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.

2011

2010

Abstract

Currently, very little data exist on the exposure of soil biota to engineered nanoparticles (ENPs), in spite of soils being an important potential sink for ENPs. Though, data on exposure are essential to determine whether or not, or to which extent, a hazard constitutes a risk. This knowledge gap is mainly due to difficulties in tracing ENPs in soils where natural nanoparticles are abundant. We used neutron activated ENPs as tracers and examined the exposure (uptake, excretion and internal distribution) of nanoparticles of cobalt (Co NPs 3.9 ± 0.8 nm) and silver (Ag NPs 20.2 ± 2.5 nm) in the earthworm Eisenia fetida, and compared this to soluble cobalt and silver salts. Accumulation patterns were highly different for cobalt and silver. Concentrations of cobalt in worms after 4 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 NPs and Ag ions in earthworms were excreted rapidly, while only 32% of the accumulated Co ions and Co NPs were excreted within a 4 months depuration period. High accumulation of cobalt was found in blood, and to a lesser extent in the digestive tract. Sequential extraction and centrifugal ultrafiltration provided useful information on metal speciation, dissolution and bioavailability of Co NPs and Ag NPs. Both Ag NPs and Ag ions were strongly bound to soil constituents, whereas Co NPs and Co ions were largely found as water soluble species, in good agreement with the results from the uptake study.

Abstract

The exponential increase in the use of engineered nanomaterials (ENMs) in a variety of commercially available products has raised concerns about their release into environmental compartments. Soils in particular have been pointed out as a major environmental sink for ENMs, e.g. through the application of sewage sludge to soil. However, data are scarce on the fate of ENMs in soils and on their bioavailability to organisms once ENMs interact with the soil matrix. The main reason for this knowledge gap has been the methodological challenges to trace and quantify ENMs in complex matrices like soils due to the presence of abundant natural nanoparticles (e.g. clays, iron oxides, organic matter). Methods able to overcome this hurdle will be introduced, as well as their limitations. The aim of this lecture is to present the current state of knowledge on the fate, behavior and toxicity of some of the most commercialized ENMs (carbon nanotubes, fullerenes, metal and metal oxides) in terrestrial ecosystems. We will see the potential modifications ENMs may undergo in soils, namely agglomeration, adsorption to soil constituents, dissolution of particles, effects of pH and organic matter on their speciation, and how these parameters can influence their transport in soil and their bioavailability to organisms. Ecotoxicity will also be addressed, through studies on bacteria, nematodes and earthworms.

To document

Abstract

In terrestrial ecotoxicology there is a serious lack of data for potential hazards posed by engineered nanoparticles (ENPs). This is partly due to complex interactions between ENPs and the soil matrix, but also to the lack of suitable toxicological end points in organisms that are exposed to ENPs in a relevant manner. Earthworms are key organisms in terrestrial ecosystems, but so far only physiological end points of low sensitivity have been used in ecotoxicity studies with ENPs. We exposed the earthworm Lumbricus terrestris to silver nanoparticles and measured their impact on apoptosis in different tissues. Increased apoptotic activity was detected in a range of tissues both at acute and sublethal concentrations (down to 4 mg/kg soil). Comparing exposure in water and soil showed reduced bioavailability in soil reflected in the apoptotic response. Apoptosis appears to be a sensitive end point and potentially a powerful tool for quantifying environmental hazards of ENPs.