ECOLOGY & ENVIRONMENT

1. Environment (Concept, characteristics) & its components, types

2. Ecology, objectives, scope

Environment is a very complex multifaceted term. It is not as easy task to say

what actually environment is. The term finds its wide & wild usage each & every

living being experience various stage of life from conception till death. These

experiences are related to his diverse surroundings. This whole range of diverse

surroundings in which one perceives, experience, reacts to events and changes is

conceived as Environment. This wide array of environment includes the land, water,

air, the other living organisms and individual‟s interaction with these all. It is also

concerned with man‟s ability to adopt both physically and mentally to the continuous

chain of changes in the environment.

1. Environment: The word environment has been derived from a French word

“environier” which means to surround. The surroundings or conditions in which a

person, animal or plant lives or operate constitute environment.

The external factors such as air, water etc. Which affect an organism?

2. The totality of circumstances surrounding an organism or group of organisms

especially

(a) the combination of external physical conditions that affect and influence the

growth, development and survival of organisms. “We shall never understand the

natural environment until we se it as a living organism” (Paul Brooks).

(b) The complex of social & cultural conditions affecting the nature of an individual &

community.

(3) Merriam-Webster: The complex of physical, chemical & biotic factors (as climate,

soil and living things) that act upon an organism or an ecological community and

ultimately determine its form and survival.

The word „environment‟ is most commonly used describing natural environment &

means the sum of all living and nonliving things that surround an organism or group

of organisms. It includes all elements factors and conditions that have some impact on

growth & development of certain organisms.

In the words of M.J. Herkovitts :- Environment is the aggregate of external forces

which affect the life and development of living organisms.

P. Gisbert: Environment is something surrounding us from all sides and affecting one

life directly.

It covers all those circumstances which asset their influence on the individual since

conception to death. Whatever found around the individual may be covered by the

term environment. It has been defined by various psychologists and scientist as

follows:

Boring: A person‟s environment consists of the sum total of the stimulation which he

receives from his conception until his death.

Anastasi: The environment is everything that affects the individual except his genes.

Douglas & Holland: the term environment is used to describe in the aggregate, all the

external factors influence and conditions which affect the life, nature, behaviour and

the growth, development and maturity of living organisms.

In fact environment is composed of all elements that exist on earth in different forms.

These may be biotic or a biotic, social or economic.

The term environment refers to the surroundings of an organism which includes both

living and nonliving components. The word meaning of environment is to surround

and to develop. The words „surround‟ and „develop‟ raise two basic questions:

(1) What is surrounded and developed? The answer is man.

(2) What surrounds and develops the ma

The simple answer is other organisms e.g. other living organisms social cultural &

economic surroundings and all non living components hand, water, air, rain, humidity,

atmospheric pressure.

Thus environment consists of natural as well as socio-cultural environment.

Man has to improve the quality of his environment because these are so many hazards

deterioting the environment and have led to life threatening ecological imbalance.

Basic characteristics of environment

Wood worth and marquis: Environment covers all the outside factors that have acted

on the individual since he began life.

In the words of Grouter (1983), “Environment is any evening or condition outside the

organism that is presumed to influence or be influenced by person‟s development.

According to Marshall McLuhan, “Environment is not just containers, but is processes

that change the content totally.

According to good (1959), “Environment as a term designates the entire objects and

conditions that affect the individual through such stimuli as he is able to receive.

According to Chapman & Reiss (1992): Environment is surrounding of an organism,

including other organism and other physical features.

Basic Characteristics of environment

Above discussion leads us to following basic characteristics of environment.

(1) Sum total of conditions which surround man at given point in space & time.

(2) Sum total of the stimulus man receives from the time of conception until his

death.

(3) Everything affecting the individual except his genes.

(4) All external forces affecting growth & development of living organisms.

(5) Includes biotic as well as a biotic components as well as physical, chemical,

biological, social, economic, political & cultural processes.

(6) It has direct as well as indirect effect.

(7) Biome, Habitat and energy constitute the three basic components of the

environment‟s structure.

(8) Well organised system of mutually interacting and well integrated elements,

with elements of a component interacting not only among themselves but also

with elements of other components.

(9) Open system characterised by a perfectly continuous system of input and

output of matter & energy.

Perfect functioning system in which each unit is intimately related with each other

unit through a series of large cyclic mechanisms such as biogeochemical cycles,

water cycle, energy cycle.

Empowered mainly by the input of solar energy.

Is self sustaining & has its own productivity. It generates organic matter. Its rate of

growth of course depends upon the availability and amount of energy.

Normally maintains ecological balance unless there is disturbance in one or more

controlling factors.

Components of Environment

Experts engrossed in the study of environment opine that environment is both

physical and biological concept which encompasses both living and nonliving

components and they in turn are empowered by energy component. So we can say

that environment consists of three basic components.

(a) Abiotic (physical or inorganic or nonliving)

(b) Biotic (Organic or living or biological)

(c) Energy

Abiotic Component

The physical and the chemical components of the ecosystem build up the

abiotic structure. They consist of

(a) Lithosphere (physical space)

(b) Atmosphere (Climate)

(c) Hydrosphere (Water)

Lithosphere: It consists of the soils and the sediments which are the chief reservoir

of mineral nutrients. It occupies 29% of earth‟s area and provides the habitat for

most of the plants and animals. Lithosphere is a dynamic component and is

undergoes continuous formation & modification through forces which may be

endogenetic (internal) and exogenetic (external). Endogenetic forces perform the

role of modification. Exogenetic forces have their origin point in atmosphere,

hydrosphere and even in the sun and moon also. There are innumerable no of

forces like geochemical cycles, tectonic processes, hydrologic cycle, geological &

geothermal processes. Which alone or their combined effect have produced a

tremendous variety of geological & geomorphic features each of which is of great

significance for human beings.

Atmosphere

It is the blanket of air around the earth which is a chief reservoir of gases essential for

organic life. It performs many crucial functions for the sustenance of life on earth.

It protects the living organisms from various harmful cosmic radiations and maintains

the favourable climate on earth. By permitting the penetrations of adequate quantities

of life giving sunlight to earth‟s surface.

It also acts as filter or well as thermal insulator. Keeping the earth‟s surface

much warmer. It also provides the media for transporting energy and moisture from

one place to another. So atmosphere shapes the climate of the earth and determines the

nature and distributions of life.

The various constituents of atmosphere interact in an extremely complex way

not only with in an extremely complex way not only with incoming solar energy but

also with solar energy escaping from the earth which lead to variations in temperature.

It height varies from 16-29 kilometres from seal end. Its general composition is

as follows:-

Table Composition of atmosphere

Nitrogen Water vapour

Oxygen Particulates

Argon

Carbon dioxide

Other inert gases

Its composition varies from place to place but still wind & diffusion of gases

helps in maintaining uniformity water vapours also vary in amount from place to place

and there amount decreases from equator to poles. Particulates help in scattering of

solar radiations giving various colours & hues to the sky. Besides this they help in

cloud formation and condensation.

Besides these constituents, atmosphere has one another important feature that

controls life i.e. temperature. It is highest near the earth‟s surface and goes on

decreasing upward at the rate of 1oF for every 300 feet upto tropopause. Beyond this

temparture is either steady or slightly rises Fig. Layers atmosphere.

Hydrosphere

It is the chief reservoir of water and includes all the water and includes all the

water bodies like oceans, lakes, ponds, rivers and even the ice caps & glaciers,

underground water, and the water in the soil. It plays an important role in the

circulation of nutrients. Its flow determines the configurations of earth‟s surface and is

the basis for human settlements & transportation. Its flow in nature is regulated by the

sun in the form of water cycle. Total amount of water in the environment remains

constant. Only its form and location undergoes change from time to time and place to

place.

Fig. 3 Pg -18 (R.C. Chandna)

Out of all the sources of water, oceans provide one of the most hospitable

environments for organism life. They constitute the largest single habitat. They put a

tremendous effect on the coastal environment through sea waves, ocean currents and

tides.

Abiotic components may also be further divided into two categories.

Diagram............

BIOTIC COMPONENTS

Earth is the only known planet to have life in various forms that too upto few

kilometres of the earth‟s layers. There is no sign of life below or above this belt. This

belt of earth that sustains life is called biosphere. This whole life in the biosphere can

be further categorised into three.

(a) Producers

(b) Consumers

(c) Decomposers

Producers

These are mainly consists of green leafy trees and plants. They are called

producers because only they have the capacity to trap solar energy and to use elements

from earth to convert them a form that can be used both by them as well as other

forms of life. In other words only they can perform photo synthesis to make their own

food. They are also termed as autotrophs.

Consumers

Consumers or the heterotrophs are those organisms which depend upon green

plants for their food either directly or indirectly. All animals including man fall under

this category. They are further of 3 types.

(a) Herbivores – eat only plants

(b) Carnivores – eat only animals

(c) Omnivores – eat both plants as well as animals.

All these cannot produce food themselves they consume food produced by

plants.

Decomposers

Or the Scavengers they are the nature‟s way of cleansing this earth. They form

an important link in returning back the nutrients taken from earth by plants and

animals in various forms. These include all the micro organisms like bacteria & fungi

which decompose the dead animals and plants and recycle the nutrients.

All these abiotic components are not living but support other living organisms.

If any of these components loses its balance. Whole of the life gets disturbed and

where are these three reservoirs intermingle in optimum amount that area becomes the

most fertile area for organic life.

All flesh is grass. This simple statement conveys the basic principle of biology.

It means that fundamental source of food for all consumers is green plants the grass.

These consumers including man may be herbivorous, carnivores or omnivorous. They

all obtain energy and nutrients for their sustenance, growth & reproduction directly or

indirectly (by eating animals that have eaten animals which in turn have eaten plants)

on plants.

Energy Component

Energy is another vital component of the environment without which life could

not have existed on the planet. Energy is essential for generation and reproduction of

all biological life on this planet. It is the input of matter and energy which makes the

life a possibility. The pattern of energy flow in the environment is governed by first

two laws of thermodynamics.

1st law: Energy can neither be created nor be destroyed. It can only be converted

into other form.

2nd

law: In any transfer of energy, there is always a loss of available energy.

All sources of energy whether in the form of solar energy, wind energy,

hydro energy or tidal energy lie virtually outside the biosphere sun of course is the

major source of energy for proper functioning of the ecosystem. Flow of energy is

unidirectional and this energy flow and the system of matter distribution and

circulation are most critical for functioning of the ecosystem.

Types of Environment

The term environment is a very comprehensive term. However by adding a pre-fix to

the term environment, its meaning gets restricted. According, authors have recognised

following types of environment with each type carrying only a restricted meaning.

Physical Environment: Only nonliving elements it comprises surrounding

an organism.

Biological Environment: Comprises only living elements that surround and

organism including the organism itself.

Socio-Cultural Environment: Comprises all human activities, his interactions

with other humans and his living conditions

facilities and equipments he uses and his

settlements.

Perceptual Environment: It is the environment as perceived by an organism

so it varies from person to person and is an abstract

concept.

Conceptual Environment: It comprises the ideas that govern the form and the

use of the constructs. It emphasises the superiority

of human mind in relation to other organism.

Human Environment: It comprises of interactions between organisms and

their surroundings. Among all organisms, man is

bestowed with intelligence and is superior to other

organisms. HE is the one who can modify his

environment to suit his requirements. He has

turned the natural environment of earth to

manmade landscapes.

Operational Environment: Comprises all those factors which are perceivable

as well as non-perceivable, living as well as

nonliving including viruses.

Total Environment: All the forces and materials on earth in any

situation that may or may not influence behaviour

in a specific situation e.g. gravitational force,

magnetic field of earth, attitude etc.

So from above we can see that all these types cannot be isolated from each other.

They are not enclosed in water tight compartments. There is a relationship of give and

take environment is a conglomeration of all of these. It is a comprehensive term.

Ecology

The term ecology was coined by Ernst Haeckel as Oecology or Oekology

(derived from two greek words „Oikos‟ meaning dwelling or house or habitat and

„Logos meaning the study of).

So we can say ecology is the study of habitats or the study of relationships between

organisms and their environment.

Alles et al. (1949) considered ecology as, “the science of inter-relation between living

organisms and their environment, including both the physical and biological

environments and emphasizing inter-species as well as intra-species relations.”

G.L. Clarke (1954) defines ecology as “The study of inter-relations of plants and

animals with their environment which includes the influences of other plants and

animals as well as those of the physical features.

McFadden (1957) defined ecology as, “a science which concerns itself with the inter-

relationships of living organisms, plants, animals and their environments”.

L.R. Taylor (1967) have defined ecology as “the study of the way in which individual

organisms, populations of some species and communities respond to those changes.”

Southwide (1976) defined ecology as, “the scientific study of the relationship of living

organisms with each other and with their environments.” He further explained his

definition of ecology by stating that, “it is the science of biological interactions among

individuals, populations and communities, and it is also the science of ecosystems the

inter-relations of biotic communities with their non-living environments.

Pinalea (1973) described ecology as, “the study of relations between organisms & the

totality of the biological & physical factors affecting them or influenced by them.

C.J. Krebs (1985) defined ecology in simple and in comprehensive ways as “Ecology

is the scientific study of the interactions between organisms and nature that determine

the range/distribution and abundance of organisms.”

Basic Characteristics

1. It is basically science of ecosystems.

2. It is the study of interrelationships and interdependence between organisms and

environment.

3. It include the structure & function together for full understanding of this vast

nature.

4. It is the scientific approach for controlling and regulating the welfare of living

organisms.

5. It emphasises inter organisms as well as intra organismic relations.

6. It is a philosophy in which the world of life is interpreted in terms of natural

processes.

Fundamental Principles

1. Man being an active agent or environmental change, modifies the ecosystem

through the exploitation of natural resources.

2. Ecosystem instability results when an ecosystem becomes unable to adjust with

environmental changes.

3. All living organisms and physical environment are mutually reactive. The

organisms interact among themselves and affect each other and physical

environment.

4. Ecosystem functions through the input of energy mainly solar radiation which

is trapped by green plants and is used to prepare food through the process

photosynthesis. The solar radiation is the main driving force of the ecosystem.

In any system of constant mass, energy is neither created nor destroyed but is

can be transformed from one type to another type.

5. Natural hazards affect adversely the biological communities in general and in

particular. When biological processes are associated with physical events, yet

severe hazards are created.

6. Sustained life on earth is a characteristic of ecosystem, not of individual

organisms or population.

7. Ecosystem is a fundamental unit of ecological study because it comprises both

biotic and abiotic components.

8. The ecosystem productivity depends on two factors:

(a) The availability of the amount of solar radiation to the primary producers.

(b) The efficiency of plants to convert solar energy into chemical energy.

9. Environmental principles of holistic nature of natural environment which

largely affect the biological communities in a biospheric ecosystem.

10. The physical and biological processes follow the principle of uniformitarian

which states the same physical and biological processes, as the environment is

influenced by human activity.

Aims and objectives of Ecology

1. To provide the true understanding of the structure and functions of the mother -

nature.

2. To study the wide network of relationships between living beings and their

environment.

3. To analyse the interdependence between various components of environment.

4. Evolving scientific approaches to control and regulate welfare of living

organisms.

5. To study these interrelations from evolutionary point of view of development.

6. Evolving mathematical models of interaction between various components of

environment.

7. Employing system analysis approach to improve the status of environment.

8. Providing comprehensive awareness to the masses of there relationships and

interdependence.

9. To study conservation and management of natural resources and environmental

pollution.

10. To observe the biological productivity of nature and how the products may be

used to improve the quality of life of man.

Branches of Ecology

It is broadly divided into two branches:

1. Autoecology: It concentrates on one species of organism in all aspects

like life cycle, home range, populations, dynamics &

Behaviour e.g. Royal Bengal Tiger.

2. Synecology: It deals with ecological studies of entire ecosystem like a

forest or a desert etc.

Besides this ecology has been classified on the basis of specialization:

Branch of Ecology Area of Study

1. Habitat Ecology : The study of different-habitats on earth and their

effects on the organisms.

2. Geographic Ecology : The study of geographical distribution of plants and

animals

3. Ethology : The interpretation of animal behaviour under

natural surroundings.

4. Human Ecology : The study of man and man‟s relation to the

environment and man‟s effects on biosphere and

implication for man.

5. Community Ecology : The study of the local distribution of animals in

various habitats.

6. Population Ecology : The study of growth, structure and regulation of

population of organisms.

7. Applied Ecology : The study of the human needs and the applications

of ecological concepts e.g. agriculture, forestry,

land use etc.

8. Production Ecology : It deals the production of different ecosystems like

fresh water, crops sea water etc.

9. Sociology : The study of ecology and ethology of mankind.

10. Radiation Ecology : The study of effects of radiation on environment

and organisms.

11. System Ecology : It deals the analysis and understanding of the

structure and function of ecosystem. It employs

mathematical models.

Biosphere, Community, Population, ecosystem, levels major ecosystem of the world.

Hierarchy in Nature

Hierarchy is a form of organization in which certain components of a system

regulate the activity of other components. Three kinds of hierarchy are recognized in

nature:

1. Physical

2. Biological

3. Ecological

1. Physical Hierarchy: The smallest structural unit of both nonliving and living are

protons, neutrons and electrons. These particles combine to form atoms. The atoms

combine to form molecules. The latter join together to form complexes of compounds

in living objects, the complexes of compounds form organelles. The organelles form is

living unit called the cell.

2. Biological Hierarchy: It begins from the cell. Cells combine to form tissues which

in turn constitute the organs. The organs form the organ systems. All the organs

systems together form an organism.

3. Ecological Hierarchy: Organism is the smallest unit of ecological hierarchy. It

forms populations, species, biotic communities and ecosystems. All the ecosystems of

the world constitute the biosphere or ecosphere.

Diagram........

Organism

It is the basic unit of ecological hierarchy. An individual is a distinct living being

which carries out all the life processes in its body. Separate from these being

performed in the body of others. It may be unicellular or multi cellular. It is the lowest

level which can survive individually. Belo this level, no component can survive

individually. Below this level no component can survive individually separate from it.

It has its distinct identity and has a particular life span. They show movement, growth,

self regulation, self repair, reproduction etc.

Individual organisms are grouped variously to produce populations,

community, ecosystem and biosphere.

Population

It is a nearly permanent aggregation of individuals of the same kind which inhabit a

particular space or geographical area at a particular time. These may be several rather

numerous such geographically localised groups belonging to one type of organism or

species e.g. spotted deer in various forest, a grass in various localities, and bull frogs

in different ponds. The different populations of the same organism are often called

local populations. Members of the local population freely interbreed. A local

population may be adapted genetically to its particular environment. It is then called

ecotype.

Species

All the populations of the same kind of organisms which can interbreed successfully

from a species e.g. all humans form one species Genus-Homo, Species sapiens.

Community

The organisms of all the species that live in a particular area and interact in various

ways with one another form biotic community. It is a group higher than population. It

is an assemblage of all the populations of different organisms occurring in an area.

The different Populations of a community do not remain isolated. They show

interactions and inter-dependence.

Ecosystem

Any unit that includes all the organisms in a given area, interact with physical

environment so that flow of energy leads clearly defined trophic structure, biotic

diversity and material cycle within the system is called ecosystem.

All parts of an ecosystem-organic and inorganic, biome and habitat may be regarded

as interacting factor which in a mature ecosystem are in approximate equilibrium, it is

through their interactions that the whole system is maintained. It is an open system

which is characterised by continuous input and output of matter & energy. It is

powered by energy of various sorts but the solar energy is the most significant

radiation and tends to be relatively stable equilibrium. It has the natural resources

system. It is well organized and structure system. It has its own productivity which is

the process of building organic matter based on availability and amount of energy

passing through ecosystem. The productivity refers to the rate of growth of organic

matter in a space unit per time unit.

Components of Ecosystem

There are the three major components of ecosystems:

1. Energy Components – Radiant (Solar) and fixed (fwd) energy.

2. Physical Components – Land, water, air and sunlight

3. Biological Components – Plants & Animals including Human beings.

Table

Types Components & Substances

1. Abiotic (Physical) : Land, Soil, Water, Air & Sunlight

2. Biotic : Plants and animals – carbohydrates, proteins, fats &

liquid substances

3. Biogenic : Carbon, nitrogen, hydrogen, calcium and potassium

4. Energy : Radiant (solar energy) and fixed energy.

Biosphere:

It is the biologically inhabited part the earth comprising of all the ecosystems

of the planet.

Classifications of Ecosystems

Characteristics of an eco systems are determined by a no of factors. The important

ones are:

(i). Temprature range (ii) Latitude and attitude

(iii) Intensity and duration of summer & winter.

(iv) Amount and periodicity of rainfall

(v) Soil characteristics

(vi) Geographical barriers like mountain or sea

(vii) Topography

(viii) Water mass

There are different types of ecosystems of nature. Broadly these can be classified into

three categories.

a. Natural Ecosystems

b. Artificial Ecosystems

c. Space Ecosystems

Natural Ecosystems:- They operate by themselves under natural conditions without

any major interference by man and based upon the particular kind of habitat, they are

further divided into two sub categories.

a). Terrestrial b). Aquatic

Terrestrial

It includes latitudinal & attitudinal ones:

A. Latitudinal Ecosystems:

The major terrestrial ecosystems are : (i) Tundra (ii) Taiga (iii) Deciduous forest

(iv) Tropical rain forest (v) Chapporal (vi) Tropical Savannah (vii) Grassland and

(viii) Desert

1. Tundra: It lies north of timberline or 60oN latitude below the polar ice. It

occurs only in the arctic region.

2. Physical Characteristics: This area receives very little precipitation around 25

cm per year that tooin the form of snow. So climate is extremely cold with

winter temp. as low as – 30oC to 40

oC. Summeris short (i.e. 45 75 days). The

highest summer temp. is 10oC. Most of the soil is permanently frozen only

upper 10-20 cm melts during summer.

This alternate thawing and freezing of the upper layers produces cracks leading to

formation of ponds, pools, marshes & bogs.

Life: Life is scarce. Both plants and animals exist.

Flora: Flora is characterised by this low growing vegetation devoid of any tree. Only

those plants grow which either complete their life cycle in brief summer or can remain

alive when covered by snow. They are shallow rooted and include mosses like

sphagnum and lichens like Caledonia. Other vegetation includes grasses, sedges,

heaths, a few shrubs, dwarf willows and birches. Plants show xerophytic characters

with small and hairy leaves and folded margins.

BIOGEOCHEMICAL CYCLES

A biogeochemical cycle is a pathway by which a chemical element or molecule moves

through both biotic (biosphere) and abiotic (lithosphere), atmosphere, and

hydrosphere) compartments of earth. A cycle is a series of change which comes back

to the starting point and which can be repeated.

The term “biogeochemical” tells that biological, geological and chemical factors are

all involved. The circulation of chemical nutrients like carbon, oxygen, nitrogen,

phosphorous, calcium and water etc. through the biological and physical world are

known as biogeochemical cycles. In effect, the element is recycled, although in some

cycles there may be places (called reservoirs) where the element is accumulated or

held for a long period of time (such as ocean or lake for water).

Hence, a constant interaction between the biotic and abiotic component of the

biosphere makes it a dynamic, but stable system. These interactions coveist of a

transfer of matter and energy between the different components of the biosphere.

The most well known and important biogeochemical cycles, for example, include:-

Water cycle, the nitrogen cycle, oxygen cycle and carbon cycle.

WATER CYCLE

The water cycle, also known as the hydrological or H2O cycle, describes the

continuous movement of water on, above and below the surface of the earth. Although

the balance of water on earth remains fairly constant over time, individual water

molecules can come and go, in and out of the atmosphere. The water moves from one

reservoir to another, such as from river to ocean, or from the ocean to the atmosphere,

by the physical processes of evaporation, condensation, precipitation, infiltration, run

off and subsurface flow. In doing so, the water goes through different phases: liquid,

solid (ice) and gas (vapour).

The whole process in which water evaporates and falls on the land as rain and later

flows back into the sea via rivers is known as the water cycle. This cycle is not so

straight forward. All the water that falls on the land does not immediately flow back

into the sea. Some of it seeps into the soil and becomes part of the underground

reservoir of fresh-water. Some of this underground water finds its way to the surface

through springs.

Water is also brought to the surface for use through wells or tube-wells. Water is also

used by terrestrial animals and plants for various life processes. Also, water is capable

of dissolving a large number of substances. As water flows through or over rocks

containing soluble minerals, some of them get dissolved in the water. Thus, rivers

carry many nutrients from the land to the sea, and these are used by marine organisms.

The water cycle involves the exchange of heat, which leads to temperature

changes for instance, when water evaporates; it takes up energy from its surroundings

and cools the environment. When it condenses, it releases energy and warms the

environment. These heat exchanges influence climate. By transforming water from

one reservoir to another, the water cycle purifies water, replenishes the land with fresh

water, and transports minerals to different parts of the globe. It is also involved in

reshaping the geological features of the earth, through such processes as erosion and

sedimentation. Finally the water cycle figures significantly in the maintenance of life

and ecosystems on earth.

The various processes unsolved are:

Evaporation: The transformation of water from liquid to gas phases as it moves from

the ground or bodies of water into the overlying atmosphere. The source of energy for

evaporation is solar energy. Evaporation also includes transpiration from plants.

Condensation: The transformation of water vapour to liquid water droplets in the air,

creating clouds and fog.

Precipitation: Condensed water vapour that falls to the earth‟s surface. Most

precipitation occurs as rain, but also includes snow, hail, fog drip and sleet.

Approximately 505,000 km3 (121,000 cumi) of waterfalls as precipitation each year,

398,000 km3 of it over the oceans.

Run off: The variety of ways by which water moves across the land. This includes

both surface run off and channel run off. As it flows, the water may seep into the

ground, evaporate into the air, become stored in lakes or reservoirs, or be extracted for

agricultural or other human uses.

Snowmelt: The run off produced by melting snow.

Infiltration: The flow of water from the ground surface into the ground.

Advection: The movement of water-in solid liquid or vapour states through the

atmosphere.

Oxygen Cycle

Oxygen is a very abundant element on our earth. It is found in the elemental form in

our atmosphere to the extent of 21%. It also occurs extensively in the combined form

in the earth‟s crust as well as also in the air in the form of carbon dioxide. In the crust,

it is found as the oxides of most metals and silicon, and also as carbonate, sulphate,

nitrate and other minerals. It is also an essential component of most biological

molecules like carbohydrates, proteins, nucleic acids and fats (or lipids)

The oxygen cycle is the biogeochemical cycle that describes the movement of oxygen

within its three main reservoirs; the atmosphere (air), the total content of biological

matter within the biosphere (the global sum of all ecosystems), and the lithosphere

(earth‟s crust). Failures in the oxygen cycles within the

The main driving force for the oxygen cycle is photosynthesis, which is responsible

for the modern earth‟s atmosphere and life as we know it.

Oxygen from the atmosphere is used up in three processes; namely combustion,

respiration and in the formation of oxides of nitrogen. Oxygen is returns to the

atmosphere in only one major process, that is, photosynthesis. Hence it involves:-

Plants does photosynthesis to let off oxygen for organisms to use.

Animals including man use up the oxygen through respiration and let off carbon

dioxide.

The carbon dioxide through various human activities is passed on to the atmosphere

and green plants can use it once again.

This cycle repeats is the form of oxygen cycle.

Carbon Cycle

Carbon is found in various forms on the earth. It occurs in the elemental form as

diamonds and graphite. In the combined state, it is found as carbon dioxide in the

atmosphere, as carbonate and hydrogen-carbonate shells and salts in various mineral.

While all the life forms are based on carbon containing molecules like proteins,

carbohydrates, fats, nuclear acids and vitamins. The endoskeletons and exoskeletons

of various animals are also formed from carbonate salts.

Carbon is incorporated into life forms through the basic process of photosynthesis

which is performed in the presence of sunlight by all life-forms that contain

chlorophyll. This process converts carbon dioxide from the atmosphere or dissolved in

water into glucose molecules.

These glucose molecules are either converted into other substances or used to provide

energy for the synthesis of other biologically important molecules. The utilization of

glucose to provide energy to living things involves the process of respiration in which

oxygen may or may not be used to convert glucose back into carbon dioxide. This

carbon dioxide then goes back in to the atmosphere.

Another process that adds to the carbon dioxide in the atmosphere is the process of

combustion where fuels are burnt to provide energy for various needs like heating,

cooking, transportation and industrial processes. In fact, the percentage of carbon

dioxide in the atmosphere is said to have doubled since the industrial revolution when

humans started burning fossil fuels on a very large scale. Carbon like water cycle, is

thus cycled repeatedly through the different forms by the various physical and

chemical and biological activities.

Thus, the carbon cycle is the biogeochemical cycle by which carbon is exchanged

among the biosphere, pedosphere, geosphere, hydrosphere and atmosphere of the

earth. The carbon cycle involves a sequence of events of sustaining life; it describes

the movement of carbon as it is recycled and reused through the biosphere. The global

carbon cycle is divided into following major reservoirs of carbon:

The atmosphere

The terrestrial biosphere

The oceans, including dissolved inorganic carbon and living and non-living

marine biota.

The sediments, including fossil fuels, fresh water systems and non-living

organic material, such as soil carbon.

The earth‟s interior, carbon from earth‟s menthe and crust.

The carbon exchanges between reservoirs occurs as the result of various chemical,

physical geological and biological processes.

Nitrogen Cycle

Nitrogen gas makes up 78% of our atmosphere and nitrogen is also a part of many

molecules essential to life like proteins, nuclear acids (DNA and RNA) and some

vitamins. Nitrogen is also found in other biologically important compounds such as

alkaloids and urea. Nitrogen is thus, an essential nutrient for all life forms and life

would be simple if all there life forms could use the atmospheric nitrogen directly.

However, other than a few forms of bacteria, life-forms are not able to convert the

comparatively inert nitrogen molecule into forms like nitrates and nitrites which can

be taken up and used to make the required molecules. These „nitrogen-fixing‟ bacteria

may be fee-living or be associated with some species of dicot plants. Most commonly,

the „nitrogen-fixing‟ bacteria are found in the roots of legumes (generally the plants

which give us pulses) in special structure called „root modules‟ other than these

bacteria, the only other manner in which the nitrogen molecule is converted to nitrates

and nitrites is by a physical process.

During lightning, the high temperatures and pressures created in the air convert

nitrogen into oxides of nitrogen. These oxides dissolve in water to give nitric and

nitrous acids and fall on land along with rain. These are then utilized by various life-

forms.

Plants generally take up nitrates and nitrites and convert them into amino acids which

are then used to make proteins. Some other biochemical pathways are used to make

the other complex compound containing nitrogen. These proteins and other complex

compounds are subsequently consumed by animals. Once the animal or the plant dies,

other bacteria in the soil converts the various forms of the compounds of nitrogen

back into nitrates and nitrites. A difficult type of bacteria convert nitrates and nitrites

into elemental nitrogen.

Thus, there is a nitrogen cycle in nature in which nitrogen passes from its elemental

form in the atmosphere into simple molecules in the soil and water, which gets

converted to more complex molecules in living beings and bank again to the simple

nitrogen molecule in the atmosphere.

Nitrogen cycle in nature

The process of nitrogen cycle, thus, involves following steps:

Nitrogen fixation (Conversion of N2)

Biological fixation – by some symbiotic bacteria and some free living bacteria for e.g.

Rhizobium (Symbiotic) and Azotobaiter (free living).

Industrial N-fixation – Under great pressure, at temperature of 600oC and with irons

catalyst, hydrogen and nitrogen can be combined to form ammonia (NH3) in the

Haber-Bosch process.

Combustion of fossil fuels – Automobile engines and thermal power plants, which

release various nitrogen oxides (NOx).

Other processes formation of no from N2 and 02 during lightening.

Assimilation: Plants take nitrogen from the soil, by absorption through their roots in

the form of either nitrate ions. Animals, fungi, and other heterotrophic organisms

obtain nitrogen by irgestion of amino acids, nucleotides and other small organic

molecules.

Ammonification: When a plant or animal dies, or an animal expels waste, the initial

form of nitrogen is organic, Bacteria, or fungi in some cases, convert the organic

nitrogen within the remains back into ammonium (NH4+), a process called

ammonification or mineralization.

Nitrification:

Ammonium (NH4+) Nitromones Nitrites (N0-2)

Nitrites (N0-2) Nitrobcuter Nitrates (N0-3)

It is important for the ammonia to be converted to nitrates because nitrites are toxic to

plant life.

Denitrification: Denitrification is the reduction of nitrates back into the largely inert

nitrogen gas (N2), thus completing the nigtrogen cycle.

Ammonium Oxidation (An aerobically): In the biological process, nitrite and

ammonium are converted directly into elemental nitrogen (N2) gas.

Air pollution occurs when the concentration of a normal component of air or a new

chemical substance added or formed in air builds up to undesirable buildings & other

materials. The chemical substances causing air pollutions are called air pollutants.

Causes

The air pollution is caused by many natural activities & human activities. The natural

sources of air pollution are forest fires, volcanic eruptions releasing poisonous gases,

pollen disposal, natural bacterial decomposition of organic matter, evaporation of

volatile organic compounds from leaves, wind erosion of soil, natural radio-activity

etc.

The main manmade sources responsible for polluting air are burning of fuel in

domestic & industrial processes (coal, oil, gasoline, etc), emission from vehicles,

industrial emission of gases, thermal power generation stations, deforestation,

agricultural activities, wars, etc. The transportation & rapid industrialization are major

sources of air pollution. With the growing rate of vehicles & setting of industries, the

danger of air pollution is also increasing. The automobiles such as cars, scooters,

motors, teocies, trucks etc. are continuously releasing hug amount of poisons gases

such as corlion monoxide, oxides of nitrogen, hydrocarbons & particular had because

of incomplete combustion of petrol & diesel. A large number of industries such as

chemical industries, paper & pulp mills, textile industries, petroleum refineries,

mining, synthetic rubber industries, metallurgical plants, etc. are polluting the air by

various types of harmful inorganic toxic gases & particular matter.

Air pollution

Although there are hundreds of potential air pollutants, about 90% of the air pollution

problem is caused by five groups of pollutants. These are carbon monoxide, nitrogen

oxides, sulphur oxides, volatile compounds & suspended particulate matter.

The air pollutants may be divided into two types:-

1. Primary air pollutants

2. Secondary air pollutants

Primary air pollutants: - The primary air pollutants are the harmful chemical

substances which directly enter the air as a result of natural events & human activities.

Some of the common primary pollutants are oxides of carbon, nitrogen oxides,

sulphur oxides, hydrocarbons, suspended particulate matter etc.

Secondary pollutants: - The secondary pollutants are harmful chemical substances

which are formed in the air because of chemical reactions between two or more air

pollutants or a primary pollutant & one or more air components. For example, sulphur

dioxide is a primary air pollutant. It reacts with oxygen gas in the atmosphere to form

the secondary pollutant sulphur dioxide.

Oxides of carbon

Carbon monoxide is one of the serious air pollutants. It is produced in the atmosphere

by the natural processes such as forest fires, natural gas emission, marsh gas

production, volcanic activity & some human activity mainly automobiles exhausts. Of

the total CO pollution, about 74% is contributed by automobiles exhausts.

Effects of oxides of carbon:

On human health: - CO is very toxic gas because it combines with haemoglobin in the

blood, decreasing its function as an oxygen carrier. Haemoglobin in the blood

combines with CO to form carboxy haeglobin for transport of oxygen decreases & it

reduces the blood‟s activity for carrying oxygen. Excessive amount of CO inhalation

leades to fatigue, headache, dizziness, deficiency in awareness & judgement; visual

perception etc. The higher concentration of CO leads to loss of consciousness are even

death.

The smokers have more risks from CO dangers because smoke contains CO due to

incomplete combustion of the cigarettes. Therefore, the haemoglobin in their blood is

chronically tied up as the carboxy haeboglobin complex.

On Plants: Carbon monoxide has detrimental effects on plants such as decrease in

nitrogen fixing ability of bacteria, leaf drop, leaf curling, premature aging of the plants

etc.

On environment:- Normally, CO2 is not very toxic & is not considered as a pollutant.

However, its increasing concentration may effect the atmosphere causing undesirable

change in climate. The excess CO2 in the atmosphere may lead to increase in earth‟s

atmosphere. This effect is known as Geen House effect.

Green House Effect

Green house effect is caused by gases such as CO2, methane produced by fossil fuels,

agricultural activities & deforestation, trap the heat radiated from earth. Thus

increasing earth‟s atmosphere & causing in weather & sea-level. This is due to the fact

that earth receives a large amount of energy from the sun. But the earth absorbs

energy in the visible region & emits in the infrared region of electromagnetic region.

These partially radiated infrared radiations from the earth are absorbed by CO2 in the

air. This results in excessive heating of the earth‟s atmosphere leading to increase in

surface temperature. It has been estimated that the average temperature of earth has by

1oC in the last 50 years. The scientists have predicted that if the global temperature

rises by 4-6oC due to green house effect, the polar ice caps & glaciers will melt at sea

level resulting increase in sea level.

Remedial Measures:- The main remedies to control CO pollution are to modify

internal combustion engines to reduce the amount of pollutants formed during fuel

combustion.

Oxides of Nitrogen (NOx)

Among the oxides of nitrogen, nitric oxide & nitrogen dioxide are main pollutant;

These oxides come in the atmosphere from the combustion at high temperature in the

automobile engines & electric power stations.

The basic reaction leading to the formation of these oxides are:-

N2 + O2 high temp 2 NO

Nitric oxide

2NO + O2 2NO2

Nitrogen dioxide

These are also formed during natural activities such as bacterial oxidation of ammonia

in soil, forests fires & lightning. Many industries are also rebasing these nitrogen

oxides in the atmosphere.

Effects on health:- The oxides of nitrogen are not very toxic. The health effects of

these vary with the degree of exposure. The smaller concentration of oxides of

nitrogen leads to inflammation of lung tissues but higher concentration may cause

irritation effects on mucous membrane, bronchitis & other respiratory problems.

These oxides of nitrogen play important role in the formation of veritants called

photochemical smog.

Effects on plants:-

The oxides of nitrogen can cause damage to plants leading to leaf spotting &

break down of plant tissues.

Oxides of Sulphur (SOx)

Among the oxides of sulphur, sulphur dioxide (SO2) is the main pollutant. Most

of the sulphur dioxide in the atmosphere comes from the combustion of fossil fuels &

from industrial plants which convert certain metal containing ores to metal or metal

oxides. The industries such as smelting & roasting industries, manufacture of

sulphuric acid, fertilizers, rubber industries, manufacture of electricity etc. release SO2

in the atmosphere. Volcanic sourced also contribute SO2 in the atmosphere.

Effects on human health:- SO2 is very irritating gas & adversely affects humans,

animals, plants & materials. It affects respiratory tract producing nose, ey & lung

veritating. Higher concentration of SO2 may cause permanent lung disease & lung

disease & lung cancer. In fact, it has been considered the most serious single air

pollutant causing many health hazards. Air pollution is very harmful disease.

Effects on monuments:-

Acid Rain

Acid rain is one of the most serious environmental problems facing many parts of the

world. It is a manmade pollution problems & the term acid rain was first used by

Robert Augus in 1872. It literally means presence of excessive acids in rain water. The

two predominant acids present in acid rain are sulphuric acid & nitric acid. These

acids come from oxides of sulphur & nitrogen. These oxides undergo many

photochemical reactions in the atmosphere & form H2SO4 & HNO3. Both these acids

are soluble in water & are strong acids. During rains, these acids fall to earth with

rain. This polluted rain is called acid rain.

Effects of Acid Rain

Acid rain is very damaging & causes extensive damage to buildings & sculptural

materials of marble, lime stone, slate etc. The Taj-Mahal in India is facing the same

problem. In Greece & Italy many valuable statues have partially by acid rain. The

acid rain water also corrodes metals.

The acid rain damages leaves of trees & plants & has retarded the growth of forests. It

has also resulted in the elimination of life from some fresh water lakes by destroying

the living bodies.

Effects of Oxides of Sulphur on plants:

Atmosheric sulphur dioxide is also harmful for plants. It damages

vegetables crops & affects plant growth & nutrient quality of plant products. The long

exposure of plants to SO2 caused damage to leaf tissue & caused chlorooses (a

lillaching of green portions of leaves). Sulphur dioxide is not only injurious to humans

& plants but it also deteriorates not only injurious to human & plants but it also

deteriorates buildings, statues, roofing etc. Emission of SO2 from Mathura refinery has

been causing serious damage to Taj Mahal of Agra.

Other Gaseous Pollutants

Hydrogen Sulphide: Hydrogen sulphide (H2S) is also a gaseous pollutant which

coucists with sulphur dioxide. Volcanic activity & natural decay of animals &

vegetable matterare main natural sources of H2S pollution. Some industrial processes

such as paper mills, oil refineries, natural gas plants add H2S to the atmosphere. It is

very toxic & caused giddiness. It is dangerous to plants gases like ammonia,

phosgene, halgones, hydrogen halides, etc. are air pollutants.

Hydrocarbons: Hydrocarbons are emitted in the atmosphere by natural sources

particularly trees. Methane is the major naturally occurring hydrocarbons produced by

the bacteria during anaerobic decomposition of organic matter in water, soil &

sediments. Automobiles exhausts & some industrial processes are other sources of

hydrocarbon pollution.

The hydrocarbons are not very harmful as such but these are involved in

photochemical reactions forming photochemical songs which causes variation of eyes,

nose, throat & respiratory problems. Some hydrocarbons have carcinogenic effects on

lungs, cause irritation to mucus membrane, cough etc. Benzophyrene which is present

as trace amounts in tobacco, charcoal or gasoline exhausts is a dangerous cancer

including hydrocarbon pollutant.

Particulate pollutants

Air borne small solid particles & liquid droplets having size ranging from 0222 um to

500 um are collectively called particulate. Some of the common examples of

particulate are dust, smoke, fumes, fly, ash, mist spray, fog, smog etc. These include

organic & inorganic matter, several metals, metal salts, mineral particles, radio-active

nucleides etc.

The particulate pollutants originate from natural, domestic, industrial & agricultural

sources. The natural process include volcanic eruptions, blowing of dust & soil by the

wind etc. Many inorganic & organic particulates are entering the atmosphere by

manmade activities in the form of dust from many industries, fly ash from power

plants, mining processes & smoke from incomplete combustion processes. The

inorganic particulates many originate from metallic oxides, sulphides, carbonates etc.

during the burning of fuels combustions of fuels, automobiles & vegetations. 10 poly

cyclic aromatic hydrocarbons (PAH) are important components of organic particulates

matter because of their carcinogenic nature.

Effects on Human Health:

The particulate pollutants cause various allergic reaction such as bronchial asthma,

tuberculosis & other infections because these attack the respiratory tract & harm

tissues in the lungs. Workers exposed to aliestos pollutants develop cancer

mesothelioma head, the most serious pollutant released from automobiles ochausts

cause metalislic disturbances in human body & lead to muscular paralysis, mental

retardation, abnormalities in facitlity & pregnancy & other neurological problems.

Effect on Health: Some plants are also adversely affected by particulate matter.

Several particulate pollutants fall on the soil with rain & make the soil unsuitable for

plant growth & make it infertile. Particulate also affect the materials. The particulates

damage the buildings, painted surface & accelerate ceerosion of metals.

Photochemical Smog

The term was originally given to a combination of smoke & fog laced with SO2 Which

was prevalent earlier in London. This was first experienced as brownish colour hoze

in the atmosphere in the forties in hos-angeles in California. Therefore, it was earlier

called hog Angeles Smog. The photochemical smog is produced in cities in which the

atmosphere is loaded with large quantities of automobile exhaust, smoke, stagnant air

masses & intense sun light. The prime constituents of the reactions leading to

photochemical smog are oxides of nitrogen & hydrocarbons. It has high concentration

of photochemical oxidants & is, therefore, oxidizing in nature.

Effects: Photochemical smog reduces visibility & causes nose, throat & eye irriation

& many chronic disease. The ozone & peroiyacylnitrate (PAN) components of

photochemical smog affect respiratory tract of human beings. The worst disaster

which focused attention in 1952 in London towards this air pollution caused 4 to 5

thousands direct & indirect deaths. Photochemical smog affects plant growth &

damages plant & other materials.

Sources

Air Pollution by Industries & its Control:- Air Pollution is caused by the industries

engaged in the manufacture of chemicals bricks, pesticides, iron, power, sugar, pulp &

paper, points & caustic soda. All of these industries need simple & inexpensive

treatment technologies to control pollution.

The electrical power supply in India in based primarily on the burning of domestic

coal with a high ash content. Ash content of power plant coal can vary between 20%

& 60% in a day electrostatic precipitators being used are mostly. Ash removed by the

use of wet method & fly ash suspended is dumped leading to soil & ground water

pollution. SO2 missions are seriously polluting air areas expertise for fly ash

utilization, nitrogen dioxide removal, flue gad desulphurization, falueic filters &

continuous waste gas measuring devices is lacking in our thermal plants.

Air pollution is severe in weban centres & undustrial estates. People are now worried

abount health risks due to poor air quality. Air pollution is normally caused by

transport systems & industry is the second culprit for this heatlh hazard.

Air pollution by vehicular emissions:- The single most important source of

atmospheric pollutants fostered by human activity is the motor vehicle. According to

environmental protection agency (EPA) of America, transportation vehicles yearly

emit more than 100 million tons of the major air pollutants.

Autos powered by internal combustion engines emit carbon monoxide, oxides of

nitrogen & hydrocarbons as pollutants. In addition, lead is emitted in exhaust when

leaded gasoline is burned.

A catalytical converter chemically changes the hydrocarbons & carbon mono-oxide is

exhaust into carbon dioxide & water vapour but this device works only when unleaded

petrol is used, in fact lead actually destroys the catalytical converters.

Very recently cases of respiratory troubles, cancer & heart problem have been

documented to increase.

Air pollution due to Foul Gases:

Another big problem of our metropolitan cities & even many other big cities is air-

pollution due to foul smells of all sorts at different places due to purification of leaked

or accumulated siwarage, unhygienic habits of people to defected & pass urine at

public place.

These foul smells are a great nuisance & mar the aesthetic sence & beauty of certain

locations in big cities.

Preventive Measures

Check on Vehicles:-

Some ways an individual can help control air pollution is to use alternate means of

transportation to places like shopping and work.

However, if office is too far away to walk on then things like carpool with co-workers

also decrease amount of pollution.

Car should be properly maintained to keep it in good running condition to avoid

smoke emission. Unleaded gasoline should be used in cars.

Old & unrepaired vehicles should be banned as they emit excessive smoke. Similarly,

the pollution level of vehicles should be regularly inspected.

Check on Industries:-

Industries which produces high smoke should be set up out of the city where there are

more number of trees. Direct mixing of smoke and dust particles from stone crusher,

cement factory, brick kiln, biogas, fuel etc. should be checked by applying various

measures.

When it comes to air pollution control on a large scale then it is the job of

businessmen to get the proper equipment needed to control each type of pollution.

There are many different kinds of products that can be purchased to help prevent &

sometimes eliminate pollution of the air. These products include bag house filters,

activated carbon absorbers & gas absorption towers.

Avoid Cigarette Smoking:-

It is best to avoid cigarette smoke whenever possible. Government should stop the

business of cigerattes and cigerratte smoking should be banned in public placed

especially. Centres for dereliction of smoking should be opened and smokers should

be encouraged to become a part of such centres.

Select Air Friendly products:-

The home, yard and office are common places where products containing harmful

smog-forming chemicals are used. Preventing this type of air pollution is achieved by

selecting water based products or items that possess low amounts of volatile organic

compounds (VOCs). When painting water-based paints with labels containing the

words „Zero-Voc‟ are used.

Instead of using a sprayer painting with brush is suggested. When storing solvents

airtight containers help contains the product to prevent leaks & skills. When making

the lawn, ignore gas-powered models & purchase a push are electric lawn mover.

Prevent Indoor Pollution:-

The home, yard & common placed where products containing harmful smog forming

chemicals are used.

At least 80% of most people spend their time indoors which supplies its own kind of

harmful air pollution. Smokers send their smoke through the roof with their unhealthy

habits therefore sending them outside to do their dirty work suggested. Limiting the

amount of household products that contain harmful chemicals is also recommended.

This includes cleaning agents a paints & glues.

Ventillation is also required to lessen the amount of indoor air pollution. When

cleaning baking soda may work just as well as harsher chemical cleaners. Gas

appliances & heaters should undergo inspections & maintenance. The inside of the

home should be kept clean on a regular basis in order to eradicate dust & mold

accumulation. Use of alternative energy sources should be in spared instead of

traditional sources like firewood, cow dung cake & other agricultural residues etc.

3 Rs. Of Solid waste management:-

Adopt the 3 Rs of solid waste management reduce, reuse and recycle Inorganic

materials such as metals, glass, plastic also organic materials like paper can be

reclaimed & recycled. This takes into account that the proven solution to the problem

of proper waste management is proper disposal in the waste bins for collections &

neet in the street where it could fall into drains, waste degregation & collection &

recycling.

Air pollution control devices

Electrostatic precipitatators: They can handle over 1000,000 m3/h of dry and wet grass

at operating temperature upon 500oC. Particulate size of less than .01 km is almost

collected to around 100 percent efficiency by these collectors.

Cycloned:- They are available with high efficiency tubes & medium efficiency tubes

& of hardness of 400-500 BHN. They can tolerate gas temperature upto 550oC with

efficiency of over 80 percent.

Bag filters:- They are also low ratio & high ratio filters with three different types of

filters cleaning mechanism i.e. shaking, compressed air flow & reverse flow. They can

handle gas nearly 100 percent. The materials of which these filters also made are

polyester polyacrylic, poly propylene, Teflon etc.

Wet Scrubbers:- They are available in different capacities for corrosive & high

pressure conditions. Sulphur containing gases emitted from thermal power stations

using lime as scrubbing agent are also available.

Water Pollution

Meaning:-

The word „pollution‟ has a greek root means „defilement‟. It one ecosystem is defiled

all other systems are polluted. Man can‟t live in isolation from other forms of animal

life & from plant life bearing layer, which together constitute the biosphere, which is

very shallow layer in comparison with hydro sphere.

The U.S. National Research Council defines pollution as “an underirable change

characteristics of our air, land & water that they may or will harmfully affect human

life or that of the other desirable species, one industrial processes, living conditions &

cultural assets, or that may or will waste or deteriorate our raw material resources.”

It must therefore be