Heavy Metal Bioremediation in Soil Systems

Soil contamination by heavy metals poses a persistent threat to ecosystems, human health and agricultural productivity. Bioremediation in soil systems harnesses the metabolic and physicochemical activities of plants, microbes and fungi, often in conjunction with tailored soil amendments, to immobilise, transform or remove toxic metals. Strategies include phytoremediation with hyperaccumulator plants, microbial-driven redox transformations, and amendment-assisted immobilisation via biochar, clays or phosphate minerals. Central to these approaches is the promotion of stable mineral phases—such as chloropyromorphite and other insoluble metal phosphates—through controlled release of phosphate by phosphatase enzymes or organic acids. Extracellular polymeric substances further concentrate metals and foster biofilm formation, enhancing local reaction zones. Soil parameters such as pH, salinity and competing ions critically influence metal speciation and microbial activity. Recent interdisciplinary research has integrated omics-based microbial consortia design, material science innovations and nutrient management to advance field-scale deployment, offering resilient and cost-effective solutions for diverse contaminated sites.

Research from Nature Portfolio

One seminal study has demonstrated that filamentous fungi decompose organic phosphates under carefully adjusted acidity to drive lead immobilisation via the formation of chloropyromorphite on hyphal surfaces. Modest acidic stimulation enhanced phytase secretion, maximised phosphate release and shifted mineral speciation towards stable lead phosphates, whereas stronger or weaker pH regimes promoted more soluble anglesite formation. This work provides a clear proof of concept for exploiting fungal enzymatic pathways and environmental control to stabilise heavy metals in situ.

Heavy Metal Bioremediation in Soil Systems publication trend

The graph below shows the total number of articles in heavy metal bioremediation in soil systems across all publications each year (not limited to Nature Index journals).

Technical terms

Bioremediation: Use of living organisms to degrade, transform or stabilise environmental pollutants.

Phosphate-solubilizing bacteria/fungi: Microorganisms that release phosphate from insoluble sources via acid secretion or enzymatic hydrolysis.

Biochar: Charred biomass amendment that adsorbs metals, buffers pH and supports microbial colonisation.

Pyromorphite: A highly stable lead phosphate mineral phase that immobilises Pb in soils.

Extracellular polymeric substances (EPS): Complex microbial exudates that bind metals and support biofilm-mediated reactions.

Immobilisation: Conversion of contaminants into forms with reduced mobility and bioavailability.

References

1. Lead immobilization assisted by fungal decomposition of organophosphate under various pH values. Scientific Reports (2019).
2. Isolation and screening of phosphorus solubilizing bacteria from saline alkali soil and their potential for Pb pollution remediation. Frontiers in Bioengineering and Biotechnology (2023).
3. Remediation of Lead Contamination by Aspergillus niger and Phosphate Rocks under Different Nitrogen Sources. Agronomy (2022).
4. Lead remediation is promoted by phosphate-solubilizing fungi and apatite via the enhanced production of organic acid. Frontiers in Bioengineering and Biotechnology (2023).