1. Accessibility of selenium in food products (60 credits)
The main objective of this thesis is to evaluate and define the human accessibility of Se-rich food products.
The work includes the use of enzymatic extractions - protease and human gastrointestinal enzymes (juices) - of enriched wheat, enriched broccoli, enriched onion, Se-enriched chicken breast meat, Se-Se-enriched chicken liver, salmon and crab.
Evaluation criteria are:
Extraction yield of enzymes
Degradation of Se-proteins
Composition of Se-species in water/salt extracts, propanol/ethanol extracts, HCl extracts and enzymatic digested food samples.
Methods to be used are: SDS-PAGE, SEC-HPLC-ICPMS, AE-ICPMS and RP-ICPMS.
Collaboration – research group
The thesis/project is joint project between UMB-IPM, UMB-IKBM and the University of Pau, France. It will be applied for ERASMUS scholarship for the Master student as parts of the analytical work will be carried out by University of Pau in France, if funded. The Master thesis project is a part of the ongoing research project “Anti-inflammatory and anti-carcinogenic effect of Se-enriched plant foods”, funded by the Norwegian research Council.
Background:
Selenium is an essential element for humans and has proven to be especially interesting with regard to prevention of cancer in humans. Some of its functions are in the antioxidant defence system, reduction of inflammation, thyroid hormone production, DNA synthesis, fertility and reproduction. In Norway and Europe, the soil Se content is low and the Se content of plant products is therefore insufficient to meet the daily human requirement. Researchers in many countries are actively working on strategies to increase the intake of Se in the population, focusing on food products. BUT - little is done to evaluate the strategies with respect to the bioavailability of Se in food. This thesis will be a valuable contribution to the debate.
As the total content of Se in food products does not provide information on the bioavailability of Se, the research work will focus on the determination of selenium speciation as well as the composition of Se metabolites in food and to study their bioavailability - commonly named accessability.
Contact information:
Dr. Espen Govasmark Prof. Brit Salbu
UMB-IPM, Miljøkjemi UMB-IPM, Miljøkjemi
e-ma e-ma
Tel: +47 404 80 233
Is in France, Pau during 09.2010-07.2011.
Prof. Gerd Vegarud UMB-IKBM
e-ma
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2. Characterization of metal containing particles deposited in shooting ranges in Norway (60 credits)
The main objective is to identify ammunition residues in soils, to characterize their composition and to evaluate the remobilization potential of associated metals such as Pb, Cu, Zn and Sb using sequential extraction techniques.
Evaluation criteria are:
Scanning electron microscopy and XRMA images of particles
Extraction yield of metals
Methods to be used are: Scanning and Transmission electron microscopy (SEM, TEM), ICP-OES, ICP-MS, INAA. For particles well defined in SEM, synchrotron radiation microscopic techniques (Hasylab, Germany) will be applied to characterize metal distribution within individual particles, crystallographic structures and potentially oxidation states. The work includes field work in Norway.
Collaboration – research group
The thesis/project is included in a joint project between UMB-IPM and the Norwegian Defense Research Institute (FFI): “Økt kunnskap om effekter av ammunisjonsrelaterte forurensinger på akvatiske organismer”, and funded by FFI.
Background:
In shooting ranges large amounts of ammunition residues have been deposited during the years. Due to weathering processes a series of metals such as Pb, Cu, Zn and Sb are remobilized from the ammunition residues and are transported by run-off water to downstream ecosystems. As these metals can induce negative effects in biota, it is essential to characterize the source (particle characterization; composition, particle size, structure, oxidation state) and the remobilization potential to estimate the environmental risk.
Contact information: IPM/Miljøkjemi
Prof. Brit Salbu, e-ma Forsker Lene Sørlie-Heier,
e-ma 1.amanuensis Ole Christian Lind e-ma
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3. Silica products as countermeasures to detoxify aluminium in fresh water, brackish water and marine water systems (60 credits)
The main objective is to identify silica products having most suitable properties to detoxify aluminium in aquatic systems, and to develop procedures giving optimal effect of the countermeasure agent.
Evaluation criteria are:
Selection of silica products having suitable properties
Characterization of detoxifying effects from fish model experiments
Development of procedures for optimal use of the agent
Gill reactivity of Al will be used as a measure of toxicity, as the use of silica products will reduce the gill reactivity of Al. Methods to be used are: Spectrophotometry and ICP-OES.
The work includes field work in Norway.
Collaboration – research group
The work is included in a joint project between UMB-IPM and the Norwegian Institute of Water Research (NIVA), and funded by Directorate for Nature Management (DN).
Background:
In southern Norway, several lakes and rivers are limed to increase pH and to detoxify aluminium to reduce negative effects on the salmon population. However, when fresh water is mixed with sea water (estuaries), Al can be mobilized from humic materials and can deposite on gills. Therefore, liming is not sufficient to detoxify Al in such systems. Sodium silicate has proved to be a useful detoxifying agent and can replace liming in such systems. As the detoxifying effects of silicate depend on the structure and functional groups of the product, different silicate solutions will be tested to identify the most efficient agent. A selection of a highly efficient silica products are of importance for management authorities as well as for the aquaculture industry.
Contact information: IPM/Miljøkjemi Forsker Hans-Christain Teien
e-ma Prof. Brit Salbu,
e-ma
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4. Speciation, bioavailability and toxicity of trace metals in run-off from mining areas (60 credits)
The main objective is to characterize the speciation of metals in run-off water from a selected mining area, and perform fish experiments in lab to identify the deposition on gills (gill reactivity metal species) and uptake in fish. Mixed exposure of fish will be performed to identify synergism.
Evaluation criteria are:
Characterization of metal species in run-off waters
Identification of metals deposited on fish gills and associated negative effects
Identification of metal uptake in fish
Gill reactivity of metals will be used as a biomarker. Methods to be used are:
Spectrophotometry, ICP-OES and ICP-MS. Large volumes of water will be transported to UMB for lab experiments.
Collaboration – research group
The work will be included in a new joint project between UMB-IPM and the Norwegian Institute of Water Research (NIVA).
Background:
In mining areas, run-off waters are usually enriched with respect to a series of heavy metals such as Fe, Cu, Zn etc. As these metals can induce negative effects in fish, it is essential to characterize the source (concentrations and distribution of metal species), transformation processes on dilution affecting metal species, the bioavailability and uptake of metals species in fish as well as negative effects. As the mining run-off represent a multiple stressor exposure, controlled fish experiments will be performed where fish is exposed to a mixture of key metals to identify synergism. Results will be utilized for environmental risk assessments.
Contact information: IPM/Miljøkjemi Forsker Hans-Christain Teien
e-ma Prof. Brit Salbu,
e-ma Forsker Frode Kroglund, NIVA
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