Unit-1 ppt Introduction to Environmental Science

ENVIRONMENTAL SCIENCE
Dr. M. Saraswathi

 ENVIRONMENT is derived from the word “Environner”
which mean “encircle or surround”.
 Environmental Studies deals with every issue that affects
an organism.
 The term environment means surroundings i.e. air
(atmosphere), water (hydrosphere), soil (lithosphere) and
living entities (biosphere).
INTRODUCTION

 Environment can be defined as the sum of all social,
economic, biological, physical and chemical factors
constituting the surroundings of man.
 Environmental science is a branch of Philosophy that
deals with a systematized knowledge of the facts of
nature.
 ENVIRONMENT refers to surroundings which vary
from place to place and continent to continent depending
upon Physiography, Topography, Climate and the
available Natural resources.

The environment consists of four components
 Atmosphere
 Hydrosphere
 Lithosphere
 Biosphere
The understanding of the function of the various
components of environment is called Environmental
Sciences.
GENERAL COMPONENTS OF ENVIRONMENT

 Environment is concerned with day – to – day interaction with the
surroundings of which human being is closely associated.
 Environmental Science is related to multiple branches of Sciences.
 Environment is concerned with the importance of wild life and its
protection.
 Environmental Science explains the significant role of biodiversity in
establishing ecological balance.
 Environmental Science gives information relating to population
growth, population explosion and impact of population growth
 Environmental Science also gives information about Natural
resources and their conservation.
IMPORTANCE OF ENVIRONMENT &
ENVIRONMENTAL STUDIES

Environmental science is nature science and as a subject it
has wide scope. It includes the following:
 Natural Resources, Management and its Conservation
 Ecology and Biodiversity
 Major Environmental issues and Control
 Weather and Climate
 Population and Environment
These are the basic aspects of environmental studies which
have direct relevance to society.
SCOPE OF ENVIRONMENTAL STUDIES

Natural
Resources
Dr. M. saraswathi

 Any form of energy which can be used by human being is called Nature.
 Natural Resources are provided by nature
 Environmental resources are provided by environment

Natural
Resources
Renewable resources are
resources which can be
regenerated further
e.g. soil, air, water, Wind
Non-renewable resources
are resources which can
not be regenerated or
recycled once exhausted
e.g. oil, coal, gas,
uranium
 Natural Resources on the basis of origin
(i) Biotic Resources: The resources that are derived
from the living world (Animal, plants)
(ii) Abiotic Resources: The resources that are derived
from the non-living world.
eg: Land, water and air.

DEFINITION
 Water is essential component for all living things.75% of earth is
covered by water. All organisms are made by water.
 Eg: a tree is made up to 60% of water. Human being is made up of 50-
65% of water.
 Water is the most abundant, inexhaustible renewable resource. Only
3% is available as freshwater.
 From this 3%, roughly 2% is frozen in polar icecaps and only a
fraction of the remaining 1% is used as drinking water (potable). 90%
of the water is utilized for agricultural purposes in India.

FRESH WATER SOURCES
Surface Water Ground Water

USE OF SURFACE AND GROUND WATER
 Consumptive use: In such uses, water is completely utilized
and cannot be reused. Ex: Domestic, industrial and irrigation
 Non-consumptive use: In such uses, water is not
completely utilized and is reused Ex: Hydropower plant
Other uses:
 Water is used for domestic purposes like drinking, bathing,
cooking, washing. etc.
 Water is used in commercial establishments like hotels,
theatres, educational institutions, offices, etc.
 Almost 60-70% of fresh water is used for irrigation
 20-30% of water is used for industrial operations by
refineries, iron & steel industries, paper & pulp industries,
etc.
 Water plays a key role in sculpting the earths surface,
moderating climate and diluting pollutants.

OVER-UTILIZATION OF GROUND WATER
 The rapid increase in population and industrial growth led to severe
demand on water resources. After using all available surface water
resources to the maximum, human beings began using groundwater
to meet their needs.
Effects on over utilization of water:
1. Decrease of ground water:
Due to increase usage of ground water decrease the natural
recharge levels caused decrease in ground water level.
2. Ground subsidence:
When the ground water withdrawn is more than its natural
recharge rate the sediments in the aquafier get compacted in that way
the earth layer will be skinned this called ground subsidence.
3. Lowering of water table:
Over utilization of ground water in drought areas for
agriculture disturbs the hydrological cycle means caused lowering of
water.

4. Intrusion of salt water:
In coastal areas, over exploitation of ground water
would lead to rapid intrusion of salt water from the sea. So water
not used for drinking and agriculture.
5. Earth quake and land slides:
Over utilization of water caused earth quakes and land
slides (mass of earth fall where the slope of the earth).
6. Drying up of wells:
As results over utilization of water, the level of ground water depleted
as much faster than their regeneration rates. So, this leads drying
up wells and bores.
7. Pollution of Water:
When the ground water level decreases the land surface
decreased so in that decreases the nitrogen content is more due
using nitrogen containing fertilizers this nitrogen is percolate in to
ground water and get polluted nitrogen content is 45mgs/lit.

FLOODS
Floods have been a serious hazard. Defined as a
flood is an overflow of water, whenever, the
magnitude of water exceeds the carrying capacity
of the channel with in its bank.

CAUSES OF FLOOD
 Heavy rainfall, melting of snow, sudden release of
water from dam
 Prolonged downpour can also cause the over-flowing of
reserves and lakes resulting floods.
 Reduction in the carrying capacity of the channel due
to accumulation of sediments and soil.
 Deforestation, over grazing, mining increasing the
runoff from rains and flood raises.

EFFECTS OF FLOODS
• The cultivated land effected and plain land
eroded with mud and sand.
• Extinction of civilization in some coastal areas
also occurred.
• Due to flood, water spreads in the surroundings
areas and submerges them.

FLOOD MANAGEMENT
•Floods are controlled by constructing of dams
•Channel management and embankments also
control the floods.
•Encroachment of flood ways should be banned
•Flood hazard may also reduced by forecasting
‘or’ flood warning.

Unit-1 ppt Introduction to Environmental Science

Drought is nothing but scarcity of water, which
occurs due to inadequate rainfall.
Types of drought:
• Metrological drought
• Hydrological drought
• Agricultural drought
• Socio-economic drought

1. Meteorological drought:
It occurs when the total amount of rainfall is
less than 75% of normal rainfall.
2. Hydrological drought:
It occurs when the total amount of rainfall is
less than average rainfall. It is associated with reduction
of statically average of water reserves available in lakes,
reservoirs, rivers, aquifers.
3. Agricultural Drought:
This occurs due to shortage as well as the
timing of overall rainfall. It will reduces the ground water
level.
4. Socio – Economic Drought:
It occurs due to reduction in the availability
of food, social security of people affected areas.

Causes for Drought
• when the rainfall is below normal and less than
evaporation, drought is created
• high population also another cause for drought
• Intensive cropping pattern and over exploitation
of water
Eg: East African countries has been no recovery
from drought
• deforestation is also caused for drought

Effects of Drought
• Drought causes hunger malnutrition
and scarcity of drinking water and
also change the quality of water.
• Drought causes failure of wide
spread crops and shortage of food.
• The drought indicates the worst
situation and initiation of
Deforestation.
• Raw materials for agro based
industries are critically affected.
• Due to drought, natural resources
are degraded.
• Drought leads to large migration of
people.

DROUGHT MANAGEMENT
• Indigenous knowledge in control
drought – desertification is very
useful for dealing with the
problems.
• Rain water harvesting programme
is another fruitful method.
• To improve ground water level,
construction of reservoirs is
essential.
• Modern irrigation technology is one
of the good technique to control the
drought
• when Afforestation activities also
improved
• Mixed cropping is best method to
minimize the risks of crops failures
in dry areas.

DAMS
Dam is a solid barrier constructed at a suitable location
across a river valley to store flowing water.
Purpose of Dams
• 48 % of Dams – for irrigation contributes for large quantities of
food production
• 15% of Dams – Domestic & Industrial water
• 8% of Dams – Flood control
• 4% of Dams – Recreation +Inland navigation fish farming
• 20 % of Dams – Generates hydropower
• 40% dams in Europe are hydropower dams

BENEFITS OF DAMS
 Dams are built to control the floods.
 Dams are used for diverting part of
the water from river into a channel.
 Dams are used mainly for drinking
and agricultural purpose. 30-40% of
268 million hectares of irrigated land
is watered from dams
 Dams are built for generating
electricity. 19% of world energy
comes from hydro-electric power
( which includes 150 countries)
 Dams are used for recreational
purpose
 Navigation and fisheries are
developed in the dams.

PROBLEMS WITH DAMS
 The problems of dams can two
types
 Upstream Problems
 Downstream Problems

UPSTREAM PROBLEMS
1. Displacement of tribal people
2. Loss of Non – forest land
3. Loss of forest land, floura and funa
4. Land slips, sedimentation and
siltration occurs
5. Stagnation and water logging
around the reservoirs retards plant
growth
6. Breeding of vectors and spread of
vector - borne diseases
7. Causes earth quakes
8. Navigation and aqua culture
developed.

DOWNSTREAM PROBLEMS
1. Water logging and salinity due
to over irrigation
2. Reduced water flow and slit
deposition in reserves
3. Salt water intrusion at river
mouth.

Save It
Conserve It
Preserve It

FOREST RESOURCES
“Men have grasped the first idea
of architecture from the forests.”

 The word forest is derived from a Latin word “ Foris” means
Outside.
 Forest are one of the most important natural resources of the
earth.
 Approximately 1/3rd
of the earth’s total area is covered by forests.
 It is a dense growth of trees, together with other plants,
covering a large area of land.
 Covering the earth like a green blanket these forests not
only produce commercial material goods, but also
provide several environmental services which are
essential for life.
Forest Resources

FUNCTIONS OF FORESTS
The functions of forest may broadly classified into following
categories
 Protective Function
 Productive Function
 Regulative Function
 Accessory Function

PRODUCTIVE FUNCTIONS
 Forest Provide various products like, gum resins, medicines, catchew,
honey, pulp, bamboo, timber, and fruits

PROTECTIVE FUNCTIONS
 Forest Provide protection against Soil erosion, Droughts,
floods, noise, radiations
Soil erosion Floods Droughts

REGULATIVE FUNCTIONS
 The Forest regulates the level of Oxygen and carbon dioxide
in atmosphere. The forests also help in regulating temperature
conditions

ACCESSORY FUNCTION
 Forest provides aesthetics, habitat to various flora and fauna
besides that it also has an recreational value.

ECOLOGICAL IMPORTANCE OR
USES OF FORESTS
A tree produces commercial goods worth Rs. 30,000. it
provides environmental services worth 1,00,000. it
shows the important of trees for environmental
protection.
Production of Oxygen
 The Trees are produced Oxygen by Photosynthesis. This is
important to which are live in the earth. So we called as
forests are earth lungs.

Reduction of Global Warming
 The main green house gas co2 is used by forests for photosynthesis
process the forest act as a sink for co2 there by reducing the green
house effect due to co2

CONTROL OF WATER FLOW
 The forest act as a giant sponge they slow down runoff,
absorbing and holding water that recharges springs, streams,
and ground water.

HABITAT TO WILD LIFE
 They provide the habitat for high wild life species

ABSORPTION OF NOISE
 Forest cover absorbs the noise and helps in preventing noise
pollution

ABSORPTION OF AIR POLLUTANTS
 Forest absorbs many toxic gasses and air pollutants and can
help in keeping air pure.

OVER-EXPLOITATION
Over exploitation or over usage of forest resources
Causes:
 Demand for Timber.
 Demand for cleared land to create agricultural
land & house construction.
 Mining
 Demand for fuel wood.
 Deforestation due to road construction.
 Construction of Hydro power projects.
 Short-term economic gains made by conversion of
forest to agriculture, or overexploitation of wood
products, typically leads to loss of long-term
income and long term biological productivity.

DEFORESTATION
 Forest are exploited since early times for humans to meet human
demand
 The permanent destruction of forest is called deforestation

CAUSES OF DEFORESTATION
 Shifting of Cultivation: In the world there
are 300 million people as shifting cultivation
which practice slash burn agriculture.
 Fuel Requirements: Fuel wood required
about 300-500 million tons for every year.
Thus, thereby increasing the pressure on
forests.
 Raw materials for Industrial use: wood
for making boxes, furniture, railway
sleepers, plywood, match boxes, pulp for
paper industry etc causes the deforestation.

 Development of Projects: Destruction of forest by
developing various projects like hydrolytic projects,
big dams, road construction, mining etc.
 Growing food needs: In developing countries this is
the main reason for deforestation. To meet the
demands of rapidly growing population agricultural
lands and settlements are created permanently by
clearing forests.
 Pest attack: Forests pests like insects etc. destroy
trees by eating up the leaves booring in shoots and
spreading diseases.
 Natural forces: floods, storms, snow, lighting are
the natural forces which are damaged forests.
 Over grazing: Overgrazing of land by cattle result
into soil erosion, desertification.

EFFECTS OF DEFORESTATION
Deforestation adversely affects and damages
the environment. The adverse effect of
deforestation are discussed below:
 Soil erosion: The soil gets washed away
with rain water on sloppy areas in the
absence of trees leading to soil erosion.
 Expansion of deserts: Due to strong
winds laden by rock dust, land mass
gradually gets converted in deserts.

 Decrease in rainfall : In the absence of
forest, rainfall declines considerably because
forest bring rains due to high rate of
transpiration. It maintains humidity in
atmosphere
 Loss of fertile land: Less rainfall results
into loss of fertile land owing to less natural
vegetation growth.

 Lowering of Water table: Lack of recharging
of underground reservoir, results into
lowering of water table
 Economic Losses: Deforestation will cause
loss of industrial timber and non timber
products
 Loss of biodiversity: Loss of flora and fauna
result into loss of bio-diversity leading to
disturbance in ecological balance world wide.
 Environmental changes: It will lead to
increase in carbon dioxide concentration and
other pollutants which results in Global
warming.

AFFORESTATION
 The conservation measure against
the deforestation is afforestation.
The main objective of afforestation
 To control the deforestation by
planting trees
 To prevent soil erosion
 To regulate rainfall and maintain
temperature

 To control atmospheric condition by keeping it clean
 To promote planned uses of wasteland
 To Protect forest ecosystem and to get benefits of forest products.

INTRODUCTION
 Minerals are an indispensible part of our lives.
 Minerals are found in varied forms in nature,
ranging from the hardest diamond to the softest
talc.
 Minerals: Minerals are naturally occurring
inorganic and crystalline solids having definite
chemical and physical composition.
 Ores: Ores are minerals or combination of
minerals form, which are useful substances eg:
metals.

CLASSIFICATION OF MINERALS
MINERALS
Energy Minerals
Non-Metallic
Metallic
Ferrous Containing
Non-Ferrous
Precious
Mica , Salt , Potash
, Sulphur , Granite ,
Limestone ,
Marble , Sand
Stone.
Etc;
Coal , Petroleum ,
Natural Gas

ENVIRONMENTAL IMPACTS OF
EXTRACTING MINERAL RESOURCES
Impacts of
Mining
Activities
Physical impacts
Land subsidence
Soil erosion
Under ground fires
Landscape destruction
Negative Socio-
Economic impacts
Encroachment and
evacuation
Resettlement
&Rehabilitation issues
Occupational Health
impacts
Health hazards due to long
term exposure to
chemicals
Accidents
Environmental
Pollution
Air Pollution
Water Pollution
Soil Pollution
Positive Socio –
economic impacts
Employment‘
Economic gains
Ecological impacts
Deforestation and de-
Vegetation
Loss of flora and fauna
Ecosystem degradation

 The efficient use and protection of mineral
Resources
 Modernization of mining Industries
 Search for new deposits
 Reuse and recycling of the metals
 By adopting eco-friendly mining
technologies to consume the environmental
pollution
 Low grade ores can be leached by microbial
techniques

WHAT IS ENERGY?
“The capacity to
do work”

ENERGY FORMS
 Heat
Light
Sound
Kinetic
(movement)
Chemical
Electrical
Gravitational
Elastic (potential)

THE WORLD CONSUMES ENERGY IN THE
FOLLOWING FASHION
PETROLEUM PRODUCTS = 40%
NATURAL GAS = 22.5%
COAL = 23.3%
HYDEL POWER = 7%
NUCLEAR POWER = 6.5%

SOURCES OF ENERGY
All forms of energy are stored in
different ways, in the energy sources
we use every day. These sources are
divided into 2 groups.

TYPES OF ENERGY
 Renewable
An energy source that can be replenished
in a short period of time.
 Non – Renewable
An energy source that we cannot replace.

RENEWABLE
ENERGY
• Solar Energy
• Wind Energy
• Hydro Energy
• Biomass (plants)
• Geothermal
• Ocean Energy

SOLAR ENERGY
 Solar Energy: The energy, which gets directly from the sun, is
called solar energy. The nuclear fusion reactions occurring inside
the sun release enormous amount of energy in the form of heat
and light.
 By using solar cells, solar batteries, solar heat collectors are
harvesting the solar energy.
A Solar
Panel

WIND ENERGY
 Wind energy: Moving air is called wind. Energy
recovered from the force of wind is called wind energy.
 Wind energy harnessed by making use of wind mills.
Wind Energy

HYDRO ENERGY
 Large amount of the kinetic energy of the flowing
water is tapped using water turbines. Hydro power
projects involve constructing of dams.
 Eg: produced electrical energy
Dam
Potential
Energy
Kinetic
Energy
Mechanical
Energy
Electrical
Energy

Biomass
Biomass is the organic
matter, produced by
plants or animals, used
as a source of energy.
Most of the biomass is
burned directly for
heating, cooling and
Industrial purpose. Bio
gas, bio fuels and
hydrogen fuels are the
types of biomass energy.

Biofuel
• Biofuel (also called
agro fuel) is a
bioorganic fuel .It is
obtained by the
fermentation of
biomass.
• The process by which
micro-organisms break
down complex organic
substances generally in
the absence of oxygen to
produce alcohol and
carbon dioxide is called

Examples of Biofuel
Ethanol:
It is produced from sugarcane .Its
CALORIFIC VALUE is less than petrol. It
also less heat when compare to petrol.
Methanol:
It is easily obtained from ethanol .Its
CALORIFIC VALUE is too low when
compared to gasoline and diesel.
Gasohol:
It is a mixture of ethanol + gasoline .It is
used in cars and buses.

GEOTHERMAL ENERGY
http://volcano.und.edu/vwdocs/volc_images/img_white_island_fumerole.html
http://lvo.wr.usgs.gov/cdf_main.htm
Geo thermal energy is the energy which lies embedded with in the
earth’s crust. There is an increase in temperature of the earth with
increasing depth below the earth surface.
Geo thermal energy can also used for producing power, space
heating, Industrial purpose.

OCEANIC ENERGY
Ocean energy: An Ocean energy resource includes tidal energy and
wave energy. Ocean energy is indicting form of solar energy. The seas and
oceans are absorbed solar radiations. This results the temperature in the
water surface – downwards i.e. warm surface water and colder deep
water. This temperature difference can be utilized to generate electricity.

NON- RENEWABLE ENERGY
Oil
Coal
Natural
Gas
Nuclear
Petroleum
gas

COAL
 Coal: Coal is a solid fossil formed by
burning of plants. It is non – renewable,
commercial or conventional source of
energy. 6 lakhs billon tones of coal lies
under the earth crust, but now 200 billion
tones have been used.

TYPES OF COAL
COAL
Peat Lignite
Sub-
Bituminous
Bituminous
Coal
Anthracite Graphite

PETROLEUM
 Oil or Petroleum: Petroleum is an
inflammable liquid composed of
hydrocarbons and also constitutes organic
compounds like O2, N2, S and traces of
organo – metallic compounds.

PRODUCTS OF PETROLEUM
• Kerosene
• Petrol
• Diesel
• Jet fuel
• Liquefied petroleum gas (LPG)
• Lubricants
• Bulk tar
• Paraffin wax
• Plastics

NATURAL GAS
 Natural gas: Natural gas found above the oil in
oil well. It is a mixture of 50-90% methane and
small amount of other hydrocarbons.

 Natural gases are two types
 Dry gas: If the natural gas contains lower
hydrocarbons like ethane and methane called dry gas
 Wet gas: If the natural gas contains higher
hydrocarbons like butane and propane called wet gas.

NUCLEAR ENERGY
A physical reaction which
involves changes in the nucleus
of an atom is called a NUCLEAR
REACTION
The energy released during a
nuclear reaction is called
NUCLEAR ENERGY

Earth’s Non – renewable
Resources Are
Getting Used Up!
To Save Them,
Follow 3 Simple Steps:
Save, Recycle And Grow Tree

WHAT IS SOIL?
Top most layer of earth crust
consisting of organic and inorganic
matters is called soil.
Soil is a renewable resource.
Soil is a living system.
Unweathered
parent bed rock.
Top soil the upper soil layer.
Subsoil weathered rocks
sand and silt clay.
Substratum
weathered parent
rock material.

IMPACTS OF LAND USE ON ENVIRONMENT
 Land Degradation
 Soil erosion

Land degradation
Land degradation is the process of deterioration of soil or loss of fertility of the
soil.
Causes of land degradation:
 Population: With increasing population growth of demands for arable (cultivate) land
for producing food, fiber and fuel wood.
 Urbanization: The increased urbanization due to population growth reduces the extent
of agricultural land.
 Pollution of land: Increase applications of fertilizers and pesticides are needed to
increase the crop productivity caused land pollution.
 Damage of top soil: Increase in food production leads to damage to top soil through
nutrient depletion.

Effects of Land Degradation:
 The soil texture and soil structure are deteriorated
 Loss of soil fertility due to loss of valuable nutrients
 Increase in water logging, salinity, alkalinity and
acidity problems.
 Loss of social, economic gains
 Loss of biodiversity.

CONTROL MEASURES TO LAND
DEGRADATION
 Need to decrease constant increase in population
 Decrease number of births
 Decrease number of immigrants
 Need to increase productivity of arable land
remaining
 Find new technology to improve land quality
 Use new methods so land does not become overused and
allowed to degrade or erode away

SOIL EROSION
Soil erosion is the movement of
soil components from one place to
another due to wind and rainfall.
Causes of Soil erosion:
 Water effects soil erosion in the form
of Rain
 Wind carry away the soil particles one
place to another and create soil
erosion
 Overgrazing, mining and
deforestation are the major causes for
soil erosion
 Landslides also causes the soil erosion
 Construction of dams, roads and
buildings removes the vegetation
cover and leads the soil erosion

EFFECTS OF SOIL EROSION
 Soil fertility is lost because of loss of top soil layer
 Loss of ability to hold water and sediments
 Sediment runoff can pollute water and kill
aquatic life

PREVENTION OF SOIL EROSION
 Counter forming: crops
are grown in rows
across, rather than up
and down, a practice
known as Counter
forming
 Terracing: It involves
conservation of steep
slopes into a series of
broad terraces, which
can run across contour
and control the soil
erosion soil erosion.

FUTURE
Soil will become even more crucial World population doubles every 40 years only 7
% of earth's surface is suitable for agriculture.

FOOD RESOUCES
 Food is necessary for the growth and development of living
organisms
 Major food is obtained from traditional land based agriculture,
Livestock and fisheries etc.
World food problems:
 Increasing population: due to over growth of population, our needs also
increased greater than the population. The prices of food grains are
shooting up due to droughts and floods.
 Unbalanced diet: An average Indian is able to take only carbohydrates, as
he depends on ill nutritious grains.
 Protective food: Like milk, fish, egg, fruits and vegetables are absent in
the meal leads malnutrition.
 Eg: we required 2500calories/day, lack of calories leads to weakness and
inability to work.
 The distribution of food quality is not satisfactory.
 Many of us a large amount of food carelessly.
 840million people starving for food and 18million people dieing each year
due to starvation.
 -This creates stress on our environmental resources.

 Effects of Modern Agriculture:
 Fertilizer problem:
 Fertilizer is very essential for increasing productivity in
agriculture
 Fertilizer contribute to 70% of growth in agriculture.
 Application of chemical fertilizer creates lots of problems related
to soil and food.
 The fertilizer is washed off the lands through irrigation, rainfall
and rainfall enter into rivers and streams leads phosphate, and
nitrogen pollution caused Eutrophication.
 Pesticides Problem:
 Harm to fish
 Harm caused by herbicides
 Wild life, when exposed to pesticides suffered by health issues
 Harm to bees
 Harm to human beings
 Water logging and salinity
 Intensive irrigation leads water logging
 Leads anaerobic conditions in the affects the crop productivity.
 Salinity affects soil quality

Unit-1 ppt Introduction to Environmental Science

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