Environmental Studies involves scientific study of the environmental system and the status of its inherent or induced changes on organisms.
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In addition to study of physical and biological characters of environment, it also describes the social and cultural factors and the impact of man on environment.
According to UNESCO (1971), the Objectives of environmental studies are:
(i) Creating awareness about different environmental problems.
(ii) Imparting fundamental knowledge regarding environment and its allied problems.
(iii) Developing an attitude of concern for environment.
(iv) Motivating public to participate in environmental protection and environmental improvement.
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(v) Striving to attain harmony with nature.
(vi) Acquiring skills to help the concerned individuals in identifying and solving environmental problems.
The broad term environmental studies include environmental sciences, environmental engineering and environmental management.
(i) Environmental Science:
This branch of environmental studies deals with the scientific study of environmental components (air, water, land and soil), the inherent or induced changes on organisms and the environmental hazards occurring due to uninterrupted interactions of human beings with environment.
(ii) Environmental Engineering:
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This branch of environmental studies discusses the study of technical processes involved in the protection of environment from the potentially deleterious effects of anthropogenic activities and improving the environmental quality.
(iii) Environmental Management:
This branch of environmental studies covers environment and enterprise objectives, scope and structure of environment, interaction of nature, society and enterprise, environmental impact assessment, economics of pollution, prevention, environmental management standards environmental audits etc. Thus, environmental studies are multidisciplinary in nature.
Environment:
The term environment means the surrounding of a species to which it remains totally adapted and to which it continuously interacts for every activity of life in some or other way for its survival. Biologically environment constitutes the abiotic component of nature such as soil, water, air, light, energy, humidity, temperature etc. which affect the existence, growth and metabolism of the organism.
Environment can be defined in a number of ways:
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(i) “Environment is the sum of all social, economical, biological, physical and chemical factors which constitute the surrounding”.
(ii) According to C.C. Park (1980), “Environment refers to sum total of conditions which surround man at a given point in space and time”.
(iii) “Environment is the combination of all the organic and inorganic substances surrounding man”.
(iv) According to a ‘Goudie (1984), “Environment is the representative of the physical components of the earth wherein man is the important factor influencing its environment.”
(v) According to K.R. Dikshit (1984), “the space we live in, the air we breath, the food we eat, the water we drink and the other sources we need, constitute our environment”.
(vi) According to B.K. Sharma (1994), “Environment consists of an inseparable whole system constituted by physical, chemical, biological, social and cultural elements, which are interlinked individually and collectively in myriad ways.”
Classification of Environment:
Since the environment is both physical and biological concept, it encompasses both the living and non-living components of the planet earth.
Thus on the basis of basic structure, the environment may be divided into two basic units:
(i) Physical or Abiotic environment
(ii) Biotic environment.
On the basis of physical characteristic and state, abiotic environment may be further subdivided into three broad categories:
(i) Solid;
(ii) liquid and
(iii) Gas.
Thus, the three basic division of physical environment may be termed as:
(i) Lithospheric environment (solid);
(ii) Atmospheric environment (Gas), and
(iii) Hydrosphere environment (liquid).
These may be further broken into smaller units based on different spatial scales e.g.
(i) mountain environment;
(iii) plain environment;
(iii) plateau environment;
(iv) lake environment;
(v) River environment;
(vi) Maritime environment; and
(vii) Glacier environment etc.
The physical environment may also be viewed in terms of climatic conditions providing certain suits of habitat for biological communities e.g. tropical environment temperate environment, polar environment etc.
The biotic component of the environment consists of plants (flora) and animals (fauna) including man as an important factor.
Thus, the biotic environment may be divided into:
(i) Floral environment; and
(ii) Faunal environment.
All the organisms work to form their social groups and organizations at several levels and thus are formed social environment wherein the living organisms work to derive the matter from the physical environment for their sustenance and development. This process generates economic environment.
Man derives and utilizes resources from the physical and biotic environment with his skills and technologies which may be termed as physical, social and economic functions of man. The economic function of man makes him an environmental geomorphic process because through him matter and energy from one ecosystem can be transferred to other.
The biotic and abiotic components constitute together the Biome environment. The energy component includes solar energy, geochemical energy, thermo-electrical energy, hydro-electrical energy, nuclear and atomic energy etc.
Factors Influencing Environment:
The life of an organism is surrounded and effected by a number of external forces. These forces are known as environmental or ecological factors. There are actually four categories of ecological factors which affect the environment.
These factors may be outlined as below:
(a) Topographic or Physiographic factors:
These factors include altitude, direction of mountain chains, plateaus, plains, lakes, rivers, sea level and valleys etc.
(b) Climatic or Aerial factors:
These include atmosphere, light temperature, humidity, rainfall etc.
(c) Edaphic factors:
These comprise lithosphere or soil.
(d) Biotic factors:
These include all types of interactions between different forms of life. For example, man, animals, plants, micro-organisms etc. All these ecological factors operate in conjunctions and not individually, affecting the life of organisms.
Components of Environment:
Environment consists of four components or segments, they are:
(1) Atmosphere;
(2) Hydrosphere;
(3) Lithosphere; and
(4) Biosphere.
(1) Atmosphere:
The invisible protective thick gaseous cover of air which envelopes the earth is known as atmosphere. It sustains life on earth and saves living organisms from the hostile environment of outer space. It extends to a height of about 1600km. from the earth’s surface. The major components of the atmosphere are nitrogen and oxygen while the minor components are argon, carbon dioxide and some trace gases (shown in Table 1.1.)
Some important functions of atmosphere are outlined below:
(i) It maintains heat balance of the earth through absorption of infrared radiation emitted by the sun and re-emitted from the earth.
(ii) It absorbs most of the cosmic rays from outer space and a major portion of the electromagnetic radiation from the sun.
(iii) It filters tissue damaging ultraviolet radiation below 300 nm.
(iv) It is a source of oxygen (for respiration), carbon dioxide (for photo-synthesis) and nitrogen (for nitrogen fixation).
(v) It is a medium for the operation of different bio- geochemical cycles.
(vi) It acts as a carrier of water from ocean to land.
(vii) It maintains and stabilises weather and climate.
2. Hydrosphere:
The hydrosphere includes all types of water resources such as oceans, seas, rivers, lakes, streams, reservoirs, glaciers, polar ice caps and ground water. Out of the total water resources, 97% is present in oceans as salty water, 2% is present as ice cap and rest 1 % is available as fresh water for our day-today use.
Some important uses of water are as follows:
(i) It is used for drinking, cooking and cleaning purposes
(ii) It is used for irrigation and power generation.
(iii) It is used in different industrial operations.
(iv) It is used for navigation, fisheries and aquaculture.
(v) Its most important use is waste disposal.
3. Lithosphere (Land):
Land forms the crucial platform for a dynamic interaction in between the biotic and abiotic environment. It is the outer mantle of the solid earth, consisting of minerals occurring in the earth’s crust and the soil. The soil consists of a complex mixture of minerals, organic matter, air and water.
In the present technologically developed world, changes in the farming practices with continued use of agricultural chemicals, industrial proliferation, mining activities and unplanned urbanization have altered the land forms and their quality, making land more and more scarce.
Some important uses of land are as follows:
(i) It is used for agriculture and horticulture (to get food)
(ii) It is used for afforestation.
(iii) It is used for industrialisation and urbanisation.
(iv) It is used for transportation by road and rail.
(v) It is used for amenity and recreation.
4. Biosphere:
Biosphere is that part of atmosphere, hydrosphere and lithosphere where all the living organisms survive together and interact with one-another.
In atmosphere, the living organisms exists up to a distance of 6 km from the surface of the earth and in ocean, the living organism exists up to a depth of 7 km from the surface. Such a distance of 13 km is known as biosphere. The living species in biosphere may be animals or plants. The living organisms in biosphere differ from one-another by their shape, size, distribution and characteristics.
Both the biosphere and environment are influenced considerably by each other. For example, green plants use carbon dioxide for photosynthesis and in turn release oxygen in the atmospheres. On the other hand, animals inhale oxygen during respiration and release carbon-dioxide.
Thus, a continuous set of interactions takes place among the living organisms of the biosphere. Besides, all the living organisms depend upon abiotic environment for their survival and entire unit is responsible for the existence of living organism or biosphere.
Environmental Resources:
The environmental resources in the form of matter and energy are of vital significance for the survival of all types of living organisms in general and man in particular. Since all aspects of human society depend on resources, it is therefore, highly essential to have a clear-cut understanding of the meaning, classification, assessment and evaluation, uses and abuses, conservation and management of all sorts of resources either natural or cultural, renewable or non-renewable.
The resources are fundamental base for the economic growth and development of society but their withdrawal from the nature, mode of their uses and their disposal has enormous adverse effect on the environment.
It is thus, imperative to study the linkage between resource use and the environment, so that proper management of resources and remedial measures of environmental pollution and degradation arising out of resource use and disposal of waste materials may be made possible.
Now-a-days, the society is concerned about few aspects of resources.
These are:
(i) Extensive consumption of raw materials by the industries at an alarming rate in order to meet growing demands. This may result in low supply of certain key minerals or even in complete depletion. The consumption of resources by developing and developed countries is shown in Table 1.2.
(ii) Impact of extensive use of minerals on environment. For example, extraction of minerals creates pits and scars on earth surface which leads to destruction of biotic community. Withdrawal of ground water results in the formation of large cavities beneath the earth’s surface which ultimately cause surface collapse and subsidence.
(iii) The second type of industrial resource is fossil fuels such as mineral oils, coal and natural gases. The fossil fuels are also used for the supply of most of the energy in the industrial, transport and domestic sectors. These resources are being used at such faster rate that we may run out of these resources within few hundred years.
(iv) The combustion of fossil fuels release a number of gaseous pollutants to the atmosphere which have far-reaching consequences like depletion of ozone layer, global warming, smog formation, acid rain etc.
(v) The mishandling of resources and negligence of the upkeep of the resources also affect the environment adversely. For example, the leakage of 100000 tons of crude oil from the crashed huge oil tanker near Lacoruna off the Spanish coast (1976), leakage of crude oil off the Alaskan coast (1989) and leakage of killer gas from the Union Carbide factory at Bhopal (India) in 1984 are few such examples of many such incidents.
Environmental Degradation:
The phenomenal increase in human population in the present century has put tremendous pressure on the natural resources, in order to meet out the demand of ever increasing population, rapidly growing industries and increasing urbanisation. The development of modern technologies and increased economic functions of man have further accelerated the rate of exploitation of natural resources.
All these have modified a few of the components of environment to such an extent that the adverse effects on the environment cannot be set right by self -regulatory mechanism of the environment (homeostatic mechanism). Consequently, the changed environmental conditions adversely affect the living organisms of the biosphere.
Thus, environmental degradation refers to the deterioration in its physical components brought in by the biological processes mainly through anthropogenic activities which cannot be set right by the self- regulatory mechanism of the environment.
In other words, environmental degradation means overall lowering of environmental qualities because of adverse changes brought in by human activities in the basic structure of the components to the environment to such an extent that these changes adversely affect all living organisms in general and man in particular. Environmental degradation causes ecological imbalance because of the marked reduction in the ecological diversity and eco-system.
Environmental degradation and pollution may be distinguished on the basis of causative factors and scale of deterioration of environmental quality in terms of intensity and covered area. Pollution means lowering of the quality of environment at local scale caused exclusively by anthropogenic activities whereas environmental degradation means lowering of environmental quality at local, regional and global scales by both natural and anthropogenic activities.
Environmental degradation is a wider term which means disturbance of various magnitudes in ecosystem equilibrium, environmental stability and ecological balance caused by human activities. When environmental degradation exceeds the critical limits to such an extent that it becomes lethal to the living organisms in general and human beings in particular, it becomes pollution.
Thus, pollution is the upper limit of environmental degradation. Sometimes, the adverse changes in the environmental quality at local level due to human activities become so immense that the environment is degraded at global level.
For example, increase of concentration of carbon dioxide in the atmosphere through the burning of fossil fuels in an industry increases green house effect of the atmosphere at a local level but simultaneously, it changes radiation balance of the earth and the atmosphere at global level.
Thus, it is not possible to differentiate environmental degradation and pollution on the basis of factors and causes of the lowering of the environmental quality and the area affected by environmental changes.
Types of Environmental Degradation:
On the basis of factors responsible for the lowering of environmental quality and the level and magnitude of lowering, environmental degradations are of two types:
(1) Extreme events and hazards and
(2) Pollution.
1. Extreme Events and Hazards:
On the basis of causative factors, hazards are of three types:
(A) Natural hazards:
Natural hazards are caused by natural factors. The natural hazards are again divided into three subgroups:
(i) Terrestrial natural hazards:
These occur on earth’s land surface. Some examples of terrestrial hazards are : volcanic eruptions, earthquakes, submergence and emergence, faulting etc.
(ii) Atmospheric natural hazards:
These are caused by atmospheric processes but affect the living organism and non-living components of the natural environment.
Some atmospheric natural hazards are:
Tropical cyclones, lightening, forest fire etc.
(iii) Cumulative atmospheric hazards:
These are caused due to accumulation of effects of certain atmospheric phenomena for several years in continuation.
Some examples of such hazards are:
Flood, drought etc.
(B) Anthropogenic hazards:
These hazards are caused by cumulative and even sudden effect of human activities. These may be further divided into three sub-groups:
(i) Physical hazards:
Some examples are:
Large scale landslide, deliberate forest fire etc.
(ii) Chemical and nuclear hazards:
Some examples are:
Release of toxic chemicals through deliberate human activities, sudden outburst of lethal gases, nuclear explosions etc.
(iii) Biological hazards:
Some examples are:
Explosion of human population, locust swarms, epidemics etc.
2. Pollution:
Pollution is caused by human activities and can be divided into two categories:
(A) Physical Pollution; and (B) Social Pollution.
(A) Physical Pollution:
Physical pollution is caused due to lowering of quality of abiotic components of the environment by human activities. Physical pollution may be further divided into the following sub-groups:
(i) Air Pollution:
Some examples are: depletion of ozone layer, decrease in quality of air, green house effect.
(ii) Water Pollution:
Some examples are: pollution of sea water, pollution of ground water, pollution of streams, pollution of rivers, lakes etc.
(iii) Land Pollution:
Some examples are: desertification, soil pollution, salinization etc.
(B) Social Pollution:
Social pollution is caused due to different aspects of the society by cumulative effects of extreme events. Different types of social pollutions are: population explosion, economic pollution (poverty) and sociological pollution (educational and social backwardness, crime, communal riots).
Environmental Management:
The over-utilization of natural resources leading to imbalance of the eco-system gives birth to environmental degradation. Environmental degradation and pollution have caused a catastrophe and havoc to entire living organisms. Therefore, it is imperative to safeguard the natural resources for our present benefit as well as the benefit of the future generations. This can be possible through a well planned strategy of environmental management.
The main objectives of environmental management are as follows:
(i) To maintain environmental quality through suitable manipulations.
(ii) To maintain ecological balance.
(iii) To restrict and regulate over-exploitation of natural resources.
(iv) To renew natural resources with suitable devices.
(v) To protect the environment from degradation.
(vi) To formulate stringent laws and regulations and take necessary steps for their strict implementation.
(vii) To adopt engineered technology without creating adverse effect on environment.
The main components of environmental management may be outlined as follows:
(i) Control of environmental degradation and pollution,
(ii) Environmental perception and people awareness,
(iii) Environmental impact assessment to review the existing technology,
(iv) Environmental education and training,
(v) Control over population and over consumption.
Environmental Impact Assessment:
The probable impact of anthropogenic activities regarding the use of environmental resources on natural environment is termed as environmental impact and the assessment and evaluation of environmental effects of human activities are collectively called as environmental impact assessment (EIA).
The possible effects of human activities during the exploitation and processing of natural resources on natural environment are called as environmental impact statement. According to K. J. Gregory and D.E. Walling (1981), environmental impact assessment and environmental impact statement (EIS) together refer to studies which firstly attempt to suggest the estimates of future environmental changes attributable to a proposed action and secondly, attempt to suggest the likely impact of environmental changes due to human activities, on man’s future well being.
Thus environmental impact assessment is a method of evaluating environmental consequences (i.e., environmental changes which are likely to be caused by the proposed human activities related to land use changes, construction of dams, roads, rails, bridges etc., industrial location, urbanisation etc.) and the possible detrimental environmental changes (environmental degradation and pollution resulting into ecological imbalance and ecosystem disequilibrium).
Methods of Environmental Impact Assessment:
In 1969, United States of America introduced an Act for environmental impact assessment, which is known as national Environmental Policy Act (MEPA).
This Act had four major objectives:
(i) To declare a national policy to encourage “productive and enjoyable harmony between environment and man.
(ii) To promote efforts to prevent or eliminate damage to the environment and its biosphere, and stimulate health and welfare of the human beings.
(iii) To increase understanding of ecological system and natural resources important to nation.
(iv) To establish a Council on Environmental Quality (CEQ).
In USA, no approval would be given to any proposed development planning and projects without the environmental impact assessments and statements. The MEPA envisages to find out and develop methods and procedures which will ensure that presently unqualified environmental amenities and values are given appropriate considerations.
The fundamental steps of environmental impact assessment of NEPA (USA) are described below:
(i) To describe the baseline conditions of the present environment.
(ii) To describe the project, including purposes and needs.
(iii) To describe both short-term and long-term impacts.
(iv) To suggest and compare alternatives.
(v) To describe the effects of the projects.
(vi) To provide a projection of the future of the site with and without the project.
(vii) To suggest remedial measures.
The procedures of Environmental Impact Assessment (EIA) and Environmental Impact Statement (EIS) are widely adopted by Federal Agencies in U.S.A. Now other countries like Germany, France, Denmark etc. have adopted the EIA and EIS procedures as formulated by the US Council on Environmental Control (EC).
Environmental impact assessment and statement, thus, includes the following considerations:
(i) Presentation of the existing environmental conditions in terms of physical, biological, social and economic conditions of the site of the proposed project or plan before the implementation of proposed plan.
(ii) Statements on the possible expected effects of the proposed project if implemented on the existing environmental conditions.
(iii) Statements about those unavoidable adverse effects which may come after implementation of the project.
(iv) Presentation of variable alternative projects to the proposed project.
(v) Statements on the relationship between local short term uses of the environment and the maintenance of long term productivity and stability.
(vi) Evaluation of the cost of the project and its probable benefit to the society.
(vii) Statements on suitable remedial measures of adverse effects arising out of the project after its implementation.
A number of new methodologies and procedures for formulating environmental impact assessment and statement have been devised by scientists and scientific research organisations such as “Principles and Procedures of Environmental Impact Assessment by SCOPE (Scientific Committee on Problems of the Environment, Paris) in 1975; Procedures for “Environmental Impact Assessment” and “Leopold Matrix for Environmental Impact Assessment by Luna Leopold and Others, 1971 and many others.
Some procedures for environmental impact assessment are proposed by Luna Leopold et al. (1971) which may be outlined as follows:
(i) Statement of Objectives: Definition of the objectives sought by the proposed development (plan)
(ii) Technical possibilities of achieving the objectives.
(iii) Proposed actions and alternatives (plans): for achieving the stated objectives.
(iv) Report on the character of the environment before action begins.
(v) Principles of alternative engineering proposals submitted as reports, with analysis of monetary cost and benefits of each engineering alternative.
(vi) Proposed plan and the report on the present environment are considered; this allows evaluation of the likely environmental impact of the proposal. Impacts are evaluated for each major alternative plan.
Attention centres on:
(a) Magnitude of the impact (Scale).
(b) Importance of the impact (significance).
(vii) Assessment of environmental impacts of each alternative plan of action.
(viii) Environmental Impact Statement is produced: this summarises the whole analysis and lists final recommendations and the relative merits of each of the main alternatives.
Leopold et. al (1971) suggested a matrix for the assessment of environmental impacts of proposed plan, which is commonly known as LEOPOLD MATRIX. Leopold matrix involves 100 project actions along the horizontal axis and 88 environmental characteristics and conditions which are liable to be affected by project actions listed in the horizontal axis, in the vertical axis of the matrix. The followings are the variables of project actions and the environmental conditions to be affected by the project actions. 
It may be noted that separate matrices are prepared for each alternative proposals or plans. The final environmental impact statement (EIS) includes four information’s and reports viz.
(i) a justification of the proposal,
(ii) a description of the environmental characteristics and conditions to be affected,
(iii) detail description of the proposed projects or actions, and
(iv) the completed Environmental Impact Assessment.
The procedure of Environmental Impact Assessment of Leopold et al suffers from the following limitations:
(i) It requires a lot of paper works by requiring detailed reports which obscure the central and important issues.
(ii) Insertion of numerous information and reports makes the scheme confusing and it becomes difficult for the concerned authorities to pick-up important but most relevant information.
(iii) It has bias towards physical-biological environment.