Assessment of exposure, intake and toxicity of fluoride from groundwater sources in Unnao district of Uttar Pradesh

Fluoride is one of the most commonly found elements in the earth’s crust. It is naturally found d in water and helps in healthy tooth development and cavity prevention. However its high concentration in water can be harmful to human health. The amount of Fluoride (F) occurring naturally in groundwater is governed principally by climate, composition of the host rock, and hydrogeology. As per the World Health Organization and Indian Council of Medical Research the permissible limit to fluoride in drinking water is 1.5mg/L. Anything more than this value can cause fluorosis (dental and skeletal), which can affect the bones and teeth. In the backdrop of this aspect of water quality, this paper in RASĀYAN Journal of Chemistry,  tries to assess the exposure to fluoride through drinking water consumption and to elucidate fluoride endemic areas through mapping in Unnao district of Uttar Pradesh.

The authors state in the introduction that the number of villages, blocks, districts and states endemic for fluorosis have been steadily increasing ever since the disease was discovered in India in 1930’s. Thanks to overgrowth of population, which necessitates more and more need for water, the indiscriminate digging of tube wells, resorting to the use of hand pump water, unawareness regarding the importance of checking water quality, specially for fluoride and due to water shortage the incidence of fluorosis is increasing at a rapid rate. Endemic fluorosis is affecting 65 million people in India spread across 20 states.

With more number of people getting affected by fluorosis and the increased interest to know more about its adverse impact on health this study was undertaken in one of the severly affected districts of Uttar Pradesh- Unnao. The authors state that the study will be useful to perform remedial measures and can be helpful to give awareness about fluorosis to the villagers residing in the particular area.

The results of the study are as follows:

  • The fluoride (F) concentration range in the study area was found between 0.32 mg/L - 2.90 mg/L
  • The downward percolating water is not inactive, and it is enriched in CO2
  • The chemical composition of ground water vary and depending upon several factors i.e. frequency of rain, which will leach out the salts, time of stay of rain water in the root-zone, intermediate zone and presence of organic matter etc.
  • The variation of fluoride concentration among all the clusters are due to composition of ground water, which varies from time to time and from place to place.
  • The high levels of fluoride are due to geogenic sources.
  • Variation in fluoride concentration may be because of the presence of fluoride bearing minerals in the host rocks and their interaction with water.

Finally the authors state that it is high time that an affordable solution should be found to minimize the fluoride contamination for maintaining good health. Further they call for the need to carry out studies on hydro-chemical and hydro-geological aspect of occurrence of fluoride which can be useful to mitigate fluorosis in the district. The government authorities should install defluoridation tanks and also explore possibilities of bringing safe water from nearby villages, which can also be planned with village people and local authorities through community participation.

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