Soil-microbe-plant continuum under ZnO and TiO₂ nanoparticle stress: An insight into toxicological implications, risk evaluation and management strategies

Zinc oxide (ZnO) and titanium dioxide (TiO₂) are the most synthesized and widely used engineered nanoparticles. These can largely enter the plant and soil systems through anthropogenic sources related to their widespread industrial production and application. These nanoparticles influence the soil system by altering the physicochemical parameters and microbial functions, often leading to detrimental effects on the activity of key enzymes that ultimately impact plant health. Compared to information in a similar domain, our review aims to synthesize and analyse the recent developments across the soil-microbe-plant continuum under the stress of ZnO and TiO2 NPs. Further, it integrates toxicological findings, mechanistic insights, risk assessment, and management strategies in one unified framework. The comprehensive reviews like this one may broaden the scientific understanding beyond fragmented findings, equipping the scientific community and stakeholders with the conceptual and practical tools needed to evaluate and manage nanoparticle-associated risks. Furthermore, by synthesizing evidence on long-term persistence, bioavailability, and ecological disruption across soil, microbes, and plants, this review offers guidelines for monitoring, remediation strategies, and safer usage of nanomaterials.