Ecotoxicological insights into fluoride pollution affecting soil, plant and human health

Abstract

Fluoride contamination impacts the water-soil-plant continuum, with consequences for soil functions, crop performance, and dietary exposure. Although fluoride occurrence data are extensive, interpretation and cross-study comparability remain constrained by inconsistent reporting of total fluoride versus fluoride fractions up taken in edible plant parts, limited co-measurement across matched water-soil-plant compartments, and a shortage of long-term field evaluations of mitigation impacts on soil fertility and ecosystem services. To address these limitations, we (i) consolidate dominant sources and transfer pathways linking groundwater, soils, crops, and food webs; (ii) summarize the geochemical and soil controls governing the fluoride mobility and uptake, including pH/alkalinity, major-ion chemistry, Ca/Al/Fe-mediated complexation and precipitation, and sorption to clays and metal (hydr)oxides; (iii) integrate ecotoxicological evidence for soil processes and crop-relevant physiological endpoints; and (iv) critically assess the remediation and management options. Across the literature, a central finding is that risk is governed less by total soil fluoride inventories than by the fluoride concentrations up-taken in edible plant parts, which increases under alkaline conditions and in bicarbonate-, and sodium-rich systems and can be sustained through chronic irrigation loading. Evidences indicate that elevated fluoride suppresses microbial activity and enzyme functions essential for nutrient cycling, disrupts Ca-P homeostasis, reduces photosynthetic capacity in sensitive crops, and transfers to edible tissues and beverages, thereby increasing dietary exposure, including in vulnerable populations such as children. Hotspot assessments require explicit consideration of co-contaminant stressors and confounding geochemical conditions. We conclude that effective management should emphasize source control, mechanism-based immobilization (e.g., Ca-based amendments and targeted sorbents), and integrated approaches validated through multi-season field trials. Future priorities include standardized fraction metrics, matched compartment monitoring, crop dose-response datasets, and evaluation of remediation durability, agronomic trade-offs, and cost-effectiveness.