Green Chemistry is nothing but environment
friendly chemistry. It is defined as the
design of chemical products and processes that reduce or eliminate the use
and generation of hazardous
substances. The ultimate aim of green
chemistry or environment friendly chemistry is to prevent pollution at the
source. The first principle of the United Nations Conference on the Human
Environment held at Stockholm
It is a fact that the earth does not belong
to man; rather man belongs to the earth.
Whatever befalls the earth befalls the sons of the earth. Man did not weave the web of life; he is
merely a strand in it. Whatever he does
to the web, he does it to himself. The
basic human right of ordinary human beings is the right to live in a clean
environment and to be protected from the environment degradation created by
others. Hence, there is a need to reexamine
the methods of assessing development benefits and public attitude to the
environment.
GREEN
CHEMISTRY: MEANING
Green
Chemistry deals with various chemical phenomena taking place in the
environment. It can be defined as the
physical surroundings and conditions which affect the lives of the people,
plants and animals. Environment is
composed of lithosphere, hydrosphere and
atmosphere. So, it is necessary to
maintain a fine balance between the above mentioned three components. When this balance is disturbed if the
abundance of a naturally occurring substance becomes more than normal or a new
substance is introduced due to human activities.
CAUSES
FOR ENVIRONMENT POLLUTION
Human
activities and Natural phenomena
may be changed by excessive addition of undesirable materials to the physical
or biological environment, making it less fit or unfit for life is called pollution. Increasing population and industrialization
required more natural resources, when it diminished, man has been trying to
prepare many natural things artificially cause for the rise and growth of
industries. In order to improve the
product by using New Technologies, many waste products were also released into
the environment which causes pollution.
In such a way pollution has become a “global phenomenon”. With deforestation, many of the wild animals
and birds are also getting extinct.
Water of the rivers and ponds are getting polluted. As some of the
pollutants are entering inner layers of the earth cause for the loss of
fertility of the soil and less useful for cultivation. Thus, life on earth is in great danger. A substance released into the environment due
to natural or human activity and which affects adversely the environment is
called as pollutant.
Pollutant may be classified into three
different points of view as follows:
1. Accoring
to their existence in nature – Quantitative
and Qualitative pollutants. For instance Carbon –di-odixe are the
substances, which normally occur in nature but are also added in large
quantities by using fires, industries and automobiles by human beings; where as
qualitative pollutant do not occur in nature but are added by using
insecticides and herbicides by man.
2.According
to their natural disposal - Biodegradable
pollutants and Non degradable pollutants.
For instance sewage and heat are disposed off by microbial action and
radiation [ by natural means]; where as Non degradable pollutants like D.D.T.,
arsenic salts of heavy metals, glass , tin containers, radioactive materials,
and plastics are not degraded or degrade
very slowly in nature. These pollutants accumulate and may get biologically magnified as they
pass through the food chains.
3. According to the form in which they persist
after release into the environment-Primary and Secondary Pollutants. For instance Plastic persist in the form in
which they are added to the environment; whereas Nitrogen oxides and
hydrocarbons from motor vehicles are react in the presence of sunlight to form
two secondary pollutants viz. peroxyacyl nitrate and ozone, which is more toxic
than the primary pollutants. This type
of increasing toxicity by reaction among the pollutants is called synergism.
Atmospheric
pollution
Atmospheric pollution refers to the release
in to the atmosphere, of materials that are harmful to all living and non
–living things. The main sources are Fossil fuel burning, furnaces, power
houses release Carbon monoxide; Volcanic activity, refineries release Sulphur
oxides; Chemical industries release Nitrogen –di – oxides; Aerosol propellants,
chemicals used for dry cleaning release CFC [chlorofluorocarbons]; Asbestos and
cement industries, Textile mills release dust.
Natural activities like Dust storms, Fumes, Fires, Volcanic eruptions,
Natural organic and inorganic decays release harmful gases; dust and sulphurous
gases.
Effects of Atmospheric pollution
on Human Beings
Gaseous pollutant cause severe damage to
respiratory system; Carbon monoxide
reacts with haemoglobin in blood
and reduces its oxygen carrying capacity; Sulphur di oxide affect
larynx; Nitrogen oxides cause pulmonary
haemorrahage in higher concentration;
Hydrocarbon cause Lung cancer; Asbestos cause scarring of lungs known as
asbestosis; and Lead from automobile exhaust gets accumulated in the body
damages bones and so on. If we want to
protect atmosphere, the following
methods help us to minimize the atmospheric pollutants:
i.By planting Phaseolus
vulgaris, coleus blumeri , which can fix carbon monoxide, and pinus, juniperus
can metabolise nitrogen oxides, which help us to depollute the air and
minimizing the use of automobiles, which will not only conserve oil and prove
economically.
ii.By law, all motor
vehicles should use low-surphur or sulphur-free and lead- free fuel and exhaust
gases should be cleaned by using catalyst to reduce Sulphur Oxide release into
the air.
iii.All factories should use
tall chimneys and industrial smoke should be filtered before releasing into the
air.
iv.Poisonous gases should be
removed by passing the fumes through water tower scrubber or spray collector.
v.Mining area should be
afforestated.
vi.Conventional fuels should
be replaced by electricity or natural gas, because it do not emit Sulphur
vii.Modern smokeless
chullahs (induction stove) should be used for cooking, as it avoids wastage and
encourage the people to use solar equipments to avoid pollution.
viii.Avoid Nuclear
explosions and wars.
HYDROSPHERE POLLUTION
Foreign substances like organic, inorganic,
biological or radiological added to water and change Hydrosphere physical
property and make it less fit or unfit for use.
Water pollution cause of soil particles enter water by its erosion,
minerals dissolve in water, animal wastes dead fallen leaves fall into water
sources and decaying of organic matter also pollute hydrosphere. When it gets polluted the colour of the water
changed and increase in the salinity, bad odour starts emanating from water
bodies, uncontrolled growth of weeds in water and decrease in the growth of
fish.
Effects of Hydrosphere Pollution on
Human beings
Inorganic
Pollutants like salts, trace elements like copper, zinc, arsenic etc., metals
coming out from chromium plating industry, leads to diseases like cholera,
jaundice, typhoid and diarrhea; scarcity of drinking water, and affect aquatic life. Metals and complex compounds disturb the
water system. Algae cannot grow properly
and decrease photosynthesis and increase air pollution directly. Cyanides, hydrogen sulphides, carbon di oxide,
nitrogen di oxide and sulphites change the acidity or alkalinity of water and becomes toxic to
aquatic animals and plants. Algae
nutrients like carbon di oxide, hydrogen, oxygen, nitrogen, nitrates,
phosphates, sulphates and micro
nutrients like boron, chlorine, copper, iron, manganese, vanadium, zinc etc.,
compounds causes excess growth of the
algae and subsequently the ponds get dried up or eutrophication of the pond.
The following measures can minimize
hydrosphere pollution
i.The common usage water
bodies should not be used for supplying drinking water and separate water
bodies should be reserved for cattle and other animals.
ii.Domestic and industrial
waste should be suitably “Treated” before releasing into water, which can
reduce the harmful effect of the wastes. Periodical checkup is required to
enforce the law effectively.
iii.Over use of chemical
fertilizers and pesticides should be avoided and substitute by bio fertilizers.
iv.Hot water should be
cooled and release from the factories, and solid water should be recycled where
ever possible.
LITHOSPHERE
[Land] POLLUTION
Chemicals, pesticide, Fertilizers, organic
manure, Radioactive wastes and discarded materials adversely affect the physical, chemical and
biological properties of the soil and reduce its productivity is called
Lithosphere pollution or soil pollution.
Effects of lithosphere pollution on Human
Beings
The Chemicals and pesticides may kill
essential soil organisms which contribute to the structure and fertility of
soil and also make the soil toxic for plant growth. Many pesticides or their degradation products
are absorbed by plants and may reach animals and humans via food chains, and
prove harmful. Excreta of animals and human beings may contain pathogens that
contaminate the soil and vegetable crops and affect the health of man and
domestic animals. Radio active dust may find its way from the soil into crops,
livestock and humans via food chains.
The following steps help us to
reduce the pollution in lithosphere
i.Control of soil and
landscape pollution mainly involves the disposal of solid wastes. Burning of solid wastes pollutes atmosphere
besides leaving a large amount of residue for further disposal.
ii.Pyrolysis [burning without oxygen] is very costly but consumes
energy in large amount.
iii.Recycling of wastes is
practicable, beneficial, consumable, reduces the amount of residue and
conserves the natural resources. For
instance, recycling of paper is costly but recovery of one ton of paper can
save 17 trees.
iv.Jute waste is changed
into hardboard.
v.Cattle dung used in gobar
gas plants, which can substitute electricity, fuel, and enriched dung
manure. In villages bio – gas can be
produced easily. So, it should be
encouraged to use renewable resources.
vi.Domestic wastes can be
composting , which not only reduces environmental pollution but also provides
humans to replenish depleted soil resources.
vii.‘Treatment’ of sewage
and industrial wastes can be reused for gardening.
REMEDIAL MEASURES TO REDUCE ENVIRONMENTAL DEGRADATION The goals of Government should be to change
both local bodies’ and public behaviour; to provide continuous incentives and
rewards for improvement; and to move steadily from pollution control to pollution prevention. Agencies which are responsible
for pollution control can issue leaflets
to create awareness in the minds of people to preserve nature. In addition they can also levy environmental cess that can be passed on to local bodies /
governmental agencies to meet the expenses for preserving the nature.
The general principles on environmental
conservation enunciated by the Government
Charter are as follows:
1.Nature shall be respected and its essential
processes shall not be impaired.
2.The genetic viability on the earth shall not
be compromised; the population levels
of all life forms, wild and domesticated, must be at least sufficient for their
survival, and to this end necessary habitats shall be safeguarded.
3.All areas of the earth, both land and seas,
shall be subject to these principles of conservation; special protection shall
be given to unique areas, to representative samples of all the different types
of ecosystems and to the habitats of rare or endangered species.
4.Eco-systems and organisms, as well as the
land, marine and atmospheric resources that are utilized by man, shall be
managed to achieve and maintain optimum sustainable productivity, but not in
such a way as to endanger the integrity of those other eco-systems or species
with which they coexist.
5.Nature shall be secured against
degradation.
CONCLUSION
Every one is aware about the types of
pollution and preventive measures well.
But many of them unwilling to adopt and practice it. Especially, the highly educated throw the garbage
without segregating it into Biodegradable and Non degradable waste; over usage
of vehicles without maintenance, using car as a prestigious issue and never
encourage their wards to walk, wealth cause for adopting use and through
system and so on led to the
environmental pollution. For instance, in Chennai, Nolambur area, recently the
government has laid New National Highways, at present these national highways
are being used for dumping many tonnes of garbage every day. All educated
crossed by, but no one is taking steps to stop dumping. Two months back all residents send telegram
and e-mail to the Collector to take action against it. At once they clear up. But, still the area is suffering from worst
environmental degradation. Permanent
solution is required to remove garbage from the residential area all over
Chennai. Moreover, insist every domestic waste should be segregated by the
individual family and collected by the government and recycle the waste. Once again the Government
can reintroduce “Downward Filtration
Theory” and educate the highly educated ‘illiterate environmentalist’.
By observing strict rules and punishment like Singapore
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