Effects of Nanoparticles on Soil Microorganisms

Nanoparticles, one of the most important benefits of nanotechnology, are solid particles with sizes between 1-100 nm. The usage areas of nanoparticles including cosmetics, paints and coatings, plastic additives, communications, electronics, sensors, packaging, biomedical diagnostics, textiles, antibacterial agents are quite wide. For this reason, the release of nanoparticles to the soil directly or indirectly through air and water is gradually increasing. Therefore, the soil is contaminated with nanoparticles in the long term and soil microorganisms can adversely be affected by these accumulated nanoparticles. Soil microorganisms play vital roles in soil carbon cycling, nitrogen fixation, and nutrient acquisition for plants. Nanoparticles can show different toxic effects on soil microorganisms according to their physical and chemical structures. Also, the humic acid, organic matter, pH, and ionic in the soil strengths affect the toxicity of nanoparticles. Nanoparticles may show toxic effects on soil microorganisms directly or indirectly, such as changes in the bioavailability of toxins or nutrients, toxicity due to their interaction with natural organic compounds or toxic organic compounds. Also, nanoparticles can have a lethal effect on soil microorganisms by causing the production of reactive oxygen species by damaging the membrane permeability, cell signaling processes, and the stability of enzymes and protein structures. The effect of nanoparticles such as C6 0 fullerenes, Fe2 O3 , Ag, ZnO, CeO2 , TiO2 on soil microorganisms and the mechanisms of their toxicity are comprehensively reviewed and discussed in this mini-review.