Fluoride Concentration in Groundwater:A Case Study From Ramanagaram Taluk, Karnataka, India

Groundwater is a hidden resource and a critical component as it is being used to meet the demands of growing population. It occurs in different geological formations, but in hard rocks it is found mostly in secondary porosity like fractures or fissures. Groundwater contains dissolved inorganic chemical constituents due to interaction between water and geological materials. The interaction between geological materials and groundwater produces various dissolved inorganic constituents which in excess may cause health problems. Among all physico-chemical parameters, fluoride is one, which below <0.6 mg/l and above 1.5 mg/l (as per BIS/WHO) is a slow poison and has significant adverse impact on public health.

Groundwater is a major source of water supply for drinking and irrigational purpose in rural and urban parts of Ramanagaram district, Karnataka state. Groundwater samples from 50 villages of Ramanagaram taluk were collected and studied for 4 important parameters like pH, total hardness (TH), total dissolved solids (TDS) and fluoride.

In the present study, the average pH value is 7.32 with a range of 6.8 to 7.9 and TH between 113 mg/l and 468 mg/l. The TDS value for most of the water samples are just above the desirable limit (500 mg/l) and the fluoride concentration in the study area ranges between 0.3-5.0 mg/l. Fluoride in 80% of the villages in the study area is above 1.5 mg/l. The causes for higher fluoride in groundwater along with some recommendations to minimize its content adopting some simple techniques have been discussed.