Effect of engineered nanoparticles on soil biota: Do they improve the soil quality and crop production or jeopardize them?

Nanoscience and nanotechnology have been shown to have the capacity to help study, manipulation,design, and synthesis of new nano-sized materials to manufacture new products with desirable features never seen before. The unique properties of materials at nanoscale opens an excellent possibility for nanotechnology to be used in soil environmental remediation, and water, and air decontamination. In crop management, nanomaterials are used to regulate the controlled release of nutrients, fertilizers, and pesticides. However, it is not only necessary to expose the positive effects by the application of the nanomaterials but also to demonstrate the impacts on soil and nontarget organisms (plants, mesofauna, macrofauna, and soil microbiota). In this context, pieces of evidence on the adverse effects of engineered nanoparticles (ENP) on the physicochemical and biological properties of soils are discussed in this paper. We have found a diversity of contradictory results. The summaries, findings, and conclusions of most of the investigations support the need to understand the biological or physicochemical transformation and transport of ENP in soil, and in the plant-organism relationship. Better understanding regarding the soil biota coupled with the ecological ENP behavior could ensure the safe use of ENP. Nanomaterials can change the physicochemical and biological properties of the soils; consequently, long-term in situ field trials are required, and meanwhile, land-application of nanomaterials should be limited to scientific experiments to fill knowledge gaps to not jeopardize the global food production or the environment and worldwide human health.