Engineered nanoparticles as contaminant carriers

Speaker:

Anders Baun Associate Professor, DTU Enviroment

Co-Author(s):

Nanna Hartmann

The ecotoxicity of engineered nanoparticles (ENP) receives increasing attention, but the potential carrier effect of ENP is still a somewhat overlooked issue in environmental toxicology to day. However, after discharge to the aquatic environment ENP may interact with already existing contaminants and influence the bioavailability of these. In this presentation we will show how this may lead to changes in toxicity and accumulation for range of xenobiotic organic chemicals and metals. Our studies cover the interaction of a range of organic environmental contaminants in contact with aqueous suspensions of C60. Furthermore, we have carried out studies with Cd(II) in contact with different sizes of TiO2 (25 nm, 100 nm, 300 nm). We used standardized algal and daphnia tests for evaluation of toxicity and accumulation. For these species, we found that while no changes in toxicity occurred for nonyl- and decyl-amines, methylparathion, methylparaben, and propylparaben in contact with C60, a lowering of the toxicity occurred for pentachlorophenol in contact with C60. For atrazine and phenanthrene an increase in toxicity was observed in the presence of C60 in aqueous suspension and higher steady-state concentrations of pentachlorophenol and phenanthrene were found in daphnids upon contact with C60. In algal tests with Cd(II) in contact with TiO2 it was found that the intercellular amounts of cadmium decreased and that toxicity was affected as a result of changes in bioavailability due to a surface complexation of Cd2+ with TiO2 in combination with the inherent inhibitory effect of TiO2 nanoparticles. This study underlines that some of the focus in nano(eco)toxicology must be directed towards the potential carrier effects of ENP to evaluate the environmental safety of nanomaterials.