ENHANCING PHYTOSTABILIZATION OF HEAVY METAL-CONTAMINATED SOILS THROUGH MICROBIAL ASSISTANCE

Abstract

Heavy metal contamination arising from industrialization, mining, agricultural practices, and urban development represents a significant threat to ecosystems, agricultural sustainability, and human health. Toxic metals, including cadmium (Cd), lead (Pb), mercury (Hg), chromium (Cr), and nickel (Ni), are persistent environmental pollutants that accumulate in soils, enter food chains, and disturb ecological processes. Conventional remediation techniques, such as soil excavation and chemical amendments, are often costly, environmentally disruptive, and may negatively affect soil structure and fertility.

Phytoremediation, particularly phytostabilization, has emerged as a sustainable and environmentally friendly approach that utilizes plants and their associated rhizosphere microorganisms to immobilize heavy metals. By reducing metal mobility, limiting leaching into groundwater, and decreasing metal transfer to the food chain, phytostabilization contributes to the restoration of contaminated soils. Metal-tolerant plant growth-promoting rhizobacteria (PGPR) further enhance this process through the production of siderophores, exopolysaccharides, biofilms, and phytohormones, which promote metal immobilization, improve plant stress tolerance, and support soil fertility. In addition, these beneficial microorganisms suppress soil-borne pathogens and enhance nutrient availability, facilitating plant establishment and growth under metal-stressed conditions.

Despite its considerable potential, the widespread application of rhizobacteria-assisted phytostabilization is constrained by challenges such as limited plant biomass production, variability in soil properties, and uncertainties regarding long-term stability and effectiveness. Future research should focus on improving the understanding of plant–microbe interactions and optimizing microbial consortia under diverse environmental conditions. Rhizobacteria-mediated phytostabilization represents a promising eco-friendly strategy for reducing heavy metal pollution, restoring degraded soils, and supporting sustainable agricultural productivity