| |
Nature
has taken hundreds and thousands of years to shape
this world up. And we, the human beings, are
determined to destroy the earth at the earliest. Water
is being contaminated and polluted like
anything.
Geographically,
70 % of earth is made up of water and the rest is made
up of land. But as a matter of fact, human beings are
bringing the entire 70 % of water under peril and
intoxicating it through a careless attitude to the
environment. Industrial effluents, sewage and farm
wastes are the major pollutants threatening the
sanctity of our water resources.
The organic and inorganic contaminants are acids,
alkalis, carbohydrates, dyes, fats, soaps, waxes,
gases, suspended matter, oil, toxic metals and
pesticides including radioactive materials and heated
effluents that impose thermal load on receiving
waters. Biological pollutants include bacteria,
viruses, plants and animals. The other main
contaminants are:
Acids:
Both organic and inorganic acids are discharged into
rivers as industrial wastes. Sulphuric acid is the
main constituents with nitric acid, hydrochloric acid
and phosphoric acid. These acids can damage metals or
concrete structures by their corrosive action.
Alkalis:
Alkalis alter the pH value in rivers resulting in the
break off of the natural buffer system. Alkalis too
destroy bacterial and other micro-organisms to
restrict the self-purification of the stream. Fishes
and other aquatic life are also affected in the
process.
Suspended Impurities:
Insoluble matter in suspension is the common form of
pollution as it is present in sewage and industrial
waste waters reducing the photosynthetic activity of
water-plants. Suspended matter chokes the gills of
fish and destroys aquatic life.
Gaseous Pollutants:
It includes ammonia, free chlorine, hydrogen sulphide,
ozone and phospine. Ammonia produces a spasm of the
glottis leading to death and acts like poison to
fishes when it enters their body through gills.
Oils:
Replacement of coal by oil as a fuel has aggravated
the problem of pollution. Oil spreads over the surface
of water, thus inhibiting the diffusion of oxygen into
water thereby coating the gills of fishes and
affecting their respiration.
Toxic Metals:
It includes metals such as mercury, cadmium, lead,
chromium, copper and arsenic.
|
