Impact of engineered nanoparticles on the activity, abundance, and diversity of soil microbial communities: a review

This report presents an exhaustive literature review of the effects of engineered nanoparticles on soil microbial communities. The toxic effects on microbial communities are highly dependent on the type of nanoparticles considered. Inorganic nanoparticles (metal and metal oxide) seem to have a greater toxic potential than organic nanoparticles (fullerenes and carbon nanotubes) on soil microorganisms. Detrimental effects of metal and metal oxide nanoparticles on microbial activity, abundance, and diversity have been demonstrated, even for very low concentrations (<1 mg kg−1). On the opposite, the negative effects of carbon nanoparticles are observed only in presence of high concentrations (>250 mg kg−1), representing a worst case scenario. Considering that most of the available literature has analyzed the impact of an acute contamination of nanoparticles using high concentrations in a single soil, several research needs have been identified, and new directions have been proposed. The effects of realistic concentrations of nanoparticles based on the concentrations predicted in modelization studies and chronic contaminations should be simulated. The influence of soil properties on the nanoparticle toxicity is still unknown and that is why it is crucial to consider the ecotoxicity of nanoparticles in a range of different soils. The identification of soil parameters controlling the bioavailability and toxicity of nanoparticles is fundamental for a better environmental risk assessment.