Engineered Nanoparticles in Agro-ecosystems: Implications on the Soil Health

Soil health has been considered as one of the important factors for maintaining ecosystem boundaries, balanced biogeocycles, sustaining plant growth, support habitat, and balanced environmental functions. However, along with the presence of persistence xenobiotics, the entry of newer engineered nanoparticles (ENPs) to the agro-ecosystem has directly influenced the soil health. ENPs are now having tremendous potential to shape the global economy and thus their production has increased deliberately. They are refined from bulk materials to offer unprecedented interactions with small-scale molecules or naturally occurring compounds that are produced on a scale of ~1–100 nm. These nano-architects are chiefly employed for controlled delivery of fertilizers, pesticides, hormones, genetic material, nano-sensors, and rebuilding of soil structure in agro-ecosystem. However, they undergo various transformations like aggregation, sorption, dissolution, decomposition, dispersion, and transportation in soil environment which directly affects the soil health. Thus, their exposure has resulted in various implications like disturbed soil microflora, impeded decomposition of organic matter, lowered nutrient and carbon reserves, and additionally toxicity to soil microbial communities. The scientific communities have widely reviewed major concerns about their origin, interaction, distribution, toxicity, and mitigation in the soil ecosystem. However, the unethical and uncontrolled liberation of ENPs to the environment always made it a matter of concern. Therefore, strong regulation, risk assessment, and mitigation strategies are required for the sustainable use of ENPs. Here, we have attempted to review the structures, properties, mobility, interaction with soil components, impact on soil health, toxicological profile, effects on soil microbial communities, and assessment methods. This will provide valuable approaches to tackle the challenges associated with ENPs and directions for future research.