och användning av modeller för tolkning av laktester
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport är en av fyra underlagsrapporter som legat till grund för framtagandet av en preliminär metodik för användning av laktester vid riskbedömning av förorenade områden (”Laktester för riskbedömning av förorenade områden”). Arbetet har utförts av Kemakta Konsult i samarbete med SGI och DHI under våren 2004 till sommaren 2005 på uppdrag av Naturvårdsverket inom ramen för kunskapsprogrammet Hållbar sanering. Denna underlagsrapport har upprättats av Kemakta Konsult; Gabriella Fanger, Mark Elert, Lars Olof Höglund och Celia Jones.Rapporten är uppdelad i tre kapitel och inleds med en sammanställning, utvärdering och tolkning av ett hundratal utförda laktester i ca. 30 svenska efterbehandlingsprojekt. Slutsatser kring generella samband mellan påverkan av olika faktorer på utlakningen av föroreningar har dragits och använts för den föreslagna metodiken. I kapitel 2 görs en fördjupad beskrivning av styrande processer för utlakning med hjälp av matematisk-kemisk modellering för ett urval av de utförda skak- och perkolationstesterna (kolonntesterna). Modelleringarna har visat på vissa begränsningar med utförande och tolkning av dagens standardiserade laktester och behov av kompletterande arbeten. I kapitel 3 redovisas slutligen hur resultat från laktester kan tolkas och användas som indata till spridnings- och riktvärdesmodeller. Resultaten från samtliga delarbeten har sammanvägts i metodikrapporten där en rekommendation om hur laktester bör utföras och tolkas i riskbedömningssammanhang ges.
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| 5. |
- Hlebowicz, Joanna, et al.
(författare)
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Effects of 1 and 3 g cinnamon on gastric emptying, satiety, and postprandial blood glucose, insulin, glucose-dependent insulinotropic polypeptide, glucagon-like peptide-1, and ghrelin concentrations in healthy subjects.
- 2009
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 1938-3207 .- 0002-9165. ; 89, s. 815-821
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A previous study of healthy subjects showed that intake of 6 g cinnamon with rice pudding reduced postprandial blood glucose and the gastric emptying rate (GER) without affecting satiety. OBJECTIVE: The objective was to study the effect of 1 and 3 g cinnamon on GER, postprandial blood glucose, plasma concentrations of insulin and incretin hormones [glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1)], the ghrelin response, and satiety in healthy subjects. DESIGN: GER was measured by using real-time ultrasonography after ingestion of rice pudding with and without 1 or 3 g cinnamon. Fifteen healthy subjects were assessed in a crossover trial. RESULTS: The addition of 1 or 3 g cinnamon had no significant effect on GER, satiety, glucose, GIP, or the ghrelin response. The insulin response at 60 min and the area under the curve (AUC) at 120 min were significantly lower after ingestion of rice pudding with 3 g cinnamon (P = 0.05 and P = 0.036, respectively, after Bonferroni correction). The change in GLP-1 response (DeltaAUC) and the change in the maximum concentration (DeltaC(max)) were both significantly higher after ingestion of rice pudding with 3 g cinnamon (P = 0.0082 and P = 0.0138, respectively, after Bonferroni correction). CONCLUSIONS: Ingestion of 3 g cinnamon reduced postprandial serum insulin and increased GLP-1 concentrations without significantly affecting blood glucose, GIP, the ghrelin concentration, satiety, or GER in healthy subjects. The results indicate a relation between the amount of cinnamon consumed and the decrease in insulin concentration.
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| 6. |
- Hlebowicz, Joanna, et al.
(författare)
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The botanical integrity of wheat products influences the gastric distention and satiety in healthy subjects.
- 2008
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Ingår i: Nutrition Journal. - : Springer Science and Business Media LLC. - 1475-2891. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Maintenance of the botanical integrity of cereal kernels and the addition of acetic acid (as vinegar) in the product or meal has been shown to lower the postprandial blood glucose and insulin response and to increase satiety. However, the mechanism behind the benefits of acetic acid on blood glucose and satiety is not clear. We hypothesized that the gastric emptying rate could be involved. Thus, the aim of this study was to evaluate the possible influence of maintained botanical integrity of cereals and the presence of acetic acid (vinegar) on gastric emptying rate (GER), postprandial blood glucose and satiety. METHODS: Fifteen healthy subjects were included in a blinded crossover trial, and thirteen of the subjects completed the study. Equicarbohydrate amounts of the following wheat-based meals were studied: white wheat bread, whole-kernel wheat bread or wholemeal wheat bread served with white wine vinegar. The results were compared with a reference meal consisting of white wheat bread without vinegar. The GER was measured with standardized real-time ultrasonography using normal fasting blood glucose <6.1 mmol/l or plasma glucose <7.0 mmol/l as an inclusion criterion. The GER was calculated as the percentage change in the antral cross-sectional area 15 and 90 minutes after ingestion of the various meals. Satiety scores were estimated and blood glucose was measured before and 15, 30, 45, 60, 90 and 120 min after the start of the meal. RESULTS: The whole-kernel wheat bread with vinegar resulted in significantly higher (<0.05) satiety than the wholemeal wheat bread and white wheat bread with vinegar and the reference bread. Wheat fiber present in the wholemeal wheat bread, or the presence of wheat kernels per se, did not affect the postprandial blood glucose or GER significantly compared with white wheat bread, neither did the addition of vinegar to white bread affect these variables. There was no correlation found between the satiety with antral areas or GER CONCLUSION: The present study shows higher satiety after a whole-kernel wheat bread meal with vinegar. This may be explained by increased antral distension after ingestion of intact cereal kernels but, in this study, not by a lower gastric emptying rate or higher postprandial blood glucose response. TRIAL REGISTRATION: NTR1116.
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| 7. |
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| 8. |
- Schippers, Axel, et al.
(författare)
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Geomicrobiological and geochemical investigation of pyrite – containing tailings from Kristineberg, Northern Sweden
- 2005
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Ingår i: Proceedings, Securing the Future. Skellefteå, Sweden. ; , s. 866-875
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Konferensbidrag (populärvet., debatt m.m.)abstract
- Pyrite - containing tailings in Impoundment 1 in Kristineberg, northern Sweden were covered in 1996 with a soil cover consisting of 0.3 m compacted till and 1.5 m unspecified till. From the 1940s until 1996, the impoundment was unremediated and sulfide oxidation occurred to depths of 1 m in the tailings. This study focuses on the importance of microorganisms for pyrite oxidation and the release of oxidation products in the remediated tailings. Three cores containing material from the sealing layer and the zones of oxidized and unoxidized tailings were taken in September 2003 and geomicrobiologically and geochemically analyzed. Most-probable-number (MPN) numbers of pyrite-oxidizing, acidophilic Fe(II)-oxidizing microorganisms of the type Acidithiobacillus ferrooxidans were highest with up to 106 cells g-1 dw at the interface between the oxidized and unoxidized tailings, which correlates with maximum metal and sulfate pore water concentrations, a shift of pH and pe, as well as with high potential biological pyrite oxidation rates measured by microcalorimetry at atmospheric oxygen content. The mean proportion of biological pyrite oxidation was 80 % for the oxidized tailings. The potential pyrite oxidation rate for an assumed 0.3 m thick oxidation zone within the oxidized tailings was 4.7 x10-6 mol m-2 s-1 tailings surface (18 kg FeS2 m-2 year-1). The potential chemical pyrite oxidation rate was highest for the unoxidized tailings where Fe(II)-oxidizing microorganisms could not be detected and where the pyrite content was much higher than in the oxidized tailings. The results show that pyrite is biologically oxidized in particular zones of the mine tailings.
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| 9. |
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| 10. |
- Öhlander, Björn, et al.
(författare)
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Redistribution of trace metals in a mineralized spodosol due to weathering, Liikavaara, northern Sweden
- 2003
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Ingår i: Applied Geochemistry. - 0883-2927 .- 1872-9134. ; 18:6, s. 883-899
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Tidskriftsartikel (refereegranskat)abstract
- The till east of the Liikavaara Östra ore deposit in northern Sweden is in some parts rich in Cu and other sulphide-associated metals. Groundwater flowing in this till has higher concentrations of Cu than groundwater in a reference area where the till has low concentrations of Cu and other metals. To understand the processes that release metals from the mineralized till at Liikavaara into the groundwater, the authors performed a detailed study of the <2 mm fraction of a till profile where the highest metal concentrations in the Liikavaara area occur. The geochemistry and mineralogy of the till were determined, and the soil water was sampled by tension lysimeters. The importance of local diffusion of Cu-bearing airborne dust from the adjacent Aitik mine tailings impoundment was quantified and solid speciation of metals in airborne material was performed by sequential extraction. The results from Liikavaara were compared to results from the reference area. Glacial ice picked up sulphide-rich material from the Liikavaara Östra Cu ore during its flow. This material was deposited in the till east of the ore body when the ice melted. The sulphides have been dissolved in the <2 mm fraction during 8.7 ka of weathering since the glacial ice retreated. After dissolution of the sulphides, Cu was redistributed and secondarily retained in association with Fe-oxyhydroxides and altered biotite. Other sulphide-associated elements such as Co, Ni and Zn show the same pattern in the till profile as Cu, though the concentrations are much lower. Uptake of Cu2+ in the biotite through ion exchange with K+ may be an important mechanism for Cu-enrichment in biotite at Liikavaara. The airborne dust is not the source of Cu in the till. Although the soil water at Liikavaara has higher concentrations of Cu and other metals than the soil water at the reference area, the Cu-concentration is too low for infiltrating soil water to explain the high Cu-concentrations observed in groundwater. The high metal concentrations in the till, of Cu in particular, cause the increased concentrations in the local groundwater. A fluctuating groundwater table washes out Cu and other metals from the till. It is possible that increased Cu concentration in the local groundwater is caused by dissolved organic complexes, or by colloids (<0.45 μm) rich in organic matter and/or Fe-oxyhydroxides.
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