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NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2020

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Sammendrag

Wood in service is sequestering carbon, but it is principally prone to deterioration where different fungi metabolize wood, and carbon dioxide is released back to the atmosphere. A key prerequisite for fungal degradation of wood is the presence of moisture. Conversely, keeping wood dry is the most effective way to protect wood from wood degradation and for long-term binding of carbon. Wood is porous and hygroscopic; it can take up water in liquid and gaseous form, and water is released from wood through evaporation following a given water vapour pressure gradient. During the last decades, the perception of wood-water relationships changed significantly and so did the view on moisture-affected properties of wood. Among the latter is its susceptibility to fungal decay. This paper reviews findings related to wood-water relationships and their role for fungal wood decomposition. These are complex interrelationships not yet fully understood, and current knowledge gaps are therefore identified. Studies with chemically and thermally modified wood are included as examples of fungal wood substrates with altered moisture properties. Quantification and localization of capillary and cell wall water – especially in the over-hygroscopic range – is considered crucial for determining minimum moisture thresholds (MMThr) of wood-decay fungi. The limitations of the various methods and experimental set-ups to investigate wood-water relationships and their role for fungal decay are manifold. Hence, combining techniques from wood science, mycology, biotechnology and advanced analytics is expected to provide new insights and eventually a breakthrough in understanding the intricate balance between fungal decay and wood-water relations.

Sammendrag

Sør-Varanger kommune i Øst-Finnmark har vært utsatt for luftforurensning fra russisk smelteverksindustri siden 1930-tallet, særlig fra smelteverket i byen Nikel som ligger bare ca. 10 km øst for den norske-russiske grensen ved Svanvik i Pasvikdalen. I tillegg til svoveldioksid inneholder utslippene store mengder tungmetaller, særlig kobber og nikkel. Formålet med denne undersøkelsen var å kartlegge tungmetallinnholdet i multer og blåbær og sammenligne nivået med tidligere studier. Resultatene fra innsamling i 2020 viser et tydelig geografisk mønster i innholdet av nikkel i blåbær og multer med til dels betydelig høyere konsentrasjoner i de delene av grenseområdet som er mest utsatt for forurensing. For kobber var variasjonsmønsteret mindre tydelig. På nær alle flater der vi har gjentak over tid finner vi også høyere konsentrasjoner av kobber og nikkel i 2020 enn i 1992, og 2008. Tidlig i 2020 kunngjorde russiske myndigheter at smelteverket i Nikel ville bli stengt i løpet av året. Bærinnsamlingen i 2020 er den mest fullstendige som er foretatt på norsk side i grenseområdet og er derfor et godt utgangspunkt for å overvåke tungmetallnivåene etter at smelteverket i Nikel er lagt ned.

Sammendrag

Organic industrial and household waste is increasingly used in biogas plants to produce bioenergy, generating at the same time extensive amounts of organic residues, called biogas digestates. While agricultural soils can benefit from the organic matter and nutrients, in particular nitrogen and phosphorus, contained in biogas digestates, we need to assess the environmental and health risks associated to the undesirable substances that may come along. Among those, only a few are covered by actual regulations. For instance, the quantity of plastic materials below 4 mm in biogas digestate is currently not limited to any threshold, despite its likely occurrence in organic waste (waste bag remains and wrong waste sorting) and persistence in the environment. The aim of our study was identify and quantify plastic materials in digestates from Norwegian biogas plants, that are using various types of organic waste sources (e.g. sewage sludge, food waste, animal manure). In addition, a lab-scale experiment was set up to assess the physical and chemical transformations undergone during biogas processes by plastic materials commonly found in digestates. The methods used in our study included simultaneous thermal analysis coupled to Fourier transform-Infrared spectroscopy (for analysis of polymer composition), scanning electron microscopy (for assessment of physical transformations), and a range of physical and chemical extractions for recovering plastic materials from biogas digestates. While all digestates complied with current regulations, plastic particles with a size of 0.2-3 mm made up to 1% (on dry mass basis) of the samples analyzed. Analysis of the polymeric composition of the recovered plastic fragments confirmed that they originated both from the waste bags themselves (shredded during the first steps of waste handling) and from wrong waste sorting. In addition, the lab-scale biogas treatment was shown to considerably change the structure of the studied plastic materials, illustrating a pathway for the formation of secondary microplastics. Some analytical challenges linked to the size and aging of the plastic materials, as well as the complex composition of the digestates, will be discussed. From a broader perspective, a few options will be presented to address the presence of plastic materials in biogas digestates, and thereby minimize the risk associated to their use as soil amendment.