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 of engineered nanomaterials, concerns are raised about their inevitable spreading and fate in the environment. In this study we examined the uptake and excretion kinetics of cobalt and silver nanoparticles (NPs) in Eisenia fetida, as well as their internal distribution within earthworms. We hypothesised that the uptake, retention time and internal distribution of cobalt and silver depend on their speciation, i.e. whether they are absorbed as ions or nanoparticles. Nanoparticles were subjected to neutron activation prior to the experiment, in order to facilitate tracing and quantification in earthworms by gamma counting and autoradiography. Ions and NPs were added to the food, horse manure (HM). The treatments were Co2+ 0.70 µg/kg HM, CoNP 0.69 mg/kg HM, Ag+ 0.54 mg/kg HM, AgNP 0.45 mg/kg HM, and control. The experiment followed the OECD guidelines, with one month uptake and two months excretion for silver treatments, and four months excretion for cobalt treatments. The patterns of accumulation were highly different for cobalt and silver. The concentration ratios (Bq/g worm / Bq/g food) after one month uptake were 0.93 ± 0.36 and 2.02 ± 0.65 for CoNP and Co2+ respectively, and almost all absorbed CoNP and Co2+ remained within the worms after 4 months excretion. The Ag concentration ratios after one month uptake were 0.015 ± 0.016 and 0.054 ± 0.024 for AgNP and Ag+ respectively, with a subsequent excretion of almost all AgNP and Ag+ within a few days. In addition to information on uptake and excretion kinetics, gamma counting on individual organs, coupled to autoradiography on worm transects gave information on distribution of cobalt and silver NPs within the body, and the target organs for these NPs.
Authors
Belachew Asalf Tadesse Arne Stensvand David M. Gadoury Robert C Seem Andrew Dobson Anne-Marte TronsmoAbstract
Development of ontogenic resistance to powdery mildew (Podosphaera aphanis) in strawberry fruit has not been quantified, and thus cannot be exploited in disease management programs. Four commercially-relevant strawberry cultivars were evaluated for ontogenic resistance to powdery mildew. Fruits were inoculated at one of the four growth stages: flowering, green, white and early pink fruit. There was a significant difference between and within cultivars at the bloom and green stage of inoculations (P <0.05) for both disease incidence and severity. On average 16.4, 39.5, 48.7, and 60.3 % of the fruits inoculated at bloom developed powdery mildew in cultivars Elan, Korona, Frida and Inga, respectively. None of the cultivars developed powdery mildew when inoculated at the pink stage. It may be concluded that flowers and green fruits of strawberry were much more susceptible to powdery mildew infection than white and pink fruits. The high susceptibility of cultivars at the flower and early green stages seemed coincident with the succulent nature of the fruits at these stages, making it easy for penetration and establishment of mildew. Control measures targeting at these critical windows of fruit susceptibility are likely to reduce yield loss.
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Authors
Daniel P. Rasse Karin Knoth de Zarruk Line Tau StrandAbstract
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Authors
Håkon BorchAbstract
This poster presents a new low cost model for modelleing phosphorus and soil loss from agriculture land, and to do evaluation of different mitigation scenarios where the cost effectiveness of the meassures influence each other. The model has been used in several Norwegian catchments to evaluate mitigation options, and to build packages of measures to comply with the demands from the European Water Framework Directive.
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No abstract has been registered