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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.

2009

Abstract

Due to the exponential increase in production and marketing of engineered nanomaterials, concerns are raised about their inevitable spreading in the environment. Soils, with their high proportion of solid phase, are likely to constitute the major ultimate sink for engineered nanoparticles (ENPs). Regrettably, data are scarce on the potential environmental risks of ENPs on soil ecosystems. The main reason for this key knowledge gap was the lack of methodologies able to trace the ENPs in complex environmental matrices like soils, which already contain a high background of natural nanoparticles (e.g. clays, organic matter, iron oxides). Using neutron activation as a tracer technique enabled us to overcome this hurdle: neutron activated ENPs can readily be quantified by gamma spectrometry, in all kind of samples, including living organisms. Here we examined the uptake and excretion kinetics of cobalt (Co-NPs, APS 3.9 ± 0.8 nm) and silver nanoparticles (Ag-NPs, APS 20.2 ± 2.5 nm) in the earthworm Eisenia fetida, as well as their internal distribution within worms. We compared the uptake, retention time and internal ditribution of Co-NPs and Ag-NPs with those of soluble salts of cobalt and silver. Earthworms were fed over a 28d period with horse manure contaminated with either neutron activated Co-NPs and Ag-NPs, or Co and Ag salts spiked with the radiotracers 60Co and 110mAg. Accumulation and excretion kinetics were assessed by gamma spectrometry on living earthworms along a three month period for silver treatments and a five month period for cobalt treatments. The patterns of accumulation were highly different for cobalt and silver. The concentration ratios [(Bq/g worm) / (Bq/g food)] after 28d uptake were 0.93 ± 0.36 and 2.02 ± 0.65 for Co-NP and Co2+, respectively, while corresponding values for Ag-NPs and Ag+ were 0.015 ± 0.016 and 0.054 ± 0.024, respectively. Almost all absorbed Co-NPs and Co2+ remained within the worms four months after transfer to clean soil, while Ag concentration ratios fell to almost zero within a few days. We investigated futher the distribution of Co-NPs and Co2+ in worms bodies by coupling autoradiography images of worm transects and gamma spectrometry on individual organs. The body wall, mainly composed of muscular fibers, and the reproductive organs (e.g. spermathecae and seminal vesicles) accumulated lower amounts of cobalt than the digestive tract. By far, the highest accumulation was found in the blood, namely in the pseudo-hearts.

Abstract

Of the 41 countries participating in ICP Forests, 27 countries reported national results of crown condition surveys in the year 2008 for 210 964 trees on 14 786 plots. The transnational result on the European-wide scale relied on 111 560 trees on 5 002 plots of the 16 x 16 km grid in 25 out of 35 participating countries. Mean defoliation of all sample trees of the transnational survey was 20.2%. Of the main species, Quercus robur and Q. petraea had by far the highest mean defoliation (24.9%), followed by Fagus sylvatica (19.4%), Picea abies (19.3%) and Pinus sylvestris (18.2%). These figures are not comparable to those of previous reports because of fluctuations in the plot sample, mainly due to changes in the participation of countries. Therefore, the long-term development of defoliation was calculated from the monitoring results of those countries which have been submitting data since 1990 every year without interruption. In the period of observation the species group Quercus ilex and Quercus rotundifolia shows the severest increase in defoliation, with 10.3% in 1990 and 21.2% in 2008. A similar increase in defoliation, namely from 11.1% to 20.4%, was experienced by Pinus pinaster. Defoliation of these Mediterranean species is largely attributed to several summer drought events. Defoliation of Fagus sylvatica increased from 17.9% to 19.7%. In contrast, Picea abies, Quercus robur and Quercus petraea and in particular Pinus sylvestris recuperated from peaks in defoliation in the mid 1990s. The spatial and temporal variation of bulk deposition and throughfall of sulphate, nitrate, ammonium, calcium, sodium and chlorine was analysed as a basis of ongoing and future studies. Between 174 and 302 intensive monitoring plots were involved in the study. Mean deposition of the years 2004 - 2006 shows spatial patterns reflecting partly regional emission situations. The temporal variation was calculated for the period 2001 - 2006. Sulphur throughfall decreased from 6.0 kg ha-1 yr-1 in 2001 to 4.5 kg ha-1 yr-1 in 2006. Bulk deposition of sulphur shows a similar decrease at a lower level, namely from 4.9 kg ha-1 yr-1 in 2001 to 3.6 kg ha-1 yr-1 in 2006 (corrected for sea salt input). Nitrogen deposition shows a less pronounced rate of decrease.

Abstract

This paper examines emotional dilemmas occurring when Norwegian smallholdings are converted from permanent to second homes. These are properties that might have been in the family for generations as permanent homes, and which successors often feel obliged to take over and maintain by having them as second homes. Second homes are usually associated with `leisure and pleasure`, a retreat to `recharge the batteries`. However, this paper argues that having a smallholding which used to be your permanent home as a second home might involve emotional dilemmas, and it discusses relations between on the one hand, aspects of idyll and comfort and on the other hand, aspects of duty and responsibility. Further, the paper examines how emotional and social property relations influence how smallholdings as second homes become enacted.

To document

Abstract

This paper examines emotional dilemmas occurring when Norwegian smallholdings are converted from permanent to second homes. These are properties that might have been in the family for generations as permanent homes, and which successors often feel obliged to take over and maintain by having them as second homes. Second homes are usually associated with leisure and pleasure, a retreat to recharge the batteries. However, this paper argues that having a smallholding which used to be your permanent home as a second home might involve emotional dilemmas, and it discusses relations between on the one hand, aspects of idyll and comfort and on the other hand, aspects of duty and responsibility. Further, the paper examines how emotional and social property relations influence how smallholdings as second homes become enacted.

To document

Abstract

Field experiments in the high rainfall zone (HRZ) and the medium rainfall zone (MRZ) in Zambia were designed to determine the natural occurrence of fumonisins (FB1-2) in Zambian maize hybrids, accumulation of FB1-2 resulting from artificial inoculation with Fusarium verticillioides and effects of climate and planting time on FB1-2 in maize. Combined FB1-2 concentrations varied from 0 to 13,050 ng/g, with an overall mean of 666 ng/g. Maize from the HRZ had low incidences of FB1-2-positive samples (mean 41%) which contained FB1-2 below 500 ng/g. In the MRZ, higher incidences (mean 97%) and concentrations (40% of samples > 1,000 ng/g) were recorded in two out of three years. There was no correlation between mean location FB1-2 concentrations in individual years and precipitation, number of rain days or monthly precipitation. Postponing the planting time with 10 or 20 days did not significantly affect FB1-2 concentration, but it reduced the yields in some years.

Abstract

In recent years the market share for wooden window products has continuously decreased in Europe. Plastics and aluminum have partly replaced wooden window constructions. Service life and maintenance costs lead the customer to a preferable use of other materials than wood. Additionally the use of tropical hardwoods is decreasing because the market demands sustainable alternatives. A transnational research project is initiated to evaluate the use of an alternative wood material for the production of wooden windows. This project involves both, industry and research institutes from Germany, Sweden and Norway. The objective is to establish Kebony furfurylated wood within the window market of the involved countries. Furfurylation of wood using European timbers has been a research topic for many years and is already commercially produced for different applications. The treatment improves dimensional stability, durability and some mechanical properties. This paper presents the first part of the project, where wood properties such as dimensional stability, water sorption, ecotoxicity, capillary water uptake and water vapor diffusion are evaluated.