Environmental fluoride exposure and its toxic effects on plants: a review

The most reactive electronegative element, fluorine, cannot exist naturally in an uncombined state; it is always found in the form of minerals. It is not an micronutrient for humans, animals, and plants, and when too much fluoride is present in the environment, it poses serious health risks, has a negative effect on the food chain, and disturbs the ecological balance. Depending on the concentration and duration of fluoride exposure, the harm fluoride causes to the environment and plants can be either acute or chronic. Fluoride toxicity in plants influences a variety of physiological, morphological, biochemical, germination, and growth parameters, and it even significantly lowers crop yields, which is economically detrimental to a nation. Human health is highly at risk from consuming fluoride-enriched foods as well as other naturally occurring and man-made sources of fluoride, as high fluoride intake and exposure can alter reproduction, impair growth, and result in dental fluorosis, skeletal fluorosis, mental retardation, and many other disorders. In this review article, a variety of fluoride-related topics have been covered, including the types of fluoride that are present in the atmosphere, their sources, how plants absorb fluoride, and illnesses that may be caused by fluoride toxicity in both plants and animals, most notably humans. The use of fluoride-degrading bacteria created using novel "recombinant DNA techniques" and the use of genetically modified "hyper-accumulator plants" for efficient phytoremediation have both been discussed in relation to defluoridation techniques.