Occurrence of Fluoride in the Groundwater of Purulia District, West Bengal and its Effect on Biotic Community

Fluoride contamination in drinking water is a burning environmental issue of the world today. Ingestion of excess fluoride in the human body may cause dental, skeletal and non-skeletal fluorosis. Again, low fluoride less than 0.5 mg/l causes dental caries. Proper safeguards are, therefore, required to be taken to ensure safe fluoride level in drinking water. According to BIS and ICMR, the highest desirable limit of fluoride is specified at 1.0 mg/l and the maximum permissible limit is 1.5 mg/l. Water samples were collected from 17 different locations of Purulia spreading over the three worst-affected blocks, viz., Purulia I, Purulia II and Hura. Highest concentration of fluoride was recorded as follows: Purulia I - 1.56 mg/l, Purulia II - 1.69 mg/l and Hura - 1.52 mg/l. In order to mitigate the rising problem of fluorosis, one has to ensure fluoride free, safe drinking water to the rural communities of Purulia. The following action plan is suggested as a holistic alternative to mitigate the rising fluorosis problem:

• Supply of fluoride-free safe water.

• Extensive water quality monitoring.

• Proper diagnosis and treatment of fluorosis.

• Growing awareness and motivation about fluoride toxicity. The option for fluoride-free safe water supply system could be the following:

• River or lake water-based piped water supply.

• Big diameter tube well-based piped water supply (selecting the fluoride safe aquifers).

• Installation of deep tube wells attached with hand pumps (selecting fluoride safe aquifers, if available).

• Hand pump-attached excess fluoride removal units.

• Fluoride removal units attached with big bore tube wells for piped water supply.

• Use of traditional water sources (lakes/ponds) after treatment.

• Rainwater harvesting.