Hopp til hovedinnholdet

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.

2017

To document

Abstract

Understanding how toxic contaminants affect wildlife species at various levels of biological organization (subcellular, histological, physiological, organism, and population levels) is a major research goal in both ecotoxicology and radioecology. A mechanistic understanding of the links between different observed perturbations is necessary to predict the consequences for survival, growth, and reproduction, which are critical for population dynamics. In this context, experimental and modeling studies were conducted using the nematode Caenorhabditis elegans. A chronic exposure to external gamma radiation was conducted under controlled conditions. Results showed that somatic growth and reproduction were reduced with increasing dose rate. Modeling was used to investigate whether radiation effects might be assessed using a mechanistic model based upon the dynamic energy budget (DEB) theory. A DEB theory in toxicology (DEB-tox), specially adapted to the case of gamma radiation, was developed. Modelling results demonstrated the suitability of DEB-tox for the analysis of radiotoxicity and suggested that external gamma radiation predominantly induced a direct reduction in reproductive capacity in C. elegans and produced an increase in costs for growth and maturation, resulting in a delay in growth and spawning observed at the highest tested dose rate.

Abstract

The major fraction of engineered nanomaterials (ENMs) released in the environment are transiting through wastewater treatment plants (WWTPs). How do the microorganisms responsible for the removal of nitrogen in WWTPs react when exposed to wastewater-borne ENMs? We investigated the potential for Ag and TiO2 nanoparticles (and their transformation products) to cause a decrease in the operational efficiency of WWTPs, more specifically on nitrogen removal by denitrification. To gain a mechanistic understanding of the potential effects of Ag and TiO2 NPs on denitrifying bacteria, we exposed pure cultures of bacteria isolated from activated sludge to various concentrations of NPs, and monitored gas kinetics during the transition from oxic to anoxic respiration. We also conducted similar exposure experiments on indigenous bacterial communities present in actively operating WWTPs. Results obtained with suspended and biofilm associated microorganisms will be presented, in order to complement eco-physiological studies on single organisms.

To document

Abstract

Two types of nano-scale zero-valent iron (nZVI-B prepared by borohydride reduction and nZVI-T produced by thermal reduction of iron oxide nanoparticles in H2) and amicro-scale ZVI (mZVI) were compared for PCB degradation efficiency in water and soil. In addition, the ecotoxicity of nZVI-B and nZVI-T particles in treated water and soil was evaluated on bacteria, plants, earthworms, and ostracods. All types of nZVI and mZVI were highly efficient in degradation of PCBs in water, but had little degradation effect on PCBs in soil. Although nZVI-B had a significant negative impact on the organisms tested, treatment with nZVI-T showed no negative effect, probably due to surface passivation through controlled oxidation of the nanoparticles.