Read the passage and answer the questions:
Water Pollution
Indiscriminate use of water by increasing population and industrial expansion has led degradation of the quality of water considerably. Surface water available from rivers, canals, lakes, etc. is never pure. It contains small quantities of suspended particles, organic and inorganic substances. When concentration of these substances increases, the water becomes polluted, and hence becomes unfit for use. In such a situation, the self-purifying capacity of water is unable to purify the water. Though water pollutants are also created from natural sources (erosion, landslides, decay and decomposition of plants and animals, etc.) pollutants from human activities are the real causes of concern. Human beings pollute the water through industrial, agricultural and cultural activities. Among these activities, industry is the most significant contributor. Industries produce several undesirable products including industrial wastes, polluted waste water, poisonous gases, chemical residuals, numerous heavy metals, dust, smoke, etc. Most of the industrial wastes are disposed off in running water or lakes. Consequently, poisonous elements reach the reservoirs, rivers and other water bodies, which destroy the bio-system of these waters. Major water polluting industries are leather, pulp and paper, textiles and chemicals. Various types of chemicals used in modern agriculture such as inorganic fertilisers, pesticides and herbicides are also pollution generating components. These chemicals are washed down to rivers, lakes and tanks. These chemicals also infiltrate the soil to reach the ground water. Fertiliser induces an increase in the nitrate content of surface waters. Cultural activities such as pilgrimage, religious fairs, tourism, etc. also cause water pollution. In India, almost all surface water sources are contaminated and unfit for human consumption.
Which of the following is a consequence of disposing waste into running water?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Poisonous elements reach the reservoirs.
Option (1) Poisonous elements reach the reservoirs. — Correct. Most industrial wastes are disposed of in running water or lakes. The flowing water carries these wastes onward, so poisonous elements reach the reservoirs, rivers and other water bodies, where they destroy the bio-system of these waters.
Option (2) The bio-systems of surface water bodies gain biodiversity. — Incorrect. The poisonous elements destroy the bio-system; they do not add life.
Option (3) Increases the frequency of smogs. — Incorrect. Smog comes from pollution of the air, not from waste in rivers.
Option (4) This water helps in treatment of many diseases. — Incorrect. Water carrying poison is unfit for use, let alone for treating disease.
NCERT (2025-26): “Water Pollution … Industries produce several undesirable products including industrial wastes, polluted waste water, poisonous gases, chemical residuals, numerous heavy metals, dust, smoke, etc. Most of the industrial wastes are disposed off in running water or lakes. Consequently, poisonous elements reach the reservoirs, rivers and other water bodies, which destroy the bio-system of these waters. Major water polluting industries are leather, pulp and paper, textiles and chemicals.” |