UNIT - III

NATURAL RESOURCES

Dr. D. BalajiAssociate Professor

Department of Chemical Engineering

Natural Resources

o Renewable Resources

o Non- Renewable Resource

The Natural ResourcesThe natural resources are of two kinds

o Renewable resources: - Inexhaustive - Regenerated withina given span of time.e.g. forests, wildlife, wind energy, biomass energy, tidalenergy, hydro poweretc.Solar energy is also a renewable form of energy as it is aninexhaustiblesourceof energy.inexhaustiblesourceof energy.

o Non-renewable resources: which cannot be regeneratede.g.Fossil fuels like coal, petroleum, minerals etc.Once we exhaust these reserves, the same cannot bereplenished.

Natural Resources

A nonrenewable resource is a natural resource thatcannot be re-made or re-grown at a scalecomparable to its consumption

Nuclear energyNuclear fission uses uranium to create energy.

Nuclear energy is a nonrenewable resource because once theuranium is used, it is gone!

Coal, petroleum, and gas

Coal, petroleum, and natural gas areconsidered nonrenewable becausethey can not be replenished in a shortperiod of time. These are called fossilfuels.

How is coal made ?

How are oil and gas made ?

What was the difference between coal and oil/gas?

If nonrenewable resources are resources that cannot be re-made at a scalecomparable to its consumption, what are renewable resources?

Renewable Resources

Renewable resources are natural resources that can bereplenished in a short period of time.

• Solar

• Geothermal• Geothermal

• Wind

• Biomass

• Water

Solar

Energy from the sun.

Geothermal

Energy from Earth’s heat.

Wind

Energy from the wind.

Biomass

Energy from burning organic or living matter.

Water or Hydroelectric

Energy from the flow of water.

Resources

o Forest resources

o Water resources

o Mineral resources

o Food resources

o Energy resources

o Land resources.

Production of oxygen: The trees produce oxygen byphotosynthesiswhich is so vital for life on this earth.They are rightly called asearth’s lungs.

Reducingglobal warming: The main greenhousegas

Forest Resources

Reducingglobal warming: The main greenhousegascarbon dioxide (CO2) is absorbed by the forestsas araw material for photosynthesis. Thus forest canopyacts as a sink for CO2 thereby reducing the problem ofglobal warming caused by greenhouse gas CO2.

Wild life habitat: Forests are the homes of millions of wild animals andplants.About 7 million species are found in the tropical forests alone.

Regulation of hydrological cycle: Forested watersheds act like giantsponges, absorbing the rainfall, slowing down the runoff and slowlyreleasing the water for recharge of springs. About 50-80 %ofthe moisturein the air above tropical forests comes from their transpiration which helpsin bringing rains.

Soil Conservation: Forests bind the soil particles tightly in their roots andprevent soil erosion. They also act aswind-breaks.

Pollution moderators: Forests canabsorb many toxic gasesand can help inkeeping the air pure. They have also been reported toabsorb noiseand thushelp in preventing air and noise pollution.

Deforestation

Deforestation refers to theloss of forest cover; land that ispermanently converted from forest to Agricultural land, golfcourses, cattle pasture, homes, lakes or desert.

FAO-Food and Agriculture Organizationof the UN defines tropicaldeforestation as“ change of forest with deletion of tree crown cover morethan 90%”depletion of forest tree crown cover less than 90% is considered

.

Deforestation

forest degradation.

United Nations conference on Environment and development (UNCED) in1992 defines deforestation as : land degradation in arid, semi-arid, and sub-humid areas resulting from various factors including climatic variations andhuman activities”.

The following are the major causes of deforestation around the world.

Agriculture- poor formers cut down small areas and burn the trees and proceedwith agriculture.

Commercial logging-logging rods enable landless people to access the interiorsof the forest, which in turns result in further deforestation and poaching.

Causes of deforestation

The cash crop economyEg. In Malaysia over 3.5 million hectares of forest have beencleared for therubber and oil palm plantations.

Mining and dams-Mining, industrial development and hydroelectric schemesare also significant causes of deforestation.

Causes

- Shift in cultivation

- for Fuel

- Raw material for industries

- Development process

- Growingfoodneed- Growingfoodneed

- Overgrazing

(i) It threatens the existence of many wild life species due to destruction of their natural habitat.

(ii) Biodiversity is lostand along with that genetic diversity is eroded.

Effects of Deforestation

(iii) Hydrological cycle gets affected, thereby influencing rainfall.

(iv) Problems of soil erosion and loss of soil fertility increase.

(v) In hilly areas it often leads to landslides.

Timber Extraction: Logging for valuable timber, such as teakand Mahogany not only involves a few large trees per hectarebut about a dozen more trees since they are stronglyinterlocked with each other by vines etc. Also road constructionfor making approach to the trees causes further damage to theforests.

Major Activities in Forests

Vines

Forest location in Tamilnadu

Forest cover in India

Mining:Mining operations forextracting minerals and fossil fuelslike

coal often involves vast forest areas.

Mining from shallow deposits is done bysurface miningwhile

that from deep deposits is done bysub-surface mining.

More than80,000haof landof thecountryis presentlyundertheMore than80,000haof landof thecountryis presentlyunderthe

stress of mining activities.

Mining and its associated activities requireremoval of vegetation

along with underlying soil mantle and overlying rock masses. This

results in defacing the topography and destruction of the

landscape in the area.

Mining is a process of removing ores from area which is verymuch below the ground level. Mining is done for the extractionof several minerals of metals likeFe, Mn, Au, Ag, etc. Theminerals are especially foundin thick forests.

Mining can be carried out in two ways

1. Surface mining

2. underground mining or sub-surface mining

The effects of under ground mining on forest reserves iscomparatively less than that of surface mining

There are two successful cases of reclamation of mined areas in India. They are :

(1) Neyveli Lignite Corporation Ltd. in Tamil Nadu.

(2) Stone Quarries of Sayaji Iron Works in Gujarat

• India has large numbers of minerals, one-quarter of world’s known mineralresources.

• About2/3 of Iron deposits lies in Orissa and Bihar• Haemaite deposits in MP, Karnataka, Maharashtra, Goa and Magnetite

iron-ore in TN, Bihar, Himachal• 2nd place for Manganese MP, Maha.., Bihar-Orissa• Chromide deposits at Bihar, Orissa, AP, Karna• Bauxite deposits in Bihar, Kashmir, TN, Kerala, UP, Maha, Karnat.• India supplies 75% of the world’s Mica- Bihar, Andra, Rajasthan, Sikkim,

KarnatKarnat• Gypsum in TN, Rajasthan,• Nickel ore- Orissa, Ileminite -Kerala, Silimanite-Maha,MP, Copper-

Andhra, bihar, Rajashthan,• Diamond-Andra, MP, UP, Petroleum- Assam, Gujarat, Uranium-

Tumalapalli village located in Kadapa, A.P.

Relation between forest and climate change:

Forests both influence and influenced by climate change. They play an important role in the carbon cycle and the way we manage forests could significantly affect global warming.

Forestshold morethan50 per centof the carbonthat is storedForestshold morethan50 per centof the carbonthat is storedin terrestrial vegetation and soil organic matter. Hence,deforestation contributes significantly to net emissions ofcarbon dioxide into the atm.

Dams - Positive impact

• These dams are regarded as symbol of national development.• provides large scale employment of tribal people and increase

the std. of living of them• contribute for economic uplift and growth• help in checking flood• generateelectricity• generateelectricity• reduce power and water shortage• provide irrigation water• provide drinking water to remote areas• promote navigation and fishery.

Dams

• Negative Impacts– Displacement of species.

– Loss of fauna and flora, earthquake

– Quality changes and stagnation

– Microclimate change and growth of aquatic weeds

– Breading of disease vector

Upstream problems

– Water logging and salinity

– Salt water intrusion at mouth of river

– Loss of fertility- due to sediments

– Disease spread

– Microclimate changes

Downstream problems

Major projects

Dams in India as on 2012: 3200

Dams in Tamilnadu as on 2012 : 114

(i) Sardar Sarovar Project, Gujrat.(i) Sardar Sarovar Project, Gujrat.

(ii) Narmada Sagar Project, M.P.

(iii) Bodhghat Project, M.P.

(iv) Tehri Dam Project in U.P.

Sardar Sarovar Dam

Forest Conservation and Management• Sustainable supply of tree products and services to people

and industry

• Maintenance of long-term ecological balancethroughprotection, restoration and conservation of forest cover.

• Afforestationprogrammes

To achieve goal

(i) protection or conservation forestry(i) protection or conservation forestry- degraded forests to allow recoupment of their flora and fauna

- Well-stocked forests are managed

– Designated as national parks and sanctuaries

(ii ) production or commercial forestry.- Production plantations of fast growing trees (e.g., Eucalyptus)

- Social forestry and agro forestry programmes

• Social forestry: aims to plant trees and shrubs on all unused and fallowland to providefuelwood, fodder, etc., to avoid stress on forest.

• For example, unused farmland, community land, road and rail sides, etc.are planted with suitable indigenous and/or exotic tree species.

Agro-forestry• a variety of land uses, where woody species are grown in combination with

herbaceouscrops(sametime or in sequence)herbaceouscrops(sametime or in sequence)

Steps to prevent deforestation or the role of individual in preserving forest resources

1. Starting afforestation (tree planting) programs.

2. Educating people about the ill effects of deforestation through movies, documentaries, play, newsletters etc.

3. Strict implementation of Forest Conservation Act

4. Implementing people’s participatory programmes. Example: 4. Implementing people’s participatory programmes. Example: Joint Forestry Management (JFM).

5. Avoids diversion of forest lands for other activities through acts like Forest Conservation Act and Wild life (protection) Act

6. Control forest diseases and forest fire

7. Recycling or replacing forest products may result in less dependence of forest.

about 97% is salty water

and only

Water Resources

3% is fresh water

Unique features of water

1. High specific heat

2. High latent heat of vapourisation

3. Good solvent for oxygen, nutrients and pollutants

4. Anomalous expansion on freezing

5. High surface tension

6. Universal solvent

Groundwater

• About 9.86% of the total fresh water resources is in the form of

groundwater and it is about 35-50 times that of surface water supplies.

• Till some time back groundwater was considered to be very pure. However, of late, even groundwater aquifers have been pure. However, of late, even groundwater aquifers have been found to be contaminated by leachates from sanitary landfills etc.

Surface Water

• The water coming through precipitation (rainfall, snow) when does not percolate down into the ground or does not return to the atmosphere as evaporation or transpiration loss, assumes the form of streams, lakes, ponds, wetlands or artificial reservoirs known as surface water.

• The surface water is largely used for irrigation, industrial use, • The surface water is largely used for irrigation, industrial use, public water supply, navigation etc. A country’s economy is largely dependent upon its rivers.

• Creates declining of water levels

• Crops failure and reduction in agricultural production

• Over pumping of ground water create drought, famine and food shortage

• Over pumping of ground water sea water intrusion in coastal aquifers

• land subsidence may due to over pumping of ground water

• River pollution due to industrial activities and dumping of waste into rivers, which in turn force to utilize the ground water, ultimately leads to over

Water pollution or contamination

which in turn force to utilize the ground water, ultimately leads to over pumping

• Clean water is universal right. It is the responsibility of everyone to ensure the purity of water. Water is a valuable commodity and it has to be

conserved.

Surface water

When evaporation and transpirationrates are lower than therainfall, surface water body like lake, river, pond, streams etc.will get dried.

Flood: over flow of water,whenever the water in flow is greaterthan the carrying capacity of the channels flood occurs.

Causes

1. heavy rainfall, snow melt, sudden release of water from dams. 1. heavy rainfall, snow melt, sudden release of water from dams.

2. Prolonged down pour leading to overflowing of rivers and lakes

3. Reduction in carrying capacity due to obstructions or sediments etc.

4. Deforestation, overgrazing, mining increases water run off

5. Removal of dense forests from hilly regions

Effects

1. Submerges the flooded area

2. Loss of soil fertility due to soil erosion

3. Extinction of civilization at costal area

Flood management

1. Dams and reservoirs can be constructed

2. Embankments and proper channel management

3. Flood way should not be encroached

4. Forecasting or flood warning

5. Decrease of run off by infiltration through afforestation or rain water harvesting etc. water harvesting etc.

Drought

Drought Unpredictable delay in climatic condition occurring due to monsoon rain failure.

Types

Meterological : in order of month or year, actual moisturesupply at a given place consistently falls below critical level.

Hydrological: deficiency in surface and subsurface watersupplies.supplies.

Agricultural: inadequate soil moisture to meet the need of aparticular crop at particular time or susceptibility of cropsduring different stages in its development

Socioeconomic: reduction in the availability of food and socialsecuring of people

Causes• Deforestationand lesser rainfalls coupled with cutting of trees

for timber leads to desertifictation.

• Over drafting of ground water, subsidence of soil, drying of wetlands

• Pollution of soil with solid waste, industrial effluents etc makes land useless and dry

• Population explosion in man and livestock leads to enhanced • Population explosion in man and livestock leads to enhanced requirement of timber, fuel wood, grazing

• Shifting cultivation

Effects

• Increase of water in stream pond

• Ground water table get declined

• Loss of agricultural crops

• Loss of biodiversity

• Government spent a lot of money as drought relief fund

Control measures • Rain water harvesting

• Watershed management

• Prevent deforestation

• Encourage afforestation

Conflicts over water

• People lack accesses to safe water • 6000 Childs die every day (80% - developing countries)• Water usage 2 times increased due to population• 90% of water released to env. Without any treatment• One flush of a western toilet = one day need of a man in a developing

countryClassification of conflict Classification of conflict

control of water resourcesmilitary toolpolitical toolterrorismmilitary targetdevelopment disputes

History of conflicts over water around the worldKarnataka Tamilnadu- violence erupts when karanataka rejectsan interim order handed down by the Cauvery waters tribunal,setup by the Indian supreme court. The tribunal was establishedin 1990 to settle two decades of dispute between karnataka andTamil Nadu over irrigation rights to Cauvery river.

During the gulf war, Iraq destroys much of Kuwait’s During the gulf war, Iraq destroys much of Kuwait’s desalination capacity during retreat.

Summary Natural Resources

Renewable –Non Renewable

Forest Resources

Water Resources

Land Resources

Land Resources

Land is critically important national resource which supports all livingorganisms including plants and animals. The soil profile ofland determines itsability to serve socio-economic needs.

It has been estimated that more than5000 million tonsof top soil is erodedannually along with5 million tones of nutrients. About 1/3 of this is lost in seawhile the rest in reservoirs and rivers leading to flood.

About 38% of the area in India suffers from moderate to high degree of waterbased erosion.The per capita availability of land in the country has declinedfrom 1.37 hectare in 1901 to 0.33 hectare in 2000. All these lands cannot beutilized for agricultural purpose. Some land would be required for otheractivities (to maintain urban area).

Land Resources

Effective steps have to be taken for preventing diversion ofland suitable for

sustainable farming to non-farm uses. Simultaneously, degraded lands and

waste lands have to be improved byecological restoration. The Department of

Land Resources was setup in April 1999 by ministry of Rural Developmentto

act as nodal agency for land resource management.

The main objectives of the Department are:The main objectives of the Department are:

To increaseproductivity of rainfed/degraded landthrough the process of

integrated watershed management.

To support the States/UTs for implementation ofNational Land Records

Modernization Programme (NLRMP)

Land reforms and other related matters relating to land likeadministration of

Land Acquisition Act, 1894, National Rehabilitation and Resettlement Policy

of 2007 , Registration Act, 1908 etc.

Land Degradation

Land Degradation: Land degradation is defined as thereductionin soil capacityto produce in terms of quality, quantity goodsand services. The definition is also based on1. sustainability or ability to produce continuously andindefinitely.2. quality of land resource that makesit sustainable or resistantto degradationto degradation3. carrying capacityor the number of people and animals theland can normally support without significant stress.

Landscapes generally undergo degradation but are usuallycompensated by natures inherent recovering ability. Wheneverdegradation occur exceeding natures restorative capacity, theresult will be a disaster.

Causes of Land Degradation

•Land clearance, such as clear cutting and deforestation• Agricultural depletion of soil nutrients through poor farming practices• Overgrazing• Urban conversion• Irrigation• Irrigation• Land pollution including industrial waste• Weeds• Walking tracks

Land Slide

Kedarnath, Uttarakhand

There are two types of slides

1. Slides due to natural factors 2. Slides induced by man and his activities

Some of the human activities that cause land sliding are • Massive deforestation • Massive deforestation • Erratic agricultural practices • Road building • Unscientific quarrying etc. • Engineering. Constructions

Soil Erosion

•Soil erosion is oneform of soil degradationalong with soilcompaction, low organic matter, loss of soil structure, poorinternal drainage, salinisation, and soil acidity problems.

• Soil erosion is a naturally occurring process on all land. Theagentsof soil erosionare water and wind, eachcontributingaagentsof soil erosionare water and wind, eachcontributingasignificant amount of soil loss

• The loss of soil from farmland may be reflected in reduced cropproduction potential,lower surface water qualityand damageddrainage networks.

Soil erosion

Terracing: Terracing reduces soil erosion onsteep slopes byconcerting the land into a seriesof broad, level terraces. This retains water forcrops at each level and reduces soil erosion bywater run off.

Contour Farming: This method isadopted forgently sloped land. This involvesplanting crops in rows across the contour ofgently sloped land

Soil erosion

Alley Cropping or Agro forestry: In thismethod crops are planted together in stripsor alleys between trees and shrubs thatcan provide fruits and fuel wood. The treesand shrubs provide shade which reducewater loss by evaporation and preserve soilmoisture.

Wind Breaks or Shelter Belts: Wind breaksand shelter belts or trees are establishedto reduce wind erosion and also forretaining soil moisture.

Soil Erosion by Water

The rate and magnitude of soil erosionby water is controlledby the following factors:

– Rainfall Intensity and Runoff– Soil Erodibility - is an estimate of the ability of soils to resist erosion, based on the physical characteristics of each soil.erosion, based on the physical characteristics of each soil.

Generally, soils with faster infiltration rates, higher levels of organic matter and improved soil structure have a greater resistance to erosion.

– Slope Gradient– Vegetation

Soil Erosion by WindThe rate and magnitude of soil erosionby wind is controlledby the following factors:

– Erodibility of Soil - Very fine particles can be suspendedby the wind and then transported great distances.

– Soil SurfaceRoughness– Soil SurfaceRoughness– Climate - Soil moisture levels can be very low at the surfaceof excessively drained soils or during periods of drought, thusreleasing the particles for transport by wind

– Unsheltered Distance – lack of wind breaks– Lack of vegetative Cover

Onsite Effects of Soil Erosion

The main on-site impact is the reduction in soil quality which resultsfrom the loss of the nutrient-rich upper layers of the soil, and thereduced water-holding capacity of many eroded soils.

A diminution of the soil’s suitability for agriculture or otherA diminution of the soil’s suitability for agriculture or otherVegetation

The on-site impact of erosion: severe rilling on a hillslope at Rottingdean on the UK South Downs in 1987

Off-site Effects of Soil ErosionMain off-site effect is themovement of sediment and agriculturalpollutants into watercourses. This can lead to the silting-up ofdams, disruption of the ecosystems of lakes, andcontamination ofdrinking water.

In some cases, increased downstream flooding may also occurdue to the reduced capacity of eroded soil to absorb water

Land DegradationSoil ErosionSoil Erosion by WaterSoil Erosion by Wind

Summary

Soil Erosion by WindOnsite Effects of Soil ErosionOnsite Effects of Soil Erosion

Minerals Resources Minerals Resources

Mineral resources

Minerals arenaturally occurring, inorganic, crystalline solidshaving a definite chemical composition and characteristicphysical properties.

A few common minerals likequartz, feldspar, biotite, dolomite,calcite,lateriteetc.calcite,lateriteetc.

These minerals, in turn, are composed of some elements likesilicon, oxygen, iron, magnesium, calcium, aluminium etc.

Some Important Mineral Elements and their Uses

Mineral Selected uses

Metal elements

Aluminium Structural material, packaging

Chromium Chrome plate, steel alloys

Copper Alloys material in gold jewellery, silverware, brass

and bronze, electric wiring, pipes, cooking

vessels

Gold Jewellery, dentistry, alloysGold Jewellery, dentistry, alloys

Iron Primary component of steel

Lead Pipes, battery electrodes, pigments

Manganese Alloy steels, disinfectants

Nickel Coins, alloys, metal plating

Platinum Jewellery, equipments, industrial catalyst

Potassium Fertilizer, glass, photography

Silver Jewellery, vessels, photography, alloy

Uranium Nuclear bomb, electricity, tinting glass

Tin Cans/containers, alloys

Zinc Brass, electrodes, medicine

Non Metal Resources

Energy generating minerals

Coal and lignite: West Bengal, Jharkhand, Orissa, M.P., A.P.

Uranium (Pitchblende or Uranite ore): Jharkhand, Andhra Pradesh (Nellore,Nalgonda), Meghalaya, Rajasthan (Ajmer).

Other commercially used mineralsAluminium (Bauxite ore): Jharkhand, West Bengal, Maharashtra, M.P.,Tamilnadu.Tamilnadu.

Iron (haematite and magnetite ore):Jharkhand, Orissa, M.P., A.P., Tamilnadu,Karnataka, Maharashtra and Goa.

Copper (Copper Pyrites):Rajasthan (Khetri), Bihar, Jharkhand, Karnataka,M.P., West Bengal, Andhra Pradesh and Uttaranchal.

Major minerals in India

NALCO (National Aluminium Company) is India's largest bauxite mining company, most of its operations are located at Damanjodi in Orissa.

Other major producers are Hindalco, INDAL (Indian Aluminium Company), BALCO (Bharat Aluminium Company), Sterlite Industries and MALCO (Madras Aluminium Company).

INDAL's bauxite mines are at Panchpatmali in the Koraput district, Orissa.

Environmental impacts of mineral extraction and use

Indian Scenario: India is the producer of 84 minerals the annualvalue of which is about Rs. 50,000 crore. At least six major minesneed a mention here which are known for causing severeproblems:problems:

Impacts of mineral extraction

•Jaduguda Uranium Mine, Jharkhand.exposing local people to radioactivehazards.

•Jharia coal mines, Jharkhand.undergroundfire leading to land subsidence andforced displacement of people.

• Sukinda chromite mines, Orissa.seeping of hexavalent chromium into riverposing serious health hazard, Cr6+ being highly toxic and carcinogenic.

•Kudremukh iron ore mine, Karnataka. causing river pollution and threat tobiodiversity.

•East coast Bauxite mine, Orissa.Land encroachment and issue of rehabilitationunsettled.

•North-Eastern Coal Fields, Assam.Very high sulphur contamination ofgroundwater.

The environmental damage caused by mining activities are as follows

Devegetation and defacing of landscapeSubsidence of landGroundwater contaminationSurface water pollutionSurface water pollutionAir pollutionOccupational Health Hazards

Environmental impacts of over extraction of mineral resources

Depending on the conditions of terrain and depth of ore deposits 2 types of miningoperations are carried out.1. open cast mining and2. underground mining.

In both types each steps in mining processing produce several environmentaleffects such as,

• Deforestation takes place due to removal of vegetal covers.

• Great volume of debris has been generated which disrupt the surface andground water circulation. It also reduces the water carrying capacity of streamsvery close to mining area

•The stacking of over burden and building of soil banks creates problems oflandslides

•Under ground fire in coalmines is a hazard that is difficult to control

•Mining and ore processing normally causes air pollution andwater pollution

•The acid water generated in coalmines can pose a serious problem of waterpollution, which adversely affects the flora and fauna.

•Deeper excavation of ground causes lowering of water table,which leads todrying of wells or sea water intrusion

•In stone quarries, blasting of rocks not only annoying the people nearby, but alsocause hazard from fly rocks and dusts and damage to buildingsdue to vibrations

•The disposal of waste material produced after concentrations of ore createincrease concentration of heavy metals and toxic elements in the environment.

Acid Mine Drainage

AMD occurs when oxygen-rich water percolates throughsulfur-bearing mineralsexposed by mining. Watercontaining sulfuric aciddrains out of the mine.

AMD is the most serious environmental problem in mining today. Itresults from the formation of sulfuric acid caused by miningof sulfur-based materials, particularly high-sulfur coal and metalsulfide ores.

Remedial measures

Safety of mine workers is usually not a priority subject of industry. Statisticaldata show that, on an average, there are30 non-fatalbut disabling accidentsperton of mineral producedand one death per 2.5 tons of mineral produced.

In order to minimize the adverse impacts of mining it is desirable to adopt eco-friendly mining technology. The low-grade ores can be better utilized by usingmicrobial-leachingtechnique. ThebacteriumThiobacillusferroxidanshasbeenmicrobial-leachingtechnique. ThebacteriumThiobacillusferroxidanshasbeensuccessfully and economically used for extracting gold embedded in ironsulphide ore. The ores are inoculated with the desired strains of bacteria, whichremove the impurities (like sulphur) and leave the pure mineral. This biologicalmethod is helpful from economic as well as environmental point of view.

Food resources

Food resources

The main food resources include wheat, rice, maize, potato, barley,oats, cassava, sweet potato, sugarcane, pulses, sorghum, millet,about twenty or so common fruits and vegetables, milk, meat, fishand seafood.

Amongst these rice, wheat and maize are the major grains,about1500million metrictonsof which aregrowneachyear,whichabout1500million metrictonsof which aregrowneachyear,whichis about half of all the agricultural crops.

About 4 billion people in the developing countries have wheat andrice as their staple food.

Food resources

The Food and Agriculture Organization (FAO) of United Nationsestimated that on an average the minimum caloric intake on aglobal scale is 2,500 calories/day. People receiving less than 90%of theseminimum dietarycaloriesarecalledundernourishedandof theseminimum dietarycaloriesarecalledundernourishedandif it is less than 80% they are said to be seriously undernourished

Impacts of malnutrition

World food problems

•Problems mainly under nutrition and malnutrition•Natural calamities:-famine, drought, earthquake, flood,gale, storm•Disease and medical facilities•Pest damage:-insects, bacteria, viruses, parasites consume 60% ofworlds food production• Hunger•Populationexplosionin ruralareas•Populationexplosionin ruralareas• Environmental pollution•Lack of water for irrigation• Less rainfall due to deforestation• Livestock overgrazing•Overfishing

Changes caused by agriculture and overgrazing

Traditional Agriculture•Until about four decades ago, crop yields in agricultural systems depended oninternal resources, recycling of organic matter, builtin biological controlmechanisms and rainfall patterns.

• Agricultural yields were modest, but stable. Production was safeguarded bygrowing more than one crop or variety in space and time in a field as insuranceagainst pest outbreaks or severe weather.

• Inputs of nitrogen were gained by rotating major field crops with legumes. Inturn rotationssuppressedinsects,weedsanddiseasesby effectivelybreakingtheturn rotationssuppressedinsects,weedsanddiseasesby effectivelybreakingthelife cycles of these pests.

• Most of the labor was done by the family with occasional hired help and nospecialized equipment or services were purchased from off-farm sources.• In these type of farming systems the link between agriculture andecology was quite strong and signs of environmental degradationwere seldom evident

Modern Agriculture

•As agricultural modernization progressed, the ecology-farming linkage wasoften broken as ecological principles were ignored and/or overridden

• Evidence has accumulated showing that whereas the presentcapital- andtechnology-intensive farming systems have been extremelyproductive andcompetitive, they also bring a variety of economic, environmental and socialproblems

• Evidencealso shows that the very nature of the agricultural structureand• Evidencealso shows that the very nature of the agricultural structureandprevailing policies have led to this environmental crisis by favoring large farmsize, specialized production, crop monocultures and mechanization.

• Lack of rotations and diversification take away key self-regulatingmechanisms, turning monocultures into highly vulnerable agroecosystemsdependent on high chemical inputs.

Problems due to Fertilizer usage

•Fertilizers have been praised as being highly associated with the temporaryincrease in food production observed in many countries• But the bountiful harvests created at least in part throughthe use of chemicalfertilizers, have associated, and often hidden, costs. A primary reason whychemical fertilizers pollute the environment is due to wasteful application and thefact that crops use them inefficiently.

•The fertilizer that is not recovered by the crop ends up in the environment,mostlyin surfacewateror in groundwater.mostlyin surfacewateror in groundwater.

• Nitrate contamination of aquifers is widespread and in dangerously high levelsin many rural regions of the world.

• In the US, it is estimated that more than 25% of the drinking water wells containnitrate levels above the 45 ppm safety standard. Such nitrate levels are hazardousto human health and studies have linked nitrate uptake to methaemoglobinemia inchildren and to gastric, bladder and oesophageal cancers inadults

•Fertilizer nutrients that enter surface waters (rivers, lakes, bays, etc.) can promoteeutrophication, characterized initially by a population explosion of photosyntheticalgae.

• Algal blooms turn the water bright green, prevent light from penetrating beneathsurface layers, and therefore killing plants living on the bottom. Such deadvegetation serve as food for other aquatic microorganisms which soon depletewater of its oxygen, inhibiting the decomposition oforganicresidues,whichaccumulateon thebottom.organicresidues,whichaccumulateon thebottom.

• Eventually, such nutrient enrichment of freshwater ecosystems leads to thedestruction of all animal life in the water systems. In the USit is estimated thatabout 50-70% of all nutrients that reach surface waters is derived from fertilizers.

Problems Associated with Pesticides

•harmful side effects on non-target organisms (people,animals, soil, water, etc.)• revival of pest populations (because natural control isdisrupted)• the development of resistance• the cost• the cost

Overgrazing

Impact of Overgrazing

Land DegradationSoil ErosionLoss of useful species

Overgrazing

•Overgrazing occurs when plants are exposed to intensive grazing forextended periods of time, or without sufficient recovery periods. Itcan be caused by either livestock in poorly managed agriculturalapplications, or by overpopulations of native or non-native wildanimals.• It reduces the usefulness, productivity, and biodiversity of the landandis onecauseof desertificationanderosionandis onecauseof desertificationanderosion

• Overgrazing is also seen as a cause of the spread of nonnativeplants and weeds.

Ecological Impacts of Overgrazing

•Overgrazing typically increases soil erosion. Reduction in soil depth, soilorganic matter and soil fertility impair the land's future productivity.

• Soil fertility can sometimes be mitigated by applying the appropriatelime and fertilizers. However, the loss of soil depth and organic mattertakes centuries to correct. Their loss is critical in determining the soil'swater-holding capacity and how well pasture plants do during drywater-holding capacity and how well pasture plants do during dryweather

Ecological Impacts of Overgrazing

An area almost completely denuded by overgrazing.

Most of what little rain may fall in this area runs off the surface andcannot benefit the soil's moisture reserves. The chances ofvegetationreestablishing itself are correspondingly reduced.

Water logging / salinisation

Saturation of soil with irrigation water or excessive

precipitation. So that water table rises close to surface. Water

logging results when soils are over irrigated without drainage.

Occursin clayeysoil, soil root zonebecomessaturatedwith soOccursin clayeysoil, soil root zonebecomessaturatedwith so

much water blocking oxygen supply for growth and soil

becomes unsuitable. Carbondioxide and ethylene accumulate

around roots and affects plants

Summary

Mineral ResourcesEnvironmental impacts of over extraction of mineral resources Food ResourcesWorld food problemsWorld food problemsOvergrazing

Energy Resources

Coal

• Readily combustible material, black or brownish-black material

• Coal was formed from layer upon layer of annual plant remainsaccumulating slowly that were protected from biodegradation byusually acidic covering waters that gave a natural antiseptic effectcombating microorganisms and then later mud deposits protectingagainst oxidization.• Coal, a fossil fuel, is the largest source of energy for the• Coal, a fossil fuel, is the largest source of energy for thegeneration of electricity worldwide, as well as one of the largestworldwide anthropogenic sources of carbon dioxide emissions

• Approximately 40% of the world electricity production uses coal

• To last for another 200 years, at the present rate of utilization

Types of CoalPeat – a precursor of coal

Lignite – brown coal, the lowest rank of coal, exclusivelyused for electricity generation

Sub-bituminous coal – used as fuel for electricity generation,synthesisof light aromatichydrocarbonssynthesisof light aromatichydrocarbons

Bituminous – fuel for electricity, coke

Anthracite – residential and commercial space heating

Graphite – difficult to ignite, used for producing lubricants

Coal and coal Mining

Environmental Effects of Coal Usage

Release of carbon dioxide – Coal is the largest contributor tothe human-made increase of CO2 in the air

• Generation of hundred of millions of tons of waste products,including fly ash, bottom ash, flue gas desulfuriation sludge,that contain mercury, uranium, thorium, arsenic,and otherthat contain mercury, uranium, thorium, arsenic,and otherheavy metals

• Acid rain from high-sulfur coal

• Dust nuisance

Petroleum

OPEC (Organization of Petroleum exporting countries). About 1/4th

of the oil reserves are in Saudi Arabia

At the present rate of usage, the world.s crude oil reserves areestimated to get exhausted in just 40 years.

petroleumgas, kerosene,petrol, diesel, fuel oil, lubricating oil,petroleumgas, kerosene,petrol, diesel, fuel oil, lubricating oil,paraffin wax, asphalt, plastic etc.

Petroleum is a cleaner fuel as compared to coal as it burnscompletely and leaves no residue. It is also easier to transport anduse. That is the reason why petroleum is preferred amongst all thefossil fuels.

Natural gas

It is mainly composed of methane (95%) with small amounts ofpropane and ethane. It is a fossil fuel. Natural gas depositsmostly accompany oil deposits because it has been formed bydecomposing remains of dead animals and plants buried underthe earth.

Nuclear energy

(i) Nuclear Fission: It is the nuclear change in whichnucleus of certain isotopes with large mass numbers aresplit into lighter nuclei on bombardment by neutrons anda large amount of energy is released

ii) Nuclearfusion: Here two isotopesof a light element(ii) Nuclearfusion: Here two isotopesof a light elementare forced together at extremely high temperatures (1billion °C) until they fuse to form a heavier nucleusreleasing enormous energy in the process.

Energy Content of Fuels

Coal: energy content ~ 24 GJ/Ton (6.67 kW.h/kg)

– The typical thermodynamic efficiency of coal power plants isabout 30%, so of the 6.67 kW.h of energy per kilogram of coal,30% of that—2.0 kW.h/kg—can successfully be turned intoelectricity; the rest is waste heat. So coal power plants obtainapproximately2.0 kW.h perkilogramof burnedcoal.approximately2.0 kW.h perkilogramof burnedcoal.

• Oil: 42 GJ/Ton

• Natural Gas: 54 GJ/Ton

Energy Usage Distribution

The world average energy consumption per person is equivalent to 2.2 ton of coal per year (~ 1 ton of oil)

In industrialized countries people use four to five time more than the world average

An American uses 32 times more commercial energy than an IndianAn American uses 32 times more commercial energy than an Indian

Rate of world energy usage in terawatts (TW) (1965-2005)

Global Energy Usage (2006)

Energy Use by Sector

Renewable Energy Resources

Solar energySolar heat collectorsSolar cellsSolar cookerSolar water heaterSolar water heaterSolar furnaceSolar power plant

Solar cell

Solar pump

Solar cocker

Wind energy

The high speed winds have a lot of energy in them as kineticenergy due to their motion.

The wind energy is harnessed by making use of wind mills. Theblades of the wind mill keep on rotating continuously due to theforce of the striking wind.

The minimum wind speed required for satisfactory working of awind generator is 15 km/hr.

The largest wind farm of our country is near Kanyakumari inTamil Nadu generating 380 MW electricity.

Hydropower

The water flowing in a river is collected by constructing a bigdam where the water is stored and allowed to fall from aheight. The blades of the turbine located at the bottom of thedam move with the fast moving water which in turn rotate thegeneratorandproduceselectricity.generatorandproduceselectricity.

Tidal energy

Ocean tides produced bygravitational forces of sun andmoon contain enormous amounts ofenergy. The high tide. and .low tide.refer to the rise and fall of water inthe oceans. A differenceof severalthe oceans. A differenceof severalmeters is required between theheight of high and low tide to spinthe turbines.

The bay of Fundy Canada having 17-18 m high tides has a potential of 5,000 MW of power generation.

Ocean thermal energy (OTE)

The energy available due to the difference in temperature of water atthe surface of the tropical oceans and at deeper levels is calledOcean Thermal Energy.A difference of 20°C or more is required between surface water anddeeper water of ocean for operating OTEC (Ocean Thermal EnergyConversion) power plants.The warm surfacewater of oceanis used to boil a liquid likeThe warm surfacewater of oceanis used to boil a liquid likeammonia. The high pressure vapours of the liquid formed by boilingare then used to turn the turbine of a generator and produceelectricity.The colder water from the deeper oceans is pumped to cool andcondense the vapours into liquid. Thus the process keeps on goingcontinuously for 24 hours a day.

Geothermal Energy

The energy harnessed from the hot rocks present inside the earth iscalled geothermal energy. High temperature, high pressure steamfields exist below the earths surface in many places. This heatcomes from the fission of radioactive material naturally present inthe rocks.

Sometimes the steam or boiling water underneath the earth do notfind any place to come out. We can artificially drill a hole up tothe hot rocks and by putting a pipe in it make the steam or hot watergush out through the pipe at high pressure which turns the turbine ofa generator to produce electricity. In USA and New Zealand, thereare several geothermal plants working successfully.

Biomass Energy

Biomass is the organic matter produced by the plants oranimals which include wood, crop residues, cattle dung,manure, sewage, agricultural wastes etc.

(a) Energy Plantations: Solar energy is trapped by green plants throughphotosynthesis and converted into biomass energy.

crop plants like sugarcane, sugar beet, aquatic weeds like water hyacinthand sea-weeds and carbohydrate rich potato, cereal etc. aresome of theimportant energy plantations. They may produce energy either by burningdirectly or by getting converted into burnable gas or may be converted intofuels by fermentation.

(b) Petro-crops: Certain latex-containing plants like Euphorbias and oilpalms are rich in hydrocarbons and can yield an oil like sub- stance underhigh temperature and pressure. This oily material may be burned in dieselengines directly or may be refined to form gasoline. These plants arepopularly known as petro-crops.

(c) Agricultural and Urban Waste biomass: Crop residues,bagasse (sugarcane residues), coconut shells, peanut hulls, cottonstalks etc. are some of the common agricultural wastes whichproduce energy by burning. Animal dung, fishery and poultrywaste and even human refuse are examples of biomass energy. InBrazil 30 % of electricity is obtainedfrom burningbagasse. InBrazil 30 % of electricity is obtainedfrom burningbagasse. Inrural India, animal dung cakes are burnt to produce heat. About80 % of rural heat energy requirements are met by burningagricultural wastes, wood and animal dung cakes.

Bio gas

Biogas is a mixture of methane, carbon dioxide, hydrogen andhydrogen sulphide, the major constituent being methane. Biogasis produced by anaerobic degradation of animal wastes(sometimesplant wastes)in the presenceof water. Anaerobic(sometimesplant wastes)in the presenceof water. Anaerobicdegradation means break down of organic matter by bacteria inthe absence of oxygen.

Floating gas holder

Fixed gas Holder

Biofuels

Biomass can be fermented to alcohols like ethanol andmethanol which can be used as fuels. Ethanol can beeasily produced from carbohydrate rich substanceslike sugarcane. It burns clean and is non-polluting.However,as comparedto petrol its calorific value isHowever,as comparedto petrol its calorific value isless and therefore, produces much less heat thanpetrol.

Available Renewable Energy

Role of individual in conservation of natural resources

Natural resources-forest, water, soil, food, mineral and energyOveruse of these resources cause problems Conserve water:•Dont keep water taps running•Install water saving toilets• Check for water leaks•Reusesoapywater•Reusesoapywater•Use drip and sprinkling irrigation•Conserve energy•Turn off lights, fan when not in use•Use solar cooker for cooking•Try riding bicycle

Protect soil:

Don t uproot plants Grow grass which binds soil and prevent erosion Make compost Use green manure Don t over irrigate Use mixed cropping

Promote Sustainable Agriculture

Do not waste food. Take as much as you can eat.

Reduce the use of pesticides.

Fertilizeyourcropprimarily with organicfertilizers.Fertilizeyourcropprimarily with organicfertilizers.

Use drip irrigation to water the crops.

Eat local and seasonal vegetables. This saves lot of energy on transport,storage and preservation.

Summary

Energy ResourcesRenewable and Non Renewable Energy Resources.Role of individual in conservation of natural resources