Influence of a nanoparticle mixture on an arctic soil community

Interest is growing in understanding not only the impact of individual nanoparticles (NPs) on ecosystems but also the effect of NP mixtures. In the present study, the impact of a combination of three different NPs, silver, copper, and silica (all at 0.022%, w/w), on an arctic microbial community was investigated. After adding the NPs, soil microcosms were incubated for 176 d, and subsequent estimates of microbe diversity were obtained using culture-dependent and culture-independent assessments. The treated soil appeared to show a reduction in the ability to use carbohydrate and amino acid substrates and demonstrated an altered pattern of major fatty acid peaks. Polymerase chain reaction-denaturing gradient gel electrophoresis showed consistent differences in the pattern of predominant rRNA gene sequences. Although this is an initial investigation of soil contaminated with mixed NPs, these results demonstrate that even at the relatively modest concentrations used such pollutants have the potential to disrupt microbial communities.