Role of root exudates on the transformation and ecological effect of
engineering nanomaterials in soil system: A critical review
Abstract
Due to the widespread use of engineered nanomaterials (ENMs) for soil
remediation and nano-enabled sustainable agriculture, there is a growing
concern regarding the behavior and fate of ENMs released into soil
systems in the presence of natural root exudates (REs). Herein, we
investigate the influence of REs on the fate and ecological effect of
ENMs from a comprehensive perspective. We summarize the key roles
reported in the literature for REs in physical changes (e.g.,
adsorption, dispersion/aggregation), chemical changes (e.g.,
oxidation/redox reactions, and dissolution), and biotransformation of
ENMs, which will further determine the ecological risk of ENMs in
natural soil systems. Moreover, this review highlights the potential
adverse effects of ENMs on different soil organisms (e.g., bacteria,
plants, and eisenia foetida) in the presence of REs. The remaining
unclear mechanisms (e.g., oxidative stress and DNA damage) of ENMs
toxicity at the cellular level influenced by REs are reviewed and
presented. Finally, the review concludes by addressing the current
knowledge gaps and challenges in this field.