Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2011
Abstract
The recent flooding episode in Norway from May this year shows the necessity of understanding the processes of water discharge from small tributaries feeding the larger river systems. The major objective of the recently started ExFlood project is to define and analyze measures to combat negative impact of extreme weather events on infrastructure in small watershed areas in Norway and to incorporate this in a land use planning tool. Urban, agriculture, nature, and forest areas and infrastructure elements demands different approaches concerning impacts of and opportunities for extreme weather events. The approach of the ExFlood project is to reduce the peak flow and delay the peak time to avoid damages on infrastructure. Three municipalities from different climate regions in Norway contribute to the project where the planning tool will be tested, and an experimental catchment site is selected to conduct in depth process studies.
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Abstract Due to difficulties in tracing engineered nanoparticles (ENPs) in complex media, there are few data on the exposure of soil biota to ENPs. This study used neutron activated cobalt (Co NPs) and silver (Ag NPs) nanoparticles, as well as soluble cobalt and silver salts, to assess the uptake, excretion and biodistribution in the earthworm Eisenia fetida. Concentrations of cobalt in worms after four weeks exposure reached 88% and 69% of the Co ions and Co NPs concentrations in food, respectively, while corresponding values for Ag ions and Ag NPs were 2.3% and 0.4%. Both Ag ions and Ag NPs in earthworms were excreted rapidly, while only 32% of the cobalt accumulated from Co ions and Co NPs were excreted within four months. High accumulation of cobalt was found in blood and in the digestive tract. Metal characterization in the exposure medium was assessed by sequential extraction and ultrafiltration. The Co NPs showed significant dissolution and release of ions, while Ag ions and particularly Ag NPs were more inert.
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Due to sewage sludge application on soils, terrestrial ecosystems are very likely to be exposed to silver nanoparticles (AgNPs) and it is thus important to understand the behavior of Ag NPs once in contact with soil components. The aim of this work was to compare the behavior of silver under three forms, silver nitrate, citrate stabilized AgNPs (C-ANPs) and uncoated AgNPs (P-AgNPs), in two soils with contrasting organic matter content, and over time. The physical and chemical properties of the studied soils as well as the nanoparticles size, shape, crystallographic structure and specific surface area were characterized. Soil samples were spiked with silver nitrate, C-AgNPs or P-AgNPs, and let for ageing 2 hours, 2 days, 5 weeks or 10 weeks before they were submitted to sequential extraction. The ionic silver solution and the two AgNPs types were radiolabeled so that we could detect and quantify silver by gamma spectrometry by measuring the 110mAg tracer in the different sequential extraction fractions. We thereby obtained for each silver form, soil type and time point a distribution of silver in the different fractions. Silver was generally more mobile in the mineral soil, although the fractionation patterns were very different for the three silver types in both cases. Over 20% of the total C-AgNPs concentration were water soluble in both soils (<5% for AgNO3 and P-AgNPs) the first two days after spiking, but the fraction decreased to trace levels thereafter. This was compensated by an increase in the reducible fraction. Regarding P-AgNPs, 80% were not extractable at all, but contrary to AgNO3 and C-AgNPs, the water soluble and ion exchangeable fractions did not decrease over time in the mineral soil, and even increased in the organic soil.
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Authors
Adam Paruch Trond Mæhlum Hanna Obarska-Pempkowiak Magdalena Gajewska Ewa Wojciechowska Arkadiusz OstojskiAbstract
This article describes Norwegian and Polish experiences concerning domestic wastewater treatment obtained during nearly 20 years of operation for constructed wetland (CW) systems in rural areas and scattered settlements. The Norwegian CW systems revealed a high performance with respect to the removal of organic matter, biogenic elements and faecal indicator bacteria. The performance of the Polish CW systems was unstable, and varied between unsatisfied and satisfied treatment efficiency provided by horizontal and vertical flow CWs, respectively. Therefore, three different concepts related to the improvement of CW technology have been developed and implemented in Poland. These concepts combined some innovative solutions originally designed in Norway (e.g. an additional treatment step in biofilters) with Polish inspiration for new CWs treating rural domestic wastewater. The implementation of full-scale systems will be evaluated with regard to treatment efficiency and innovative technology; based on this, a further selection of the most favourable CW for rural areas and scattered settlements will be performed.
Authors
Frank MillerAbstract
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