Fluoride Contamination and Accumulation in Agricultural Systems

Fluoride enters agricultural soils through both natural processes—such as weathering of fluorine-bearing minerals—and anthropogenic activities, including industrial emissions, phosphate-based fertilisers and irrigation with polluted water. Once in the soil, fluoride exists in multiple fractions: water-soluble, exchangeable and mineral-bound. Its bioavailability is governed by soil pH, cation exchange capacity and competing anions. Certain crop species, notably tea (Camellia sinensis), act as hyperaccumulators, translocating high concentrations of fluoride from root to shoot. Uptake pathways involve membrane-bound transporters and cation-mediated exchange mechanisms, with subsequent sequestration in vacuoles or incorporation into cell walls. Excessive fluoride accumulation can impair photosynthesis, alter nutrient balance and reduce yield, while entry into the food chain poses risks of dental and skeletal fluorosis in consumers. Management strategies span soil amendments to adjust pH and ionic composition, breeding for low-accumulation cultivars and use of ameliorants to immobilise fluoride in soil.

Research from Nature Portfolio

Advanced transcriptomic analysis in a key crop has elucidated molecular responses to fluoride exposure. Gene expression profiling in tea plants subjected to controlled fluoride treatments revealed induction of receptor-like kinases and activation of autoinhibited calcium-transporting ATPases. These transporters appear to mediate uptake of fluoride ions into root cells, with downstream signalling pathways modulating defence-related gene networks. Differentially expressed unigenes linked to membrane transport and ion homeostasis have been proposed as targets for genetic intervention to limit fluoride accumulation in edible tissues. This foundational work establishes a framework for breeding or engineering varieties with modified transporter activity to mitigate fluoride uptake.

Fluoride Contamination and Accumulation in Agricultural Systems publication trend

The graph below shows the total number of articles in fluoride contamination and accumulation in agricultural systems across all publications each year (not limited to Nature Index journals).

Technical terms

Hyperaccumulator: A plant species that absorbs and concentrates unusually high levels of a specific element, such as fluoride, in its tissues.

Biochar: Charcoal-based soil amendment produced by pyrolysis of biomass, used to adsorb contaminants and modify soil chemical properties.

Exchangeable aluminium (Ex-Al): Aluminium ions loosely bound to soil colloids that can be displaced by other cations, influencing soil acidity and fluoride mobility.

Receptor-like kinase (RLK): A membrane-associated enzyme that perceives extracellular signals and activates intracellular responses, including ion transporter regulation.

Cation exchange capacity (CEC): The total capacity of soil to hold exchangeable cations, affecting nutrient availability and mobility of anions like fluoride.

References

1. Biochar addition to tea garden soils: effects on tea fluoride uptake and accumulation. Biochar (2023).
2. Root-specific expression of CsNPF2.3 is involved in modulating fluoride accumulation in tea plant (Camellia sinensis). Horticulture Research (2025).
3. Effect of fluoride treatment on gene expression in tea plant (Camellia sinensis). Scientific Reports (2017).
4. Effect of soil contamination with fluorine on the yield and content of nitrogen forms in the biomass of crops. Environmental Science and Pollution Research (2017).
5. Fluoride in Human Health and Nutrition. Acta Chimica Slovenica (2019).