Assessing the risks of silver nanoparticle-concentrated matrix application in agricultural soil: Implications for plant and soil enzymes

Abstract

The practice of reusing biosolids may be an effective strategy for addressing nutrient reuse and soil shortages. However, the accumulation of silver nanoparticles (AgNPs) in biosolids poses a major ecological hazard to organisms. In this study, we evaluated the effects of AgNPs on plant and soil enzymes in terrestrial ecosystems by exposing soybean Glycine max, as well as soil, to varying concentrations of AgNPs embedded either on the surface soil layer or throughout the soil matrix. We found that exposing the plants to 20 mg AgNPs/kg soil that was embedded throughout the soil matrix had a significant impact. Conversely, soil enzymes (dehydrogenase, urease, and fluorescein diacetate hydrolase) were affected by exposure to 20 and 80 mg AgNPs/kg of soil embedded on the surface soil layer or throughout the soil matrix at 20 mg AgNPs/kg soil. The toxic effects of AgNPs were induced by different receptor habitats.The presence of AgNPs in soil led to developmental retardation, inhibited root growth, reduced photosynthetic activity, and decreased transpiration rates in leaves. These plants also produced fewer fruits compared to soybean plants grown in regular soil without AgNPs. Moreover, most of the AgNPs soil groups demonstrated a decrease in soil enzyme activity in the surface soil; therefore, soil-capping patterns involving embedded stressors should be considered. These findings provide valuable insights that will contribute substantially to advancements in the field of biosolids for land applications.