Teaching note prepared by Deepak Gautam Sir (Shantideep English School, Pokhara-14)

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Revised in accordance with the latest revised curriculum prescribed by curriculum development centre
(CDC), Government of Nepal
Environment Science
Class: 10
Author
Deepak Gautam
M.Sc. NRMRD (TU)

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PREFACE
Environment is the sum of all factors and forces that affect life of all living organisms. All the organisms depend
upon the environment to sustain their life. The healthy environment is essential to fulfill the organism's basic
necessities such as food, shelter, water, oxygen, temperature etc. But, due to human intervention the quality of these
basic necessities are decreasing day by day. So, in order to deal with this situation the knowledge of environment is
essentialform the schoollevel.
This book entitled "Environment Science Refresh Book" has been designed according to Curriculum development
Centre (CDC) curriculum. I am happy because this is my first book in the market in the field of environment. I hope
this book will be very useful for the SLC appearing students.
I express my sincere thanks to all the teachers and staffs of Shantideep English School (SDES), Majheripatan-14,
Pokhara. My special thanks goes to Mr. Ramji Poudel Sir (English teacher of SDES) for his valuable time for
editing the text of this book. Similarly, I would like to thank my dear wife Asmita Poudel for her support while
computerizing the materials. Finally, I am grateful to my parents for their love and encouragement during my study
and professionalcarrier.
Lastly, I want to request all the students and teachers to help me to improve this book by giving feedback in my
mail: gautamdeepak77@yahoo.com.

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UNIT: 1. GREENHOUSE EFFECT
INTRODUCTION
Earth's atmosphere consist various gases. These gases act as a blanket around the earth and maintain the earth's
temperature by absorbing and reflecting the solar energy in right amount by natural process. However, the over
production of greenhouse gases such as water vapour, CO2, CH4, SO2, CFCs etc. by human activities trap more heat
and increase greenhouse effect resulting global warming. Similarly, global warming increases the temperature of the
earth which changes the weather pattern resulting in climate change.
1.1 GREENHOUSE EFFECT AND GLOBAL WARMING
The greenhouse effect is the natural process by which the atmosphere traps some of the Sun's energy, warming the
Earth enough to support life. The huge amount of greenhouse gases causing a global rise in temperat ure is called
global warming. Natural level of green house gas traps the solar heat and makes life possible on the earth, without
which the average temperature of the earth would be -30oC.
1.2 GREEN HOUSE GASES AND THEIR SOCURCES
Green house gases are those gases which trap and hold the solar heat in the atmosphere. By increasing the heat in the
atmosphere, green house gases are responsible for the greenhouse effect, which ultimately leads to global warming.
The short descriptions of some green house gases are as follows:
Carbon Dioxide (CO2): It is the most common greenhouse gas in the atmosphere responsible for about 50 % of the
total greenhouse effect. Burning of fossil fuels, operation of automobiles, industries, burning of wood, firewood etc
are the major sources of CO2 in the atmosphere. Similarly, volcanic eruption, decayed plants and animals and
respiration release large amount of CO2 in the atmosphere.
Chlorofluorocarbons (CFCs): They are non-toxic, inert chemical compounds containing chlorine, fluorine and
carbon molecules. Air conditioner, refrigerators and plastic foams are the major sources of these compounds. They
are responsible for 22% of total greenhouse effect.
Methane (CH4): Rice plants, landfills, fossil fuels, dead and decayed plants and animals are the major source of
methane. Methane is produced naturally in large amount from organic matters too. It is responsible for 15% of the
total greenhouse effect.
Nitrous oxide (N2O): Major sources of nitrous oxides are: burning fossil fuels, fertilizer, livestock wastes and nylon
production. Tilling operation of the fields also release nitrous oxide. It is responsible for 6% of the total greenhouse
effect.
Ozone (O3): Ozone of the troposphere is a serious pollutant. It reacts with oxides of nitrogen in the presence of
sunlight and increases greenhouse effect. It is responsible for 7% of the total greenhouse effect.
1.3 CAUSES OF GREENHOUSE EFFECT
Burning of fossils fuels : Fossil fuels like coal, oil and natural gas have become an integral part of our life. They
are used on large basis to produce electricity and for transportation. Pollution which gets emit from vehicles contains
carbon dioixde, which is one the main gas responsible for increase in greenhouse effect.
Deforestation: Forests hold a major green area on this earth. Plants and trees intake carbon dioxide and release
oxygen, through the process of photosynthesis,for the survival of human beings. Large scale development have
forced people to look for alternate places for living which has resulted in cutting down of trees. The wood that is
produced,when burnt releases more carbon dioxide into the atmosphere.

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Increase in Population : Over the last few decades, there have been huge increases in the population. Now, this
has resulted in increased demand for food, cloth and shelter. New manufacturing industries have come up release
some harmful gases into the atmosphere which increases the greenhouse effect. Also, more people mean more usage
of fossil fuels which in turn has aggravated the problem.
Industrial waste and landfills: Industries which are involved in cement production,fertilizers, coal mining
activities, oil extraction produce harmful greenhouse gases.Also,landfills filled with garbage produce carbon
dioxide and methane gas contributing significantly to greenhouse effect.
1.4 EFFECT OF GREENHOUSE GASES
Increase temperature (Global warming): They increase the greenhouse gases which accelerates global warming.
Consequences of global warming are rise in sea level due to melting of ice caps and snow, change in the agricultural
patterns etc.
Change in climate: Increase in greenhouse gases in the atmosphere increase global warming which causes the
change in the climate. Change in climate affects the physical and biological aspects of the environment. For
example: Every organism has its own tolerance range for temperature. If temperature is above or below than their
existence is affected. So, global biodiversity is underparticular risk.
Similarly,
*They increase in evaporation and transpiration which result long drought and scarcity of water.
*They increase in precipitation and flooding, which increases soil erosion and mass wasting.
*They deplete the ozone layer which increases skin cancer, cataracts, skin crack etc.
1.5 CONTROL MEASURES OF GREEN HOUSE GASES
Due to the high emission of greenhouse gases, we are facing various problems such as global warming and climate
change. If the emission of these gases continue then the problem will be more disastrous. Following measures
should be taken into consideration to control the greenhouse gases.
By minimizing the production of green house gases: Most of the green houses gases are evolve from industries.
So, there should be treatment plants along with the industries.
By expanding forest area: Forest conserves the water resources as well as lowers the temperature and reduces CO2.
By proper management of pollution and population: The proper management of solid wastes and pollutants as
well as control of over population significantly reduced greenhouse gases.
By conserving water resources: Water plays vital role in balancing the temperature. Oceans are huge sources of
water, which absorb certain amount of CO2. So, the conservation of water resources should be initiated from all
sectors.
By conserving and avoiding unnecessary use of fossil fuels: By using alternative sources of energy such as solar
energy, hydropower, biogas etc, instead of fossil fuels, this helps to decrease the production of greenhouse gases.
By policy formulation and implementation: Stick policy should be formulated and implemented effectively to
reduce the emission of greenhouse gases.Fore.g. Prohibit the use of old vehicles which are more than 20 years old.

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1.6 WORLDWIDE EFFORTS ON REDUCING GREENHOUSE EFFECT
The major world wide programmes on reducing greenhouse gases are:
 United Nation Environment Programme (UNEP) was established in 1972 by United Nations General Assembly
(UNGA) to promote international cooperation in environmental matters.
 UNEP launched various programme such as earth watch, trend analysis, adoption of environmental protection
projects, etc. to reduce the green house gases.
 UNEP has initiated projects on protecting ozone layer, climate, water, energy, biodiversity etc.
 UNEP has promoted the program on health, population and environment by enhancing education.
 In 1993, the National Research Council of the USA published a report on worldwide increase of carbon dioxide. The
report also emphasized to control CO2 and greenhouse gasses.
 In 1995, UNEP, World Climate Organization and Scientists Association organized a conference on CO2 and
greenhouse effect to reduce greenhouse effect.
 In 1988, UNEP organized first international conference on conservation of ozone layer and to find out the
alternatives of CFCs.
 In 1992, UNO organized international conference on environment to promote the environment.
 Nepal has adopted the following policies, acts and sections for climate change:
 Climate change vulnerability mapping 2010
 National Adaptation of Action (NAPA) to climate change 2010.
 Climate change policy 2011
Extra Notes:
Common causes of green house effect/ global warming/ climate change:
 *Burning of fossil fuels.
 *Deforestation
 *Use of old vehicles and industries.
 *Emission of CFCs by refrigerators and air conditioners.
 *Over population and pollution (more people more exhale of CO2)
*High use of halogens and nitrogen fertilizers etc.
Common effects of green house effect/ global warming/ climate change:
*Loss of biodiversity
*Increment in natural disasters
 *It reduces the crop fields by reducing moisture.
*It increases the temperature of atmosphere.
 *Change in climate pattern changes crop patterns.
Common control measures of green house effect/ global warming/ climate change:
 *By controlling production of green house gases.
 * By expanding forest areas
 *By controlling pollution and population.
 *By conserving water resources
 *By minimizing the use of fossil fuels
*By minimizing the use of halogens and nitrogen fertilizers.

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Model questions:
Mention any four major negative impacts of green house effects and explain one of them in brief.
There are many negative effects of green house effects. Some of them are listed below:
*It causes global warming.
*It reduces the crop fields by reducing moisture.
*It changes the climatic pattern which alters crop pattern.
*It increases the temperature which results melting of polar ice and snow of mountain region etc.
The explanation of one major effect is given below:
It causes global warming: The huge amount of greenhouse gases causing a global rise in temperature is called global
warming. Global warming leads to rise in sea level, increases natural disasters like drought or floods etc. which
directly affect human health and whole ecosystem..
Define climate change. Write down the impacts of climate change.
Climate change may refer to a change in average weather conditions. It means change in all the weather
determinates like precipitation (rainfall, snowfall, hail fall etc) temperature etc.
The impacts of global warming are:
*Loss of biodiversity.
*Increment of natural disasters.
* Change in traditional calendars.
*Shift in cultivation and harvesting period of crops.
*Shifting of vegetation from lower altitude to upper altitude.
What is artificial green house? Write its advantages.
A house made up of plastics or glasses is called artificial greenhouse or simply greenhouse. Plants are grown inside
it artificially. The wall of green house allows the incoming solar rays to pass inside but does not let escape out of it.
Thus,the wall of green house keeps warmer inside it by trapping infrared radiation.
The Advantages ofgreen house are:
*Summer plants can be grown in winter season
* Desert plants can be grown in non-desert areas.
How it traps the solar heat and maintains the temperature of the earth?
As like artificial green house, when the solar radiation falls on the earth's atmosphere they can enter the earth
because they have shorter wave length but the reflected radiations are trapped by the greenhouse gases because
reflected radiation has longer wave length. In this way, gaseous layer helps to maintain the temperature of the earth
surface. The principle of heating of earth surface is similar to that of the green house. So this process is termed as
green house effect.

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UNIT: 2. OZONE LAYER
2.1 INTRODUCTION
The layer of the air surrounding the earth is called atmosphere. The main constituents of the atmosphere are
nitrogen (78%), oxygen (21%), argon (0.9%), CO2 (0.03%), water vapour, dust particles and other gases.
Atmosphere is further divided in five layers. The short information of five distinct layer of atmosphere are:
Troposphere: The lowermost layer of the atmosphere is called troposphere. It is 16km thick. The topmost layer of
the troposphere is called tropopause.
Major features of this layer are:
 It contains large amount of heavy gases like CO2, N2, O2, inert gases,water vapourand dust particles.
 Various activities related to the weather like cloud formation, wind, rain, lightening, thunder, fog, storm etc
take place in this layer.
 About 6.5 0C temperature falls per km of increase in altitude.
 About 95% of earth’s atmosphere is in troposphere.
Stratosphere: The layer of the atmosphere above troposphere is called stratosphere. It is extended from16km -50km
above the earth. The topmost layer of the stratosphere is called stratopause.
Major features of this layer are:
 Ozone layer is found at the upper part of this layer.
 This layer consists less amount of humidity.
 The temperature of this layer decreases with altitude.
Mesosphere: The layer of atmosphere above the stratosphere is called mesosphere. It is extended from 50km -80km
above the earth. The topmost layer of the mesosphere is called mesopause.
Major features of this layer are:
 The temperature of this layer decreases with altitude.
 Strong wind blows in this layer.
 This is the coldest region of the atmosphere.
Thermosphere: The layer of the atmosphere above mesosphere is called thermosphere. It is extended from 80km to
720km above earth. Its topmost layer is called thermopause.
Major features of this layer are:
 The temperature of this layer is very high.
 The region consists ions of nitrogen, oxygen etc.
 The upper regions of this layer contains hydrogen,helium etc.
Exosphere: The topmost layer of the atmosphere is called exosphere. It is extended above 720km from the earth’s
surface. Major features of this layer are:
 There is no effect of gravity in this layer. So, it is called fringe layer.
 Gases blow with very high velocity.
 This layer mainly contains hydrogen and helium.

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2.2 CONCEPT OF OZONE LAYER: A pale blue gas which is found in the uppermost part of stratosphere is
called ozone. The layer of pale blue gas which is found in the uppermost part of the stratosphere is called ozone
layer.
2.3 FORMATION OF OZONE LAYER: A pale blue gas which is found in the uppermost part of stratosphere is
called ozone. When an oxygen molecules absorb high energy of solar radiation it disassociates into nascent oxygen.
The nascent oxygen then combines with an oxygen molecule to form ozone. The equation is given below:
O2 Solar radiation → O + O (nascent oxygen)
O2 + O → O3 (formation of ozone)
2.4 IMPORTANCE OF OZONE LAYER: There are many importance of ozone layer. Four of them are given
below:
*It protects the earth from over heating
*It protects us from UV rays of the sun.
*It helps to evolve terrestrial animals.
*It helps to evolve and protect terrestrial animals. etc.
2.5 DEPLETION AND CAUSES OF OZONE LAYER: The destruction of ozone in the stratosphere by the
action of CFCs, CO2, oxides of nitrogen etc is called ozone layer depletion. The major causes of ozone layer
depletion.
*Emission of large amount of artificial green house gases such as CFCs, CO2 etc.
*Excessive use of fossils fuels such as petrol, kerosene, diesels etc.
*Excessive use of nitrogen fertilizers release oxides of nitrogen which deplete ozone layer.
*Destruction of forest and increment of air pollution.
*Extensive use of halogens (Cl, F, Br, I) as a fire extinguisher deplete ozone layer.
2.6 EFFECTS OF OZONE LAYER DEPLETION
Effects on health: Due to the depletion of ozone layer, ultraviolet radiation easily enters the earth as a result various
diseases such as sunburn,skin cancer, eyes diseases,skin crack etc. occurs.
Effects on plants and animals: The ultraviolet radiation entering the earth due to ozone layer depletion hampers the
growth and development of plants. It also reduces the reproductive ability of animals.
Increase in temperature: More amount of heat coming from sun gets accumulated in the atmosphere causing
green house effect. As a result the temperature increases.
Reduce crop production: Over exposure to UV rays destroy the protein content of plants, depletes the chlorophyll
formation, which reduces photosynthesis.As a result there is low crop production.
Loss of plants and animals: Due to over exposure to UV rays small organism are unable to adapt to the new
environment. As a result they may die.
2.7 PROTECTION OF OZONE LAYER
We can protect the ozone layer in the following ways:
*CFCs emitting devices should be banned.
*Educate the people about the importance of ozone layer.
*Encourage the use of renewable sources of energy such as solar energy, hydropower etc.
*Use of nitrogen fertilizers should be minimized
*Reduce the use of fossil fuels.

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Model questions:
Write down the prime cause of depletion of ozone layer.
The ozone layer is depleted mainly due to the action of CFC products and the oxides of nitrogen. It is estimated that
a CFCs molecule can destroy about 100,000 molecules of ozone.
For e.g. when the oxides of nitrogen reach the stratosphere, they react with ozone forming oxygen. The reaction
takes place as follows:
NO +O3→NO2+O2
2NO2+O3→N2O3+2O2
Note: O3 Solar radiation→ O2 +O (depletion of ozone)
Define ozonosphere and ozone hole. Ozone layer is called protective layer. How?
Thick layer of ozone is called ozonosphere. An ozone hole is defined as the region of space in the stratosphere
where there is a drastic reduction of ozone content.
Ozone layer is called protective layer because, it absorbs most of the solar radiations and save th earth from the
harmful ultraviolet radiation. It prevents us from the dangerous diseases like skin cancer, skin crack and deficiency
of immunity due to over exposure of ultraviolet radiation. It also helps to reduce greenhouse effect. So, this layer is
called protective layer.
Note: Infrared radiation is invisible radiant energy, electromagnetic radiation with longer wavelengths than those
of visible light.

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LESSON: 3.ENERGY
3.1 INTRODUCTION OF ENERGY AND IMPORTANCE
The capacity of doing work is called energy. Its SI unit is joule. "Energy can neither be created nor be destroyed
but it can be converted fromone formto another form, hence total energy always remains conserved". This principle
is called conservation of energy.
3.2 USES OF ENERGY
(a) Lighting
It is a form of energy which gives sensation of vision. During the day time, we get light fromthe sun but at night we
get light from other sources of energy such as electricity, fossil fuels, wood, biogas, candles etc. Plants obtain energy
from the sunlight. They convert solar energy into storable chemical form by photosynthesis. Fossils fuels are the
remains of plants and animals. Energy released from fossil fuels is in fact the chemical energy converted from
sunlight.
(b) Heating
Heat is a form of energy which gives sensation of warmth. We get heat energy from various sources. The main
source of heat energy is sun. Heat from the sun causes water cycle. Heat energy obtained from fossil fuels, fire-
woods etc. is used to cook the foods. Fuel is the major source of heat which is used to run the automobiles and
industries. The flow of energy takes place from sun to plants by photosynthesis process. The flow of energy occurs
from plants to herbivorous and ultimately from herbivorous to carnivorous. Therefore life on the earth is possible
due to sun.
(c) Fuel
A substance that burns and gives out heat energy is called fuel. Its advantages are:
(a) Fuels such as petrol, diesel, coal etc are used to run the vehicles.
(b) Fuels such as agricultural residues, animal dung, firewood etc are used to cook food in rural areas.
(c) Fuels are used to run industries,generators etc.
(d) Run Industries
Various types of energy are essentialto run the industries. Industries produce goods which are daily consumed by
human beings for various purposes.Electrical energy, fossils fuels, etc are used to run the industries.
(e) Transportation:
Fossils fuels are largely used in transportation in Nepal. Various other sources of energy such as s olar energy,
electrical energy are also used to run the vehicles. Similarly nuclear energy and gases are also use to run the
vehicles. Reliable transportation helps to carry the goods from one place to another place.
3.2 SOURCES OF ENERGY
Primary sources of energy
Those sources of energy which can be used in the same form in which they occur in nature are called primary
sources of energy. Primary sources can be used directly, as they appear in the natural environment: coal, oil, natural
gas and wood, nuclear fuels (uranium), the sun, the wind, tides, mountain lakes, the rivers (from which
hydroelectric energy can be obtained) and the Earth heat that supplies geothermal energy.
Secondary source of energy
Those sources of energy which are derived from primary energy sources are called secondary energy sources. A
secondary energy source is one that is made by using a primary resource. For example: petrol, diesel, charcoal,
biogas etc.
Note: Electricity is secondary resource, and can be generated by a number of different primary sources, biogas,
coal, petrol, charcoal, diesel etc.

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3.2.1 RENEWABLE SOURCES OF ENERGY (RSE): Those sources of energy which can be obtained
continuously and can be used again and again are called renewable sources of energy. Some of the renewable
sources of energy are: solar energy, wind energy, hydroelectricity, bio -fuel, tidal energy, geothermal energy etc.
Some of them are described below:
Solar energy
The energy obtained from the sun is called solar energy. Solar energy is produced by nuclear fusion reaction in its
core. This energy can obtained continuously.So, we can use and store this energy for various purposes.
Its advantages are:
(a) Plant converts solar energy to chemical energy through photosynthesis.
(b) It is use to run the solar vehicles and solar equipments.
(c) It is a cheap source of energy.
(d)It is pollution free.
Wind energy
The energy obtained from blowing wind is called wind energy. Out country Nepal has good potentiality for
windmill electricity in Mustang, Dolpa and Jumla. A 20 KW wind energy plant has been established in Kagbeni,
Mustang.
Its advantages are:
(a) It is a renewable source of energy.
(b) It is pollution free.
(c) It is a cheap source of energy
(d) This energy is used to generate electricity.
Hydroelectricity
The electricity generated from running water is called hydroelectricity. We have great potentiality for producing
hydroelectricity because our country is rich in water resources. The estimated electricity generating power of our
country is about 83,000MW.
Its advantages are:
(a) It is pollution free.
(b)It is a renewable source of energy.
(c) It is cheap in long run and easy to transform and use.
(d) Modern equipments and devices are also operated by it.
Note: Nepal has capacity (potentiality) of producing 83,000 Megawatt hydroelectricity. At present we are producing
just about 1000 MW. The first hydropower of Nepal is Pharping (1965B.S). Other popular hydropower are:
kaligandaki, kulekhani, Trisuali etc.
Bio-fuel
Fuel obtained from the organic source is called bio-fuel. Wood, bio-gas, hay, straw, etc all are organic sources of
fuel. The use of bio-fuel is effective in village and hilly areas. In modern days, biogas is more popular. Government
has also provided help and subsidy for the construction of bio-gas plant.
Its advantages are:
(a) It is used to produce heat for domestic purpose.
(b)It is a cheap source of energy
(c) It is pollution free (clean energy)
(d) It is a renewable source of energy.
(e)Biogas can be used to generate electricity.
(e)Biogas burns completely without leaving any residue

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Note: How is the biogas formed? The wastes of plants and animals can be decomposed into airtight vessel.Then the
remains will decay by anaerobic bacteria in the presence of water. Then, different gases formed (CH4, H2 etc).
Combination of these gases is called biogas.
Geothermal energy
The heat energy obtained from interior (inside the surface) of the earth is called geothermal energy. This energy can
be used to generate electricity. Some countries are utilizing this energy to produce electricity but in our country it is
used for the special treatment of skin disease at different springs like Tatopani(hot water).
Its advantages are:
(a)It is renewable source of energy
(b)It is a cheap source of energy
(c)It is pollution free.
Tidal energy
The energy obtained from the tides of the sea or ocean is called tidal energy. The rise of ocean level due to the
attraction of the sun and moon is called high tides where as fall of the ocean level is called low tides. The sea level
raised during the high tides is trapped in dams. This water is then allowed to fall down slowly on the blades of the
water turbines. The rotating turbines drive generator, which ultimately produce electricity as like hydroelectricity.
Its advantages are:
(a)It is renewable source of energy
(b)It is a cheap source of energy
(c)It is pollution free.
Note: It is applicable in the costal areas.
3.2.2 NON- RENEWABLE SOURCES OF ENERGY (NRSE)
Those sources of energy which gets depleted and cannot be used again and again are called non-renewable sources
of energy. They are present in limited amount. Natural gases, mineral oil and coal are the non-renewable sources of
energy. It takes longer period for formation and they are available in limited amounts. Fossil fuels and Nuclear
energy are the types of non renewable sources of energy.
Fossil fuels
Fuels obtained from fossils are called fossil fuels. For example: natural gas, Mineral oil, coal etc.
Natural gas
It is a flammable gaseous mixture consisting mostly of hydrocarbons. It contains about 85% methane and 10%
ethane. It is used as a fuel and raw materials in the manufacture of chemicals. It is also used as a source of heat in
making glass. LPG gas prepared from crude oil is used for cooking, heating,transportation,machinery uses etc.
Mineral Oil
The fossilized remains of plants and animals are called mineral oils. For examples: petrol, diesel, kerosene etc.
Mineral oil is formed by the decomposition of dead bodies of plants and animals in the presence of high temperature
and high pressure in the absence of oxygen by the action of bacteria.
Its advantages are:
(a) It is a source of heat and light.
(b)It is used as lubricants in industries and vehicles.
(c) Artificial rubbers, polish, cosmetics etc are made from it.
(d) It is used to run vehicles and industries.

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Note: Countries like USA, Netherland, Canada, Germany, Iran Iraq, Venezuela etc have biggest reserve of mineral
oil. In Nepal Muktinath, Dailekh, Dang, Salyan, Pyuthan, Surkhet, jhapa, morang and Chure hills have some
reserve of this oil.
Coal: The fossilized remains of plant is called coal. It is dark coloured solid fuel which is found in the deposits of
sedimentary rock. Coal is formed by the decomposition of dead plants due to the presence of high pressure and
temperature in the absence of oxygen. There are four types of coal. They are anthracite, bituminous, lignite and peat.
Its advantages are:
(a) It is used as a source of heat energy.
(b)It is used at home, factories, trains etc.
(c) It is used to generate electricity.
In Nepal, there is possibility of coal reserve in Dang district. The coal found in Nepal is of low quality.
Caution: Burning of mineral oil and coal produces carbon-dioxide and carbon-monoxide which cause environmental
pollution and accelerates global warming
Nuclear energy
Energy produced from nuclear reaction (nuclear fission/ nuclear fusion) is called nuclear energy. The reactions in
which the nucleus of an atom undergoes a change forming new atoms and releasing a tremendous amount of energy
are called nuclear reactions. Sun releases large amount of energy by nuclear reaction
(a) Due to the continuous emission of heat and light energy.
(b) Due to the presence of heavier nucleus formed by the nuclear fusion of helium atoms.
Beside this, uranium or heavy elements are spitted to produce large amount of energy. Developed countries such as
USA, Germany, China, Japan etc have produced a large amount of energy from nuclear reaction.
Nuclear fission Nuclear fusion
*The process of breaking heavy nucleus into two or
more lighter nuclei is called NF.
*Nuclear fission reaction is controllable.
*Atomic bomb is based on nuclear fission
*It is less powerful and less destructive than nuclear
fusion.
*For example: uranium nucleus splits up into barium
and krypton nuclei with the release of energy.
*The process of combining two or more lighter nuclei
to form a single nucleus is called nuclear fusion.
*Nuclear fusion reaction is uncontrollable so far.
*Hydrogen bomb is based on nuclear fusion
*It is more powerful and more destructive than nuclear
fission.
*For example hydrogen nuclei fuse together to form a
helium nucleus with the release of energy.
Note: Fusion is the source of the energy from the sun and stars where as fission is the source of nuclear reactor.
The process in which an unstable nucleus of a heavy atom like Uranium -235 splits up into two medium weight
nuclei with libration of a large amount of energy is called nuclear fission. The nuclear fission reaction is carried out
by bombarding the heavy nuclei with neutrons.
3.3 PRESENT STATUS OF ENERGY IN NEPAL (ENERGY REQUIREMENT IN NEPAL)
In Nepal, the large amount of the energy need is dominated by fuel wood (68%) agricultural waste (15%), animal
dung (8%), and imported fossil fuel (8%). All commercial fossil fuels (mainly oil and coal) are either imported from
foreign countries. Only about 1% energy need is fulfilled by electricity. Therefore, out of total energy consumption
of Nepal in 2011A.D about (9% energy is obtained fromcommercial energy sources (fossil fuels, hydroelectric etc)
and 90% is obtained from traditional energy sources (firewood, animal dung, agricultural wastes etc).
3.4 CONSERVATION ENERGY
The wise use of energy is called energy conservation. Conservation of energy means keeping the sources of energy
from damage and wastage. The conservation or saving of energy is necessary in today’s world because the crisis of
non-renewable sources ofenergy may happen in future. So, to save such resources, the conservation is a must.

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Ways to save/conserve energy
*Using energy efficient equipments. For e.g. Use of CFL bulb instead of filament bulb.
*Changing energy wasting habits and lifestyle. For e.g. Switch off the light when it is not needed. Use bicycle
instead of car or bike for a short trip etc.
*Energy saving equipment should be used in industries.
*Solar vehicles should be used instead of traditional vehicles.
*Energy efficient vehicles should be used.
*Pricing policy combined with incentives should be encouraged.
3.5 CONSERVATION OF RENEWABLE SOURCES OF ENERGY
 Development of biomass energy
 Wise use of the energy
 Energy saving technology
 Development of alternative sources of energy
 Proper management of energy resources
3.6 CONSERVATION OF NON RENEWABLE SOURCES OF ENERGY
 Sustainable use of fossil fuels
 Protection of mines
 Development of non fossil fuel energy resources.
3.7 ENVIRONMENTAL IMPACT DUE TO LACK OF ENERGY CONSERVATION
The lack of conservation of energy may bring the consequences such as destruction of natural resources/forests,
destruction of wildlife, climate change,crisis of energy, problems of pollution, and effects on health.
Effect on ecosystem
As there is shortage of energy, the dependency rate on forest resources increases as a result forest get destroyed,
which directly affect the whole ecosystem.
Energy crisis
Lack of energy conservation leads towards the energy crisis which creates various problems to the human beings.
For example we may face the problem of load shedding,the rate of the fuel become too high etc.
Destruction of wildlife
Dependency on forest resources causes the reduction of the forest resources and areas as a result the habitat of the
wild life gets damaged which leads to the destruction of the wildlife.
Change in Climate
Climate of the earth has been changing due to the overuse and misuse of the energy resources. Over use of non
renewable sources of energy such as fossil fuels play vital role to increase global warming which results climate
change.

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3.8 ENERGY CRISIS AND ALTERNATIVE SOURCES OF ENERGY
Energy crisis
The shortage of essential energy on the earth is called energy crisis. It occurs due to over use or misuse of renewab le
and non-renewable sources of energy. More than 80% of the total energy is fulfilled by fossil fuels. Due to increase
in population and industrialization the demand of energy is increasing day by day. The demand of energy is high but
supply is less, which results energy crisis.
We can solve the energy crisis by the following ways:
(a) By using fuel wisely and economically.
(b) By conserving the existing fuel.
(c) By developing alternative energy sources.
Alternative energy sources
Energy sources which can be used to preserve the non-renewable energy sources for the future are called alternative
energy sources. The population is increasing day by day. Due to this, the needs of people based on the sources of
energy are also increased. Our need can not be fulfilled only by non-renewable sources of energy because these
sources of energy are not produced continuously. For examples: petrol, coal, natural gases are limited sources of
energy in nature. So, to balance the sources of energy and to fulfill the demand of increasing population, the
development and use of alternative energy source is necessary. Alternative energy sources like hydropower, wind
energy, solar power are pollution free and renewable. Similarly, modern electrical devices and equipments are also
operated through them. Hence, the development and use of alternative source is necessary in modern days.
Model questions:
The Sun is considered as an ultimate source of energy
Because it provides the energy for all living beings on the earth directly or indirectly. We use solar energy for
cooking food, drying clothes and generating electricity. Coal and mineral oil etc are the outcome of solar energy.
Plants store solar energy in the form of chemical energy. It means that the plants use solar energy for photosynthesis.
Hydropower is also an outcome of solar energy. Water in the river is either formed by melting of ice or raining. For
melting of ice solar energy is needed. Similarly water of river and ocean must be evaporated for raining which is
only possible due to the presence of solar energy. Therefore, sun is considered as ultimate source of energy.
Nepal has given high priority for the production of hydroelectricity
Because hydropower is the most potential source of energy in Nepal. Nepal is the second richest country in water
resources. It is cheaper on long-term basis, renewable and pollution free .Most of the modern equipments and
devices are also operated by it
Distinguish between RSE and NRSE
Renewable sources ofenergy Non renewable sources of energy
1. The type of energy which we can get
continuously.
2. Mostly pollution free e.g. solar energy, wind
energy,
3. They don't extinguish
1. The type of energy which we can not get
continuously
2. They are not pollution free. E.g. fossil fuels.
3. They may be extinguished.

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LESSON: 4. HAZARDOUS WASTE
4.1 INTRODUCTION
The flammable, corrosive, reactive or toxic substances are called hazardous wastes. These wastes may be in solid
or liquid or gas state. Hazardous wastes can cause illness, injury, or even death and can destroy the environment if
improperly treated, stored,transported and managed.
4.2. SOURCES OF HAZARDIUS WASTES
Hazardous wastes are produced mainly from industries,business centers,agriculture and household areas.
Industrial wastes: Industries generate a large amount of hazardous wastes. Almost all industries generated
hazardous wastes such as acids, metal pieces, different solutions, toxic gases, oily goods, mercury, chromium,
various paints etc. These wastes should be minimized and disposed safely.
Medical wastes: Hospitals and health centers produce various hazardous wastes such as needles, sharp objects, glass
wears, drugs,chemicals, wastes contaminated with blood, which must be treated and disposed carefully.
Household Wastes: Wastes produced from houses such as food particles, dust, drugs, flammable solvents, plastics,
papers etc. are the major sources of household wastes. Generally, from urban houses more amount of non-
biodegradable wastes are produced. Both bio-degradable and non-biodegradable wastes should be collected
separately and disposed properly.
Agricultural wastes: Agricultural straw, agricultural residues, herbicides and pesticides used in agriculture are the
major sources of hazardous wastes.Use of highly toxic herbicides and pesticides should be band.
Research Centre's wastes: Different research centers such as industrial testing laboratory, hospital laboratory, food
testing laboratory etc produce large amount of hazardous wastes. These wastes should be treated and disposed
carefully.
4.3 TYPES OF HAZARDOUS WASTES
Hazardous wastes may be in the form of solid, liquid and gas. Some of the hazardous wastes are as follows:
Compounds of Mercury: The industries which manufacture fluorescent lamps, electric switches, mercury batteries,
acetic acid etc are particularly associated with mercury hazards. Exposure exposed to mercury dust, mercury
vapour, show physical weakness, fatigue, loss of body weight and gastro intestinal disorders. So, use of mercury
compound should be minimized and carefully disposed.
Acids: Acids are normally used in laboratories and various industries. They are corrosive in nature. These are
injurious to health. Some industries produce acids and are thrown in the form of wastes. Acids like sulphuric acid,
hydrochloric acid, chromic acid and nitric acid are hazardous acids. It directly affects human health when exposed to
it.
Cyanides: Cyanide is a poisonous chemical. It is found in various forms such as sodium cyanide, potassium
cyanide and metallic cyanide. Even a very small quantity of it could be fatal (deadly). It directly affects human
health when exposed to it.
Lead Compounds: Lead is present in a variety of compounds such as lead chloride, lead nitrate, lead oxide etc.
Metallic lead is used in dry cells. It is also used in the preparation of various kinds of paints, pigments (colouring)
etc. It directly affects human health when exposed to it.

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RADIATION HAZARDS (radioactive pollution)
The pollution which is caused by the radioactive materials is called radioactive pollution (radiation hazards).
Radioactive elements like uranium and radium emit radiations that are harmful to us.
Types of radiations: There are two types of radiations. They are given below:
1. Electromagnetic radiaions
The electromagnetic radiations are similar to light in their physical proportions. These are ultraviolet rays,
x-rays, gamma rays, infrared rays etc.
2. Particulate radiations:
It includes the particles having high energy and speed. These rays include cosmic rays, neutrons, protons,
alpha particles, beta particles etc.
4.4 LEAKAGE OF RADIATION AND ITS EFFECTS
Outflow of hazardous radiation such as X-rays, radioactive rays, ultraviolet rays, infrared radiation, uranium
radiations etc is called leakage of radiation. These rays pollute the environment and directly affect human health
when exposed to them. The major sources of hazardous radiation are:
Natural sources
Radioactive elements (uranium, radium) are more common in environmental resources like plants, animals, water,
and soil. These elements emit radiations in a small scale.
Anthropogenic sources
It includes x-rays machines, metal welding machine, radioactive wastes, industrial and medical wastes, luminous
watch dials etc.
EFFECTS OF HAZARSOUS RADIATION
*Exposure to X-rays and radioactive rays temporarily or permanently damage the cellular functions and destroy the
living cells.
*It causes genetic variation due to the attack of x-rays to the DNA, chromosomes and reproductive parts.
*Exposure to ultraviolet rays affects skin and eye. Over exposure may cause skin cancer.
*Exposure to infrared radiations affects the eyesight of the human.
4.5 MANAGEMENT OF HAZARDOUS WASTES
Burying in the ground: Garbage is the major problem of these days. Bio-degradable garbage can be safely buried
in the ground but it should be far from water resources.
Reduction of sources of wastes: Use of hazardous wastes can be minimized by proper treatment of such wastes
within the production areas.
Proper use: The hazardous wastes should be used properly and after use they should be safely disposed.
Reuse: The hazardous wastes should be collected and managed is such a way that they could be reused as far as
possible. For e.g. Sulphuric acid wastes can be treated with ammonia wastes to form ammonium sulphate, which is a
kind of fertilizer.
Similarly, (a) By recycling the wastes (b) By disposing the wastes in the proper place and (c) By formulating and
implementing rules and regulation of hazardous wastes also we can manage the hazardous wastes properly.(d) By
land filling and incineration etc.

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4.6 EFFECTS OF HAZARDOUS WASTES IN ENVIRONMENT
Hazardous wastes pollute soil, air and water. Pollution of soil may also affect plants and animals including human
beings.
Land pollution: The contamination of land/soil with hazardous wastes is called land pollution. Pollution of the land
decreases the quality of the soil which lowers the productivity of the crops.
Air pollution: Air pollution causes various diseases such as eye irritation, nose and throat irritation, irritation of
respiratory tract etc. Air pollution on the other hand increases global warming also.
Water pollution: Majority of communicable diseases are water-borne diseases. The diseases like cholera, diarrhea,
dysentery, typhoid, roundworms etc. spread through polluted water. Water pollution directly affects the
environment adversely.
Destruction of living things: All the living things get destroyed when they are exposed to polluted soil/water /air
and take the food from these polluted areas.
Effect on health: Health of living beings including human beings, is adversely affected when air, water, s oil get
polluted. Bad smell from polluted water/air/soil can spread in surrounding areas and affects the human settlement
and otherliving beings too.
4.7 PREVENTIVE MEASURES OF HAZARDOUS WASTES
The preventive measures of hazardous wastes are:
 By establishment of industries far from the water resources and residential area.
 By proper treatment and control of hazardous wastes.
 By conducting public awareness programmes.
 By using alternative sources of energy instead of fossil fuels.

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LESSON: 5. ANIMALS
INTRODUCTION
Animals are the most diversed forms of life on the earth. They live in a various range of habitats, from deserts and
Arctic tundra to deep sea floor. The human life has been associated with both domestic and wild animals directly or
indirectly. The misuse and mismanagement of the animals have caused the decrease in their population and they are
becoming rare.
5.1 IMPORTANCE OF DOMESTIC ANIMALS
They are important because of following reasons:
*Some animals such as goat, pig, buffalo etc. have been used as source of food (meat and milk).
*The dead animals and their excreta are used to make compost manure.
*Some animals such as bull, horse,donkey etc. are used as animal power in agriculture and transportation.
*Farming of goat,chicken etc. uplift the economic status of farmers.
*Some animal’s body parts are used as raw materials for making tools and cloths. For e.g. leather jacket.
5.2 WILDLIDE AND ITS IMPORTANCE
Wildlife is an important renewable natural resource with diversed use. The colourful and magnificent wildlife had
made tremendous contribution towards our culture, religion, customs, traditions, education, economy, entertainment
and aesthetic values by maintaining the balance of nature.
Commercial importance: Wildlife is more productive and economically profitable. Selling and buying of animals
such as fish contribute a lot for the upliftment of the livelihood of human beings.
Ethical importance: Ethically we have no right to kill or destroy the wild species. Many followers of Buddhism
and Hinduism believe its wrong to kill animals.
Scientific importance: The medicines for many incurable diseases are also being derived from wild animals.
Medicinal values have been found from some wild animals as well. For. e.g : snail: cancer research, snake venom:
anti-venom from snake bite, desert toad, Muskdeer pod: for medicine and perfume.etc.
Educational importance: Various scientists focused their study on wildlife to maintain the ecology. Some study
focused on habitat improvement, increase in production etc.
Recreational (game) importance: People derive benefits of pleasure, adventure and enhance physical and mental
conditions from viewing wild animals in the reserves and zoos. These wild animals can be used in sports. For e.g.
legal hunting, fishing etc.
Biological /ecological importance: Ecology is the interrelationship between living beings and their environment.
Wildlife contributes a significant role in maintaining the ecosystem.
Aesthetic importance: The value of wildlife and their habits are the objects of beauty or historical significance as
they become a part of literature, poetry, art, music etc. and is the aesthetic value. For e.g.: People visit national
parks and zoos to watch wild animals.
Social/cultural importance: Many tourist visit rural society because of wildlife assets which enhance their
economy. Similarly, snakes decorated in the neck of Lord Shiva, association of tiger with goddess durga etc. are
some cultural importance.

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5.3 SOME IMPORTANT ANIMALS FOUND IN NEPAL
Animals of Himalayan Region Animals of Hilly Region Animals of Terai region
Musk deer
Red panda
Snow leopard
Black bear
Yak etc.
Leopard
Jungle cat
Bear
Monkey
Fox etc.
Tiger
Elephant
Rhinoceros
Wild buffalo
Black buck etc.
Birds of Himalayan Region Birds of Hilly Region Birds of Terai Region
Danfe
Munal
Kalij
Chilime etc.
Titra
Kalij
Jureli
Baaj (falcon)
Eagle etc.
Saras
Peacock
Duck
Parrot
Dhanesh etc.
5.4 CAUSES OF EXTENCTION/ DISAPPERANCE OF ANIMALS
There are several causes of disappearing of animals. Some main causes are described below:
Natural disasters: Natural disasters such as flood, earthquake, storms etc destroy the life and natural environment
of the animals which directly affects in the number of the animals.
Haphazard Hunting: People hunt animals for various reasons such as for their skin, feathers, bones, meat etc. Due
to such hunting the number of animals is decreasing day by day.
Loss of habitat: The natural habitat is destroyed due to human activities such as deforestation, construction works,
agricultural works etc. This damages the food and habitat. As a result they may get extinct.
Lack of awareness: Due to the lack of awareness, people destroy the habitat of the animals and also kill them for
various uses.Therefore, awareness program should be conducted to protect them.
Similarly, human encroachment, degradation of ecosystem, scarcity of food, lack of conservation programs etc are
also the causes of disappearing of animals.
5.5 INTRODUCTION OF SOME MAJOR ENDANGERED AND PROTECTED ANIMALS
Some of the animals including birds and reptiles found in Nepal are endangered. They are listed as protected
species. 27 mammals, 9 birds and 3 reptiles are endangered and protected species. Some of them are described
below:
BENGAL TIGER ( Panthera tigris)
 Tiger is carnivorous.
 Largest member of the cat family.
 They live alone in large area in dense forest.
 They are found in Terai (CNP, BNP, PWR and SWR)
 They have yellow or light orange coat,
with black or dark brown stripes and a white belly.
 The incubation period of tiger is 105 -112 days.
 They bear 2-6 cubs.
 Their average life span is 20 years.
 There are 198 tigers in Nepal (DNPWC,2013)
 Less than 5000 Bengal tiger are the on the earth.
 Tiger is killed for its beautiful skin, meat, bones etc.

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ONE HORNED RHIONOCEROS (Rhinoceros unicornis)
 Rhino is herbivorous.
 They are found in Terai (CNP,BNP &SWR)
 They prefer to live in swamps and grassy plains.
 They feed on grasses like khar (imperata) and dubo (Cynodon)
 They also browse on tree and shrubs.
 Its incubation period is 480- 570 days.
 They bear 1-2 youngs.
 Their average life span is 40-50 years.
 There are all together534 rhinos in Nepal.
 One horned rhinoceros is killed mainly for its horn.
MUSK DEER (Moschus Spp.)
 It is herbivorous.
 It is solitary shy animal.
 Found in Himalayan region (RNP, LNP, SNP, DHR, MBNP & CA)
 It has no horns. Its body is dark brown in colour with coarse hairs.
 It feeds on lichens, mosses,leaves of Rhododendron,fir, juniper and deodar.
 Male has musk pod in its abdomen.
 Its incubation period is 180 days.
 It bears 1-2 young.
 Its average life span is 12-15 years.
 Musk is used to make medicine and perfume. So, male is much hunted.
GREY WOLF (Canis Lupus)
 It is carnivorous.
 It is the world's most widely distributed mammals.
 Found in mountain region.
 It is the largest wild dog having powerful teeth and bushy tail.
 The fur of gray wolf is red yellow or yellow grey with black patches on back and side and white on its
chest and abdomen.
 Its incubation period is about 62-63 days.
 It bears 3-9 young.
 Its average life span is 12-15 years
 It is mainly hunted for sport,for their skins, to protect livestock
 It is included in CITES appendix-I and II.
LEOPARD CAT (Prionailurusbengalensis)
 It is a carnivorous animal.
 Its size is like the of domestic cat.
 It is a small wild cat of South and East Asia
 It is found in Himalayan region in Nepal. (Makalu Barun NP and Kanchenjunga Conservation area)
 They are yellow in colour and black dots are present.
 Ear are circular with white dots.
 Its incubation period is 60-70 days.
 It bears 3-4 cubs.
 Its average life is 13 years
GAUR BISON (Bos gaurus)
 It is found in the forest of Terai. (CNP, PWR and BNP)
 It is herbivores. It feeds on grass and shoots of bamboo.
 It is reddish-brown or blackish brown.

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 Legs from hooves to knees are white.
 Adult male is about 1.6-2.2m.
 The baby gaur is golden in colour but the colour changes to black when it becomes and adult.
 There are 333 recorded in gaur census 2007.
 It bears 1 calf.
 They live in hear of 6-12 individuals.
 Its life span is about 30 years.
 It is highly threatened by poaching for commercial trade in meat and trophies.
BLACKBUCK (Antilope cervicapra)
 It is vulnerable species of Nepal.
 Found in BNP
 Lives in open ground in heard and sparse forest.
 It likes to feed on cynodon ( dubo), soft red gram(rahar), Bengal gram 9chana) etc.
 Female are light brown usually hornless.
 Male are dark brown with horns.
 Body under part and ring around eyes are white.
 Its incubation period is 180 days.
 It bears 1-2 young ones
 Its average life span is 15 years
 It is endangered because it is hunted for their flesh and skin.
GHARIAL CROCODILE (Gavialis gangeticus)
 It is carnivorous reptile.
 It is found in rivers, lakes and water logged areas of Terai.(koshi, karnali and narayani)
 It mostly feed on fish, tortoise,birds and small mammals.
 They consists long and narrow snout.
 Body is covered with exoskeleton.
 It contains about 17 osteoderms (katla)
 It lays 15-65 eggs
 Eggs hatch after 83-94 days
 Its life average life span is about 29 years
 They are rare due to collection of their eggs,human encroachment on their habitat etc.
GOLDERN MONITOR LIZARD
 It is an endangered reptile found in Nepal.
 It is listed in CITES appendix-I
 It is brown in colour.
 It lives at branches of trees, dry woods, holes and inside stones.
 It is also found in wetlands such as paddy field, fishing pond and rivers.
 It is carnivorous. Small mammals, birds and their eggs, eggs of crocodile, small reptiles and fishes are its
food items.
 Its hatching period is 240-270 days.
 It lays 20-30 eggs.
 Its average life span is 15-20 years
 It is hunted foe its beautiful skin.
SNOW LEOPARD
 It belongs in cat family.
 Found in mountain region.
 Snow leopard hunts on blue sheep,musk deer, yak and rodents.
 Body colour is soft grey, with brown sports and white belly.
 Cubs are relatively darker than adults.

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 Its incubation period is 90-110 days.
 It bears 1-2 cubs.
 Its average life is 8-9 years.
 Snow leopards have been over hunted for their fur and are now endangered.
DANFE (IMPEYAN PHEASANT)
 It is a national bird of Nepal.
 It is an endangered bird species.
 It is found in Himalayan region.
 Male (colourful): upper parts contains green purple and blue colour. Naked red face & long green horn.
Black chest. Short wide and rounded tail
 Female: brown colour.
 It is about 70 cm in height.
 Its hatching period is 27 days
 It lays 4-6 eggs.
 It is hunted for its beautiful feathers and meat.
5.6 WAYS OF CONSERVING ANIMALS
1. By establishing protected areas such as national parks, wildlife reserves etc.
2. By conserving the forest.
3. By establishing zoos and botanical gardens. .
4. By helping for the restoration of habitat of the wildlife.
5. By creating public awareness about the need and importance of wildlife.
6. By formulating and implementing wildlife laws and by laws.
5.7 IN-SITU CONSERVATION AND EX-SITU CONSERVATION
The conservation of plants and animals in their natural habitat is called in-situ conservation. For example
conservation of plants and animals in national parks, wildlife reserves etc. Similarly, the conservation of plants and
animals in man made habitat is called ex-situ conservation. For example conservation of plants and animals in zoos,
botanical gardens etc.

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UNIT: 6. WETLANDS ECOSYSTEM
6.1 INTRODUCTION
Wetland means land covered with water. It includes river, lake, pond, reservoir, water logged land etc. The
ecosystem that presents in wetland is called wetland ecosystem which is defined as "the interaction between biotic
and abiotic components of a wetland is called wetland ecosystem".
Nepal’s National Wetlands Policy 2003, defines wetlands as “ Natural or artificially created areas, such as swamp,
marsh, riverine floodplain, lake, water storage area and agricultural land containing water from underground water
resources or atmospheric precipitation that may be permanent or temporary, static or flowing and freshwater or
saline”.
6.2 IMPORTANCE OF WETLANDS
Source of food crops
Wetlands are the main source of food for many plants and animals. Paddy is the main food crop of our country,
which is grown in wetlands. Similarly, wetlands are the source of food of different animals.
Habitat of rare plants and animals
Wetland supports significant species diversity and population of globally threatened flora and fauna. For e.g.
dolphin is found in Koshi and Karnali. Gharial is found in many rivers of Terai etc. On the other hand, it provides
the shelter and pasture for terrestrial animals. For e.g pasture land near by koshi river and pasture land of Rapti river
are the major food sources of wild animals like arna, rhino, etc.
Balance the temperature
Wetlands play a vital role in balancing temperature, it absorbs huge amount of CO2 gas and help to reduce the rate
of depletion of ozone layer. Wetlands reduce desertification and rate of climate change also. They also balance the
nature by maintaining water cycle.
Religious and cultural values
Various wetlands of our country such as Gosaikunda, Ganga sagar etc are the religious sites of Hinduism. Every
year many pilgrims visit these areas.
Recreational values
Wetlands provides ample opportunities for recreational activities such as bird watching, rafting, fishing, boating etc.
For e.g. Phewa lake is famous for boating, Bhote Koshi is famous for Bunge Jump, Trishuli is famous for rafting
etc.
Economic values
They attract tourist, which help in economic growth. For e.g lakes of pokhara (for boating), Bhote Koshi (rafting and
Bunge Jump).It uplifts the livelihoods of local people.
Other values
It is used to generate electricity. For e.g Kali Gandaki hydropower, Khulekhani hydropower.etc. It is used for
irrigation. For e.g Seti river irrigation project, Pokhara.

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TYPES OF WETLANDS: Wetlands can be classified into three general categories:
Marshes: Marshes are the wetland having shallow water. They contain mostly grasses and other aquatic vegetations
but no trees. Marshes have soil with high nutrient content than swamps. Marshes can be either freshwater, saltwater,
or a mixture of both. The amount of water in a marsh can change with the season because of flooding. For example:
Mesopotamian marshes.
Swamps: Swamps are the area which is deeper than marshes that are mostly forested. Many swamps occur along
large rivers where they are mostly dependent upon natural water level fluctuations. Swamps can be either
freshwater, saltwater, or a mixture of both. Swamp soil is poorly-drained and water logged. For example:
Vasyugan Swamp
Peat lands: Peat lands are wetlands with a thick water-logged organic soil layer (peat) made up of dead and
decaying plant material. In peat lands, plants are produced more quickly than they can decay and there is
accumulation of partially decomposed plant material, which is called peat. Peat provides an organic soil that
influence s the plants growth. For example: Scotties peat land.
6.3WETLANDS OF NEPAL
Rivers: They cover about 53% of the total surface water of Nepal. The sources of river are mainly rainwater,
melting of snow and underground water. Nepal is drained by three major river systems namely the Kosi, the
Gandaki and the Karnali. The combined flow of the rivers of the country is about 200 billion cubic meters in a year.
Besides these three, there are many other rivers in Nepal such as Bagmati, Kamala, Kanki, Rapti, Mechi, Mahakali
etc. The water flow in the river is high in the rainy season where as it is less in the winter season.
Lakes: They cover about 0.7 % of the total surface water of Nepal. Water storage area which covers more than 8
hectors area and more than 2 m depths are known as lakes. Lakes are found throughout the country.
Based on nutrients content lakes are of three types:
Oligotrophic lake
*It contains low amount of nutrients.
*Such lakes lie in mountain region
* consists less aquatic plants
*For example: Rara Lake , Tilicho lake , Phoksundo Lake etc .
Mesotrophic lake
*It contains medium amount of nutrients.
* Such lakes lie in hilly region
* Consists more aquatic plants than oligotrophic lake
*For example: Phewa lake, Rupalake, Begnaslake etc.
Eutrophic lake
*It contains high amount of nutrients.
* Such lakes lie in Terai region
*Consists more aquatic plants than other types.
* For example: Ghodaghodi lake,Tara lake , Bishazari lake etc.
Ponds: Water storage which covers less than eight hector area is called pond. There are many ponds in Nepal. Some
examples of ponds are Mai Pokhari of Ilam, Kamal Pokhari and Rani Pokhari of Kathmandu, Siddha Pokhari of
Bhakatapur etc. Ponds also conserve the various types of aquatic plants and animals. Ponds having nutrition more
than required are called hyper-eutrophic ponds.

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Marsh/marshlands: Marshes are areas with shallow water. They contain mostly grasses and other aquatic
vegetations but no trees. Marshes have soil with high nutrient contents. They cover 12000 hector area of Nepal.
Marshes are rich in biodiversity. Marshes are important for fisheries too. Protected areas contain marshes which
provide the food, shelter and water to various plants and animals. The destruction of the marshes also affects the
wetland ecosystem.
MANMADE WETLANDS
Water reservoirs: Water reservoir and dams constructed are used to generate electricity, for irrigation or drinking
water supply and other purposes. They are also helps to conserve the various types of aquatic plants and animals. On
the other hand such reservoirs are the major source of water to other terrestrial animals and human beings too. Some
famous reservoir/dams are Kulekhani (the biggest artificial water reservoir of Nepal) in Makwanpur district,
Marsyangdiin Tanahu district, Koshi dam in Koshi zone etc.
Marsh Agricultural Land (Paddy field): Marsh agriculture land is a type of human made wetland. It includes
lowland of wetland, arable land, seasonal arable land, etc. It also includes paddy land, fisheries pond and lowlands.
Seasonal paddy lands contain water for around four months in a year. A fter harvesting the paddy, the moisture
remains more than ¾ months.
6.4 HUMAN IMPACTS ON WETLANDS/ WETLAND ECOSYSTEM
*Discharge of drainage and wastes.
*Discharge of insecticides,pesticides and chemical fertilizers.
*Introduction of invasive alien species.
*Tilling for crop production.
*Over fishing and collection of biological resources form it.
*Construction activities
*Run off from agriculture land.
*Sedimentation of the wastes and pebble and gravels.
6.5 POLICY AND CONSERVATION MEASURES OF WETLANDS
*By creating awareness about the importance of wetlands.
*By formulating and implementing strict rules and regulations.
*By disposing the hazardous wastes far from the sources of water.
*By stopping the encroachment of wetland resources.
*By mobilizing local people for the conservation of wetlands.
*By controlling pollution and human population.
* By creating mutual co-operation among the various stokeholds of the wetlands, for the conservation, management
and promotion of the wetlands etc.
By creating the awareness about the importance of wetlands to the local people:
Wetland has great importance because of its numerous values such as recreational, economic, cultural and religious
etc. So, we have to aware the people of its values /importance so that they will initiate themselves to conserve the
wetlands.
By formulating and implementing strict rules and regulation:
In order to reduce the human pressure on wetlands and their misuse, there should be for mulation and
implementation of strict rules and regulation.
By controlling pollution and human population:
The proper management of solid wastes and pollutants as well as control of over population significantly reduced
impacts on wetlands.
By disposing the hazardous wastes far from the water resources. For that 3R (reduce, reuse, recycle), incineration,
buried etc. methods are used.

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UNIT: 7. AGRICULTURE SYSTEM
7.1 INTRODUCTION
Agriculture is an art, the science or an industry of managing the growth of plants and animals for human use. In
broader sense, agriculture includes cultivation, growing and harvesting crops, breeding and raising livestock,
beekeeping, dairy farming and forestry.
7.2 IMPORTANCE OF AGRICULTURE/ AGRICULTURE SYSTEM
Source of food
Agriculture is the main source of food and vegetables for human beings. This includes rice, maize wheat, millet,
buckwheat, barley, cauliflower, potato,onion etc.
National Income source
Agriculture business is an important source of national income. By exporting various agricultural products such as
tea, tobacco,jute, fruits vegetables etc enhance the economic status ofthe nation.
Employment opportunities
Many people are directly or indirectly involve in agricultural activities, which provide employment opportunities to
many people. For example, there is need of human services in caring, feeding and transporting chicken in poultry
farming.
Supply raw materials for industries
Agriculture crops are the source of raw materials for many agro based industries such as jute industries, dairy, oil
industries, food industries etc. Similarly, Fruits are also a raw material of juice industries.
Source of fuel
The agriculture production is also a source of fuel. Agriculture residues are bunt to produce heat energy. Similarly,
the dry animals dung is also used as fuel.
7.3 AGRICCULTURAL DEVELOPMENT AND ENVIRONMENTAL ASPECTS
Agriculture development is very important for the development of a nation like Nepal. At present context , the
modern agriculture system includes cereal crops, pulses, animal husbandry, fisheries, bee-keeping, vegetable
farming etc. There are directly or indirectly related to various areas such as agriculture economics, agriculture
environment, sociology, marketing etc. Some of the major environmental components which affect agriculture
development are given below:
Land structure
It determines the properties of the soil and climate of the place which affects agricultural development. Land having
favorable climate and fertile soil increase the agriculture productivity. So, it helps in agriculture development.
Irrigation facilities
It enhances the productivity of the crops which helps in agriculture development.
Technology
Technology such as ploughing, seeding, weeding, transportation and machines used is harvesting crops etc. plays an
important role in agriculture development.
Livestock farming
It provides food, manure, draft power, cash income etc for farmers so it is very important for uplifting agriculture.
Fisheries
Many people are engaged in fish culture. Traditionally many people depend on fishing in rivers and lakes. So
fisheries are also helps in agriculture development.
Fertilizer
It is also one of the major factors that help in the development of the agriculture by enhancing the fertility of the so

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7.3.1 IRRIGATION AND ITS TYPES
Irrigation is the artificial watering or canalling of over water on land to sustain plant growth. Irrigation is practiced
in all parts of the world where rainfall dose not provide enough ground moisture. Irrigation plays an important role
in agriculture development and economic development of the nation. Many dams are constructed in our country to
irrigate the barren lands. Some major irrigation projects are: Bijayapur dam of Pokhara, Phewa lake dam, Koshi
dam, Begnas lake dam etc. Based on the land condition and climate, an appropriate method of irrigation should be
selected. There are four main methods used today to irrigate fields. They are flood irrigation, furrow irrigation ,
sprinkler irrigation and drip irrigation.
Flood irrigation
It is used where fields are at level and water is abundant.It is suitable for close grown crops such as rice.
Furrow irrigation
It is employed with row crops such as cotton and vegetables. Parallel furrows called corrugations which are used to
spread water over fields.
Sprinkler irrigation
It uses less water and provides better control. Each sprinkler spaced along a pipe sprays droplet of water in a
continuous circle until the moisture reaches the root level of the crops.
Drip irrigation
It delivers small but frequent amount of moisture to the root area of each plant by means of narrow plastic tube. This
method is highly used in U.S.A, Israel and Australia which control the loss of water through evaporation and
percolation.
7.3.2 FERTILIZERS AND ITS TYPES
Fertilizer is a type of natural or synthetic chemical substance or mixture used to enrich soil so as to promote plant
growth. Fertilizer is necessary to increase the fertility of soil as it adds different minerals necessary for the plants. It
is of two types (a) organic fertilizer (b) Chemical/inorganic fertilizer. The differences between organic and inorganic
(chemical) fertilizer are given below:
Organic fertilizer Chemical/Inorganic fertilizer
*It is made by decaying excreta of cattle, hay, plant products
etc.
*It supplies almost all nutrients required by plants.
*It makes the soil fertile for the longer time.
*Compost manure is an example of organic fertilizer.
*It is made by the chemical reaction between different
chemical substances.
*It supplies only particular element required to plants.
*It makes the soil fertile only for short time.
*Urea is an example of inorganic fertilizer.
Organic fertilizer
Fertilizer made from living sources is called organic fertilizer. It is made fromdead and decayed parts of plants and
animals or the wastes of animals. E.g compost manure. The advantages oforganic fertilizer are as follows:
*It improves the quality of the soil.
*It can easily absorb water.
*It provides required nutrients.
*The harder soil becomes soften.
*It increases the porosity of the soil.
*It makes the plant strong.
*The productivity of the soil becomes sustainable.
*It helps in environmental sanitation by using organic wastes.
*It reduces the economic pressure on farmers.

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Chemical fertilizer
The fertilizers made by mixing the chemicals are called chemical fertilizers. Mostly Nitrogen, phosphorous and
potassium compounds are used for making these types of fertilizer. Fertilizer having mixture of NPK elements is
called complete fertilizer. The examples of chemical fertilizer are: Urea, ammonium sulphate, potassium chloride,
superphosphate etc.
The advantage of using chemical fertilizers are:
*It helps to fulfill the necessary nutrients ofplants.
*It helps to increase the growth and development of plant.
*It increases the production of the crops.
*It is easily available in market.
Effects of chemical fertilizer
The overuse of chemical fertilizers causes various effects both on plants and animals. Some of them are as follows:
*It decreases the quality of the soil.
*It affects the growth of plants.
*It leads to water pollution: the leaching of chemical fertilizers into water bodies cause water pollution results
eutrophication.
*Children suffer from dwarfism if they drink water containing fertilizers.
7.3.3 INSECTICIDE
The chemical substances used for killing harmful insects are called insecticides. BHC (Benzene hexachloride),
Aldrene, DDT (dichlorodiphenyltrichloroethane), etc. are some insecticides.
Good insecticides/pesticides have following characteristics:
*They are biodegradable.
* They are less toxic to human and otherorganisms.
*They are chap
* They are easy to use
Advantages of using insecticides:
*They kill or destroy harmful insects quickly.
*They can control several diseases by killing germs.
* We can increase food production by killing insecticides.
Disadvantage of using insecticides:
*Most of the insecticides are non-biodegradable; hence they are harmful to living beings.
*They destroy useful insects also.
*Direct spray of insecticides may cause soil and water pollution.
*Exposure to DDT for longer time may cause cancer to the human beings.
*Direct consumption of insecticides used crops may affect our health.
*Fish lay premature eggs and bird lay eggs with fragile shells due to the effects of DDT.
*Volatile insecticides cause air pollution.
Precautions of using insecticides:
*Insecticides should be out of the reach of the children.
*Insecticides should be used as little as possible.
*The name and instructions should be labelled clearly.
*Hand and other body parts should be washes properly after using it.
*Whole body,eye, nose,ear, mouth should be protected while spraying the insecticides.
*We should be careful while using the insecticides.

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7.3.4 PESTICIDES
The chemical compounds which are used to control or kill the pests are called pesticides.The living organisms like
unwanted plants (weeds), insects,rats, fungi, mites etc are called pests.
The effects of pesticide are:
*They attack and destroy the crops.
*Weeds absorb the large amount of nutrients of soil and reduce the soil's fertility.
*Fungi destroy the crops and stored grains
*Rodents eat the stored grains and crops in the field
*Some pests transferdiseases on crops animals and humans.
NOTE:
Insecticides: chemicals used to control insects
Herbicides: chemical used to kill weeds
Fungicides: chemical used to kill fungi
Rodenticides: chemical used to kill rodents
Miticides; chemical used to kill mites.
Model questions:
Why is the use of compost manure preferred over the use of chemical fertilizer?
Chemical fertilizers are made from mixing different chemicals where as compost manure is made fro m dead and
decayed parts of plants and animals. The use of compost manure is preferred over the use of chemical fertilizers for
the following reasons:
*Compost manure enhances the fertility of soil for longer time than chemical fertilizer.
*It does not cause chemical pollution.
*It is cheaper in comparison to the chemical fertilizer.
*It can be made easily from the local materials.
*It is eco-friendly. It doesn’t harm the ecosystem.
*It supplies almost all nutrients required to plants.
Mention the methods of reducing the effects of chemical fertilizer.
The fertilizers made by mixing the chemicals are called chemical fertilizers. Chemical fertilizers have many
negative effects so its effects should be reduced to minimize the negative impacts. Some of the major methods of
reducing the effects of chemical fertilizers are:
*By using compost manure instead of chemical fertilizer.
*By educating the people about the long term negative effects of chemical fertilizer.
*By establishing organic fertilizer industries.
* By supplying the organic fertilizers to the farmers.
*By reducing the use of chemical fertilizers.
The use of insecticides is not an interest but an obligation. Justify this statement.
Insecticides are the chemical substances used for killing harmful insects. BHC, Aldrene, DDT, etc. are some
insecticides. Nepal is an agriculture country. Every year insects destroy the crops. It decreases the agricultural
products and hampers the economic condition of the people and hence of the whole country. Therefore, the use of
insecticides is a must in the country like Nepal though they have bad effects on the environment.
Terai is considered a as the storage of grains, why?
Terai is considered a as the storage of grains because of many reasons.Out of them, four major reasons are given
below:
*It consists 2/3 agriculture part of our country
*The land is flat and plain
*It gets sufficient rainfall and irrigation facilities in comparison to other areas
*It has fertile alluvial soil
*It has tropical climate

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Why modern technology is harmful in agriculture development? Give reasons.
Technology plays vital role in agricultural development but excessive use of these technologies (agricultural tools)
has various problems. Some of these are:
*Fuel used in agricultural tools pollutes air.
*Use of modern tools reduces the importance of livestock keeping.
*Modern agricultural technology needs skilled manpower for which extra investment is needed.
*Use of modern technology needs less human power, thus giving rise to unemployment problem.
*Heavy machines used in agriculture make the soil hard which reduces the productivity of land.
How can we manage pests without using pesticides?
We can manage pests without using pesticides by following ways:
*Cultural control (using the right pruning, fertilizing, selecting pest-resistant varieties or species)
*Physical control (for example, using mulches to keep weeds from growing or weed seeds)
*Mechanical control (spraying leaves forcefully with water to remove insects,or using traps or creating barriers to
exclude pests)
*Biological control (using beneficial organisms such as insects that eat or parasitize other insects)
*Replant (in extreme cases,where a plant requires regular pesticide treatment, considerreplanting with a more pest-
resistant species or variety)
Comparison: The major features of three geographical region of Nepal.
Features Mountain regions Hilly regions Terai regions
Located at about Above 4000m 1000-4000m Below 1000m
Area covered 35% 42% 23%
Number of districts 16 39 20
Climate Clod and dry Moderate Hot (tropical climate)
Prime Agriculture
system
Animal husbandry,
horticulture (apple)
Animal husbandry and
horticulture
Food crops, cash crops and
cereal crops
Major crops Potato, wheat, barely etc. Rice, maize, wheat
,soybean,barely, etc.
Rice, sugarcane, paddy,
maize
Domestic Animals Yak, sheep, chauri, Cow ,buffalo, Cow ,goat, buffalo
Wild animals Red pands, snow leopard,
musk deer
Leopard, bear, fox Tiger, deer, rhino, arna
Birds Danfe, munal, kalij Vulture, falcon, dove Peacock, saras,dhanesh
Land Very steep Steep + flat in valley Flat
Soil depth Very low (rocky) Higher than Himalayan
but lower than Terai
High
Plants Pine, rhododendron, fir,
cycus etc.
Katus ,chilaune, Sal, sisoo,khair
Soil Coarse soil Corse + loamy Loamy soil

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UNIT: 8. HEALTH, ENVIRONMENTAND SANITATION
8.1 INTRODUCTION
The state of being free from illness or injury is called health. WHO has define health as “a state of complete
physical, mental and social well-being not merely (purely) an absence of disease or infirmity (illness)”.
Environment is the sum of all physical, chemical, biological and cultural factors that affects the life of organism in
any way. Some of the Importance of environment are: Source of food, source of raw materials source of medicine,
aesthetic importance, sustain life systemetc.
WHO defines environmental health as “Those aspects of human health and disease that are determined by factors in
the environment that guarantees the proper fate of future generations”.
8.2 IMPORTANCE OF HEALTHY ENVIRONMENT
Healthy environment provides us fresh and healthy materials. So, the healthy environment is important in order to
live healthy.
A healthy environment:
*Should posses safe and peaceful settlement
*Should consists clean air, safe and sufficient water
*Should be free from germs and diseases
*Should posses enough greenery
*Should be free from pollution.
8.3 ENVIRONMENTAL POLLUTION AND ITS TYPES
Environmental pollution is an undesirable change in the physical, chemical and biological characteristics of the
environment. The major types of environmental pollution are:
 Air pollution
 Water pollution
 Land/soil Pollution
 Noise/sound pollution
Air pollution
An undesirable change in the physical, chemical and biological characteristics of air is called air pollution. Polluted
air contains dust particles, smokes, harmful gases, chemical and poison etc. simply, the contamination of pollutants
with air is called air pollution.
Causes of air pollution:
1. Pollutants such as smokes and gases produced from the vehicles, industries etc. cause air pollution
2. Smokes emitting from kitchen due to burning of dry dung, fuel woods,stakes of maize etc. causes air pollution.
3. Burning of fossil fuels is the major cause of air pollution
4. Over population and pollution also one of the major causes ofair pollution.
5. Haphazard disposal of wastes also cause air pollution by emitting harmful smells etc. causes air pollution.
Effects of air pollution on human beings
1. Eye, Nose and throat and respiratory tract irritation.
2. Gases like H2S and NH3 causes odourtrouble even at the low concentration
3. Increases in mortality rate and morbidity (depression)rate.

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4. A variety of particularly pollens, initiate asthmatic attacks.
5. High concentration of SO2, NO2 in the air cause bronchitis (inflammation of wild pipe) and asthma (difficult in
breathing)
6. Carbon monoxide combines with the haemoglobin in the blood and consequently increases stress on those
suffering from cardiovascular and pulmonary diseases.
7. Hydrogen fluoride causes diseases ofthe bone and teeth.
8. Carcinogenic agents cause cancer.
9. Dust particles cause respiratory diseases. Diseases like silicosis (lungs disease), asbestosis, etc. results from
specific dusts.
10. Certain heavy metals like lead may enter the body through the lungs and cause poisoning and lowers the
memory power.
Note: Polluted air holds more solar heat and increases the temperature of the earth’s atmosphere and cause global
warming.
Preventive/Controlling methods:
1. Old automobiles should be banned
2. Using alternative sources of energy such as solar energy, hydroelectricity, wind energy etc.
3. Afforestation and reforestation program should be launched.
4. Use less polluting fuels instead of more polluting fuels. For e.g hydrogen gas can be used instead of fossil fuels.
5. Solid wastes should be properly disposed in safe place.
6. Establish the industries after proper Environmental Impact Assessment studies.
Water pollution
An undesirable change in the physical, chemical and biological characteristics of air is called water pollution.
Polluted water contains sewage,chemical fertilizers, pesticides,arsenic, mercury, lead and cadmium etc.
Causes of water pollution:
1. Contamination of chemical fertilizer and pesticides with water.
2. Mixing of sewage with water cause water pollution.
3. Bathing and washing near the sources of water.
5. Spreading of aquatic invasive species in water sources. For example water hyacinth (jalakumbi) in Phewa Lake,
Pokhara.
6. Disposal of wastes near by the source of water etc.
Effects of water pollution
1. Polluted water of rivers, ponds and lakes harm the health of the living beings including human beings.
2. Polluted water causes severaldiseases such as cholera, diarrhea, dysentery,typhoid,worm, etc.
3. Polluted water when irrigated reduces the productivity of plants.
4. Cleaning of vegetables and utensils with the polluted water can also be harmful. The health of human beings and
other living being is degraded when they eat such vegetables and meals.
5. Bad smell from polluted water can spread in surrounding areas polluting the air. It also harms the life of
neighboring settlements.
6. Polluted water depletes aquatic life.
Preventing measures
1. We must reduce domestic wastage.
2. Disposing wastage into water should be banned.
3. Industrial discharge, lab and hospital discharge should be treated first before discharging. As far as possible such
discharge should be flown without mixing into water resource.
4. Flood, landslide, soil erosion should be properly checked.
5. Health education and other awareness – increasing campaigns should be conducted.
6. Strict rules and regulation should be formulated and effectively implemented.

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Land pollution
The contamination of pollutants such as plastics, glasses, acids, chemical fertilizers, pesticides etc with land is called
land pollution.
Causes of land pollution
1. Dumping of wastes on the land.
2. Use of Insecticides, pesticides and chemical fertilizers by farmers in their agricultural land.
3. Throwing of plastics,tin cans,etc after use.
4. Discharge of chemicals from industries.
5. Open urination and defecation.
Effects of land pollution
1. Acid rain and other chemicals reduce the fertility of the soil.
2. Salinity of the soil reduces fertility and degrades the quality of the soil.
3. It destroys the beauty of the environment and importance of cultural heritage.
4. Polluted land is the major source of bad smell which pollutes the surrounding.
5. Food produced in polluted land may cause health hazards.
6. The productivity of the crops may decrease due to the polluted land.
Preventive measures of land pollution
1. Use of non degradable wastes such as plastics, glasses etc should be minimized.
2. Solid wastes should not be thrown in the open places.
3. Urination and defecation should be done in the toilet.
4. Use of chemical fertilizers, pesticides and insecticides should be minimized.
5. Non biodegradable wastes should be reuse or recycled if possible.
Sound pollution
The production of unwanted sound is called sound pollution.
Causes of sound pollution
1. Musical instruments and electronic media that produce high volume of sound cause noise pollution.
2. Some industries like cement factory, furniture factory, stone crusheretc produce high sound.
3. Construction sites like metal works, road construction etc produce unwanted sound.
4. Sound produced by automobiles cause noise pollution.
5. Sound produced by people and speakers in the social events like marriage ceremony etc causes sound pollution.
Effects of noise/sound pollution
1. It may decrease hearing power or make the person deaf.
2. Loud noise creates headache and mental tension.
3. Loud noise disturbs our digestive systemand sleeping habit.
4. Noise pollution disturbs in communication.
5. Noise pollution may cause depression to the children and elderly people.
Methods to control noise pollution
1. Afforestation program should be launched. Trees absorb sound and control sound pollution.
2. Noisy equipments should be installed underground.
3. Educate the people about the bad impacts of unwanted noise.
4. Industries and railway should be far from residential areas.
5. Old vehicles should be prohibited.
8.4 COTTAGE INDUSTRY
The traditional type of industry which is labour oriented related to tradition of the country, art and culture and which
utilizes special skill or mobilization of local raw materials is known as cottage industry. The examples of cottage
industries are; handloom, painting, weaving and knitting.

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Importance of cottage industry
 Employment opportunities
 Less requirement of capital
 Use of local resources
 Export promotions
 Increase the living standard of people
8.5 EFFECT OF UNHEALTHY ENVIRONMENT ON HEALTH IN THE WORK PLACE
Unhealthy environment deteriorates the quality of the life and causes various diseases on human being. The major
aspects that may affect by polluted environment are described below:
1. Physical aspects
2. Chemical aspects
Physical aspect
Improper management of physical aspects such as air, water, light, noise, ventilation, radiation, temperature etc
deteriorates the health of the workers in the work place. Among various physical aspects here we have discuss about
temperature, radiation and ventilations.
Temperature
The degree of hotness or coldness of the body is called temperature. The normal human body temperature is 98.6 0F
or 370C and is the result of balance of heat produces and heat lost. People who work in the boiler, furnace, oven,
drying etc suffer from excessive heat. When the temperature of the work place increases it results various problems
in the human health. The effects of extreme temperature are as follows:
*Pulses rate increases
*Suffocation and fainting
*Thirst and Dehydration
*Dizziness and headache
*Lethargy (loss of energy, laziness)
*Heart stress (if exposed for longer time) etc.
Therefore, safety measures should be taken while working and the work placed should be properly ventilated.
Radiation
The pollution which is caused by the radioactive materials is called radioactive hazard. Radioactive elements like
uranium, radium, emit radiations that are harmful to us. It is of four types: alpha radiation, beta radiation, gamma
radiation and neutron radiation.
Effects of hazardous radiation:
*Exposure to radiations permanently damages the cellular functions and destroys the living cells.
*It causes genetic variation due to the attack on the DNA, chromosomes and reproductive parts.
*Exposure to ultraviolet rays affects skin and eye. Over exposure may cause skin cancer.
*Exposure to infrared radiations affects the eyesight of the human.
*Over exposure damages brain and nervous systemresulting to death.
*Excessive radiation damages bone marrow and the blood factory.
*Excessive radiation damages the ovaries and testis and reduces fertility.
* Exposure to radiations destroys the body immune system and decreases the body resistivity towards varieties of
diseases.

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Control measures of radiations
*Workers should wear protective tools such as gloves, foot wears, marks, goggles etc.
*Radioactive operations should be carried out by maintaining the sufficient distance.
*There should be proper ventilations at the work place.
*Exposure to the radiations should be reduced by shifting the work.
*Sanitary rules should be followed in the work places.
*The radioactive wastes should be disposed in the safe places.
*Work place should be free from radiation hazards as much as possible.
*Solar protection should be done at the work place to minimize the radiation effects.
Ventilation
The provision of sufficient fresh air and light in the room or work places is called ventilation. It is important
because of following reasons:
*ventilation is managed for the purpose of cooling the room.
*It helps to change the air which helps to maintain air quality in the room.
*It makes the room healthy and people living inside refresh.
*It helps to control the temperature of the room/working place.
*It helps to remove smoke/dust/CO2 from the room etc.
Chemical components
We use various forms of chemicals in our day to day life. The chemicals which are used in the industries are useful
but are harmful to our health. Chemicals may occur in solid, liquid or gaseous forms. Especially, gaseous chemicals
are more harmful because they come in contact easily through air. Some of the effects of chemical hazards are as
follows:
*Mercury stores the fat tissue and damage the brain.
*Lead compound may cause mental retardation, liver and kidney damage etc.
*Formaldehyde is very sensitive to the immune system.
*Contact with acids may damage the skin, eye etc.
*Exposure of cyanide is fatal. (one drop may kill you)
*Exposure to pesticides my result headache, breathing difficulties etc.
Note: refer types of hazardouswastes for more details.
Model questions:
Mention the effects of environment pollution.
Environmental pollution is an undesirable change in the physical, chemical and biological characteristics of the
environment. The natural environment is polluted due to haphazard res istance, polluted air, polluted water, polluted
land, unwanted sound, unwanted solid wastes etc. There are many effects of environmental pollution. Some of them
are as follows:
Increase in global warming
Polluted environment consists of various types of unwanted gases such as CO2, SO2, NO2 etc. These gases trap the
solar heat and increase the atmospheric temperature which causes globalwarming.

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Destruction of living things
The contaminated water resource affects the living things living in and around it. In the contaminated water the
amount of oxygen needed by living things will not be sufficient for breathing, which ultimately results the
destruction of aquatic life.
Effects on human health
Unmanaged disposal of hazardous wastes near by the sources of water in the urban areas is one of the major health
hazards of human beings. For example drinking water which contains cadmium, affect the health badly.
Degradation of healthy environment
Polluted environment consists of solid wastes, polluted water, diseases germs, diseased plants and animals etc. The
area covered by the pollution is going on increasing. The polluted environment has been degrading the healthy
environment.
Similarly, other effects are: decrease the quality of soil, decrease in the quality of water and increase in air pollution
etc.
Mention the importance of environmental health.
*Human life becomes healthier.
*Environmental pollution is minimized.
*All living beings have better quality of life
*Surrounding environment become clean
*Conserve and protect social and cultural aspects etc.

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References:
Shrestha, R. and Suwal, A, 2014. Environment Science for Grade IX. Kathmandu: Ekta Books Distributions Pvt.
Ltd. Prashugriha Marga, Thapathali, Kathmandu, Nepal.
Shrestha, R. and Suwal, A, 2014. Environment Science for Grade X. Kathmandu: Ekta Books Distributions Pvt.
Ltd. Prashugriha Marga, Thapathali, Kathmandu, Nepal.
Bhnadari, G., 2008. Environment Education, class-XII. Kathmandu: National Institute of Natural Sciences,
Maittidevi-32, kathmandu, Nepal.
Gautam, D., 2011. Impact of climate change on wetland resources and livelihoods in Rupa Lake Area.
A M.Sc. research thesis,Tribhuvan University, Institute of forestry, Nepal.
Sapkota, LN., 2015. Environment Science book-10,Kathmandu. Guinness publication Pvt. Ltd. Kathmandu, Nepal.
Sigdel, H. and Sigdel, R, 2067. Goodwill health,Population and Environment Education (Grade 10). Kathmandu:
Goodwill publication Pvt. Ltd. Adwait Marga, Bagbazar-31,Kathmandu,Nepal.
Srivastav, J.K et al., 2014. Modern graded science class-10. Kathnamdu. Vidyarthi Pustak Bhandar, Bhotahity,
Kathmandu, Nepal.

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Annex-I
PROTECTED AREAS OF NEPAL:
There are 10 national parks, 3 wildlife reserves, six conservation areas, one hunting reserves and 12 buffer zones
covering 23.23% of total area of Nepal. According to national Park and wildlife conservation Act 1973 A.D of
Nepal gives the following definitions.
National Park: An area set aside for conservation, management and utilization of animals, birds, vegetation and
landscape togetherwith natural environment.
Strict Natural Reserve: An area of ecological significance set aside for purposes ofscientific studies.
Wildlife Reserve: An area set aside for conservation and management of animals and birds and their habitats.
Hunting Reserve: An area set aside for the management of animals and birds resources for the purposes of sport
hunting.
Conservation area: an area managed according to an integrated plan for the conservation of the natural
environment and the sustainable use of the natural resources contained with in it.
Buffer zone: A specified area designed around the National Parks and wildlife reserves for the local people in order
to provide the faculty to utilize the forest products in sustainability.
List of the protected areas of Nepal.
S.N Name of the Protected Areas of Nepal Established
Date
Area
(km2)
Buffer Zones
Established Date
Buffer Zones
Area (km2)
1. Chitwan National Park 1973 932 1996 750
2. Rara National Park 1976 106 2006 198
3. Langtang National Park 1976 1710 1998 420
4. Sagarmatha National Park 1976 1148 2000 275
5. Khapatad National Park 1984 225 2006 198
6. Shey Phoksundo National Park 1984 3555 1998 1349
7. Bardia National Park 1988 968 1996 750
8. Makalu Barun National Park 1991 1500 1999 830
9. Shivapuri Nagarjun National Park 2002 159
10. Banke National Park 2010 550 2010 344
Total 10,853
11. Suklaphanta Wildlife Reserve 1976 305 2004 243.5
12. Parsa Wildlife Reserve 1984 499 2005 298.17
13. Koshi Tappu Wildlife Reserve 1976 175 2004 173
Total 979 Total 5423.67
14. Annapurna Conservation Area 1992 7629
15. Manasalu Conservation Area 1998 1663
16. Kanchanjunga Conservation Area 1997 2035
17. Blackbuck Conservation Area 2009 16.95
18. Api Napa Conservation Area 2010 1903
19. Gaurishankar Conservation Area 2010 2179
Total 15425.95
20. Dhorpatan Hunting Reserve 1987 1325

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Annex-II
Nepal's Protected Wildlife Species
SN Scientific Name Local Name Common Name Status
IUCN CITES
Mammals
1 Ailurus flugens Habre Red Panda I
2 Antilope carvicapra Krishnasar Black buck V III
3 Bos gaurus Gauri Gai Gaur V I
4 Bos mutus Yok Nak Wild Yak E I
5 Bubalusbubalis Arna Wild water buffalo E III
6 Canislupus Bwanso Tibetan woulf V I
7 Caprolagushispidus Hispid Kharayo Hispid Hare E I
8 Cervus duvaceli Barasinghe Swamp deer E I
9 Elephusmaximus Jangali Hatti Asiatic elephant E I
10 Felis lynx Lynx Lynx E II
11 Hyaena hyaena Hundar Striped hyaena E
12 Macaca assamensis Asamese Rato Bander Asamese monkey II
13 Manis pantadactyla Salak Chinese pangolin II
14 Moschus chrysogaster Kasturi Himalayan Musk Deer E I
15 Ovis ammon Nayan Great Tibetan Sheep I I
16 Panthera tigris Bagh Royal Bengal Tiger E I
17 Panthera uncia Hiun Chituwa Snow Leopard E I
18 Pantholopshodgsoni Chiru Tibetan Antelope I
19 Pardofelis nebulosa Dhwanshe Chitwa Clouded Leopard V I
20 Platanista gangetica Sauns Gangetic Dolphin V I
21 Prionailurusbengalensis Chari Bagh Leopard Cat II
22 Prionodon pardicolor Silu Spotted Lingsang I
23 Rhinocerosunicornis Gainda Greater one-horned rhinoceros
24 Sus salvinus Sano/Pudke Bandel Pigmy Hog EXN I
25 Tetracerus quadricornis Chausingha Four-horned Antelope III
26 Ursus arctos Himali Rato Bhalu Brown Bear I
Birds
27 Buceros bicornis Thulo Dhanesh Great Pied Hornbill I
28 Catreus wallichil Cheer Cheer Pheasent E I
29 Ciconia nigra Kalo Saras Black Strock II
30 Ciconia ciconia Seto Saras White Strock II
31 Eupodotis bengalensis Khar Majur Bengal Florican E I
32 Grus grus Saras Common Crane
33 Lophophorus impejanus Danfe Impeyan Pheasant I
34 Sypheotides inidica Sano Khar Mujur Lessar Florican II
35 Tragopan satyra Munal Crimsom-horned Pheasant
Reptiles
36 Gavialis gangeticus Ghadial Gharial Crocodile E I
37 Python molurus Ajingar Asiatic Rock Python V I
38 Varanus f;avescens Sun Gohoro Golden Monitor Lizard I I

41. 41
CITES status categories are:
I = Appendix I: Species threatened with extinction
II = Appendix II: Species not yet threatened,but which could become endangered if trade is not controlled.
III = Appendix III: Species that are protected by individual countries within their borders, and for which co-
operation of other convention signatories is sought.
IUCN threatened categories are:
E= Endangered: A taxa in dangerof extinction, and whose survival is the causal factors continue operating.
V= Vulnerable: A taxa believed likely to move into the "Endangered" category in the near future if the causal factors
continue operating.
R= Rare: A taxa with small world population that is not at present "Endangered" or "Vulnerable".
I = Indeterminate: A taxa known to be endangered, vulnerable or rare, but for which there is not enough
information to say which of the three categories is appropriate.
K= Insufficiently known: A taxa suspected but definitely not known to belong any of the above categories because
of lack of information.
T= Threatened: A taxa that can not be ascribed to any of the previous categories.
Threatened species are defined as those animals listed by the IUCN's Red Data Book , the Con vention on
International Trade in Endangered Species (CITES) (Appendices I, II, and III), and animals protected under
Schedule I (Protected Wildlife, pertaining to section 10) of the National Parks and Wildlife Conservation Act of
2029 (1972/1973) of Nepal. These species are considered to be rare, endangered, threatened or vulnerable to
extinction within Nepal or elsewhere within their ranges. Species listed by CITES are considered threatened by
unregulated international trade. This list was developed from information contained in the 1988 Annotated CITES
Appendices and Reservations prepared by the Wildlife Trade Monitoring Unit of the IUCN Conservation
Monitoring Center in Cambridge, England.