Related Experiment Video
Updated: Jul 13, 2026
06:29
A Method to Preserve Wetland Roots and Rhizospheres for Elemental Imaging
Published on: February 15, 2021
Decreasing arsenic bioaccessibility/bioavailability in soils with iron amendments
Jonathan L Subacz1, Mark O Barnett, Philip M Jardine
1Department of Civil Engineering, Auburn University, Auburn, Alabama, USA.
Summary
Adding iron (Fe) salts to arsenic (As)-contaminated soils effectively reduces As bioaccessibility. Soluble iron salts are more effective than metallic iron, with optimal results achieved in moist soil conditions.
Area of Science:
- Environmental Science
- Soil Science
- Geochemistry
Background:
- Arsenic (As) contamination in soils poses risks to human health and ecosystems.
- Assessing As bioaccessibility is crucial for understanding its oral bioavailability and potential toxicity.
- Iron amendments are being explored as a remediation strategy for As-contaminated sites.
Purpose of the Study:
- To investigate the efficacy of different iron (Fe) amendments in reducing arsenic (As) bioaccessibility in contaminated soils.
- To compare the effectiveness of metallic Fe versus soluble Fe(II)- and Fe(III)-halide salts.
- To understand the mechanisms and optimal conditions for Fe-based As remediation.
Main Methods:
- Treatment of As-contaminated soils with various iron amendments (metallic Fe, Fe(II)-salts, Fe(III)-salts).
- Measurement of As bioaccessibility using established extraction methods.
- Investigation of the influence of soil moisture content on the remediation process.
- Analysis of soil pH and Fe(III) (hydr)oxide content.
Main Results:
- Soluble Fe(II)- and Fe(III)-salts significantly reduced As bioaccessibility compared to metallic Fe.
- Fe(III)-salts reduced As bioaccessibility by increasing Fe(III) (hydr)oxide content and lowering soil pH.
- In situ reduction of As bioaccessibility requires sufficient soil moisture (>=30%).
- A Fe:As molar ratio of 100:1 reduced average As bioaccessibility by approximately 50% across nine soils.
Conclusions:
- Soluble iron salts are effective amendments for reducing arsenic bioaccessibility in contaminated soils.
- Soil moisture is a critical factor for in situ remediation, preventing experimental artifacts.
- Increasing the iron to arsenic ratio can enhance arsenic bioaccessibility reduction.
- Iron amendment shows promise as a viable strategy for remediating arsenic-contaminated soils.
More Related Videos
Related Concept Videos
01:19Acid Mine Drainage
Mining activities that disturb sulfide-rich rocks, particularly those containing pyrite (FeS₂), initiate a cascade of geochemical and microbiological processes with serious environmental implications. When exposed to air and water, pyrite undergoes oxidation, releasing sulfate, ultimately forming sulfuric acid and mobilizing heavy metals into surrounding water systems. This phenomenon, known as acid mine drainage (AMD), results in low pH waters laden with toxic elements that threaten aquatic...
01:27Microbial Leaching
Microbial leaching, also known as bioleaching, is an environmentally favorable method for extracting metals from low-grade ores using specific microorganisms. This biotechnological approach is particularly valuable for mining operations targeting copper, gold, and uranium, where traditional extraction methods may be economically or environmentally impractical.Copper Leaching and Microbial CatalysisIn copper bioleaching, crushed ore is arranged into heaps and irrigated with a dilute sulfuric...
01:25Microbial Bioremediation of Uranium
Microorganisms play a critical role in the transformation and immobilization of uranium in contaminated environments through four main pathways: bioreduction, biosorption, bioaccumulation, and biomineralization. These mechanisms reduce uranium’s toxicity and prevent its migration through groundwater systems, offering sustainable approaches for in situ bioremediation.Bioreduction of UraniumBioreduction is driven by anaerobic bacteria such as certain strains of Geobacter and Shewanella, which use...
01:24Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...