Assessment of fluoride contamination scenario of groundwater: a study on Purulia-i and Purulia-ii block, Purulia district, West Bengal

In recent time, Purulia district of the West Bengal faces a problem of occurrence of fluoride in groundwater and it gradually the scenario become serious. People of the many villages in Purulia-I and Purulia-II blocks have been marked with fluorosis after consuming fluoride contaminated water. Geologically, this study area is underlain by pre- cambrian metamorphic rocks like granite and gneiss etc. and have the semi- arid climatic condition. In present study a high fluoride concentration in groundwater is identified in a number of villages like Pattamputra, Bhul, in Purulia-I block and Hutmura, Chirumacha in Purulia-II blocks in Both post- monsoon and pre- monsoon season. In some of the village fluoride level have identified below the detection level. The average fluoride concentration of the study area in post monsoon and pre – monsoon season is 0.7215 mg/l and 0.8215mg/l respectively. The other water parameters such as pH, iron, and total hardness were also measured to find out the find out the hydro chemical relationship fluoride and other parameters. The groundwater of the study area is found acidic in nature but a positive relationship has been observed among the fluoride concentration and pH. Fluoride concentration has negative relation with iron and total hardness. The hydro - geological condition of the study area is a key factor for the occurrence of fluoride concentration in groundwater.