Fluoride toxicity in cropping systems: Mitigation, adaptation strategies and related mechanisms. A review

Environmental fluoride (F-) contamination, mainly due to natural geogenic processes, and in spot cases also of anthropogenic origin, is a widespread global issue, which has been recognized to affect all living organisms. From the contaminated soil and water, F- is absorbed by plants which can manifest symptoms of abiotic stress including oxidative stress and interference with essential physiological and biochemical processes involved in seed germination and plant growth and development. Depending on the diet of the population living in the high F-polluted areas, F-contaminated crops can be key contributors to excessive F- intake along food chains which can lead to human and animal health issues. Various strategies are being explored with the objective of reducing both F- bioaccumulation and its damage on plants (e.g. by means of immobilization or phytoextraction processes) or aimed at limiting the F- anthropogenic input in the soil (e.g. through the use of alternative phosphate fertilizers) but the literature is still fragmented. After a brief overview on the effects of F- on the production and safety of food crops, its sources, mobility and bioavailability in agricultural soils, this paper reviews the available F- mitigation and adaptation options and the involved mechanisms with the aim of providing stakeholders with knowledge to make informed decisions when selecting methods for coping with F- impacts in agricultural systems. Research gaps and possible areas for future studies have also been suggested.