Unit 1

Multidisciplinary nature of environmental studies

1.1   Environmental studies

Definition

Environment as a word covers the sum of extrinsic forces, factors and suitable conditions, which are essential for the origination and survival of all life forms. ‘Environment’ is composed of every external factor that has influenced all living organisms since birth.

Environment is the aggregate of physical, chemical, biological and social components on Earth which are capable of causing direct or indirect effects on the survival of living and non-living things and their interactions.

Fig1.1 Interaction of Air, Water, Land (Soil), Resources (Materials) with Living Organisms constitutes Environment.

Study of environment & its components is a multidisciplinary field as it consists of Science, Arts, Commerce, Mathematics and other specialized fields such as Geography, Topography, Anthropology, etc.

Environmental studies provide us a platform for the thorough study of living organism and its surroundings.

Fig 1.2 Depiction of Multidisciplinary Nature of Environmental Studies & its Components

• Environmental Studies as Applied Life Science: Life sciences including botany, zoology, microbiology, genetics, biochemistry, biotechnology, etc. help us in understanding the biotic components of environment and their interactions with each other and with abiotic components.

• Environmental Studies as Basic Physical Sciences: Core branches of physical sciences such as Chemistry, Physics, Geography, etc. give us an overview of chemical & physical structure of biotic components. Flow of energy transfer from one form to another also comes under this domain.

• Environmental Studies as Modelling Tool: It includes Mathematical Interpretations, Statistical Data Analysis, Computer Aided Analysis of Environment & its components.

• Environmental Studies as Technology: Branches of Civil Engineering, Chemical Engineering, Environmental Engineering, etc. have to deal with sustainable technological development without harming the environment in the form of Pollution Control, Waste Treatment and Reduction in overexploitation of natural resources.

• Environmental Studies as Management & Awareness: It covers all the rules regulations, laws and acts made in order to protect the environment and to create equilibrium between all life forms to sustain life and growth on earth.

Scope and importance

Like its multidisciplinary nature, scope of Environmental Studies is also wide as follows:

1. The study makes mindfulness among the individuals to think about different sustainable and non-renewable assets of the surroundings.

2. It gives the information about natural frameworks and circumstances related to human survival.

3. It gives fundamental idea about biodiversity and risks related to it.

4. The examination empowers one to create a cause & effect relationship of consequences caused by human activities of our natural surroundings.

5. It empowers one to choose most suitable alternative from available pool in order to reduce overuse of natural resources.

6. The awareness of Environmental Studies empowers ecologically educated residents by letting them know about the natural demonstrations, rights, rules, regulations, enactments, amendments in the existing environmental acts and so on to settle on proper decisions and choices for the insurance and improvement of the earth and its inhabitants.

7. The study reveals the social issues like over population, health, cleanliness and sanitation. It gives remedial measures to these issues in the most suitable manner.

8. The investigation attempts to recognize and create the eco-friendly skills and non-conventional technologies that would not create any hindrance in the pathway of development without putting an extra burden on environment.

9. It shows us the requirement for supportable usage of resources as these assets are acquired from our predecessors. Hence it is our responsibility to pass these on to our forthcoming generations without decaying their overall quality.

10. The scope of Environmental Studies is incomplete without its impact on employment opportunities in the form of Environmental-Journalism, Research & Development, Environmental Management, etc.

Importance :

1) Environmental studies help us to maintain ecological balance and equilibrium in the environment by providing a basic platform for interaction of environmental system and inter-related processes.

2) It gives information regarding the changes that takes place due to various factors and helps in gathering skills to analyse various environmental processes and the effect of human activities on them.

3) Environmental studies help to achieve sustainable development in order to achieve a state of optimum utilisation of resources without affecting the needs of future generations. It ultimately makes us understand the relationship between development and the environment.

4) This field helps to educate people regarding their responsibilities and lawful duties towards the protection of environment.

5) Environmental study help us to analyse the impact of human activities on various processes occurring in water, air and land which leads to contamination and results in environmental pollution

6) It also deals with the most important issues like safe and clean potable water, health-hygiene and cleanliness of surroundings

7) The discipline provides knowledge of the environment and various environmental issues. It examines the scientific base for environmental, cultural and social concerns about our present energy needs, global climate changes, toxic emission and waste disposal.

8) Development and optimum utilisation of energy resources is an important aspect of environmental studies.

9) Environmental acts, rules, regulations, law, amendments and fields like business administration, environmental engineering are emerging as new career opportunities under its domain.

10) To analyse the complex nature of vast bio-diversity on our planet, we need scientific approach of Environmental - Studies.

Need for public awareness

The Sustainable Development Goals, also called as the Global Goals, were adopted by United Nations Member States in the year 2015 to end poverty, protect the planet and ensure that all people enjoy peace and prosperity by the end of year 2030. SDG’s are as follows:

1. No Poverty
2. No Hunger
3. Good Health & Well Being
4. Quality Education
5. Gender Equality
6. Clean Water & Sanitisation
7. Affordable & Clean Energy
8. Decent Work & Economic Growth
9. Industry Innovation & Infrastructure
10. Reduced Inequalities
11. Sustainable Cities & Communities
12. Responsible Consumption & Production
13. Climate Action
14. Life Below Water
15. Life on Land
16. Peace, Justice & Strong Institutions
17. Partnerships for the Goals

1.2   Natural resources

Renewable and non renewable resources

Renewable Resource is energy which is generated from natural sources i.e. sun, wind, rain, tides and can be generated again and again as and when required. They are available in plenty and by far most the cleanest sources of energy available on this planet. Solar Energy, Wind Energy, Geothermal Energy, Biomass Energy from Plants, Tidal Energy are the examples of Renewable resources.

Non Renewable Resource is a natural resource that cannot be re-made or re- grown at a scale comparable to its consumption. Non-renewable sources are not environmental friendly and can have serious effect on our health.  They are called non-renewable because they cannot be re-generated within a short span of time.  Non-renewable sources exist in the form of fossil fuels, natural gas, oil and coal

Natural resources and associated problems

Any material which can be transformed in a way that it becomes more valuable and useful can be termed as resource. In other words, it is possible to obtain valuable items from any resources. Resource, therefore, are the means to attain given ends. The aspect of satisfaction is so important that we consider a thing or substance a resource, as so long it meets our needs. Life on this planet depends upon a large number of things and services provided by the nature, which are known as Natural Resources. Thus water, air, soil, minerals, coal, forests, crops and wild life are all examples of natural resources.

Problems associated with natural resources

1. The unequal consumption of natural resources

A major part of natural resources today are consumed in the technologically advanced or ‘developed’ world, usually termed ‘the west’. The ‘developing nations’ of ‘the east’, including India and China, also over use many resources because of their greater human population. However, the consumption of resources per capita (per individual) of the developed countries is up to 50 times greater than in most developing countries. Advanced countries produce over 75% of global industrial waste and greenhouse gases.

2. Planning land use

Land is a major resource, needed for not only for food production and animal husbandry, but also for industry and growing human settlements. These forms of intensive land use are frequently extended at the cost of ‘wild lands’, our remaining forests, grasslands, wetlands and deserts. This demands for a pragmatic policy that analyses the land allocation for different uses.

3. The need for sustainable lifestyles

Human standard of living and the health of the ecosystem are indicators of sustainable use of resources in any country or region. Ironically, both are not in concurrence with each other. Increasing the level of one, usually leads to degradation of other. Development policies should be formulated to strike a balance between the two.

1.3   Forest resources

Use and over exploitation

A forest is a biotic community predominantly of trees, shrubs and other woody vegetation, usually with a closed canopy. This invaluable renewable natural resource is beneficial to man in many ways.

The direct benefits from forests are:

(a) Fuel Wood:

Wood is used as a source of energy for cooking purpose and for keeping warm.

(b) Timber:

Wood is used for making furniture, tool-handles, railway sleep­ers, matches, ploughs, bridges, boats etc.

(c) Bamboos:

These are used for matting, flooring, baskets, ropes, rafts, cots etc.

(d) Food:

Fruits, leaves, roots and tubers of plants and meat of forest animals form the food of forest tribes.

(e) Shelter:

Mosses, ferns, insects, birds, reptiles, mammals and micro-organ­isms are provided shelter by forests.

(f) Paper:

Wood and Bamboo pulp are used for manufacturing paper (News­print, stationery, packing paper, sanitary paper)

(g) Rayon:

Bamboo and wood are used in the manufacture of rayon (yarns, artificial silk-fibres)

(h) Forest Products:

Tannins, gums, drugs, spices, insecticides, waxes, honey, horns, musk, ivory, hides etc. are all provided by the flora and fauna of for­ests.

Over exploitation of forests

Forests contribute substantially to the national economy. With increasing population increased demand of fuel wood, expansion of area under urban development and industries has lead to over exploitation of forest .At present international level we are losing forest at the rate of 1.7 crore hectares annually. Overexploitation also occurs due to overgrazing and conversion of forest to pastures for domestic use.

Deforestation

Deforestation means reckless or large-scale felling or cutting of trees by man for commercial and other purposes. Deforestation refers to the decrease in forest areas across the world that are lost for other uses such as agricultural croplands, urbanization, or mining activities.

Case studies

1. Jhum cultivation

Jhum Agriculture or shifting agriculture has destroyed large number of hectare of forest tracts in North-Eastern states and Orissa. Jhum agriculture is subsidence agriculture in which tract of forest land is cleared by cutting trees and it is used for cultivation. After few years, when productivity of the land decreases, cultivators abandon the land and clear next tract. As a result of this practise, combined with increasing population there is rapid deforestation as more and more cultivators clear forest to cultivate land. Also, with increase in population there is cultivators are forced to return to previous tracts of land in relatively shorter durations, not allowing the land to regain its productivity.

2. Chipko movement

The Chipko movement or Chipko Andolan is a social-ecological movement that practised the Gandhian methods of satyagraha and non-violent resistance, through the act of hugging trees to protect them from being felled. The modern Chipko movement started in the early 1970s in the Garhwal Himalayas of Uttarakhand,with growing awareness towards rapid deforestation. The landmark event in this struggle took place on March 26, 1974, when a group of peasant women in Reni village, Hemwalghati, in Chamoli district, Uttarakhand, India, acted to prevent the cutting of trees and reclaim their traditional forest rights that were threatened by the contractor system of the state Forest Department. Their actions inspired hundreds of such actions at the grassroots level throughout the region. By the 1980s the movement had spread throughout India and led to formulation of people-sensitive forest policies, which put a stop to the open felling of trees in regions as far reaching as Vindhyas and the Western Ghats.

Timber extraction

There has been unlimited exploitation of timber for commercial use. Due to increased industrial demand; timber extraction has significant effect on forest and tribal people.

Logging
 

• Poor logging results in degraded forest and may lead to soil erosion especially on slopes.
• New logging roads permit shifting cultivators and fuel wood gatherers to gain access to the logging area.
• Loss of long term forest productivity
• Species of plants and animals may be eliminated
• Exploitation of tribal people by contractor.

Mining

Major effects of mining operations on forest and tribal people are:

• Mining from shallow deposits is done by surface mining while that from deep deposits is done by sub-surface mining. It leads to degradation of lands and loss of top soil. It is estimated that about eighty thousands hectare land is under stress of mining activities in India
• Mining leads to drying up perennial sources of water sources like spring and streams in mountainous area.
• Mining and other associated activities remove vegetation along with underlying soil mantle, which results in destruction of topography and landscape in the area. Large scale deforestation has been reported in Mussorie and Dehradun valley due to indiscriminating mining.
• The forested area has declined at an average rate of 33% and the increase in non-forest area due to mining activities has resulted in relatively unstable zones leading to landslides.
• Indiscriminate mining in forests of Goa since 1961 has destroyed more than 50000 ha of forest land. Coal mining in Jharia, Raniganj and Singrauli areas has caused extensive deforestation in Jharkhand.
• Mining of magnetite and soapstone have destroyed 14 ha of forest in hilly slopes of Khirakot, Kosi valley and Almora.
• Mining of radioactive minerals in Kerala, Tamilnadu and Karnataka are posing similar threats of deforestation.
• The rich forests of Western Ghats are also facing the same threat due to mining projects for excavation of copper, chromites, bauxite and magnetite.

Dams and other effects on forest and tribal people

Pandit Jawaharlal Nehru referred dam and valley projects as “Temples of modern India”. These big dams and rivers valley projects have multi-purpose uses. However, these dams are also responsible for the destruction of forests. They are responsible for degradation of catchment areas, loss of flora and fauna, increase of water borne diseases, disturbance in forest ecosystems, rehabilitation and resettlement of tribal peoples.

India has more than 1550 large dams, the maximum being in the state of Maharashtra (more than 600), followed by Gujarat (more than 250) and Madhya Pradesh (130).

The highest one is Tehri dam, on river Bhagirathi in Uttaranchal and the largest in terms of capacity is Bhakra dam on river Satluj in Himachal Pradesh. Big dams have been in sharp focus of various environmental groups all over the world, which is mainly because of several ecological problems including deforestation and socio-economic problems related to tribal or native people associated with them.

The Silent valley hydroelectric project was one of the first such projects situated in the tropical rain forest area of Western Ghats which attracted much concern of the people.

The crusade against the ecological damage and deforestation caused due to Tehri dam was led by Shri. Sunder Lal Bahaguna, the leader of Chipko Movement.

The cause of Sardar Sarovar Dam related issues have been taken up by the environmental activitist Medha Patkar, joined by Arundhati Ray and Baba Amte. For building big dams, large scale devastation of forests takes place which breaks the natural ecological balance of the region.

Floods, droughts and landslides become more prevalent in such areas. Forests are the repositories of invaluable gifts of nature in the form of biodiversity and by destroying them (particularly, the tropical rain forests), we are going to lose these species even before knowing them. These species could be having marvellous economic or medicinal value and deforestation results in loss of this storehouse of species which have evolved over millions of years in a single stroke.

1.4  Water resources

Use and over exploitation of surface and ground water

Water resources are sources of water that are useful or potentially useful. • Uses of water include agricultural, industrial, household, recreational and environmental activities. • Virtually all of these human uses require fresh water

Water Resources-Use and Overutilization :

1. The water Cycle through evaporation and precipitation, maintains hydrological systems .
2. All aquatic ecosystems are used by a large number for their daily needs such as washing irrigation, cooking etc.
3. One of the greatest challenges today is the management of these water resources.
4. Due to increasing population there is an enormous supply for the available freshwater resources. India is likely to face water crisis by 2025.
5. With growth of human population larger amounts of water will be required to fulfil basic needs Today in many areas this need cannot be met.
6. Overutilization of water occurs at various levels:
7. Most people use more water than required to carry out basic activities such as brushing, bathing, washing and cleaning etc.
8. Farmers also sometimes use double the water required for irrigation.
9. There are many ways in which the farmer can increase the yield by using less water for irrigation.
10. With the growth of human population there is an increasing need for larger amounts of water to fulfil a variety of basic needs. Today in many areas this requirement cannot be met.
11. Overutilization of water occurs at various levels. Most people use more water than really needed. Most of us waste water during a bath by using shower or during washing of clothes. Many agriculturists use more water than necessary to grow crops. There are many ways in which farmers can use less water without reducing the yields such as the use of drip irrigation systems.
12. Agriculture also pollutes surface water and underground water stores by the excessive use of chemical fertilizers and pesticides. Methods such as the use of biomass as fertilizers and non toxic pesticides such as neem products reduces the agricultural pollution of surface and ground water.

Industry tends to maximise short-term economic gains by not bothering about its liquid waste and releasing it into the streams, rivers, sea.

Floods

Floods have been a serious environmental hazards from centuries. Deforestation causes flood that kills people, damage crops and destroys homes. • Rivers changes its course during floods and tons of valuable soil is lost to the sea.  As the forest are degraded, rain water no longer percolates slowly into the the sub-soil but runs off down the mountainside bearing large amount of top soil.

Droughts

In most arid regions of the world the rains are unpredictable. This leads to a periods when there is a serious scarcity of water to drink, use in farm, or provide for urban or industrial use. One of the factor that worsens the effect of droughts is deforestation. Drought is one of the major problem in our country, due to unpredictable climatic condition or due to the failure of one and more monsoon.

Conflicts over water

• Conflicts through use -Unequal distribution of water has often led to inter state or international disputes
• Constructions of dams -Hydroelectric power generation, dams are built across the rivers, which initiates conflict between the states.

Dams benefits and problems

• Water Supply - Dams gather drinking water for people.
• Irrigation – Dams helps farmers bring water to their farms
• Hydroelectrical - Dams help create power and electricity from water.
• Flood control – Dam keep areas from flooding
• Recreation – Dams create lakes for people for their needs

1.5   Mineral resources

Use and exploitation

Uses of Minerals

Due to increased population, there is increased demand of minerals by the industry, transport, agriculture and defence preparation. Depletion of almost all known and easily accessible deposits is anticipated in near future. Moreover, there may be shortage of some crucial elements such as mercury, tin, copper, gold, silver and platinum. The limited resource of phosphorus, which is an essential component of chemical fertilizers, is another area of concern. 

Exploitation of Minerals

• Depending on their use, mineral resources can be divided into several broad categories such as elements for metal production and technology, building materials, minerals for the chemical industry and minerals for agriculture. When usually we think about mineral resources we often think of metals but the predominant mineral resources are not metallic. The picture of annual world consumption of some elements is as under:

• Sodium and iron are used at a rate of about 0.1 to 1.0 billion metric tons per year.
• Nitrogen, sulphur, potassium and calcium are primarily used as fertilizers at a rate of about 10 to 100 million metric tons per year.
• Zinc, copper, aluminium and lead are used at a rate of about 3 to 10 million metric tons per year;
• Gold and silver are used at a rate of about 10 thousand metric tons per year.
• Out of all the metallic minerals, iron consumption is 95% of the metals consumed

Thus, with the exception of iron, the non-metallic minerals are consumed at much greater rates than the elements used for their metallic properties.

Environmental effects of extracting and using mineral resources

Environmental Impacts of Mineral Extraction

Extracting and use of mineral resources can affect the environment adversely. Environmental affect may depend on factors such as mining procedures, ore quality, climate, size of operation, topography, etc. Some of major environmental impacts of mining and processing operations are as under

1. Degradation of land.

2. Pollution of surfaces and ground water resources.

3. Effect on growth of vegetation due to leaching out effect of minerals.

4. Surface water pollution and groundwater contamination lead to occupational health hazards etc.

5. Air pollution due to emission of gases.

6. Deforestation affects flora and fauna.

7. Rehabilitation of affected population.

Case studies

• Ara villi mountains which covers about 10% of geographical area is rich source of minerals wealth .This mountain range play important role in control of climate and act as mini water shed. On the request of environmentalist, Honourable Supreme Court has passed the order to stop these mines in Rajasthan
• Marble mining near Rajsamant Lake has lead to drying up of lake. Marble mining was stopped on December 2002.
• Recently, mining in Goa has attained the attention of the press and media and ultimately government has to take the decision to stop this mining.

1.6   Food resources

World food problems

As per estimates of Food and Agriculture Organization (FAO), about 840 million people remain chronically hungry and out of this 800 million are living in the developing world. In last decade, it is decreasing at the rate of 2.5 million per year, but at the same time world’s population is increasing. Target of cutting half the number of world’s chronically hungry and undernourished people by 2015 will difficult to meet, if the present trend continues. Due to inadequate purchasing power to buy food, it is difficult to fulfil minimum calorific requirement of human body per day. Large number of people are in India are poor which can be attribute to equitable distribution of income. Food insufficiency can be divided into two categories into under-nourishment and malnourishment. Both of these insufficiencies are global problems.

1. Under-nourishment

The FAO estimates that the average minimum daily caloric intake over the whole world is about 2,500 calories per day. People who receive less than 90% of their minimum dietary intake on a long-term basis are considered undernourished. Those who receive less than 80% of their minimum daily caloric intake requirements are considered ‘seriously’ undernourished. Children in this category are likely to suffer from stunted growth, mental retardation, and other social and developmental disorders. Therefore, Under-nourishment means lack of sufficient calories in available food, resulting in little or no ability to move or work.

Person may have excess food but still diet suffers from due to nutritional imbalance or inability to absorb or may have problem to utilize essential nutrients. If we compare diet of the developed countries with developing countries people in developed countries have processed food which may be deficient in fibre, vitamins and other components where as in the diet of developing countries, may be lack of specific nutrients because they consume less meat ,fruits and vegetables due to poor purchasing power .

Malnourishment can be defined as lack of specific components of food such as proteins, vitamins, or essential chemical elements.

The major problems of malnutrition are:

• Marasmus: a progressive emaciation caused by lack of protein and calories.
• Kwashiarkor: a lack of sufficient protein in the diet which leads to a failure of neural development and therefore learning disabilities.
• Anemia: it is caused by lack of iron in the diet or due to an inability to absorb iron from food.
• Pellagra: it occurs due to the deficiency of tryptophan and lysine, vitamins in the diet.

Every year, food problem kill as many people as were killed by the atomic bomb dropped on Hiroshima during World War II. This shows that there is drastic need to increase food production, equitably distribute it and also to control population growth. Although India is the third largest producer of staple crops, it is estimated that about 300 million Indians are still undernourished. India has only half as much land as USA, but it has nearly three times population to feed. Our food problems are directly related to population.

Supply of adequate amount of different nutrient can help to improve malnutrition and its ill effects. Cereals like wheat and rice can supply only carbohydrate which are rich in energy supply, are only fraction of nutrition requirement. Cereal diet has to be supplemented with other food that can supply fat, protein and minor quantity of minerals and vitamins. Balanced diet will help to improve growth and health.

Changes caused by agriculture and over grazing

From centuries, agriculture is providing inputs to large number of industries involved in production, processing and distribution of food. Accordingly, agriculture has significant effect on environment. The effects of agriculture on environment can be classified as local, regional, and global level. The agriculture also makes impact on the usage of land generally as follows:

• Deforestation
• Soil Erosion
• Depletion of nutrients
• Impact related to high yielding varieties (HYV)
• Fertilizers related problems include micronutrient imbalance, nitrite pollution and eutrophication.
• Pesticide related problems include creating resistance in pests and producing new pests, death of non-target organisms, biological magnification.
• Some other problems include water logging, salinity problems and such others.

The carrying capacity of land for cattle depends upon micro climate and soil fertility. If carrying capacity is exceeded than land is overgrazed. Because of overgrazing the agricultural land gets affected as follows,

• Reduction in growth and diversity of plant species
• Reduce plant cover leads to increased soil erosion
• Cattle trampling leads to land degradation

Effects of modern agriculture

For sustainable production modern techniques are used to enhance productivity of different cropping systems under different agro-eco-zones. Adoption of modern agricultural practises has both positive and negative effects on environment. Effects of modern agriculture are briefly discussed under different heads as under:

1. Soil erosion

Raindrops bombarding bare soil result in the oldest and still most serious problem of agriculture. The long history of soil erosion and its impact on civilization is one of devastation. Eroded fields record our failure as land stewards.

Adequate rainfall is never guaranteed for the dry land farmer in arid and semiarid regions, and thus irrigation is essential for reliable production. Irrigation ensures sufficient water when needed and also allows farmers to expand their acreage of suitable cropland. In fact, we rely heavily on crops from irrigated lands, with fully one-third of the world's harvest coming from that 17% of cropland that is under irrigation. Unfortunately, current irrigation practices severely damage the cropland and the aquatic systems from which the water is withdrawn.

As modern agriculture converts an ever-increasing portion of the earth's land surface to monoculture, the genetic and ecological diversity of the planet erodes. Both the conversion of diverse natural ecosystems to new agricultural lands and the narrowing of the genetic diversity of crops contribute to this erosion.

Fertilizers-pesticides problems

For photosynthesis apart from water, sunshine and CO2, plants need micro and macro nutrients for growth. These nutrients are supplied in the shape of fertilizers. There is lot of potential to increase food productivity by increasing fertilizer use. On one hand application of artificial chemical fertilizers increases the productivity at faster rate as compare to organic fertilizers, on the other hand application of fertilizers can be a serious problem of pollution and can create number of problems. Excessive level of nitrates in ground water has created problems in developed countries. These are:

• Accumulated phosphorous as a consequence of use of phosphoric fertilizer are posing serious threat as residues in domestic water supply and for ecology of river and other water bodies. Increased level of phosphates in different water results in eutropication.
• Effect of chemical fertilizer is long term, therefore leads to net loss of soil organic matter.

To control insects, pests, diseases and weeds which are responsible for reduction in productivity different chemicals are used as insecticides, pesticides and herbicides. Successful control of insects, pests and weeds increases productivity and reduces losses and provide security for harvest and storage. Applications of these synthetic chemicals have great economic values and at the same time cause number of serious problems such as:

• Affects human health which includes acute poisoning and illness caused by higher doses and accidental exposes
• As long term effect, cause cancer, birth defects, Parkinson’s disease and other regenerative diseases.
• Long term application of pesticides can affect soil fertility.
• Danger of killing beneficial predators.
• Pesticides resistance and pest resurgence

Water logging

High water table or surface flooding can cause water logging problems .Water logging may lead to poor crop productivity due to anaerobic condition created in the soil. In India, deltas of Ganga, Andaman and Nicobar Islands and some areas of Kerala are prone to frequent water logging.

Salinity

Due to adoption of intensive agriculture practices and increased concentration of soluble salts leads to salinity. Due to poor drainage, dissolved salts accumulate on soil surface and affects soil fertility. Excess concentration of these salts may form a crust on the surface which may injurious to the plants. The water absorption process is affected and uptake of nutrient is disturbed. According to an estimate, in India, 7 million hectare of land is saline and area is showing in increasing trends due to adoption of intensive agriculture practises.

Case studies

• A study on birth defects in water birds, in Kesterson wildlife refuge in California, indicated that these defects where due to high concentration of selenium.
• Recent reports from cotton growing belt of Punjab which covers Abohar, Fazalka and part of Bathinda indicates that over use of pesticides for control of insect pest in cotton to enhance productivity has not only affected soil health, but also caused cancer in human being.
• Diclofenac is the drug for veterinary use to treat the livestocks which have strong residual nature, which leads to high persistence throughout the foodchain .Due to biomagnification it becomes more dangerous to the vultures as they are consumers of diclofenac treated cattle. Diclofenac is responsible for bringing three South Asian species of Gyps vultures to the brink of extinction. It has been banned in India since 2006.

1.7  Energy resources

Energy consumption of a nation is usually considered as an index of its development, because almost all the development activities are directly or indirectly dependent upon energy. Power generation and energy consumption are crucial to economic development as economy of any nation depends upon availability of energy resources. There are wide disparities in per capita energy use of developed and the developing nations. With increased speed of development in the developing nations energy needs are also increasing.

• The very original form of energy technology probably was the fire, which produced heat and the early man used it for cooking and heating purposes.

• Wind and hydropower has also been used. Invention of steam engineers replaced the burning of wood by coal and coal was further replaced by oil.
• The oil producing has started twisting arms of the developed as well as developing countries by dictating the prices of oil and other petroleum products.
• Energy resources are primarily divided into two categories viz. Renewable and non-renewable sources.
• Renewable energy resources must be preferred over the non-renewable resources.
• It is inevitable truth that now there is an urgent need of thinking in terms of alternative sources of energy, which are also termed as non-conventional energy sources which include:

1. Solar energy needs equipments such as solar heat collectors, solar cells, solar cooker, solar water heater, solar furnace and solar power plants .
2. Wind energy
3. Hydropower, Tidal energy, ocean thermal energy, geothermal energy, biomass, biogas, biofuels etc.

• The non renewable energy sources include coal, petroleum, natural gas, nuclear energy.

Case Study

Importance of the energy resources in present economy and as a base for our future can be underlined by the fact that recent confrontations between some powerful nations of the world have primarily been attributed driven by objective to secure their energy supplies. Examples of this have been the two gulf wars. It was the hunger for energy resources that drove Iraq to lead an offensive over Kuwait and also reason for second Gulf war has been attributed to energy security by defence experts. In recent times, world has witnessed a confrontation at South China Sea between India, Vietnam and China over the issue of exploring natural gas and petroleum under the sea bed.

REFERENCES TEXT BOOKS

1. Text book of Environmental Studies for Undergraduate Courses by Erach Bharucha for University

Grants Commission, Universities Press.

2. Environmental Studies by Palaniswamy – Pearson education

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4. Textbook of Environmental Science by Deeksha Dave and E.Sai Baba Reddy, Cengage

Publications.

5. Text book of Environmental Sciences and Technology by M.Anji Reddy, BS Publication.

6. Comprehensive Environmental studies by J.P.Sharma, Laxmi publications.

7. Environmental sciences and engineering – J. Glynn Henry and Gary W. Heinke – Prentice hall of

India Private limited.

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Prentice hall of India Private limited.