question_answer 33)

  The term 'water pollution' can be defined in several ways. Which of the following statements does not give the correct definition? (a) The addition of undesirable substances to water-bodies (b) The removal of desirable substances from water-bodies (c) A change in pressure of the water-bodies (d) A change in temperature of the water-bodies

Answer:

  (c) An undesirable change in the physical, biological or chemical qualities or water that adversely affects the aquatic life and makes the water unfit for use. is called water pollution. Pollution of water is one of the most serious environmental problems of the world. Water pollution may be of following three types (i) Surface water pollution (or inland water pollution) (ii) Underground water pollution. (iii) Marine water pollution. The contaminants leading to pollution in water include a wide spectrum of chemicals, pathogens and physical or sensory changes such as elevated temperature and discoloration. Pathogens cause water borne diseases. Alteration of physical and chemical, properties of water including change in pH, electrical conductivity, temperature and eutrophication (increase in concentration of chemical nutrients), also causes water pollution change in pressure of water bodies do not causes water pollution.