Fitoremediation

Fitoremediation, also known as phytoremediation, is a group of plant-based approaches for removing, immobilizing, or detoxifying pollutants in soil, water, or air. The technique relies on growing specific plants to extract contaminants, stabilize them, or transform them into less harmful forms, often on site (in situ) or with minimal soil disturbance (ex situ).

The main mechanisms are phytoextraction, whereby contaminants are taken up by roots and stored in harvestable shoots; phytostabilization, which reduces mobility and bioavailability; rhizofiltration, using root systems to absorb pollutants from water; phytodegradation and phytotransformation, where plants metabolize pollutants; and phytovolatilization, which releases volatile forms to the atmosphere. Many applications rely on selecting appropriate plant species and managing growing conditions to maximize contaminant uptake or immobilization.

Targets include heavy metals such as cadmium, lead, arsenic, and mercury; organic pollutants such as polycyclic aromatic hydrocarbons and pesticides; and some radionuclides. Fitoremediation is most feasible for moderately contaminated sites where contaminants are accessible to plant roots in soil or water.

Implementation involves site assessment, selection of suitable species, consideration of local climate and soil, and risk assessment. Plants are harvested and waste biomass is disposed of safely. Monitoring of contaminant levels, bioavailability, and ecological effects is required throughout and after remediation.

Advantages include lower cost, energy efficiency, aesthetic and habitat benefits, and minimal secondary waste. Limitations are long time frames, variable effectiveness depending on contaminant bioavailability, depth, and site conditions, potential spread of contaminants through biomass, and regulatory and ecological constraints.

Phytoremediation was developed and studied intensively from the 1980s onward and remains an active field. It is often used as a complementary or interim measure within broader remediation strategies, combining with soil washing, stabilization, or containment.