Prevalence of Fluoride in Ground Water in Rajasthan State: Extent, Contamination Levels And Mitigation

Abstract

Ground water is one of the major sources of water supply in Rajasthan due to absence of dependable surface water sources in the most parts of the state. Due to the scanty rainfall and over exploitation of ground water, in 2011, out of the 243 blocks, only 25 are safe from the ground water availability point of view, rest are declared dark zones. More than 80% of the water supply schemes depend on ground water and a number of tube wells, open wells and hand pumps have been dug over the past few decades. In most cases, the source either becomes dry or starts giving low yield and chemical quality gets degraded, resulting in failure of the water supply scheme. As a result, in most of the districts, ground water quality does not conform to BIS or WHO standards as it contains excessive fluorides, nitrates, chloride and total dissolved solids (TDS). The problem of fluoride in ground water has primarily existed in the western districts of the state since ages but with increasing demand for drinking water and over exploitation of ground water, it has spread to almost all the 33 districts. People in some of the districts consume water with fluoride level up to 6 mg/L. Though in some of the districts, people learnt rain water harvesting and used rain water for drinking to avoid ill effects of fluoride. Constant efforts by the government have resulted in increased awareness about the problem. In addition to promoting treatment of fluoride at source, government is now shifting its attention to surface water sources to supply safe drinking water. The state of Rajasthan is a classic example of the socio-cultural-environmental aspects of drinking water and the fight of the community against the scarcity and poor quality of ground water. This paper is an attempt to look at the problem of fluoride in Rajasthan as regards its extent, effects and various practices at the level of the government and community.