what is meant by water pollution? how does it occur? state any four sources of water pollution
Answers
Water pollution is the contamination of water bodies, usually as a result of human activities. Water bodies include for example lakes, rivers, oceans, aquifers and groundwater. Water pollution results when contaminants are introduced into the natural environment.
Water pollution is the contamination of water bodies like lakes, rivers, ground
water and oceans. It occurs due to the discharge of untreated pollutants into water
bodies. It not only affects plants and organisms living near the location of
discharge but also travels to other locations through transportation of polluted
water.
Various sources of water pollution are:
• Factories and industries which release various toxins, untreated effluents and
heavy metals and industrial solvents into natural water bodies.
• Agricultural farms releases fertilizers and pesticides which leads to
eutrophication and biomagnification. (See lesson 30- Section 30.6 .3 b and
30.6.3c for details)
• Mining exposes heavy metals and sulphur which were buried deep in the
earth into water bodies.
Sewage pipe and storm water drains release various pathogens, disinfectants
and detergents
• Air pollution releases pollutants like sulphur dioxide, oxides of nitrogen etc.
which are washed down by rains.
• Food processing units and their waste includes fats and greases.