From which one among the following water sources, the water is likely to be contaminated with fluoride ?

Fluoride contamination is primarily a geogenic issue, where fluoride is released into groundwater through the weathering and leaching of fluoride-bearing minerals like fluorite, apatite, and micas found in rock formations [t1, t4]. While fluoride exists in air and soil, groundwater is the most significant source of human exposure due to its prolonged contact with these geological layers [c1, t5]. Over-extraction of groundwater for irrigation and domestic use leads to a decline in the water table, which significantly increases the concentration of fluoride in states like Rajasthan and Maharashtra [c4]. Unlike surface water (rivers and lakes), which flows rapidly and flushes pollutants downstream, sluggish groundwater remains contaminated for extended periods [c3]. High fluoride levels in drinking water are linked to dental and skeletal fluorosis, characterized by teeth mottling and joint stiffness [c1, c2].

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 29: Environment Issues and Health Effects > ag.l.s.Fluorine > p. 414
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > 3. Hazards of ground water pollution: > p. 76
3. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > Ground Water Pollution > p. 33
4. [4] INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 4: Water Resources > Demand of Water for Irrigation > p. 44
5. [5] https://www.sciencedirect.com/science/article/pii/S1674987123002013
6. [6] https://pmc.ncbi.nlm.nih.gov/articles/PMC6838337/