Medical Geological Assessment Of Fluoride Contaminated Groundwater In Parts Of Indo-Gangetic Alluvial Plains +

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Several clinical studies and researches have been conducted to find out the impact
of fluoride concentration in drinking water on human health.

It is a well-known fact that fluoride (F−) at low concentration (<0.5 mg/L) induces dental caries, which enhances the risk of tooth decay1,2. On the other hand, ingestion of excessive fluoride imparts adverse effect on human health3. It is a well-established fact that elevated F− concentration in drinking water is linked to dental and skeletal fluorosis depending on the amount of intake and duration of exposure4,5. Excessive fluoride can also damage structure, function and metabolism of soft tissues such as kidney, liver, lung and testicles6,7,8,9. Various clinical studies suggest that ingestion of excessive fluoride promotes physiological dysfunctions like mutagenesis, immune suppression, carcinogenesis and growth retardation3,10. At times, higher concentrations of fluoride can also promote neuro-toxicological effects11,12. Several studies indicate that exposure of excessive fluoride does impart the vulnerable effect on the mental ability of the children. Choi et al.13 suggests that children with exposure to high fluoride were found with significantly lower IQ compared to children residing in low fluoride areas13.
Fluoride easily reaches the placenta, and exposure to fluoride may permanently harm the foetus14. In the human body, the thyroid gland is the most sensitive tissue to the fluoride and exposure to fluoride raises TSH (thyroid stimulating hormone) concentration and decreases T3 and T4 concentration, thereby resulting in hypothyroidism15,16. In several studies, it has been pointed out that prolonged exposure of fluoride from drinking water does develop insulin resistance in human beings17,18. Excessive consumption of fluoride ultimately leads to hyperglycemia and impaired glucose tolerance19,20. While some studies showed that exposure to high fluoride may induce adverse impact on human reproductive system, leading to infertility problems and low body weight of neonates3,21,22. Osteosarcoma is known as a potential cancer target site due to fluoride deposition in bone23,24. Cohn (1992) observed that the association of fluoride in public water with an increased incidence of osteosarcoma in young males25.