Unit 1 : introduction to environmental studies and natural resources

Definition

Environment: environment is sum total of water, air and land, inter-relationships among
themselves and also with the human beings, other living organ- isms and property

Environmental studies: Environmental Studies is an interdisciplinary field that studies the

different organism, the surroundings and various inter relationships that exist between them.

Scope:

Scope of environmental studies is broad based and it encompasses a large number of areas and
aspects, broadly listed below:

● Natural Resources—their conservation and management

● Ecology and biodiversity

● Environmental pollution and control

● Social issues in relation to development and environment

● Human population and environment

Importance:

Environmental studies is very important since it deals with the most pressing issues like safe and
clean drinking water, hygienic living conditions, clean and fresh air, fertile land, healthy food
and development that is sustainable.

Environmental law, business administration and environmental engineering are emerging as new
career opportunities for environmental protection and management

Need of Public Awareness

• The public has to be educated about the fact that if we are degrading our environment we
are actually harming our own selves.

• It is all the more important to educate the people that some- times the adverse impact of
environment is not experienced or noticed until a threshold is crossed. So we may be caught
unawares by a disaster

Natural Resources:
Definition:

Life on this planet earth depends upon a large number of things and services provided by the
nature, which are known as Natural resources. Thus water, air, soil, minerals, coal, forests, crops
and wild life are all examples of natural resources

The natural resources are of two kinds:

 Renewable resources which are inexhaustive and can be regenerated within a given span
of time e.g. forests, wildlife, wind energy, biomass energy, tidal energy, hydro power etc.
Solar energy is also a renewable form of energy as it is an inexhaustible source of energy.
 Non-renewable resources which cannot be regenerated e.g. Fossil fuels like coal,
petroleum, minerals etc. Once we exhaust these reserves, the same cannot be replenished

Different natural resources

Forest resources

Uses

Consumptive and productive value: Forests provide us a large number of commercial goods
which include timber, firewood, pulpwood, food items, gum, resins, non-edible oils, rubber,
fibers, lac, bamboo canes, fodder, medicine, drugs and many more items.

● Production of oxygen: The trees produce oxygen by photo- synthesis which is so vital for
life on this earth. They are rightly called as earth³s lungs.

● Reducing global warming: The main greenhouse gas car- bon dioxide (CO2) is absorbed
by the forests as a raw material for photosynthesis. Thus forest canopy acts as a sink for CO2
thereby reducing the problem of global warming caused by greenhouse gas CO2.

● Nild life habitat: Forests are the homes of millions of wild animals and plants. About 7
million species are found in the tropical forests alone.

● Regulation of hydrological cycle: Forested watersheds act like giant sponges, absorbing
the rainfall, slowing down the runoff and slowly releasing the water for recharge of springs.
About 50-80 %of the moisture in the air above tropical forests comes from their transpiration
which helps in bringing rains.

● Soil Conservation: Forests bind the soil particles tightly in their roots and prevent soil
erosion. They also act as wind- breaks.
● Pollution moderators: Forests can absorb many toxic gases and can help in keeping the
air pure. They have also been reported to absorb noise and thus help in preventing air and noise
pollution.

Causes of deforestation

(i) Shifting cultivation: There are an estimated 300 million people living as shifting
cultivators who practice slash and burn agriculture and are supposed to clear more than 5 lakh ha
of forests for shifting cultivation annually.

(ii) Fuel requirements: Increasing demands for fuel wood.

(iii) Raw materials for industrial use: Wood for making boxes, furniture, railway-sleepers,
plywood, match-boxes, pulp for paper in- dustry etc. have exerted tremendous pressure on
forests.

(iv) Development projects: Massive destruction of forests occur for various development
projects like hydroelectric projects, big dams, road construction, mining etc.

(v) Growing food needs: In developing countries this is the main reason for deforestation. To
meet the demands of rapidly growing population, agricultural lands and settlements are created
permanently by clearing forests.

(vi) Overgrazing:. Overgrazing by the cattle leads to degradation of forest lands.

Water resources

Water is an indispensable natural resource on this earth on which all life depends. About 97% of
the earth³s surface is covered by water and most of the animals and plants have 60-65% water in
their body.

Uses

Due to its unique properties water is of multiple uses for all living organisms. Water is absolutely
essential for life. Most of the life processes take place in water contained in the body. Uptake of
nutrients, their distribution in the body, regulation of temperature, and removal of wastes are all
mediated through water.

Human beings depend on water for almost every developmental activity. Water is used for
drinking, irrigation, transportation, washing and waste disposal for industries and used as a
coolant for thermal power plants. Water shapes the earth³s surface and regulates our climate.
Ground water:

About 9.86% of the total fresh water resources is in the form of groundwater and it is about 35-
50 times that of surface water supplies.

Effects of Groundwater Usage

(i) Subsidence: When groundwater withdrawal is more than its recharge rate, the sediments
in the aquifer get compacted, a phenomenon known as ground subsidence. Huge economic losses
may occur due to this phenomenon because it results in the sinking of overlying land surface.
The common problems associated with it include structural damage in buildings, fracture in
pipes, reversing the flow of sewers and canals and tidal flooding.

(ii) Lowering of water table: Mining of groundwater is done extensively in arid and semi-arid
regions for irrigating crop fields. However, it is not advisable to do excessive mining as it would
cause a sharp decline in future agricultural production, due to lowering of water table.

(iii) Water logging: When excessive irrigation is done with brackish water it raises the water
table gradually leading to water-logging and salinity problems.

Surface Water

The water coming through precipitation (rainfall, snow) when does not percolate down into the
ground or does not return to the atmosphere as evaporation or transpiration loss, assumes the
form of streams, lakes, ponds, wetlands or artificial reservoirs known as surface water. The
surface water is largely used for irrigation, industrial use, public water supply, navigation etc. A
country³s economy is largely dependent upon its rivers.

Rainwater harvesting

Rainwater harvesting is a technique of increasing the recharge of groundwater by capturing and

storing rainwater

Rainwater harvesting has the following objectives:

(i) to reduce run off loss

(ii) to avoid flooding of roads

(iii) to meet the increasing demands of water

(iv) to raise the water table by recharging ground water

(v) to reduce groundwater contamination

(vi) to supplement groundwater supplies during lean season

Rainwater can be mainly harvested by any one of the following methods:

• by storing in tanks or reservoirs above or below ground.

• by constructing pits, dug-wells, lagoons, trench or check-dams on small rivulets

• by recharging the groundwater.

Watershed management:

The watershed is defined as the land area from which water drains under gravity to a common
drainage channel. Thus, watershed is a delineated area with a well-defined topographic boundary
and one water outlet.

Watershed Management Practices

(i) Water harvesting: Proper storage of water is done with pro- vision for use in dry seasons
in low rainfall areas. It also helps in mod eration of floods.

(ii) Afforestation and Agroforestry: In watershed development, afforestation and crop

plantation play a very important role. They help to prevent soil erosion and retention of
moisture..

(iii) Mechanical measures for reducing soil erosion and runoff losses: Several mechanical
measures like terracing, bunding, bench terracing, no-till farming, contour cropping, strip
cropping etc. are used to minimize runoff and soil erosion particularly on the slopes of water-
sheds.

(iv) Scientific mining and quarrying

(v) Public participation.

Mineral Resources:

Uses:

(i) Development of industrial plants and machinery.

(ii) Generation of energy e.g. coal, lignite, uranium.

(iii) Construction, housing, settlements.

(iv) Defence equipments-weapons, armaments.

(v) Transportation means.

(vi) Communication- telephone wires, cables, electronic devices.

(vii) Medicinal system- particularly in Ayurvedic System.

(viii) Formation of alloys for various purposes (e.g. phosphorite).

(ix) Agriculture–as fertilizers, seed dressings and fungicides (e.g. zineb containing zinc,
Maneb-containing manganese etc.).

(x) Jewellery–e.g. Gold, silver, platinum, diamond

Impacts of mining

(i) Devegetation and defacing of landscape: The topsoil as well as the vegetation are
removed from the mining area to get access to the deposit.

(ii) Subsidence of land: This is mainly associated with underground mining. Subsidence of
mining areas often results in tilting of buildings, cracks in houses, buckling of roads, bending of
rail tracks and leaking of gas from cracked pipe- lines leading to serious disasters.

(iii) Groundwater contamination: Mining disturbs the natural hydrological processes and also
pollutes the groundwater.

(iv) Surface water pollution: The acid mine drainage often con- taminates the nearby streams
and lakes.

(v) Air pollution: mining emits large quantity suspended particulate matter

(vi) Occupational Health Hazards: Most of the miners suffer from various respiratory and
skin diseases due to constant exposure to the suspended particulate matter and toxic substances.

Energy Sources

■ RENEWABLE AND NON-RENEWABLE ENERGY SOURCES A source of energy is

one that can provide adequate amount of energy in a usable form over a long period of time.
These sources can be of

two types:
(1) Renewable Resources which can be generated continuously in nature and are
inexhaustible e.g. wood, solar energy, wind energy, tidal energy, hydropower, biomass energy,
bio-fuels, geo-thermal energy and hydrogen. They are also known as non-conventional sources
of energy and they can be used again and again in an endless manner.

(2) Non-renewable Resources which have accumulated in nature over a long span of time
and cannot be quickly replenished when exhausted e.g. coal, petroleum, natural gas and nuclear
fuels like uranium and thorium

ReNEWABLE ENERGY

Solar energy: Sun is the ultimate source of energy, directly or indirectly for all other forms of
energy. Solar energy can be harnessed by using solar collectors, Solar Cells, solar cookers, solar
heaters, solar furnace and solar power plants.

Wind Energy: The high speed winds have a lot of energy in them as kinetic energy due to their
motion. The wind energy is harnessed by making use of wind mills. The blades of the wind mill
keep on rotating continuously due to the force of the striking wind. The rotational motion of the
blades drives a number of machines like water pumps, flour mills and electric generators

Hydro-Power: The water flowing in a river is collected by constructing a big dam where the
water is stored and allowed to fall from a height. The blades of the turbine located at the bottom
of the dam move with the fast moving water which in turn rotate the generator and produces
electricity.

Tidal Energy: Ocean tides produced by gravitational forces of sun and moon contain enormous
amounts of energy. The ‘high tide’ and ‘low tide’ refer to the rise and fall of water in the oceans.
A difference of several meters is required between the height of high and low tide to spin the
turbines. The tidal energy can be harnessed by constructing a tidal barrage

Geothermal: The energy harnessed from the hot rocks present inside the earth is called
geothermal energy. High temperature, high pressure steam fields exist below the earth³s surface
in many places. Sometimes the steam or boiling water underneath the earth do not find any place
to come out. We can artificially drill a hole up to the hot rocks and by putting a pipe in it make
the steam or hot water gush out through the pipe at high pressure which turns the turbine of a
generator to produce electricity.

Biomass energy: is the organic matter produced by the plants or animals which include wood,
crop residues, cattle dung, manure, sewage, agricultural wastes etc. these waste can be burn to
produce heat which can then be use for the production of electricity.

■ BIOGAS
Biogas is a mixture of methane, carbon dioxide, hydrogen and hydrogen sulphide, the major
constituent being methane which is flammable and can be used for several activities.

■ BIOFUELS

Biomass can be fermented to alcohols like ethanol and methanol which can be used as fuels.
Ethanol can be easily produced from carbohydrate rich substances like sugarcane. It burns clean
and is non-polluting. However, as compared to petrol its calorific value is less and therefore,
produces much less heat than petrol.

Non-Renewable Energy Sources

These are the fossil fuels like coal, petroleum, natural gas and nuclear fuels. These were formed
by the decomposition of the remains of plants and animals buried under the earth millions of
years ago. if we exhaust their reserves at such a fast rate then very soon we will lose these
resources forever.

■ COAL

The ancient plants along the banks of rivers and swamps were buried after death into the soil and
due to the heat and pressure gradually got converted into peat and coal over millions of years of
time. There are mainly three types of coal, namely aлthracite (hard coal), bitumiлous (Soft coal)
and ligлite (brown coal). Coal is the most abundant fossil fuel in the world. When coal is burnt it
produces carbon dioxide, which is a greenhouse gas responsible for causing enhanced global
warming. Coal also contains impurities like sulphur and therefore as it burns the smoke contains
toxic gases like oxides of sulphur and nitrogen.

■ PETROLEUM

Petroleum is a cleaner fuel as compared to coal as it burns completely and leaves no residue. It is
also easier to transport and use. That is the reason why petroleum is preferred amongst all the
fossil fuels.

Liquefied petroleum gas (LPG): The main component of petroleum is butane, the other being
propane and ethane. The petroleum gas is easily converted to liquid form under pressure as LPG.
It is odourless, but the LPG in our domestic gas cylinders gives a foul smell. This is, in fact, due
to ethyl mercaptan, a foul smelling gas, added to LPG so that any leakage of LPG from the
cylinder can be detected instantaneously.

■ NATURAL GAS
It is mainly composed of methane (95%) with small amounts of propane and ethane. It is a fossil
fuel. Natural gas deposits mostly accompany oil deposits because it has been formed by
decomposing remains of dead animals and plants buried under the earth. Natural gas is the
cleanest fossil fuel. Natural gas is used as a domestic and industrial fuel. It is used as a fuel in
thermal power plants for generating electricity. It is used as a source of hydrogen gas in fertilizer
industry and as a source of carbon in tyre industry.

Compressed natural gas (CNG): It is being used as an alternative to petrol and diesel for
transport of vehicles. Delhi has totally switched over to CNG where buses and auto rickshaws
run on this new fuel. CNG use has greatly reduced vehicular pollution in the city.

Synthetic natural gas (SNG): It is a mixture of carbon monoxide and hydrogen. It is a connecting
link between a fossil fuel and substituted natural gas. Low grade coal is initially transformed into
synthetic gas by gasification followed by catalytic conversion to methane.

■ NUCLEAR ENERGY

Nuclear energy is known for its high destructive power as evidenced from nuclear weapons. The
nuclear energy can also be harnessed for providing commercial energy. Nuclear energy can be
generated by two types of reactions:

(i) Nuclear fission: It is the nuclear change in which nucleus of certain isotopes with
large mass numbers are split into lighter nuclei on bombardment by neutrons and a
large amount of energy is released through a chain reaction.
(ii) (ii)Nuclear Fusion: Here two isotopes of a light element are forced together at
extremely high temperatures (1 billion °C) until they fuse to form a heavier nucleus
releasing enormous energy in the process.