Reducing Heavy Metal Contamination in Soil and Water Using Phytoremediation

Abstract

The increase in industrialization has led to an exponential increase in heavy metal (HM) soil contamination, which poses a serious threat to public health and ecosystem stability. This review emphasizes the urgent need to develop innovative technologies for the environmental remediation of intensive anthropogenic pollution. Phytoremediation is a sustainable and cost-effective approach for the detoxification of contaminated soils using various plant species. This review discusses in detail the basic principles of phytoremediation and emphasizes its ecological advantages over other methods for cleaning contaminated areas and its technical viability. Much attention has been given to the selection of hyperaccumulator plants for phytoremediation that can grow on heavy metal-contaminated soils, and the biochemical mechanisms that allow these plants to isolate, detoxify, and accumulate heavy metals are discussed in detail. The novelty of our study lies in reviewing the mechanisms of plant-microorganism interactions that greatly enhance the efficiency of phytoremediation as well as in discussing genetic modifications that could revolutionize the cleanup of contaminated soils. Moreover, this manuscript discusses potential applications of phytoremediation beyond soil detoxification, including its role in bioenergy production and biodiversity restoration in degraded habitats. This review concludes by listing the serious problems that result from anthropogenic environmental pollution that future generations still need to overcome and suggests promising research directions in which the integration of nano- and biotechnology will play an important role in enhancing the effectiveness of phytoremediation. These contributions are critical for environmental scientists, policy makers, and practitioners seeking to utilize phytoremediation to maintain the ecological stability of the environment and its restoration.

Keywords: contaminant detoxification; heavy metals; hyperaccumulators; phytoremediation; rhizosphere; transporters.

Figure 1

An analysis of processes and strategies for utilizing heavy metals accumulated in common plant species. Phytoextraction involves plants extracting and translocating pollutants from soil to above-ground parts and roots. Phytovolatilization refers to the use of plants to absorb heavy metal pollutants and transform them into volatile, less hazardous chemical species via transpiration. Some of the heavy metals, such as Hg and Se, may exist in the environment as gaseous species. Rhizofiltration is the method based on plant roots’ capacity to absorb and sequester metal pollutants from the water. Phytostabilization binds soil contaminants to plant roots.

Figure 2

The critical role of hyperaccumulator plants in desert and semidesert ecosystems. The synergistic interaction between bacterial and fungal hyphae with soil particulates, crucial for maintaining soil moisture and structure. This enhances water infiltration and root penetration. It also illustrates the symbiotic relationship between flora and nitrogen-fixing bacteria, which form nodules on roots and convert atmospheric nitrogen into bioavailable compounds. Additionally, the figure shows organic carbon sequestration through photosynthesis and root development, contributing to soil organic matter formation [81].

Figure 3

Ecological benefits and phytoremediation potential of Chrysopogon zizanioides. C. zizanioides, adaptable to various soil types and low maintenance, supports ecological restoration. Its extensive root system combats soil erosion, preserves soil structure, and enhances nutrient-rich topsoil. Through rhizofiltration, the roots absorb pollutants, purifying soil and water. The plant’s symbiotic relationship with arbuscular mycorrhizal fungi boosts nutrient uptake and aids in heavy metal stabilization. It effectively accumulates heavy metals such as lead (Pb), mercury (Hg), and cadmium (Cd), demonstrating its potential for detoxifying contaminated sites [84].

Figure 4

The future of phytoremediation hinges on integrating biotechnological innovations and policy support. Genetic engineering develops hyperaccumulator species and tailors pollutant metabolism. Policy development ensures regulatory frameworks for application. Machine learning and AI optimize strategies and predict efficacy, with field-scale implementation testing these methods. This approach combines technological advancements, practical applications, policy, and genetic modifications, driving continuous improvement in phytoremediation for sustainable environmental cleanup.