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UNIT-II
NATURAL RESOURCES
The word resource means a source of supply. The natural resources include water, air, soil, minerals, coal, forests, crops and wildlife are examples. All the resources are classified based on quantity, quality, re-usability, men‘s activity and availability. Classification of Resource Exhaustible Resources : These resources have limited supply on the earth and liable to be exhausted if used indiscriminately. These resources are of two types. (1) Renewable resources : These resources have the capacity to reappear themselves by quick recycling with a reasonable span of time. Eg: forests, wildlife. (2) Non-renewable resources : Resources that exist in a fixed quantity in earth‘s crust are called non–renewable resources. These resources lack the ability of recycling and replacement. Eg: minerals, fossil fuels etc.. A few mineral resources which occur in the earth‘s crust namely copper, aluminum, mercury, gold etc.., minerals of asbestos, clay and mica are considered as non-renewable resources. Fossil fuels are derived from organic matter that accumulated during hundreds of millions of years of early bio-geological history. There is no way of recycling the energy in fossil fuels. Inexhaustible Resources: These resources are present in unlimited quantity in the nature and they are not likely to be exhausted by human a ctivities. Eg: solar energy, wind power, tidal power, rain fall, atomic energy etc… It is very important to protect and conserve, the natural resources. Natural resources are to be used in a judicious manner so that they cannot be exhausted. It doesn‘t mean that we should stop using them. Natural resources are to be used in such a way that we can make use for future generations. Among the natural resources, Water resources; Mineral resources; Energy resources; Land resources are the major ones to discuss. WATER RESOURCES Hydrologic Cycle: The continuous circulation of water from land, water bodies etc., which joins the atmosphere and finally condenses into the form of precipitation. A part of water is lost by evapo-transpiration and certain portion percolates into the ground to form ground water reservoir and the remaining water flows on the ground as runoff and joins the streams, rivers and finally into sea. This cycle is continuously repeated. Water is the main constituent of hydrosphere & is renewable resource. Water is next to air that man requires for his survival and existence. Water is
needed for daily use by organisms, for irrigation, industrial electricity production and domestic use. Hence, water is an important resource in all economic activities ranging from agriculture to industry. The distribution of water resources is not uniform over the earth‘s surface. About 97% of it is salt water in the seas & oceans, 2.6% is trapped in polar ice caps & glaciers. Only 0.4% is available as fresh water. Fresh water occurs mainly in two forms as.
- Ground water
- Surface water The distribution of fresh water is geographically uneven varying greatly from country to country & even one region to another region. Uses of water:
- Domestic use: Water used in the houses for the purposes of drinking, bathing, washing clothes, cooking, sanitary & other needs. The recommended value according to Indian standard specification for domestic use is 135 liters/day
- Industrial use: Water is required for various industries such as cement, mining, textile, leather industries.
- Public use: This includes water used for public utility purpose such as watering parks, flushing streets; jails etc.
- Fire use: Water is used in case of accidents and to prevent the fire issues.
- Irrigation: To grow crops this is the main sources for food.
- Other uses: Hydro electric power generation requires water. Effects of over use of ground water: Over use of groundwater has following effects.
- The river basin of Fordan and the Nile are the shared water resources for Middle East Countries (Asia; Africa; Europe ). Ethiopia controls 80% of Nile River water whereas Sudan (South Africa) too is trying to divert more water. The sufferer is Egypt. The following statuses have disputes: Rivers Disputing states 1.Yamuna Delhi, Haryana, Rajasthan, Himachal Pradesh, Uttar Pradesh. 2.Narmada Maharashtra, Gujarat, Rajasthan, Madhya Pradesh 3.Krishna Andhra Pradesh, Maharashtra, Tamil Nadu, Karnataka. 4.Godavari Andhra Pradesh, Maharashtra, Orissa, Madhya Pradesh. 5.Cauvery Tamil Nadu, Karnataka Dams benefits & problems : The construction of dams has their own benefits & drawbacks. Excess amount of water flowing in rivers which otherwise Join Sea can be stored as reservoirs by constructing the dams across the rivers. The dam‘s viz., Bhakra-Nangal, Heerakud, Nagarjuna sagar; srisailam etc generate electricity, to supply drinking water. Pandit Jawahar Lal Nehru called these dams as ―THE TEMPLES OF MODERN INDIA‖. Uses:
- More land can be brought under irrigation.
- Hydro-Electric power can be generated.
- Water can be supplied to towns & cities. Disadvantages:
- Causes change in a climate of region at micro level.
- Loss of vegetation & soil erosion.
- Generation of seismic activities due to heavy pressure of water.
- Blasting operations during construction of dams cause landslides.
- Sedimentation & silting of reservoirs. MINERAL RESOURCES Minerals are naturally occuring inorganic, crystalline, solid having a definite chemical composition with a certain physical properties or a substance that is naturally present in the earth and is not formed from animal or vegetable matter. In any country, the growth and development of industry depends on the availability and quality of deposits of minerals of economic importance. Mineral resources can be classified under three main types. They are metallic, nonmetallic and atomic minerals. Metallic minerals include native elements such as gold and silver ; haematite and magnetite (iron) ; Cuprite ( copper) ; Laterite ( aluminum) and nonmetallic minerals include sand ( quartz ), garnet ; steatite (talc); muscovite ( mica ) whereas atomic minerals include Pitchblende (Uranium, Thorium ). The geological processes are caused for the formation of the minerals over million of years ago in the earth‘s crust. Minerals are generally localized in occurrence and the deposits are very sporadic in distribution. Mineral resources are non renewable and the mineral /ore is extracted by the process of mining. Much risk is involved in mining process because of high temperature, pressure variations, fire hazards and lack of ventilation in mines. Minerals are used in a large number of ways for domestic, industrial, commercial sectors etc… Generation of energy by using coal ( lignite / anthracite ) ; uranium, gold, silver, platinum, diamond are used in jewellery. Copper, aluminum etc are used as cables for transmission of power. Some of the minerals are used in ayurvedam as medicine. Gold is reputed to strengthen the heart muscle and increase energy and stamina. By placing a piece of
gold (devoid of stones) into 1000 ml of water and boiling it until reduced to 500 ml. Historical dose used gold ash of 10 mcg/day or gold water of 1 tsp 3x/day. Silver is a very important healing substance due to its cooling and antiseptic properties. It is most useful for treating Vata and Pitta especially conditions involving weakness, and some of chronic fevers. It is also used for gastritis, inflammatory of the intestines. Historical dose used silver ash of 10-30 mcg/day or silver water of 1 tsp 3x/day. Copper was used to treat conditions of excess kapha (primarily) and vata (secondarily). Historical dose used: copper ash: 10-30 mcg/day or copper water: 1 tsp 3 x/day Environmental effects: Mineral extraction and processing in mines involves a negative impact on environment. Mining process involves removal of over burden of soil, ore extraction & transportation, crushing & grinding of ore, water treatment of ore, storage of waste material As a result of these activities cause air pollution, noise pollution, water pollution, loss of habitat of wildlife, concentration of toxic substances in tailing ponds and spreading of dust. People working in mines often suffer from serious respiratory system and skin diseases. Mining often causes ground subsidence which results in tilting of buildings, cracks in houses, buckling of roads, bending of rail tracks etc. Exploration process before a mining involves, geochemical, geophysical surveys drilling activities which causes for air pollution, noise pollution etc.. In addition, disturbance of all vegetation ( flora ) and fauna ( animals ) from that a region. Remedial measures : Atmospheric pollution due to mining and associated activities can be minimized by planning and using dust extractors, by optimizing the blast design, maintenance of roads and sprinkling of water for easy movement of dumpers, by using eco generators ( sound proof ), proper maintenance of equipment and the machines not only minimize the air pollution but also the noise generation. case studies of mineral resources 1)Aravalli hills in Rajasthan : The Aravallis hills spread across Haryana, Rajasthan and Gujarat and control the climate and drainage system of the region. Mining activity is being taken in this region due to immense mineral wealth ( Talc, marble, granite ). Rajasthan state alone has 9700 industrial units connected with mining and 90% of forest has been depleted over the past 20 years. When the mining activity reached below the under ground water level, a cone of depression was formed in the surrounding areas and ultimately bore wells, dug wells, dried up and affected agriculture in a massive level. Several studies have pointed out that the natural drainage system and the ground water table of the entire region have been badly affected. Pollution levels have also increased. Lung diseases, silicosis were attacked by the laborers. In November 2002, the Supreme Court imposed a blanket ban on mining activities in the Aravalli hills. The court ruling closed all 9700 units. The environmentalists have alleged that mining has affected the water, forest and the land. 2)Uranium mining in Nalgonda : The Uranium Corporation of India proposed to mine Uranium from the deposits of Lambapur and Peddagattu villages of Nalgonda dist. Processing unit was proposed at Mallapur village in Nalgonda dist by offering employment opportunities. But experts didn‘t propose mining activity because of possible contamination of water. The proposed mines are just 1 km away from human habitation and 10 km from Nagarjuna sagar dam and 4 km away from Akkampalli reservoir, which is a source for drinking water.
- Gold mining in Europe : Potassium Cyanide is used during the process of gold treatment. In 2000, the Baia Mare Gold mine in Romania ( Europe ), released 80 million litres
(e) Mountain soils : These are stony. Mountain soils are formed due to dislodgement of rocks due to landslides and occur over altitudes between 2000 to 3000 mts. Eg: Aravallis and East of Himalayas. Mountain soils are favour for growth of vegetation / forest. (f) Desert soils : These soils cover the parts of areas of Rajasthan and Kutch where the annual rainfall is less than 50 cms per annum. (g) Saline soils : Presence of salt and water retention make the soils unsuitable for agriculture. Eg: Arid ( no rain ) and Semi arid ( partly rain ) regions of northern plains and Maharashtra. Soil erosion and causes for soil erosion The top layer of the earth is called as soil. Soil erosion occurs due to deforestation, overgrazing, industrialization; desertification etc. Deforestation: Mining, industrial, urban development etc causes deforestation and leads to exposure of the land to wind and rains causing soil erosion. Cutting trees leads to deforestation which in turn loss of organic matter in the soils. Overgrazing : When sufficient amount of grass is available for the organisms usually the entire land /area may be subjected to exhaust and the land is exposed without grass and ultimately the land expose to wind/rain causing soil erosion.. Industrialization : Different processes carried out by industries and mining operations cause soil pollution which leads to degradation of land. Desertification : The process of conversion of productive lands to unproductive lands is called desertification. This occurs due to loss of top layer of soil by erosion. Erosion of top layer results in loss of water holding capacity and finally converted in to unproductive areas. Land degradation and control of land degradation Land degradation can be defined as any change in the land that alter its conditions or reduces its quality. Land degradation occurs due to both natural disasters like volcanic eruptions, earthquakes, heavy rains, fire etc or human induced activities. The other causes of land degradation consists of wind blow, salinity of water, water logging, soil acidity, loss of flora and fauna. Desertification is land degradation occurring in the arid, semi -arid regions of the world. These dry lands cover about 40% of the earth‘s surface and puts at risk more than 1 billion people who are dependent on these lands for survival. Land clearing and deforestation; Mining activity in forest areas; urban conversion; bringing more land under cultivation; soil pollution ; loss of organic matter in the soils; alkalinization of soils; salinity of water etc leads to land degradation. Severe land degradation affects in decreasing the mineral wealth and economic development of nations. The methods that are followed for the prevention of land degradation are called soil conservation methods. Some of the popular methods are; (a) Contour farming : The land is prepared with alternate furrows (a long narrow cut in the ground ) and ridges at the same level. The water is caught and held in furrows and stores which reduces run off and erosion. (b) Mulching : Stems of maize, cotton, tobacco etc are used as a mulch (decay of leaves) to reduce soil moisture, evaporation. (c) Crop rotation : Growing same crop year after year depletes the nutrients and land becomes unproductive. This is overcome by changing the crops and cultivating legumes (plants like peas, beans) after a regular crop.
(d) Strip cropping : It consists of planting crops in rows or strips along contours to check flow of water. (e) Agrostological methods : Korean grass, Mexican grasses are grown as erosion – resisting plants. (f) Miscellaneous methods : Construction of bunds, drains, widening of gullies, Afforestation methods prevent the soil erosion. Landslides and man induced land slides Landslides are always exist on this planet and the term land slide is used to describe a wide variety of process that result a downward movement of rocks under gravitational forces. In other words, mass movement of rocks, debris and soil down a slope of land. Landslides are primarily associated with steep slopes. Surface run-off and changes in drainage also cause for landslides. Landslides can also be initiated by rainfall; earthquakes; volcanic activity, changes in groundwater movement or any combination these factors. Debris-flows can travel down a hillside of speeds upto 200 miles per hour (more commonly, 30 – 50 miles per hour) depending on the slope angle, water content, and type of earth and debris in the flow. While landslides are a naturally occurring environmental hazard they have recently increased in frequency in certain areas due to human activities. Building excavations, collapses in mining ( eg : coal mine) causes landslides. However, landslides can be triggered by the human beings by induced changes in the environment. Simply landslides can be explained in three ways: (a) Inherent of rocks (weakness in the structure of a rock ) ( b) due to heavy seismic or volcanic activity and (c) due to various environmental conditions. ENERGY RESOURCES The term energy means capacity to do work. Energy can neither be created nor destroyed but transformed from one form to other. Energy is closely related to force. When a force causes an object to move, energy is being transferred from the force to kinetic energy. Energy is present in a number of forms such as mechanical, thermal, chemical, biological energy etc.. Energy production and utilization have become essential to carry out many activities in modern life. Energy is one of the important requirements that a country needs for its economic growth. At the same time, energy production has its impact on environment due to pollution and finally affects the quality of life of people. The energy is used for the following purposes: a) Cooking, heating and lighting b) Transporting people and goods by means of vehicles. c) Manufacturing consumer goods and equipment d) Conversion of fuels into other forms of energy for various use. For Example: (1) Burning coal to produce electrical energy or mechanical energy (2) Chemical to electrical by dry cell batteries (3) Using water in dams to produce electricity through mechanical energy. The power generation capacity in the country has increased from 1400 MW at the end of 1947 to 92 ,894 MW at the end of 1999 from various sectors comprising as under: Hydro sector 22,438 MW Thermal sector 67,618 MW Nuclear sector 1,870 MW
(1) Ocean Thermal Energy Conversion : The oceans collect and store huge quantities of solar on the surface of the water while the temperature of deep waters is very low. Using this temperature difference it is possible to convert heat into electricity. (2) Tidal energy : Tidal waves of the sea can be used to turn turbine and generate electricity. Asia‘s first tidal power plant of 800 - 1000 MW capacity is proposed to be set up at Kandla in Gulf of Kutch. (3) Wave energy : The wind blowing over water generates waves. A unique property of ocean waves is their ability to travel vast oceanic distances with negligible loss of energy and ultimately arrives the continental margin of that basin. India‘s first wave energy power plant of 150 KW capacity has been commissioned in Thiruvananthapuram, Tamil Nadu. 1 MW wave energy plant is being set up in Andaman and Nicobar islands. (4) Current energy : Theoretically, the ocean water used to generate energy by allowing the water to pass through a series of turbines installed under water. The turbines are to be sealed and are kept at a depth of 10 to 20 mts. A propeller with a dia of 5 mts can generate about 150 MW of power. Bio mass energy : Bio-mass is an organic material from living beings or its residues. It is a renewable source of energy derived from the waste of various human and natural activities. The bio-mass energy sources include Wood, animal manure, sugarcane waste, agriculture crops, house hold waste, roots of plants, garbage etc. The simplest way of using bio-mass energy sources is to allow them to dry out in the sun and burn them. Bio-gas : Bio-gas is a sustainable source of energy by virtue of its production from available natural organic wastes of cattle dung, human excreta, poultry waste, plant leaves, paddy husk etc…. Bio-gas is a mixture of methane (68%), CO 2 (31%) and N 2 (1%). Methane gas (CH 4 ) is produced by bio-gas plants and this gas is utilized as cooking gas whose calorific value varies from 4400 – 6200 Kilo Calories / cum. Heat value of bio gas can be improved by reducing its CO 2 content. Bio-gas production is carried out in an enclosed bio-gas plant made of bricks or steel. Slurry of waste organic matter is fed into the plant through an inlet and gas formed is tapped by an inverted drum. As gas is produced the drum rises and the gas may be drawn through an outlet. Bio-gas is commonly produced from cattle dung in a bio gas plant known as Gobar Gas plant. Bio-gas is a clean, cheap fuel that can be used for lighting purpose, lifting water through small pumps. Non – renewable energy resources include (a) fossil fuels such as coal, crude oil, natural gas and (b) nuclear energy. (a)Fossil fuels: Fossil means the remains of an animal or a plant which have become hard and turned into rock. All these found in earth‘s crust which has been formed in the past by the geological processes. Fossil fuels are solid coal (lignite), liquid (crude oil / petroleum) and gases ( natural gas). Coal: Huge quantity of plant materials buried under earth‘s crust and altered by geological process and converted into carbon rich fuel. It is a non – renewable source because it takes a very long period (million of years) for its formation. Coal is extracted by the process of mining and involves accidents due to mine collapse, ground water pollution, accumulation of poisonous material, explosive gases etc cause diseases. CO 2 pollution leads to green house effect (global warming). (^) o
Crude oil: It is obtained in the form of liquid. The crude oil is heated upto 600 C in the oil refinery and condense the vapours of hydro – carbons. Petrol and other petroleum products are refined fuels from crude oil. Petroleum products are used in large quantities in the manufacture of detergents, plastics, fertilizers, pharmaceuticals, synthetic rubber etc. The transport sector consumes about 40% of diesel; 25% industries and 19% household and rest 16% agriculture and other sectors.. Natural Gas: Gas deposits are trapped from the sedimentary formations by means drilling holes into the rock formations. While burning of natural gas, the emission of CO 2 is less and thus reduces green house effect and global warming. A total of 734 billion cubic mts of gas is estimated as proven reserves. (b) Nuclear Energy or Atomic power: It is the energy which is trapped inside the atom. It is non–renewable source of energy which is released during fission or fusion of certain radioactive elements. The most important advantage of atomic power is the production of an enormous amount of energy from a small quantity of radioactive element. For eg: 1 kg of Uranium liberates energy equivalent to 30000 kgs of coal. Energy released during nuclear reaction (mass
- energy 2 equation as per Albert Einstein‘s formula E = mc ). Nuclear Energy is produced by two Processes namely (1) Nuclear Fission (2) Nuclear Fusion. (1)Nuclear Fission : The nucleus in atoms is split by fast moving neutrons and in turn a tremendous amount of energy in the form of heat, light etc is released by a chain of reactions. Uranium is used as fuel. The energy released slowly in this process is utilized to generate electricity or else released suddenly all at once, results a tremendous explosion as in the case of Atom bomb. (2)Nuclear Fusion: Nuclear energy can be generated by fusion process which involves two hydrogen atoms combine to produce one helium atom. Eg: hydrogen bomb. The disposal of nuclear wastes during mining, fuel production and reactor operation for a long time period resulting in adverse effects on environment. Disposable of nuclear waste is a national and global problem.
