Environmental Issues
Pollution is the undesirable change brought
about by chemical, particulate matter, or biological materials to air, water,
or soil.
Air Pollution
● Air is a complex, dynamic
natural reality, which is essential for supporting life on earth.
● Air pollutant is a substance that causes harm
to the humans and other living organisms.
● Some of the common pollutants
of air
○ Nitrogen dioxide
○ Sulphur dioxide
○ Carbon monoxide and carbon dioxide
○ Volatile organic composites
○ Particulate matter
Control of Air Pollution
● Air pollution causes severe respiratory
diseases in humans and other creatures and also affects plants. It can be
controlled by the following ways:
o
Fitting smokestacks and smelters, with filters to
separate pollutants from the inoffensive gases
o
Particulate matter can be removed by using an
electrostatic precipitator. It contains electrode cables maintained at several
thousand volts, which produce electrons. These electrons cleave on to dust
patches and give them a net negative charge and are attracted by collecting
plates, which are predicated. The haste of air passing through the plates
should be low enough to allow the dust to fall.
o
A scrubber can be used to remove gases similar
as SO2 wherein the exhaust passes through a spray of water or lime.
o
Vehicular pollution can be reduced by using
less contaminating energies similar as CNG, which is more effective and less
expensive as compared to petrol or diesel. In 2002, all the buses were switched
to CNG in Delhi and this has indeed led to a fall in pollution situations in
the megacity.
o
Vehicles can be fitted with catalytic
transformers that have metals similar as platinum, precaution, and rhodium as
catalysts. These catalysts carry out the following transformations:
Unburnt
hydrocarbons → CO2 and H2O
Carbon
monoxide → Carbon dioxide
Nitric
oxide → Nitrogen gas
Unleaded petrol must be used
with catalytic transformers as presence of lead in the petrol inactivates the
catalyst.
Greenhouse Effect
It's a natural miracle that
keeps the earth’s atmosphere warm.
o
Without this miracle, the temperature of the
earth would come too cold for living beings to survive.
o
The greenhouse gases (CO2, methane,etc.) absorb
the heat of sun and the earth and emit it back to the earth’s face.
o
Therefore, these gases help a part of heat rays
from escaping into atmosphere.
o This cycle is repeated numerous times to maintain the earth’s temperature to an optimum 15ºC.
The attention of these gases has increased due to increased industrialisation, leading to the heating up of the earth’s surface ( global warming).
This has increased the overall temperature of the earth, performing in changes in the earth’s climate. During the last century, the temperature of earth has increased by 0.6 ºC.
This increase in temperature is eventually believed to cause the melting of polar ice caps, rise in the ocean position, and submerging of the coastal areas.
Greenhouse effect can be controlled by reducing the use of fossil energies, which produce greenhouse gases on burning, afforestation, effective energy operation, etc.
Water
Pollution
● Water is veritably essential
for the conservation of life on earth.
● Due to human activities,
water bodies have come defiled each over the world.
● Some of the common pollutants
and their sources are
Domestic sewage- It substantially contains organic
matter, which is biodegradable. Microorganisms involved in their declination
consume a lot of oxygen and the BOD of the water body increases leading to the
death of fishes and other submarine life.
Sewage also contains numerous
pathogenic microbes, which may cause the outbreak of numerous conditions
similar as typhoid, jaundice,etc.
Industrial Effluents −
Industrial effluents contain inorganic poisonous substances, which may suffer
biomagnification ( increase in attention of a poison at consecutive trophic
situations). The poison gets accumulated in the body of an organism and is
passed on to the coming position. For example, DDT and other heavy metals
similar as mercury, cadmium,etc.
Thermal wastewater discharge −
Heated water flowing out of the thermal power plants increase the temperature
of the water body. It eliminates the cold water species and promotes the warm
water species. In the long run, it causes damage to the indigenous biodiversity
of the water body.
● Eutrophication
o
It's the ageing of a water body due to nutrient
enrichment of its water. It can be natural or artificial.
o
The natural process takes thousands of times,
but due to human activities, this process has got accelerated ( accelerated/
artistic eutrophication).
o
Release of nutrient rich sewage and industrial
effluents lead to preface of nutrients similar as nitrogen and phosphorus and
increase in temperature and BOD of the water body, causing increased natural
exertion, thereby leading to algal blooms. This results in the loss of
indigenous flora and fauna.
o
In some
cases, large millions of floating plants (bog) develop, eventually converting
the water body into land.
·
Raw sewage can be treated using natural and
other means to remove the solid, suspended, and inorganic accoutrements before
it's released back into the terrain.
·
Nitrogenous fertilizers can be denitrified
using microbes, which can convert nitrate and nitrite into gasseous nitrogen by
a process called de-nitrification.
● Integrated waste water management as rehearsed in Arcata, California ¬ In this
approach, the water is first treated by conventional means similar as
filtration, sedimentation, and chlorine treatment, followed by bioremediation.
(Marshes having applicable plants, bacteria, fungi, and algae were planted,
which assimilate dangerous pollutants similar as heavy metals)
Solid Waste
·
Consists of all the unwanted uninvited
accoutrements thrown into the dustbin
·
It may be composed of biodegradable or non-biodegradable
wastes.
·
Open dumps used for disposing solid waste
serves as breeding ground for rats and canvases. Therefore, sanitary
landfills are used as a substitute for these.
·
Biodegradable wastes can be either aerobically
on anaerobically broken down using microbes. The non-biodegradable waste can be
reclaimed, reused, or dumped in landfills.
·
Hospitalv wastes also contain dangerous
accoutrements, which have to be disposed duly. Hospital wastes are generally
incinerated.
·
Irrecoverable computers and other electronic
goods make up e-wastes, which are moreover ditched in land fills or are
incinerated. E-waste can be recycled also to recover metals similar as copper,
iron, silicon, gold,etc.
·
To use the plastic waste in an effective way,
polyblend, a fine powder of recycled modified plastic, has been developed. When
polyblend is mixed with bitumen, it can be used to lay roads with lesser water
repellent capacity and lesser life.
Agrochemicals and Radioactive Wastes
Agrochemicals
● The increased use of pestiicides,
fertilizers for increasing the produce has led to eutrophication and
biomagnifications in water sources.
● In order to check this, the concept of
organic farming is increasingly getting popular. In this fashion, rather of
using chemical fertilizers and pesticides, natural materials and ways similar
as organic manure (cow soil ordure), compost, natural pest control, and crop
gyration are used. This leads to a balanced soil, which doesn't cause soil
infertiliity, but causes the revivification of the soil.
Radioactive Wastes
·
Nuclear energy is a non-polluting energy except
the threats posed by accidental leakage and delicate disposal of radioactive
waste.
·
Radioactive substances cause severe damages
similar as mutations and cancer in lower doses and advanced doses can be
murderous.
·
Radioactive wastes should be suitably pre-treated
in shielded holders buried under rock shells about 500 m under the earth’s surface.
● Natural resources can get
degraded by their improper use.
o
Soil erosion
and desertification – Over-cultivation,overgrazing, deforestation,
and poor irrigation ways lead to soil corrosion and desertification.
o
Water
logging and soil saltness ¬ Lack of proper drainage leads to water
logging, which affects the crops and also leads to increase in the saltness of
the soil.
Ozone Depletion and
Deforestation
Ozone Depletion
· The ozone layer is found in the upper part of
the stratosphere.
· It protects the earth from the dangerous UV rays
of the Sun. High energy UV rays break the bonds within the molecules similar as
DNA and proteins.
· Ozone is formed by the action of UV rays on
oxygen patch and its consistence is measured in Dobson units (DU).
· The ozone is
getting depleted by the action of chlorofluorocarbons (CFCs) plant in
refrigerants and scents.
· The CFCs are acted upon by UV rays in the
stratosphere, liberating the Cl atoms, which act as catalysts to degrade ozone
into molecular oxygen.
·
The ozone depletion is particularly lesser in
Antarctica, performing in the conformation of a large thinned ozone layer
generally known as ozone hole.
·
The UV rays of shorter wavelength cause skin
cancers, mutations in the cellular DNA, snow-blindness, cataract, etc.
·
To check this ozone depletion, Montreal Protocol was passed in 1987 to
control the use of substances thatcauseozone depletion.
● It's the unlimited cutting of
trees and conversion of forests into cultivable land.
● In the beginning of 20 th
century, India had 30 of its area under forestss, which was reduced to just 19.4
by the end of 20 th century.
● Deforestation is a result of
a number of human activity similar as increased population and the demand for
land.
● Trees are cut for forests,
energy, and also for Slash and burn agriculture, also called Jhum civilization.
In this, trees are cut and factory remains in the forests are burned since the
ash acts as a fertilizer.
● Some of the major goods of
deforestation are the increase in carbon-dioxide levels, loss of habitat for
wild creatures, soil corrosion, and consequent desertification.
● Deforestation can be
controlled by reforestation and afforestation.
● In 1980s, the conception of Joint Forest Management was introduced
by the government of India. In this, support of original communities was taken
for conservation of forestss and in return, the local people were free to use
the products obtained from the forests.