Environment may be consider as our surroundings which includes everything around us, i.e. the non-living (abiotic) and living (biotic) environment.
The abiotic environment consists of air, water and soil, while the biotic environment includes all the living organisms (plants, animals, microorganisms) that we regularly come in contact.
Environment – Basic Concepts:
The environment is composed of four basic components:
i. Atmosphere
ii. Hydrosphere
iii. Lithosphere
iii. Biosphere.
Environmental science basics, scope and importance
1. Environmental Science Basics, Scope and Importance
Dr. Naveen Gaurav
Associate Professor and Head
Department of Biotechnology
Shri Guru Ram Rai University
Dehradun
2. Environmental: Basic Concepts, Sources and Nature
Environment may be consider as our surroundings which includes everything around us, i.e.
the non-living (abiotic) and living (biotic) environment.
The abiotic environment consists of air, water and soil, while the biotic environment includes
all the living organisms (plants, animals, microorganisms) that we regularly come in contact.
Environment – Basic Concepts:
The environment is composed of four basic components:
i. Atmosphere
ii. Hydrosphere
iii. Lithosphere
iii. Biosphere.
There is a continuous interaction among the various components of the environment (Fig.
54.1). And ultimately, it is the biosphere that gets influenced by the other components.
3. Atmosphere:
The atmosphere consists of a blanket of gases, suspended liquids and solids that envelope the
earth. The atmosphere is basically derived from the earth itself by various chemical and
biochemical reactions. The major components of the atmosphere include the gases nitrogen,
oxygen, argon, carbon dioxide, water vapour and suspended particulates (dust, soot).
The composition of the atmosphere depends on time and space, and is highly variable. A liter of
air weights around 1.3 g. The atmosphere is vertically divided into four I ayes — troposphere,
stratosphere, mesosphere, and thermosphere. This division is mainly based on the increase in
the temperature.
Hydrosphere:
The hydrosphere primarily consists of the water on the earth’s surface. Thus, the hydrosphere
includes oceans, seas, rivers, streams, lakes, reservoirs and polar ice caps. Water is the most
abundant substance on the earth’s surface, which may be present as ice, liquid and vapour.
Approximately, 71% of the earth’s surface is covered with water, mainly in the form of oceans.
It is estimated that about 97% of the total earth’s water is in the oceans and inland seas with
high salt content. And this water is not useful for human consumption. Around 2% of the water is
present in the glaciers and ice caps.
The actual water available for human consumption is around 1% of the total earth’s water. This
includes the ground water, water from lakes and rivers and soil moisture. Humans uses water in
the homes, industries, agriculture and recreation. There is a continuous decrease in the
consumable global water. Therefore, there is a need for precious use of water, and its
conservation
4. Lithosphere: The outer boundary layer of the solid earth on which the continents and the
ocean basins rest constitutes the lithosphere. In a broad sense, lithosphere includes the
land mass and the ocean floor. However, in a general usage, the term lithosphere refers to
the land surface which is approximately 3/10th of the total surface of the earth.
From the biological point of view, the soil is the most important part of the lithosphere
because it contains the organic matter and supports growth of plants and microorganisms.
Lithosphere is involved in the production of food for humans and animals, besides the
decomposition of organic wastes.
Biosphere:
The biosphere comprises of all the zones on earth in which life is present. Biosphere is
spread over the lower part of the atmosphere, the top of the lithosphere and the entire
hydrosphere. In other words, the broad spectrum of bio resources of the earth, supporting
life constitutes the biosphere.
It is estimated that the biosphere contains more than 3.5 lakh species of plants (including
algae, fungi, mosses and higher plants) and more than 110 lakh species of animals
(unicellular, multicellular and higher animals). The biosphere provides the essential
requisites (water, light, heat, air, food, space etc.) for the existence of life.
The biosphere is very vast, and for the sake of understanding, it is divided into smaller units
namely ecosystems. An ecosystem may be considered as the smallest unit of biosphere that
possesses the requisite characteristics to sustain life e.g., ponds, seas, deserts, cities.
5. Environmental Pollution — Sources and Nature:
Man lives in two worlds—a natural world of the native environment and a built-world
created by himself. The built-world, an outcome of the advances made in the science and
technology, is associated with environmental pollution. Environmental pollution is a global
phenomenon, and therefore a matter of concern for everyone.
Pollution broadly refers to the presence of undesirable substances in the environment
which are harmful to man and other organisms. The presence of unwanted substances in
the environment may occur due to human activity discharging byproducts, a wide
spectrum of waste products and several harmful secondary products
Sources of Pollution:
As already stated, environmental pollution is mostly due to direct or indirect human
activities, arising out of the built-world created by him.
There are six major sources of environmental pollution:
1. Industrial sources
2. Agricultural sources
3. Biogenic sources
4. Anthropogenic sources
5. Unnatural sources
6. Extra-terrestrial sources.
The relative importance of each one of these sources depends on the site-specific
situation. For instance in cities, anthropogenic sources are the major contributors while in
rural areas, agricultural sources significantly add to pollution.
6. Types of Pollution:
The environmental pollution may be categorized into six major groups:
1. Air/atmosphere pollution
2. Water pollution
3. Land/soil pollution
4. Noise pollution
5. Thermal pollution
6. Radioactive pollution.
Nature of Pollutants:
The pollutants that occur in the environment may be chemical, biological and physical in
their nature.
Chemical pollutants:
Gaseous pollutants (sulfur dioxide, nitrogen dioxide), toxic metals, pesticides, herbicides,
hydrocarbons, toxins, acidic substances, carcinogens.
Biological pollutants:
Pathogenic organisms, products of biological origin.
Physical pollutants:
Heat (thermal), sound, odours, radiation and radioactive substances.
7. The Multidisciplinary Nature of Environmental Studies
Environmental studies deal with every issue that affects an organism. It is
essentially a multidisciplinary approach that brings about an appreciation of our
natural world and human impacts on its integrity. It is an applied science as it seeks
practical answers to making human civilization sustainable on the earth’s finite
resources.Its components include biology, geology, chemistry, physics, engineering,
sociology, health, anthropology, economics, statistics, computers and philosophy.
8. SCOPE OF ENVIRONMENTAL SCENCES
The deciplines included in environmental education are environmental sciences, environmental
engineering, and environmental management.
a. Environmental sciences:It deals with the scientific study of environmental system(air, water, soil, and
land) the inherent or induced changes on organisms and the environmental damages incurred as a result
of human interaction with the environment.
b. Environmental engineering:
Itdeals with the study of technical processes involved in the protection of environment from the
potentially deleterious effect of human activityand improving the environmental quality for the health
and well beings of humans.
c. Environmental management:
Itpromotes due regard for physical, social and economic environment of the enterprise or projects. It
encourages planned investment at the start of the production chain rather than forced investment in
cleaning up at the end.
It generally covers the areas as environment and enterprise objectives, scope and structure of the
environment, interaction of nature , society and the enterprise, environment impact assessment,
economics of pollution, prevention, environmental management standards etc.
THE IMPORTANCE OF ENVIRONMENTAL STUDIES
1.To clarify modern environmental concept like how to conserve biodiversity.
2.To know the more sustainable way of living.
3.To use natural resources more efficiently.
4.To know the behaviour of organism under natural conditions.
5.To know the interrelationship between organisms in populations and communities.
6.To aware and educate people regarding environmental issues and problems at local, national and
international levels.
