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sexta-feira, 20 de abril de 2012

Scientists investigate interactions between nanoparticles and the environment

Several studies have been published recently examining the effects of nanoparticles on the environment.
Researchers have found that exposure to fullerene nanoparticles induces tissue damage and gene expression alterations in earthworms, in a study published in the journal Nanotoxicology. The scientists, from the UK and the Netherlands, exposed the organisms to the substance for four weeks, or for life. Both exposure scenarios altered the expression of essential genes, and caused damage to the cuticle, skin, muscle and gut of the animals. Overall, the authors conclude that sub-lethal exposure to earthworms via the soil can have a significant effect on the organism.
A second study, by scientists from the UK and Indonesia investigating the environmental stability of silver nanoparticles coated with different materials, has found that polyvinylpyrrolidone (PVP) -coated particles are the most stable and should therefore be used for exposure studies. The researchers examined the behaviour of the different types of silver nanoparticles for 21-days in standard OECD media used for acute and chronic toxicity tests on the water flea Daphnia. They conclude that the most stable PVP-coated particles should be used for toxicity studies because dynamic changes would affect the exposure dose and the nature of the toxicant studied. The research is published in Environmental Science and Technology.
Portuguese researchers have concluded that nanomaterials can have a significant impact on the structural diversity of the soil bacterial community, following a study in which soil samples were spiked with nanomaterial suspensions and then incubated for 30 days. Their findings are published in Science of The Total Environment.