Ground Water Quality in the Western Part of Sandur Schist Belt, Karnataka, India

Close monitoring of human health reveals prevalence of different forms of fluorosis amongst the inhabitants of a section of western part of the mining-intensive Sandur Schist Belt which can be attributed to consumption of groundwater characterized by excessive concentration of the fluoride ion. Partial physico-chemical analyses of a total of 65 representative water samples collected from the study area has proved the existence of excessive fluoride ranging from 0.10 mg/L to 1.40 mg/L in surface water and from 0.30 mg/L to 3.2 mg/L in groundwater. More than 46% of the samples report fluoride concentration to be in excess of the Global Maximum Permissible Limit (1.5 mg/L) for drinking water. This excessive fluoride concentration, especially in the groundwater, is primarily derived from geogenic sources and can also be partly attributed to deterioration of water quality due to its overexploitation. A clear relation between geology and water quality has been established as indicated by the fact that fluoride concentration in groundwater from granitoid aquifers is higher than in groundwater from other aquifers. Since the area is characterized by recurrence of chronic drought episodes, scant precipitation since decades, near total dependence on groundwater for drinking, excessive concentration of fluoride in groundwater, health problems of dental- and skeletal-fluorosis and associated complexities amongst others are on the rise across age groups of the population. Aforesaid challenges faced by the masses need to be addressed on urgency by adopting measures such as supply of drinking water from the nearby Tungabhadra reservoir as a long-term solution.