Fluoride Dynamics and Environmental Impact in Soil Systems

Fluoride in soils originates from both natural sources—such as the weathering of fluoride-bearing minerals, volcanic emissions and rock phosphate deposits—and anthropogenic activities, including industrial emissions, phosphate fertiliser use and coal combustion. Once introduced to the soil environment, fluoride undergoes a complex set of processes: adsorption onto mineral and organic matter surfaces, incorporation into secondary minerals, leaching through the unsaturated zone and eventual mobilisation into groundwater or surface waters. Soil pH, clay and carbonate content, redox conditions and microbial activity exert primary control over fluoride speciation and mobility. Elevated soil fluoride levels can impair plant growth, reduce crop yields and pose health risks through the food chain, while deficient levels may limit beneficial applications such as water fluoridation in arid regions. Understanding the balance between retention and release of fluoride under diverse climatic and geochemical settings is therefore central to both environmental protection and public health. Advances in geochemical modelling, ecological risk assessment and field‐based threshold determination are now informing site‐specific management and remediation strategies worldwide.

Research from Nature Portfolio

Recent investigations have elucidated how carbonate‐rich parent material can drive fluoride enrichment in surface and mineral soils, especially in regions affected by coal combustion emissions. It was shown that high levels of Ca(Mg)CO₃ in bedrock restrict fluoride leaching to water and instead promote deposition in the clay fraction of soils. Comparative analysis of soils overlying carbonate versus non‐carbonate units revealed substantially higher fluoride concentrations in the former, despite the low fluoride content of the carbonates themselves. This work proposed an exposure pathway for fluoride derived from weathered carbonate soils and advanced a prevention principle centred on minimising clay binder in domestic briquettes and reducing carbonate weathering under humid conditions.

Fluoride Dynamics and Environmental Impact in Soil Systems publication trend

The graph below shows the total number of articles in fluoride dynamics and environmental impact in soil systems across all publications each year (not limited to Nature Index journals).

Technical terms

Adsorption: The process by which fluoride ions adhere to soil particle surfaces, reducing mobility.

Unsaturated zone: The soil layer above the water table where pores contain both air and water, influencing solute transport.

Species sensitivity distribution (SSD): A statistical model used to estimate pollutant thresholds protective of most species.

Residual fraction: The chemically stable portion of fluoride in soils, tightly bound to mineral lattices and resistant to leaching.

Carbonate weathering: The breakdown of carbonate minerals, which can release or trap fluoride depending on geochemical conditions.

References

1. Soil fluoride enrichment process and the possible adaptation prevention principle in coal-burning fluorosis area in Southwest China. Scientific Reports (2025).
2. Contamination Status and Ecological Security Thresholds of Fluoride in Farmland around a Phosphorus Chemical Plant in a Karst Area of Southwestern China. Toxics (2023).
3. Controls on Groundwater Fluoride Contamination in Eastern Parts of India: Insights from Unsaturated Zone Fluoride Profiles and AI-Based Modeling. Water (2022).
4. Feasibility of a Chemical Washing Method for Treating Soil Enriched with Fluorine Derived from Mica. Minerals (2021).