Leaching of graphene oxide nanosheets in simulated soil and their influences on microbial communities.

With the wide use of graphene-like nanosheets, especially in agriculture, their release into the environment, it is crucial to grasp the fate of nanosheets in soil and minimum ecological risks. The present work discovered that leaching and migration of nanosheets (rGO) in soil is affected by soil porosity and adsorption processes. And the contents of rGO-Pd in soil layers and leachate increased and then decreased with the decreased of soil porosity. Moreover, physicochemical properties of rGO-Pd nanosheets changed by leaching processes, especially the changes of morphology, thickness and oxygen functional groups. Leaching of rGO-Pd also interfered the soil microbial homeostasis accompanied by the increase of microbial species richness and community diversity. In addition, rGO-Pd altered the usage of carbon sources by edaphon. The utilization of carbon sources by soil microbes, such as polymers, sugars, phenolic acids, carboxylic acids, amino acids, and amines, was also reduced by nanosheets. These findings provide new insights into environmental behaviors of nanomaterials and nanogeochemistry.