Publikasjoner
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.
2018
Forfattere
Anastasia Georgantzopoulou Claire Coutris Kuria Ndungu Patricia Almeida Carvalho Ana Catarina Almeida Ailbhe MackenSammendrag
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Forfattere
Anastasia Georgantzopoulou Christian Vogelsang Claire Coutris Fabio Polesel Benedek Plosz Kuria Ndungu Patricia Almeida Carvalho Ailbhe MackenSammendrag
The increase in production and use of Ag and TiO2 nanomaterials has led to their release in wastewater streams and subsequently in the environment. Nanoparticles (NPs) can undergo transformations in environmental media such as wastewaters leading to an alteration in behavior, bioavailability and toxicity that may differ from their pristine counterparts and make predictions challenging. In this context, the overall goal of the study was to elucidate (i) the behavior and transformation of Ag and TiO2 NPs in realistic matrices such as wastewater effluents and activated sludge and (ii) the subsequent effects of transformed particles in comparison to their pristine counterparts. In this study, a laboratory-scale wastewater treatment system was established and combined with a battery of ecotoxicological assays and characterization techniques. The system contained activated sludge and was operated as a pre-denitrification system fed with synthetic wastewater spiked daily with 10 µg Ag NPs/L (PVP coated, 25 nm, nanoComposix) and 100 µg TiO2 NPs/L (nominal primary size of 5 nm, NM-101, JRC) over a period of 5 weeks. During that period the effluents were collected weekly and the excess sludge was stored for the evaluation of terrestrial toxicity. Samples from all reactors and effluents were collected weekly and analyzed by sequential filtration and ICP-MS to determine the partitioning of NPs and their transformation products. Transmission electron microscopy and sp-ICP-MS were performed on selected samples. The effects of aged particles were assessed using a battery of bioassays including freshwater and marine algae (growth inhibition and reactive oxygen species -ROS- formation), crustaceans, as well as in vitro models of relevance for NP toxicity assessement (RTgill-W1 cell line, effects on metabolic activity, epithelial integrity, ROS formation, gene expression). The extent of the observed effects was dependent on the organism exposed, with bottom feeding organisms and algae being more sensitive, while the in vitro model was a good tool for environmental samples. Furthermore, the biosolids generated from the lab-scale continuous system were used in terrestrial microcosm experiments, giving insight into the fate and potential accumulation in a model terrestrial system. Experimental data generated from the continuous-flow operation of the activated sludge system and the targeted batch experiments will be used to model the fate and the removal of NPs.
Sammendrag
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Forfattere
Merethe Kleiven Lisa Magdalena Rossbach Julian Alberto Gallego-Urrea Dag Anders Brede Deborah H Oughton Claire CoutrisSammendrag
Using Caenorhabditis elegans as a model organism, this study addresses the potential linkage between toxicity of NM300K Ag nanoparticles (AgNPs), their particle size distribution and the presence of dissolved Ag in the test media. Of the three endpoints assessed (growth, fertility and reproduction), reproduction was the most sensitive, with 50% effect concentration (EC50) ranging from 0.26-0.84 mg Ag L-1 and 0.08-0.11 mg Ag L-1 for NM300K and AgNO3, respectively. Silver uptake by C. elegans was similar for both forms of Ag, while bioaccumulation was higher in AgNO3 exposure. The observed differences in toxicity between NM300K and AgNO3 did not correlate to bioaccumulated Ag, which suggests the toxicity to be a function of the type of exposing agent (AgNPs vs AgNO3) and their mode of action. Before addition of the food source, E. coli, size fractionation revealed that dissolved Ag comprised 13-90 % and 4-8 % of total Ag in the AgNO3 and NM300K treatments, respectively. No dissolved Ag was detectable in the actual test media, due to immediate Ag adsorption to bacteria. Results from the current study highlight that information on behavior and characterization of exposure conditions is essential for nanotoxicity studies.
Sammendrag
Four lab scale biogas reactors fed with a substrate composition of ensiled fish waste and manure fixed at 13 and 87 vol %, respectively, were operated with HRTs of 20, 25, 30 and 40 days. Biogas process performance and stability were evaluated with regard to CH4 yields, NH4+ accumulation and abundance of NH4+-tolerant microorganisms. Process performance in the reactors operated at different HRTs were compared to process performance in reactors operated with constant HRT, fed with increased ratios of fish waste. The process performance and microbial dynamics were stable in reactors operated at constant amount of fish waste in the feed and with different HRTs. In the reactors added elevated ratios of fish waste, the concentration of NH4+ and abundance of NH4+-tolerant acetate oxidizing bacteria increased. The biogas process failed in these reactors simultaneously with an observed shift in microbial composition. In particular, the bacterium Tepidanaerobacter Acetatoxydans seemed to affect the biogas process stability. The hydrogenotrophic Methanomicrobiales increased in abundance in response to higher fish waste loading and NH4+ concentrations. This study showed that at a loading of 13% fish waste, it is possible to decrease the HRT from 30 to 20 days without markedly inhibiting the process stability.
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Sammendrag
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The aim of this study was to contribute to the development of pelleted compound recycling fertilizerswith favourable handling and spreading characteristics and balanced nutrient ratios by combiningnitrogen (N)- and phosphorus (P)-rich waste resources (meat bone meal, fish sludge or food waste)with potassium (K)-rich bottom wood ash. Pelleted compound recycling fertilizers with gooddurability and low dusting tendency were produced by roll-pelleting preheated waste resources at asuitable moisture content. However, the nutrient ratios in the final products were insufficientlybalanced, with too low N concentrations relative to P and K to meet crop demands. In a bioassayusing barley ( Hordeum vulgare) and a nutrient-deficient sand/peat mixture, the relative agronomiceffectiveness (RAE) of pelleted compound recycling fertilizers and reference recycling fertilizers was22–42% of that of mineral compound fertilizer. Growth limitation was due to reduced N availability(mineral fertilizer equivalent - MFE = 35–57%) or reduced P availability (MFE = 20–115%), with thegreatest P fertilizer value obtained for digestate based on dairy manure and fish sludge. Availability ofK in bottom wood ash was masked by the experimental soil.