Which of the following is responsible for the increased concentration of arsenic and fluoride in groundwater in many states of India?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Over exploitation of groundwater
Option (1) Migration — Incorrect. Migration moves people from place to place; it does not change what is in groundwater.
Option (2) Overuse of fertilizers — Incorrect. Fertilisers leave chemical residues in soil and water, but the rise of fluoride and arsenic is tied to over-withdrawal of groundwater.
Option (3) Overuse of pesticides — Incorrect. Pesticides poison soil and water with sprays; they are not the cause of the higher fluoride and arsenic.
Option (4) Over exploitation of groundwater — Correct. When more water is pumped out than is put back, the water table falls. These over withdrawals have changed the quality of the water left in the ground: they have increased fluoride concentration in Rajasthan and Maharashtra and the concentration of arsenic in parts of West Bengal and Bihar.
NCERT (2025-26): “Demand of Water for Irrigation … In Punjab, Haryana and western Uttar Pradesh, more than 85 per cent of their net sown area is under irrigation. Wheat and rice are grown mainly with the help of irrigation in these states. Of the total net irrigated area 76.1 per cent in Punjab and 51.3 per cent in Haryana are irrigated through wells and tubewells. This shows that these states utilise large proportion of their groundwater potential which has resulted in groundwater depletion in these states. The over-use of groundwater resources has led to decline in groundwater table in these states. In fact, over withdrawals in some states, like Rajasthan and Maharashtra, has increased fluoride concentration in groundwater, and this practice has led to increase in concentration of arsenic in parts of West Bengal and Bihar.” |