Water
Pollution
Water
pollution is any contamination of water with chemicals or other foreign
substances that detrimental to human,
plant or animal health. These
pollutants include fertilizers
and pesticides from agricultural
runoff ,sewage and food processing waste lead, mercury and
other heavy metals ,chemical wastes
from industrial discharges and
chemical contamination from hazardous waste sites. Worldwide nearly two billion
people drink contaminated water that could be harmful to their health.
Water has many remarkable properties. It is sometimes
referred to as ‘ the universal solvent ‘,readily dissolving
a wide range of chemical substances .It also acts
as a fluid medium
facilitating the dispersal
of un-dissolved particulate matter .
Sources of Water
Pollution
1. Domestic
Waste and Sewage :
Raw sewage contaminates
water with pathogens .Micro-organisms
causing degradation of sewage
take up most of the oxygen present dissolved in water .Organic waste gives rise to scum and sludge that makes the water
unfit for recreational and
industrial use .It induces the growth of
some algal blooms that add to the
depletion of oxygen , addition of
more organic matter and fouling of water
.Modern day detergents degrade very slowly . They fore accumulate
and render the water unfit for human and animal use. The phosphates present in
detergents further stimulate algal growth that adds to the organic loading of
water.
2. Surface
Run –Off :
The pollutants present on the
surface of land and fertilizers added to the soil are washed down in to water
reservoirs and water courses during rain. This flow of fertilizer rich water in
to streams and lakes gives rise to eutrophication.
3. Marine Pollution :
Ocean pollution is caused
by ship –generated discharges of soil and petroleum products, noxious liquids,
packaged dangerous goods, sewage, garbage etc. Migrating birds caught the oil
slicks losing their power of flight due to closer interlocking of barbules of
the feathers, is common enough.
Eutrophication:
Any lake or sheet of fresh water, to begin with is oligotrophic, supporting a
minimum of life forms .Therefore its productivity would be minimal .But in
times it comes to be occupied by immigrant life forms, which on death and decay
would make further immigration possible. The lake is then said to have reached
a mesotrophic level .Finally it comes comes to be occupied by a rich flora and
fauna when it is said to have reached the eutrophic level i.e. When its
productivity had reached its maximum. In nature, this would take place through
thousands of years but with industrialization
and other forms of human activity ,this process of eutrophication as it
is called is achieved in to a few decades.
Degree of Water Impurity:
Water pollution by organic
wastes is measured in terms of Bio-chemical Oxygen Demand (BOD).BOD is defined
as the amount of Oxygen required in milligrams for five days to metabolize
waste present in one liter of the water at 20°C .Since BOD is limited to organic wastes it is
not a reliable method of measuring water pollution. It measures all Oxygen
consuming pollutant materials present in the water.
Chemical Oxygen Demand (COD)
.It is an indicator of water or effluent quality which measures oxygen demand
by chemical means using potassium dichromate as the oxidizing agent .Oxidation
takes 2hours and the method is thus much quicker than a 5-day BOD assessment.
The BOD: COD ratio is fairly constant for a given effluent.
Control of Water Pollution
Water Pollution can be controlled to a large extent on the principle,
’the solution to pollution is dilution.’’
The various methods for the control of water pollution are
v The sewage pollutants are
subject to chemical treatment to change them in to non-toxic substance or make
them less toxic.
v Water pollution due to
organic insecticides can be reduced by the use of very specific and less stable
chemicals in the manufacture of insecticides.
v Oxidation ponds can be
useful in removing low level of radioactive waste.
v Thermal pollution can be
reduced by employing techniques through cooling, cooling ponds, evaporative or
wet cooling towers and dry cooling towers. The purpose is that the waste in the
rivers and streams should not get hot
Sources and causes
v Industrial activities: The industries all over
the world that brought prosperity and affluence, made inroads in the biosphere
and disturbed the ecological balances.
v Vehicles: The smoke emitted by
vehicles using petrol and diesel and cooking coal also pollutes the environment
.The multiplication of vehicles, emitting black smoke that, being free and
unfettered, spreads out and mixes with the air we breathe. The harmful smoke of
these vehicles causes air pollution. Further, the sounds produced by these
vehicles produce causes noise –pollution.
v Rapid urbanization and industrialization:
The urbanization and the rapid growth of industrialization are causing
through environmental pollution the greatest harm to the plant life, which in
turn causing harm to the animal kingdom and the human lives.
v Population overgrowth: Due to the increase in population, particularly
in developing countries, there has been surge in demand for basic food,
occupation and shelter.
Environment pollution has negatively affected
the life of both human beings and animals .Almost all of our gains in the
fields of industrial progress, science and technology had so far been realized
at the cost of our health .All this really leaves us wondering if all our
achievements and industrial civilization really help us climb the peaks of
prosperity or simply take us down the blind alleys of adversity. The
environmental pollution is not caused by the fall –out from nuclear tests or
industries alone. The smoke left behind the automobiles and other vehicular
traffic, the increasing use of synthetic detergents, nitrogen fertilizers and
insecticides contaminate both air and water.
v The water we drink the vegetables are all
contaminated today. As a result of this contamination our world is afflicted
with a quite a number of incurable diseases.
v Nothing in this world is immune, no life is safe
and the future of this world is bleak.
v The factories are mostly built in populated areas
and the smoke emitting vehicles play through the congested areas.
v Air pollution may causes severe
lungs-diseases,asthma,brain disorder diseases,etc.
v Soil pollution may have negative effect on farm
output ratio. It can also contaminate the ground water.
v The heat generated by industries and vehicles
causes thermal pollution by raisin the environmental temperature of the nearby
areas.
The
birth of mills and factories is the result of the growth of industry in this
machine –predominated age. As long as they will be there, they must emit smoke,
pollute the air and hasten our end by slow poisoning. The worst industrial
environment tragedy occurred at Bhopal on December 3, 1984 as a result of toxic
and poisonous leakage of methyl isocyanate (MIC) gas from a multi-national Union
Carbide pesticides manufacturing plant
.Over 2000 people including woman and children were killed, and
hundreds were severely hurt.
Solution
What then is the remedy?
There surely cannot be any radical solution, for
the existing factories cannot be bodily lifted to a place far from the
populated zone .However, the following attempts can be made to solve the
problem of environmental pollution.
v The Government can at least see that future
factories are set up at a distant place, an industrial complex far away from
the township.
v Researcher may find out how to avoid harmful smoke
from running vehicles.
v Deforestation should be stopped and Forestry should
be developed.
v Discharge of factory waste in rivers should be
banned so as to make the river water free from pollution.
Initiatives
v The UN Conference on Human Environment was convened
to study the profound changes in the relationship between man and his
environment in the wake of modern scientific and technological developments.
v The World
Health Organization also set up an international network for the monitoring and
study of air pollution on a global scale and for devising possible remedies.
Conclusion
We can very well notice
the abnormal behavior of the seasons – the cycle developing clogs in its
wheels; and worried experts fear that the disturbed balance in the biosphere
has assumed such a serious proportion that very soon our world would be
uninhabitable like Hiroshima of 1945.If we fail to restore the ecological
balance right now, it would be too late tomorrow.
