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CHAPTER - VII
ENVIRONMENTANDWATERPOLLUTION
Water and environment almost go hand in hand. Polluted water invariably
affects the environment and a polluted environment always pollutes water. It is
necessary to understand the role played by some frequently occurring elements
on earth's surface which have direct bearing on the pollution of environment.
Carbon and nitrogen are two such elements, the cycles of which is related to
earth is given below :
After hydrogen (H), helium (He), oxygen (O) and carbon (c) is the most
abundant elements in the universe. Tens of billions of tons of carbon are
recycled every year by natural processes. Diagram illustrate exchange of
carbon between vegetation and soil, water and plants. Here's how it works in
plants :
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Plants absorb carbon dioxide (CO2). Through the action of
photosynthesis, plants harvest the carbon contained in this molecule to
produce sugar for foods.
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Excess sugars are stored as cellulose in the plants cell walls, forming
stems and stalks.
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Much of the carbon stays captive for the life of the plant. When the plant
dies, decomposition releases all the plants nutrients into the soil.
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Carbon returns to the soil and is free to be taken up again by other
organisms.
Carbon is stored and released not only in plants but in atmosphere, forests,
soils, oceans and fuels as well. The action of burning wood or coal, for
example, releases carbon into the atmosphere. Ideally this would not be a
problem, because the excess carbon - in the form of carbon dioxide - would be
