Env & Eco New Age_Par1

8/20/2019 Env & Eco New Age_Par1

http://slidepdf.com/reader/full/env-eco-new-agepar1 1/34

reface VUNIT–I

. Environment 1.1 Definition 1.2 Ecology 2.2.1 Biomes 3.3 Scope 4.4 Importance of Environment 7.5 Need for Public Awareness 8.6 Ecosystems 9.7 Sustainable Ecosystem 10.8 Human Activities and Environment 11. Human Activities and their Impact on



nvironment 12.9 Agriculture 12.10 Industry 16.11 Transport 16.12 Mining 17.13 Environmental Impact Assessment (EIA) 19.14 Sustainable Development 19ontents

his pagententionally leftlank .1 DEFINITION

What is Environment and why do we now notice somuch interest in Environmental Studies in recent years?

nvironment is the sum total of all conditions and influenceshat affect the development and life of all organisms on earth.he living organisms vary from the lowest micro-organisms

uch as bacteria, virus, fungus, etc. to the highest, includingman. Each organism has its own environment (physical andiological).he word “environment” originates from “environ” which

means things that surround. As per definition of thenvironment Protection Act, environment includes all thehysical and biological surroundings and their interactions.he study of environment or rather environmentaltudies is a multi-disciplinary subject which needs knowledgenterest from physical sciences (physics, chemistry,

mathematics), biological sciences (botany, zoology,microbiology, biochemistry), social sciences, economics,

ociology, education, geography) etc. Obviously,nvironmental studies has a broad base, which requiresntegrated approach for dealing with the various aspects.. ENVIRONMENT

Unit-IEnvironment and Ecology.2 ECOLOGY he word “Ecology” was coined by a German biologist in869 and is derived from the Greek word, “Oikos” meaningHouse”. Ecology is the branch of science that deals with thetudy of interactions between living organisms and their physicalnvironment. Both are closely inter-related and they have

ontinuous interaction so that any change in the environmentas an effect on the living organisms and vice-versa. Any unitf biosystem that includes all the organisms which functionogether (biotic community) in a given area where they interact

with the physical environment is known as ecosystem.he ecosystem is the functional unit in ecology as it consistsf both the biotic community (living organisms) and the abioticnvironment. The latter has close interaction essential for

maintenance of life processes. The interaction is conducted bynergy flow (solar energy) in the system and cycling of materialsnatural cycles).rom the biological point of view, the ecosystem has the



ollowing constituents:) Inorganic substances (carbon, nitrogen, carbonioxide, water, etc.) involved in natural cycles.i) Organic compounds (proteins, carbohydrates, humicubstances) etc.ii) Air, water and substrate environment including thelimatic regime and other physical factors.v) Producers, autotrophic (i.e., self-sustaining organisms)reen plants that can manufacture food from simple

norganic substances.v) Heterotrophic (i.e., that depend on others forourishment) organisms, mainly bacteria, fungi andnimals which live on other organisms or particulaterganic matter.vi) Micro-consumers, decomposers, mainly bacteria, fungi

which obtain their energy by breaking down dead tissuesr by absorbing dissolved organic matter, extracted fromlants or other organisms. The decomposers releasenvironment 3

norganic nutrients that are utilised by producers. Theylso supply food for macro-consumers or heterotrophic

rganisms. Bacteria, fungi (and animals) often excreteormone-like substances that inhibit or stimulate otheriotic components of the ecosystem.ypical profiles of a grassland ecosystem and of a pondcosystem are shown in Fig. 1.1.utotrophictratumun

Heterotrophictratum

Grassland Ecosystem Aquatic Ecosystemarent geological material

edimentWateroilarent geological materialig. 1.1: Grassland and pond ecosystemshe common features of all ecosystems—terrestrial,

reshwater, marine and agricultural—are the interactionsetween the autotrophic and the heterotrophic components.he major autotrophic metabolism occurs in the upper “greenelt” stratum where solar energy is available while the intenseeterotrophic metabolism occurs in the lower “brown belt”

where organic matter accumulates in soils and sediments.

.2.1 Biomeshe Biome is a very large land community unit where thelant species are more or less uniform. It provides a basis forEnvironment and Ecologyatural ecological classification. The main biomes of the worldre the Tundra; Temperate, Coniferous and Deciduousorests, Temperate grassland; Tropical Savanna; Desert andropical Rain Forests.he Tundra Biome is in the polar region (north of latitude0° North)—it is characterised by absence of trees, dwarf lants and an upper ground surface which is wet, spongynd rough.



emperate Coniferous Forest Biome Coniferous forestsccur in cold regions with high rainfall, long winters andhort summers.emperate Deciduous Forest Biome These are highltitude regions about 3000–4000 metres above sea level asn the Himalayas. Here pines, fir and juniper trees are found.emperate Grassland Biome This type of grassland occurs

where there is about 25 to 75 cm of rainfall per year. Suchrasslands are found as tall grass prairies, short grass prairies

f North America and also in South America, steppes of outhern Russia and Asia.ropical Savanna Biome These are tropical grasslands

with scattered drought-resistant trees. These are found inastern Africa, Australia and South America.

Desert Biome These are found in very dry environmentwhere temperature changes from very hot to very cold.

ropical Rainforest Biome These occur near the equatornd offer the most diverse communities on earth with fairlyigh temperature and humidity. The annual rainfall is morehan 200–225 cm. Here one finds dense vegetation consistingf tall trees covered with creepers and orchids, numerous

erbs and shrubs. Tropical rainforest is the habitat of umerous vertebrate and invertebrate animals..3 SCOPEnvironmental studies as a subject has a wide scope. Itncompasses a large number of areas and aspects, which maye summarized as follows.nvironment 5

Natural resources — their conservation andmanagement

cology and biodiversityEnvironmental pollution and controlSocial issues in relation to development and

nvironmentHuman population and environmenthese are the basic aspects of environmental studies

which have a direct relevance to every section of the society.nvironmental studies can also be highly specializedoncentrating on more technical aspects like environmentalcience, environmental engineering or environmental

management.n the recent years, the scope of environmental studies hasxpanded dramatically the world over. Several career optionsave emerged in this field that are broadly categorized as:) Research & Development (R & D) in environment:

killed environmental scientists have an importantole to play in examining various environmentalroblems in a scientific manner and carry out R& Dctivities for developing cleaner technologies andromoting sustainable development.here is a need for trained manpower at every level

o deal with environmental issues. Environmentalmanagement and environmental engineering aremerging as new career opportunities fornvironmental protection and management. With theollution control laws becoming more stringent,ndustries are finding it difficult to dispose off the



wastes produced. In order to avoid expensivetigation, companies are now trying to adopt green

echnologies, which would reduce pollution.nvesting in pollution control technologies willeduce pollution as well as cut on costs for effluentEnvironment and Ecologyeatment. Market for pollution control technology

s increasing the world over. Cleaning up of the wastesroduced is another potential market. It is estimated

o be more than $100 billion per year for all Americanusiness. Germany and Japan having more stringentaws for many years have gained more experience ineducing effluents. Still there is a $ 200 billion marketor cleaning up the former East Germany alone. Inndia also the Pollution Control Boards are seriouslymplementing pollution control laws and insisting onpgradation of effluents to meet the prescribedtandards before they are discharged on land or intowater body. Many companies not complying with

he orders have been closed or ordered to shift.i) Green advocacy: With increasing emphasis on

mplementing various Acts and laws related tonvironment, need for environmental lawyers hasmerged, who should be able to plead the caseselated to water and air pollution forest, wildlife etc.ii) Green marketing: While ensuring the quality of roducts with ISO mark, now there is an increasingmphasis on marketing goods that are environmentriendly. Such products have ecomark or ISO 14000ertification. Environmental auditors andnvironmental managers would be in great demandn the coming years.v) Green media: Environmental awareness can be spread

mongst masses through mass media like television,adio, newspaper, magazines, hoardings,dvertisements etc. for which environmentallyducated persons are required.v) Environment consultancy: Many non- governmentrganizations (NGOs), industries and governmentodies are engaging environmental consultants forystematically studying and tackling environmentelated problems.nvironment 7.4 IMPORTANCE OF ENVIRONMENTnvironment belongs to all and is important to all.

Whatever be the occupation or age of a person, he will beffected by environment and also he will affect thenvironment by his deeds. That is why we find annternationally observed environment calender to mark somemportant aspect or issue of environment.

World Wetland Day February 2World Forest Day March 21World Day for Water March 22World Meteorological Day March 23

arth Day April 22nternational Biodiversity Day May 22nti-tobacco Day May 31



World Environment Day June 5World Ocean Day June 8World Population Day July 11Ozone Week Sept. 16–23World Car-free Day Sept. 22Green Consumer Day Sept. 28World farm Animal’s Day Oct. 2World Habitat Day Oct. 3World Animal Welfare Day Oct. 4

Wildlife Week Oct. 1–7World Conservation Day Oct. 24nternational Day for Natural

Disaster Reduction Oct. 13nternational Day for Biological Diversity Dec. 29

Global Vs. Local Nature of Environmentnvironment is one subject that is actually global as wells local in nature.NVIRONMENTAL CALENDER Environment and Ecology

ssues like global warming, depletion of ozone layer,windling forests and energy resources, loss of global

iodiversity etc. which are going to affect the mankind as awhole are global in nature and for that we have to think andlan globally.

However, there are some environmental problems whichre of localized importance. For dealing with localnvironmental issues, e.g impact of mining or hydro-electricroject in an area, problems of disposal and management of olid waste, river or lake pollution, soil erosion, water loggingnd salinization of soil, fluorosis problem in local population,rsenic pollution of groundwater etc., we have to think andct locally.n order to make people aware about those aspects of

nvironment with which they are so intimately associated,is very important to make every one environmentallyducated.ndividualistic Nature of Environmentnvironmental studies is very important since it deals

with the most mundane problems of life where eachndividual matters, like dealing with safe and clean drinking

water, hygienic living conditions, clean and fresh air, fertileand, healthy food and sustainable development. If we wanto live in a clean, healthy, aesthetically beautiful, safe andecure environment for a long time and wish to hand over alean and safe earth to our children, grandchildren and great

randchildren, it is most essential to understand the basicsf environment..5 NEED FOR PUBLIC AWARENESSnternational Efforts for Environmentnvironmental issues received international attentionbout 36 years back in Stockholm Conference, held on 5thune, 1972. Since then we celebrate World Environmentnvironment 9

Day on 5th June. At the United Nations Conference onnvironment and Development held at Rio de Janeiro, in992, known popularly as Earth Summit, and ten yearsater, the World Summit on Sustainable Development,



eld at Johannesberg in 2002, key issues of globalnvironmental concern were highlighted. Attention of eneral public was drawn towards the deterioratingnvironmental conditions all over the world.ward of the Nobel Peace Prize (2004) to annvironmentalist, for the first time, came as a landmark ecision, showing increasing global concern towardsnvironmental issues and recognition to efforts being madeor environmental conservation and protection.

ublic Awareness for Environmenthe goals of sustainable development cannot be achievedy any government at its own level until the public has aarticipatory role in it. Public participation is possible only

when the public is aware about the ecological andnvironmental issues.he public has to be educated about the fact that if were degrading our environment we are actually harming ourwn selves. This is because we are a part of the complexetwork of environment where every component is linkedp. It is all the more important to educate the people thatometimes the adverse impact of environment are not

xperienced until a threshold is reached. So we may beaught unawares by a disaster.drive by the government to ban the littering of

olythene cannot be successful until the public understandshe environmental implications of the same. The public haso be made aware that by littering polythene, we are not onlyamaging the environment, but posing serious threat to ourealth.0 Environment and Ecologyhere is a Chinese proverb “If you plan for one year, plantce, if you plan for 10 years, plant trees and if you plan for 100ears, educate people.” If we want to protect and manage our

lanet earth on sustainable basis, we have no other optionut to make all persons environmentally educated..6 ECOSYSTEMScosystems of the world are studied on the basis of theirrincipal habitats. Among the environmental segments, lithospherend hydrosphere are the major habitats for a wideariety of flora and fauna.and-based Ecosystemand (terrestrial) ecosystems depend largely on thelimate and soil. Higher plants and animals have evolved onand. For example, seed plants, insects, warm-bloodedertebrates and micro-organisms dominate on land now. The

major terrestrial communities consist of herbaceous plants,hrubs, grass and also woody trees besides numerous insects,rthropods, birds, etc.

Marine EcosystemOceans occupy 70 per cent of earth’s surface, offering

abitat to numerous plants (mainly algae), animals like zoolankton, shrimps, oysters, fishes, reptiles, birds and

mammals. They serve as the sink of a large quantity of runoff nd wastes from land.

Marine water has a high salt content (about 3.5% byweight) and poor fertility due to lack of nitrates and

hosphates as compared to freshwater. Marine life is



bundant near the shore and in the continental shelf. Thepecies include commercial fishes, large sea mammals like

whales and seals.reshwater Ecosystemreshwater bodies (ponds, lakes, rivers, springs) are rich

n nutrients (nitrates, phosphates) and provide good habitator phytoplankton, zooplankton, aquatic plants and fishes.nvironment 11

Wetland Ecosystems

Wetlands are transitional lands between terrestrial andco-systems where water stands at 2.5 to 300 cm during mostf the year. They include valuable natural ecosystemarbouring a wide variety of plants, animals, fishes and microorganisms.hey are at present in danger due to increasingrbanization as in the case of eastern part of Kolkata.

Mangroves (Forest between Land and Sea)Mangroves are important forest communities in tidalones or equatorial and tropical coasts. For example, theunderbans in the Gangetic estuarine delta touching the Bayf Bengal offer important mangroves, habitat of wild animalsncluding Royal Bengal Tiger and of interesting plant species.

.7 SUSTAINABLE ECOSYSTEMhe developing countries face today critical situation onconomic and environmental fronts. For economic growth theyave to give priority to agricultural industrial bases but at theost of environment. The resource base, once depleted, setsn chain of environmental degradation which finally weakenshe economy. Our population explosion remains the core issue.

Our development policy should be such that the ecosystem isustainable, i.e., it contains the element of renewability. Thisequires sound management strategy which ensures theontinuation of socio-economic development in the long run.he important components of sustainable development/

cosystem are:Population stabilisationIntegrated land use planningConservation of biodiversityAir and water pollution controlRenewable energy resourcesRecycling of wastes and residuesEnvironmental education and awareness at all levels.2 Environment and Ecology.8 HUMAN ACTIVITIES AND ENVIRONMENTood: World grain production increased almost three timesuring the last 50 years. But at the same time population

rowth increased in the developing or Third World countriest such rate that it surpassed food production. Each year about0 million people in the developing countries die of

malnutrition and starvation. In other words, our foodhortage in some areas is killing every year as many peoples were killed by the dropping of atom bomb on Hiroshimauring World War II.ndia is the third largest producer of the staple crops—

wheat, rice, maize but about 300 million people are stillndernourished (receiving less than 90% of the minimumequired calorie intake of 2500 calories/day). Our food crisesre directly linked to population explosion (See also Unit-III).



helter, Economic and Social Security: India has theowest man:land ratio—barely 0.48 ha. per capita. It hasontinuously declined since the 60s. Land is facing too muchressure on various fronts due to increasing population—ousing (shelter), agriculture, industry, urbanisation etc.n order to satisfy his needs and greeds for better lifestyle,

man has been exploiting the natural resources—forests, waterodies, minerals etc. excessively. This has led tonvironmental degradation and pollution which, in turn, have

hreatened his economic and social security and, as a matterf fact, his survival on earth.. HUMAN ACTIVITIES AND THEIR IMPACT

ON ENVIRONMENTor economic development and better living, man hasacrificed forest land for agriculture, industries, urbanizationtc. This has brought in to trail environmental disaster andackfired on man himself endangering his existence on earth.

Human Activities and Their Impact on Environment 13.9 AGRICULTUREhe dawn of human civilization can be traced back to

he discovery of agriculture almost 10,000 years ago. In the

arly period, man used the primitive practice of slash andorn cultivation or shifting cultivation, which is still prevalentn many tribal areas, as in North East India in the hill regions.he two modes of agriculture—traditional and modern

—are described below along with their impacts.) Traditional Agriculture and its Impact: It

nvolves small plots, simple tools, natural water,rganic fertilizer and several crops. The yield is,owever, low but it is still used by about 50% of the

world population. The impacts of this type of griculture are as follows:a) Depletion of Nutrients: During slash and burn of

ees in forests, the organic matter in soil isestroyed and within a short period most of theutrients are taken up by the crops. Thus the soilecomes deficient in nutrients and compels theultivators to shift to another area.b) Deforestation: Forest land is cleared by slash andurn of trees in forest for cultivation purposes.requent shifting of cultivation plots leads toeforestation i.e., loss of forest cover.c) Soil Erosion: As a result of deforestation, soil getsxposed to the weathering forces i.e., rain, windnd storms and is subjected to erosion. The net

esult is loss of top fertile soil.i) Modern Agriculture and its Impact: It is basedn high input–high output technique using hybrideeds of high-yielding variety and abundant irrigation

water, fertilizers and pesticides. This is the basis of Green Revolution” which boosted the production of

wheat and India became self-sufficient in food. But4 Environment and Ecologyhe fallout from Green Revolution has becomevident since the 90s (1990) as shown below:a) Impacts from HYV (High-Yielding Varieties):pplication of seeds of HYV gave rise to



monoculture i.e., the same species (genotype)rown over vast areas, such monoculture isulnerable to attack by some pathogen, whichpreads like wild fire, devastating crops over largereas.b) Fertilizer Problems: Essential micronutrients—itrogen, phosphorus and potassium (NPK) areupplied by chemical fertilizers. Indiscriminate usef chemical fertilizers causes micronutrient

mbalance in the soil which ultimately losesroductivity.c) Nitrate Pollution: From agricultural fieldsitrogenous fertilizers leach into the soil and finallyontaminate groundwater. When the nitrate levelf groundwater exceeds 25 mg/l, they can cause aerious health hazard known as “Blue Babyyndrome”, which affects mostly infants even

eading to their death.d) Eutrophication: Agricultural run-off waterontains fertilizer components, particularlyitrogen and phosphorus, which reaches nearby

waterbodies and causes their overnourishment.xcessive use of these fertilizers leads tovernourishment of the lakes/waterbodies andives rise to the phenomenon of eutrophicationeu = more, trophication= nutrition).s a result, there is excessive growth of algalpecies, which is known as algal bloom. The

waterbody or lake soon gets filled up with algalpecies which quickly complete their life cycle andie thus adding a lot of organic matter. Dissolvedxygen in the lake is consumed and fish get killed

Human Activities and Their Impact on Environment 15

o that the lake becomes a dead pool of waterevoid of plants and animals. Thus the lakecosystem gets degraded due to eutrophication.e) Pesticide Side Effects: Several thousand pesticidesre used in agriculture for destroying pests andoosting crop production. In the early period of uman civilization arsenic, sulphur, lead and mercury

were used to kill pests. From 1940 syntheticrganic pesticides have been used. Among these,

DDT (dichlorodiphenyl trichloroethane), discoveredy Paul Mueller (1939), deserves special mention.

During 1940-1950, it saved 5 million lives

rom malaria, typhus etc. and also protected cropsrom huge losses. But DDT and other pesticideshow a number of harmful side-effects on environment.a) Inducing Pest Resistance and Yielding New Pests:n course of time new generations of pests developesistance to pesticides so that they surviveven after pesticide spray. At present,bout two dozen pest species are known to bemmune to all types of pesticides.b) Biological Magnification/Amplification: Manyesticides including DDT are non-biodegradableo that they persist in the food chain. At each



tep of the food chain the pesticide level getsmore and more concentrated. This is the process

f biological magnification or amplification.hus, DDT builds up from 0.04 ppm in plankton

o 75 ppm in fish-eating birds. Man occupieshigh trophic level in the food chain andence gets a high dose of pesticide, which isuite harmful.v) Waterlogging: Excessive irrigation of croplands

or good growth of crop leads to waterlogging. Inhe absence of adequate drainage, excess water is6 Environment and Ecologyccumulated which seeps into the underlying waterable. Pore spaces in the soil get fully drenched

with water and soil-air becomes deficient. Thewater table rises and the roots of plants have insufficientir for respiration. There is decline inrop yield with decrease in soil strength.unjab and Haryana have faced water-loggingroblems as a result of extensive irrigation by canal

water or shallow tubewell water and consequently

harp decline in crop output.v) Salinity Problem: In addition to waterlogging,alinity also rises from excessive irrigation water.he latter contains dissolved salts which underry conditions evaporates leaving behind salts inhe upper soil profile. Saline soils are characterizedy accumulation of soluble salts such as sodiumhloride, sodium sulphate, calcium chloride,

magnesium chloride etc. in the soil profile.alinity causes stunted plant growth and reducesrop yield. Thousands of hectares of land in

Haryana and Punjab have been affected by soil

alinity.he best method for getting rid of salinity is toush out by applying freshwater to such soils..10 INDUSTRY ndustries produce environmental hazards everywhere.hey consume 37 per cent of world’s energy and emit 50 perent of world’s CO2, 90 per cent of SOx and almost all thehemicals now threatening O3 layer with depletion. Every year,hey produce 2100 m illion tonnes of solid waste and 350

million tonnes of hazardous waste. In developing countries,mall as well as big industries discharge untreated waste.here is world-wide concern about the disposal of

adioactive wastes from nuclear reactors. Nuclear reactorHuman Activities and Their Impact on Environment 17ccidents are expected to increase over the years. The stock f nuclear power stations is also ageing.n developed countries, industries have enforced economyuring the last two decades in the use of resources and energyonsumption. It is a common practice for these industries toecycle and reuse water. The average person in a developedountry still consumes 15 times more energy than in a poorountry. However, in a developed country energy is beingsed more efficiently and the expected rate of increase of energyonsumption is only 1.3 per cent per year.



.11 TRANSPORTransport is a great consumer of land and energy. The

ength of motor ways has almost doubled in developedountries over the past two decades, reaching 1,500,00 km.n 1990. Transport consumes 30 per cent of world’s energyof which 82 per cent is consumed on roads) and produces0 per cent CO-emissions, 42 per cent of NOx and 40 perent of hydrocarbon emissions.ut there is a hope of new cleaner transport becoming

opular in future. Almost one-third of Brazil’s cars run onure ethanol, obtained from specially grown crops and manyars run on ethanol/petrol mixture. Natural gas is being useds a fuel in several countries including Italy where 3 lakhars run on compressed natural gas (CNG).

Major efforts have been made in developed countries ineducing petrol consumption by 50 per cent of the amountsed two decades ago. Auto-emissions have also been cleanedp. Use of lead-free petrol has curtailed Lead (Pb) emissiony 87 per cent during 1980-1990..12 MINING

Minerals find extensive use in domestic, agricultural,

ndustrial and commercial sectors and thus form a verymportant part of any nation’s economy.8 Environment and Ecology

Minerals are broadly of two types:a) Non-metallic minerals e.g., graphite, diamond, quartz,eldspar etc.b) Metallic minerals e.g., bauxite, laterite, hematite etc.ince the early days of human civilization man has used

metals extensively. That is why history labelled the eras asronze Age and Iron Age. The most abundantly used metalsre Iron and Steel (Annual use 750 million tonnes) followedy Manganese, Copper, Chromium, Nickel and Aluminium.

Mining and processing of minerals involve majornvironmental concerns including disturbance of land, airollution from dust and smelter emissions and water pollutionrom disrupted aquifers.ndia is the producer of 84 minerals at an estimatednnual value of Rs. 50,000 crore. Six major mines are knowno cause severe environmental problems.a) Jadugoda Uranium Mine, Jharkhand: Exposing localrea and the population to radioactive hazards.b) Jharia Coal Mines, Jharkhand: Underground fireausing land subsidence and displacement of people.c) Sukinder Chromite Mine, Orissa: Seeping of

exavalent chromium into river posing serious healthazard. Chromium Cr+6 (hexavalent) is highly toxic.d) Kudremukh Iron Ore Mine, Karnataka: Causing riverollution and threat to biodiversity.e) East-Coast Bauxite Mine, Orissa: Land encroachmentnd rehabilitation issue.f) North-Eastern Coal Fields, Assam: Very high sulphurontamination of groundwater.mpacts of Mining: Mining involves extraction of

minerals/fossil fuels from deep deposits in soil employing theechniques of sub-surface mining or surface mining. Theormer method is more dangerous and expensive including



sks and accidents. The environmental damages are describeds follows:

Human Activities and Their Impact on Environment 19a) Devegetation and Defacing of Landscape: Large-scaleevegetation or deforestation leads to ecologicalmbalances besides disfiguring the landscape. Theuge debris and tailings spoil the environment of theegion and make it vulnerable to soil erosion.b) Subsidence of Land: Underground mining (e.g., coal)

auses subsidence of the soil above resulting in tiltingf buildings, cracks in soil/road, bending of rail trackstc.c) Groundwater Contamination: Mining disturbs theydrological processes and also pollutes the ground

water. Sulphur impurity in many areas gets convertednto sulfuric acid through microbial action, which

makes the water acidic.he acid mine drainage often contaminates theearby streams and lakes and damages aquatic lifeplants and fish).d) Air Pollution: Smelters in metal extraction processes

n metallurgical industries emit huge volumes of airollutants—sulphur oxides, soot, arsenic, lead,admium particles etc. These have public healthazards for local residents.e) Occupational Health Hazards: Most of the minersuffer from various respiratory and skin diseases dueo constant exposure to the suspended particulate

matter and toxic substances. Such diseases includesthma, bronchitis, black-lung disease, asbestosis,ilicosis etc..13 ENVIRONMENTAL IMPACT ASSESSMENT (EIA)he inherent conflict between development and

nvironment can be solved to a great extent by a soundnvironmental management plan which is based on balancingevelopment with environment. The necessary tool for thiss Environmental Impact Assessment (EIA). Developmenthould not be treated as an economic goal but as a multi20nvironment and Ecologyimensional concept covering economic as well as political,ocial and cultural aspects of life of common man.he basic objective of EIA is to identify, predict andvaluate the probable economic, environmental and socialmpacts of developmental activities and take necessary stepss remedial measures which will be a part of the overall

nvironmental management plan (EMP).is the government’s policy that any industrial projectarticularly major industry must obtain EIA clearance fromhe ministry of environment before approval by the planningommission. It may be mentioned that EIA is conducted byteam of experts in the field (environment), appointed by

he Ministry of Environment, Government of India..14 SUSTAINABLE DEVELOPMENTs per the definition of the then director of World Health

Organization (WHO), Prime Minister G.H. BruntlandNorway), sustainable development means “meeting the needsf the present without compromising the ability of future



enerations to meet their needs”! Nowadays sustainableevelopment is the keynote of many projects but only few of hem achieve sustainable growth.

Overexploitation of natural resources, particularly by theeveloped countries, since 1970s is fast heading towards unsustainablerowth and collapse of our life-support base. In992, the UN Conference on Environment and DevelopmentUNCED) was held at Rio de Janeiro, Brazil. The Rio declarationn Agenda-21 adopts a global programme of action on

ustainable development in social, economic and political contextsor the 21st century.he important components of sustainable developmentre:Population stabilization (growth below 0.5 per cent)Integrated land-use planningConservation of biodiversity

Human Activities and Their Impact on Environment 21Air and water pollution controlRenewable energy resourcesRecycling of wastes and residuesEnvironmental education and awareness at all levels

Questions. What is meant bya) Environment?b) Environmental studies?. What do you mean by ecosystem?. Illustrate land ecosystem and also aquatic ecosystem.. Classify the ecosystems on the basis of their habitats.

Give examples.. What is sustainable ecosystem?. Give a short account of the impacts of agriculturen environment.. What is meant by

a) Eutrophication?b) Waterlogging?c) Salinity of soil?. Enumerate the impacts of mining.. What is the significance of sustainable development?

What are its main components?2 Environment and Ecology

Nature provides life support materials or resources forustenance of life on earth for plants, animals and man. Theseesources are known as Natural Resources. Examples are

water, air, soil, forests, minerals, crops etc.here are two categories of natural resources:

. Renewable Resources: These can be recycled andegenerated within a given span of time e.g., forests,wind energy, solar energy, biomass energy,

ydropower etc.. Non-renewable Resources: These cannot beegenerated e.g., fossil fuels such as coal, petroleum,

minerals etc. With increase in consumption, thesewill be exhausted in near future.

must be noted that even renewable resources arendangered and liable to extinction if these are exploitedecklessly e.g., forests.he major natural resources are:



) Forest resourcesi) Water resourcesii) Mineral resourcesv) Food resources

v) Energy resourcesvi) Land resources.. NATURAL RESOURCES

Unit-IINatural Resources 23

.1 FOREST RESOURCESorests are one of the most important natural resourcesn earth. Providing the earth with a green cover, the forestslso offer several environmental services which are essentialor sustenance of life.bout 33% of the world’s land area is under forest cover.ormer USSR (now CIS) accounts for about 20% of the

world’s forests, Brazil for about 15% and Canada and USA,-7%. But over the years the forest cover has been reducedue to reckless deforestation by man almost all over the world,articularly in tropical Asia.orest Resources/Wealth

lants have been dominating the earth for about 3.0illion years. They have the unique art of manufacturingheir own food by photosynthesis from nature and theest of the living world depends on them for their foodnd sustenance. Plants constitute 99 per cent of earth’sving species and the rest 1 per cent include animals and

man who depend on the plant world for their food. If thisatio (99:1) is disturbed by elimination of plants (i.e.,eforestation), then the natural balance will be lost andhe entire living world will suffer most. This dynamicalance is among plants (producers), bacteria and microorganismsdecomposers who decompose mineral salts in

oil into elements which are cycled back into plants) andnimals plus man (consumers). Once this dynamic balances upset, there would be ecological crisis and the entireiosphere would be in danger.orests are renewable resources and have a key role in

mproving the quality of environment by exerting beneficialffect on the life support system. Moreover, forests alsoontribute much to the economic development of the countryy providing goods and services to people and industry. Theyre the treasure house of valuable plant and animal genes4 Environment and Ecologynd medicinal plants, most of which are yet to be discovered.

Hence tropical forests, in particular, are regarded asioreserves. Our ancient civilisation flourished in forests,where Indian philosophy was built up by our “rishis” (seers).

is well-known that forests play a vital role in the lifend economy of all forest-dwelling tribes. They supply fooduber, roots, leaves, fruits and meat from animals and birds),

medicinal herbs and other forest products for commercialse which provides for forest-based subsistence.round 3000 BC, India had about 80 per cent forest cover.

During the Maurya period of history emperor Chandra GuptaMaurya and later his grandson Ashoka adopted the policy of

ee-plantation. Emperor Ashoka also ordered the



stablishment of the first wildlife sanctuaries (abhayaranyas).arvings on stone pillars from this era show how wild animals

were treated with medicine and care.1ut waves of migrants came to India from middle-eastountries which were deserts and tree-less and they changedhe whole landscape. During the Moghul period again theicture was reversed as the Moghuls came from tree-lessountries—they converted forests into agricultural lands.

During the British period, the rate of forest conversion into

gricultural land continued. They also exploited forests formber for laying communication system, particularly after867 (India’s First War of Independence/Sepoy Mutiny).fter our independence in 1947, the situation did not

mprove rather the trend continued to draw revenue fromorests. The net result is that the forest cover has dwindledrom 80 per cent to about 12 per cent in 5000 years. Indiaas been losing 1.3 million hectares (1 ha = 2.5 acres) of orests each year.Big hunting game by Hindu kings in the earlier periods had caused destructionf wildlife and forests.

Natural Resources 25

he main causes for forest destruction are humanopulation and livestock (cattle, buffaloes, goats, sheep)opulation explosion. These enhance the demand for timbernd fuel wood (for man) and grazing land (for livestock). Athe global level wood consumption is 46 per cent for industrialnd 54 per cent for firewood purposes. In developingountries like India the picture is reverse—82 per cent forrewood and 18 per cent for industrial purpose. The present

equirements in India (in 2000) are—78 per cent for fuelwood, 16 per cent for timber and 6 per cent for pulpwoodfor paper industry)..1.1 Forest Conservation

he Forest Policy of the Government of India (1952)aid down that one-third (33 per cent) of our land should bender forest cover. However, this has not been followederiously with the result that the present forest cover hasone down to about 12 per cent. We have almost reached aritical state which must be remedied now before it is tooate for our own survival. The remedial measuresconservation) have been suggested as follows:) Conservation of Reserve Forests: These are areas

where our major water resources are located, viz.he Himalayas, Western and Eastern Ghats and areaske reservoirs, National Parks, Sanctuaries,

iosphere Reserves, etc. These must be protected ando commercial exploitation be allowed in these areas.his is an important conservation strategy.i) Limited Production Forests: These are less fertile areast high altitude (more than 1000 metres) with hillynvironment. Here the health of the forests shouldot be damaged and only limited harvesting withtmost care be allowed.6 Environment and Ecologyii) Production Forests: These are forests on the plainsnd their productivity can be enhanced by proper

management. These should be maintained to make



p for the losing of forest cover.v) Social/Commercial Forestry: Such forestry is meant

or supplying goods and services to meet the everincreasingemand for firewood, fodder, food,ertiliser, fibre, timber, medicine, etc. or for industrialurposes such as timber, plywood, matchwood, fibreoard, paper and pulp, rayon, etc. The main idea iso remove pressure on natural forests for theseequirements.

ocial forestry is based on public and common landprivate) to produce firewood, fodder, fruit and small timberor rural people.he programme should be conducted by a co-operativeystem including farmers, tribals, panchayats and NGOs (nongovernmentrganisations), etc. Degraded lands should betilised for social forestry for firewood, whereby the qualityf land improves in course of time.

Massive afforestation should be done involving multipurposepecies of plants/shrubs so that every village/town/ity is able to meet its requirements for firewood, fodder andmall timber. Production/Commercial Forestry is intended

ntirely for commercial purposes to meet the needs of theorest-based industry. Fallow lands, not used for agriculture,razing lands, etc. can be used for raising such plantations..1.2 Wood —A Major Renewable Resource

Wood is a major renewable natural resource. In USA,he production of wood and wood products is the fifth largestndustry. Wood ranks first as a raw material for the

manufacture of other products. Ideally, forests should coverne-third of the land area.

Natural Resources 27ig. 2.1: Many important products come from trees.1.3 Biodiversity

here may be about 10 million species of plants, microorganismsnd animals on earth while only about 1.5 millionpecies are on record, i.e., identified so far. Among these the

majority are insects (7,50,000), 41,000 are vertebrates (i.e.,hose having backbones or spinal columns), 2,50,000 arelants, 1,00,000 are fungi and the rest are invertebrates and

micro-organisms.iological diversity or biodiversity involves geneticiversity among species as also between individuals andcological diversity, i.e., number of species in a communityf organisms. The existing species of plants and animals arehe product of 3-billion years of evolution involving mutation,

ecombination and natural selection. Changes innvironment, e.g., warm and cool periods exerted selectionressures and have been responsible for evolution of newpecies and extinction of others who could not survive inhe struggle for survival. The dinosaur era is an example.hese giant-sized animals dominated the earth for 130 millionears and became extinct before the Ice Age.

Natural extinction, part of evolutionary process, has beenccelerated by man-made extinction wave due to constant

Rayan Ply-ellophane wood

Methanol



aperarticleoardlastics

Wood/turpentine8 Environment and Ecologyreed and need of man. By this time, 1 out of 10 million speciesas become extinct and each day we are losing one plant andne animal species. At this rate of extinction, the survival of

man himself is threatened. The specide (extinction of species)n which man is involved is more serious a crime thanenocide (mass murder). In this context we may note ouradition. Charak, the well-known ancient physician, wassked by his teacher to get a plant that was useless. Heeturned after a few days and reported that there was nouch plant. One cannot imagine a situation if Penicillium wasxtinct before man could make use of it as an antibiotic or if inchona became extinct before quinine was discovered as aure for malaria. It is, therefore, in our own interest that wehould conserve our plant as well as animal and microorganismfungus and bacteria) wealth. There is a growing

ealisation all over the world about the urgent need toonserve the biological diversity.he United Nations Earth Summit (Rio de Janeiro, 1992)dopted the Treaty on Biodiversity whereby countries agreedo conserve the Biodiversity—the living natural resourcesplants, animals, microbes) for the welfare of mankind..2 WATER RESOURCES AND WATER USES

Man is using petroleum for more than a centuryxtensively and coal for several centuries. Human civilisationpent 99.9 per cent of time without these fuels. The world’setroleum stock is likely to be exhausted in another hundredears and coal in a few centuries. This will pose a crisis before

mankind. But when we realise that our usable wateresources is also limited and will be out of stock in near future,hen we indeed have cause for panic.

Water has no alternative—it is known as “life”. It isssential for the sustenance of all living organisms includinglants, animals and man. All plants, insects, animals and menave 60–95 per cent water in their bodies. This water is partly

Natural Resources 29eleased in the form of sweat, excreta, urine and vapour. Soll these species require a lot of water daily. Besides, much

water is also needed for body growth, nutrition, etc. So it isbsurd to think of life without water. But our usable water

esources like any other natural resource is finite and is likelyo be exhausted within a century. Moreover, it is gettingolluted by man-made activities and unfit for use sooner thanxpected. Water crisis is more serious than food or populationrisis since food production or population problems arerelevant without water supply. Use of polluted water itself

akes toll of 25,000 people all over the world every day. Inndia, out of 6 lakh villages, one-third or about 2 lakh villagesre without access to water. In these villages, women haveo walk daily about 1–14 km to collect water for cooking andrinking. The United Nations Food and Agriculture

Department estimates that if the present day practices of



wasting and polluting water are not stopped, then withiness than a century the world’s biosphere including man willisappear.he world’s total quantum of water is 1.4illion cubic kilometre. If all the seabeds coulde filled up and brought at the level of thearth’s surface, then the entire water in theeas would cover the earth’s surface and make2.5 km deep watermass. About 97 per cent of

arth’s water supply is in the ocean which isnfit for human consumption and other uses dueo high salt content. Of the remaining 3 per cent,.3 per cent is locked in the polar ice caps andence out of bounds. The balance 0.7 per cent isvailable as freshwater but the bulk of it, 0.66er cent, is groundwater and the rest 0.03 perent is available to us as freshwater in rivers,akes and streams. The break-up of this 0.03er cent freshwater is—lakes and ponds 0.010 Environment and Ecologyer cent, water vapour 0.001 per cent, rivers

.0003 per cent and water confined in plants,nimals and chemicals 0.0187 per cent.The United Nations Water Conference Report,rgentina (1977)]hus we see that we have a very limited stock of usable

water, 0.03 per cent surface water (rivers, streams and ponds)nd 0.66 per cent groundwater. The quantity of water vapourrising from evaporation of sea water and river water returnsy the same volume to the earth’s surface by rainfall andack to the water sources. The hydrological cycle in natures more or less balanced in terms of charge (cloud formation)nd discharge (rainfall). But we are drawing large quantities

f groundwater for agriculture and industries while the wastewater from these is much polluted and on mixing with riverss polluting the rivers also.he mass balance of annual rainfall shows that about0 per cent is lost by evaporation and transpiration by plants,

while the remaining 30 per cent goes into the stream flow.he approximate break-up of this stream flow, as consumedy man is—8 per cent for irrigation, 2 per cent for domesticse, 4 per cent for industries and 12 per cent for electricaltilities. Irrigation for agriculture and electric power plantsre the major consumers of water.hese waste liquids (effluents) can be purified by

ltration using activated charcoal or ion exchange resins.ctivated charcoal has large surface area and is an effectivelter medium for adsorption of organic molecules. Syntheticrganic ion exchange resins are very useful for the removalf industrial waste metals (cations) and non-metals (anions).

Water Qualityis essential to enforce water quality standards in the

nterest of public health. All developed countries strictlyonform to water quality standards. Polluted water generates

Natural Resources 31water-borne diseases which kill millions of people every yearll over the world, particularly in developing countries. The



United States Public Health (USPH) has laid down standardsor water quality parameters (indicators) for drinking water.hese are the upper limits in parts per million (ppm)

1 ppm = 1 in 106 parts).able 2.1. Water quality parameters (domestic waterupplies) USPH standards (upper limits)arameters (in ppm, except for pH)H 6.0–8.5

Dissolved oxygen (D.O.) 4.0–6.0

otal dissolved solid 500.0uspended solid 5.0hloride 250.0ulphate 250.0yanide 0.05

Nitrate + Nitrite 10.0mmonia 0.5alcium 100.0

Magnesium 30.0ron 0.3ead 0.05

Mercury 0.002

rsenic 0.05hromium (VI) 0.05inc 5.5henol 0.001hemical Oxygen Demand (COD) 4.0ll parameters except pH are in ppm.ppm = 1 in 106 partshe parameters for surface water (rivers, lakes, etc.) are–5 times higher than the above values for drinking water.lean water is essential for healthy environment to

upport life systems on this planet. The task of delicatelyalancing the ratio of available and exploitable water

2 Environment and Ecologyesources and sustaining their quality is most important forndia as rainfall distribution is confined to 3–4 months in aear. Moreover, man-made global and local climatic distortionsue to global warming (see Chapter 6), deforestation, loss of opsoil, etc. have adverse effect on the monsoon pattern inndia.ndia is blessed with good rainfall (average 200 cm in aear) but 70 per cent of it is wasted. The country facesecurring problems of floods, and droughts and highlyolluted water resources. It is necessary to do rain harvesting,e., build large tanks and reservoirs all over the country to

tore rain water, flood water and excess water from the Ganga,rahmaputra and other rivers. The rivers, the lifelines of ur culture and economy, are dying because of severeollution. This water pollution abatement and resource

management should be at the top of our national agenda..3 WATER-BORNE DISEASEShe names of common water-borne diseases are given inable 3.6: p. 90. The causative agents for water-borne diseases

may be virus, bacteria, protozoa or helminths. The diseaseske viral hepatitis (hepatitis A, hepatitis B), poliomyelitis andiarrhoea are caused by virus. The diseases like cholera,acillary dysentery, typhoid and paratyphoid are caused by



acteria and the diseases like amoebiasis, giardiasis are causedy protozoa. Some common water-borne diseases areiscussed in detail in the following section.holerahis is a highly contagious disease (water-borne and foodborne),aused by the bacteria, Vibrio cholerae. Typicalymptoms are diarrhoea with rice water stool, vomitting,apid dehydration, muscular cramps and anuria. In severease, acute renal failure is possible. Epidemics of cholera had

ccurred in the past in India during Kumbha Mela or ArdhaNaturalResources 33Kumbha Mela. Outbreaks of cholera were also reported inhe past from Maharashtra, Tamil Nadu, Andhra Pradesh,

Karnataka, Bihar, Orissa and West Bengal.he bacteriology of cholera is complicated. Vibrio eltor

eplaced the classical V. cholrae by the end of 1965. Most of he Eltor vibrios isolated were found to belong to the serotype

Ogawa. V. cholerae are gram-negative, comma-shaped, activelymotile organisms. The Eltor vibrios resemble the true cholera

ibrios morphologically, serologically and also biochemically.actors for Spread of Cholera

nvironmental Factors: Among environmental factors,water, food and flies play important role in spreading choleran the community. Cholera vibrios do not multiply in waterut they may survive up to two depending on temperature,H, salt content, organic matter, sunlight and other factors.n our country there are a large number of uncontrolled

water supplies (e.g., polluted river, ponds, canals, etc.) whichre major sources of cholera infection. Cholera vibrios can

multiply readily in certain foods and drinks like milk, milk roducts and some varieties of boiled rice. Fruits andegetables get contaminated when washed or sprinkled with

water from infected areas.

ocial Factors: Big fairs like Kumbha Mela or ArdhaKumbha Mela where lakhs of people assemble at the riverhats are one of the most important factors for the spreadf cholera. The crowd bathe and drinking the same river

water (Ganga) rapidly spread the disease. Cholera is a diseasef the poor people who come from low income groups, liven slums under unhygienic and inhuman conditions. Theyarticipate in these melas and contaminate the river water.ontrol of Cholerahe control of cholera can be achieved by early detectionf the disease, isolation of the patients and their prompteatment, improvement of sanitary facilities along with

4 Environment and Ecologydequate supply of safe drinking water to the community.ctive immunisation and health awareness are also the

mportant measures for cholera control.or early detection, bacteriological examination of stools

s required for confirmation of the disease. The disease shouldt once be notified to the local authority who will send thenformation to the State Health Authority and finally to theentral Health Authority.he treatment of cholera consists of rehydration andntibiotics. Rehydration saves life. In case of kidney failure,ialysis is required. The rehydration should be accomplished



ither by injecting intravenous solutions of saline (consistingf sodium chloride: sodium bicarbonate: potassium chloride5:4:1) or by giving oral fluid containing a mixture of sodium

hloride, sodium bicarbonate, potassium chloride and glucosen the ratio of 3.5:2.5::1.5:20 gm. dissolved in 1-litre water.etracycline and co-trimoxazole should be administered asntibiotic.mprovement of sanitation for the entire community andheir residential area is the most effective approach for the

revention and control of cholera. Provision for sanitaryatrine for every household is essential for checking thencidence of cholera. Water to be used for domestic purposes,iz. drinking, washing, cooking, cleaning utensils, etc. fromources such as rivers, ponds, lakes, canals, etc. should beoiled. The provision of safe drinking water for all is theermanent solution as it will minimise the incidence of holera. It is also necessary to observe the rules of hygienegorously—household pests, flies, cockroaches, etc. shoulde eliminated; cut fruits and vegetables which are exposedo dust and flies in open markets should be avoided.moebiasis

his is a water-borne disease, defined by WHO as theondition of harbouring Entamoeba histolytica with or withoutNatural Resources 35linical manifestations. It has world-wide distribution. Theisease is characterised by liquid stools with mucous and blood.. histolytica are found as cysts or motile trophozoites.hey can live outside the human body as cysts. Trophozoitesause ulcer in the large intestine. Some amoebas reach liverhrough portal vein any may cause hepatitis or abscess.ntestinal and hepatic amoebiasis are the main manifestationsf the disease.he cysts can live for several weeks outside the human

ody, if kept moist and cool. In a refrigerator, they can live inwater for 6–7 weeks. They do not survive at moderateemperature, e.g., 50°C..

Man gets the infection through food chain (cut fruits,alads, vegetables, contaminated drinking water, cold drink,tc.). Uncooked food and vegetable can be disinfected by

washing with iodine solution (200 ppm) or acetic acid (5–10er cent) or vinegar. From water, cysts can be removed byltration and boiling. The cysts in milk can be killed byasteurisation. The diagnosis is usually based on the detectionf Entamoeba histolytica in the stools.he antibody of the parasite can be easily detected by

mmuno-fluorescence method.revention of Amoebiasishe disease can be prevented by) sanitary disposal of human excreta.i) provision of safe drinking water to all (water shoulde boiled and filtered before drinking).ii) hygienic kitchen practice (uncooked fruits andegetables must be thoroughly washed or disinfecteds described before.v) protection of foods against flies.reatmenthe drugs usually prescribed by physicians are:



6 Environment and Ecology. Metronidazole (400–800 mg) (Flagyl) to be taken oneablet thrice a day for 5–7 days.. Entrozyme (250 mg)—one tablet thrice a day for 7ays. Trinidazole (1–2 gm)—one tablet for 3 days. Furamide (500 mg)—one tablet thrice a day for 10ays.luorosis

luoride in diet or drinking water above 1.5 ppm causesuorosis. The maximum tolerance level in human body is 1.5pm (WHO standard). The daily intake of F from food andrinking water is usually less than 1 ppm. Some parts of southndia and South Africa have reported fluoride concentrationsf 4 to 8 ppm. In India, some 25 million people spread over00 districts in 15 states suffer from fluorosis. These affectedtates are Andhra Pradesh, Bihar, Delhi, Gujarat, Haryana,

Karnataka, Maharashtra, Madhya Pradesh, Orissa, Punjab,Rajasthan, Tamil Nadu, U.P., West Bengal and Kerala.

luoride does not concentrate in any tissue but only inhe bones and teeth. Fluorosis affects bones, teeth, tissues

nd other organs of the body, leading to death after prolongedlness. It also leads to dental decoloration and deformationf bones causing knock knees, bow legs and stiffening of the

oints, joint pains, back pain etc. In endemic areas, largeercentage of people suffer from gastrointestinal complaints,iarrhoea etc. The expectant and lactating mothers areulnerable groups—there is high incidence of stillbirths andbortions.rovision of safe drinking water (1-ppm fluoride) andreating awareness among people of the dangers of fluorosisre the urgent needs of the hour for prevention of fluorosis..4 MINERAL RESOURCES

Mining and processing of minerals/ores involve majornvironmental concerns, including disturbance of land, airNatural Resources 37

ollution from dust and smelter emission, and water pollutionrom disrupted aquifers.he rate of depletion of resources is measured by twoarameters—per capita mining and per capita consumption.er capita mining is calculated by dividing the amount of esource mined by the population. Per capita consumptions obtained by dividing the amount of resource actuallyrocessed by the population. It is a better index of thetandard of living of the population. Table 3.2 lists the world’s

mineral reserves along with the per capita mining andonsumption figures on a global basis.able 2.2. World’s mineral reserves: per capita mining andonsumption

Resources Reserve Occurring as Per capita Per capitaonnes) mining (kg) consumption(kg)2 3 4 5l 1.1×109 Al2O3, nH2O 15.1 2.8b 3.6×106 Sb2S3 14.8 g 17.3 gsbestos — — 1.0 0.9r 4.4×109 Fe Cr2O4 0.7 0.5oal 4.7×1012 — 580 624



o 2.2×106 CuCO2 S4, CaS2 — 5.6gu 280×106 Cu FeS2 Cu2S 1.6 1.5u 11×103 Au 0.4 g 0.4 ge 88×109 Fe2,O3, Fe3O4 110 1.9b 82×106 PbS, PbCO3 3.8 0.8

Mn 635×106 MnO2, Mn2O3H2O 2.0 2.2

Hg 115×103 HgS, Hg 2.6 g 2.2 gMo 5.2×106 MoS2 20.7 g 18.7 g

Ni 68×106 (Fe, Ni) S 145 g 135 getroleum 54.1×109 — 582 471hosphate 19.8×109 Ca5(PO4)3 (F, Cl, OH) 23 3.2otash 99.9×109 KCl, KMgCl2.6H2O 4.6 3.6g 171/103 Ag, Ag2S, Ag3, AgS3 — —i 310×106 SnO2 50.6 g 70.5

W 3×106 CaWO4, (Fe, Mn) WO4 — —U 749×103 U2O8 — 4.8 g

n 112×106 ZnS, ZnO 1.5 1.4US Bureau of Mines “Mineral facts and problems”, 1970; UN Statistical

earbook, 1970.8 Environment and Ecology

lthough quantitative in nature, the figures in the tablehow some interesting trends. The world per capita mininggures indicate that five minerals are mined to the maximumxtent—coal, petroleum iron ore, aluminium and phosphateock. However, the demand on resources is not equitablyistributed over the entire population. This is reflected inhe contrast between the per capita mining figures for thesian and North American subcontinents. This disparity is

urther aggravated by the fact that USA, for example, importsubstantial quantities of most of the resource so that its perapita consumption figure exceeds its per capita mining figure.s far as metal resources are concerned, they may be

rouped under two heads: non-ferrous (base and precious)metals and ferrous metals plus Aluminium.verage reserve Av. per capita consumption

Group 1: Metals (non-ferrous) 0.05×109 tonnes 0.42 kgGroup 2: Metals (ferrous+4) 11.8×109 tonnes 14.4 kgRatio: Group 2/Group 1 210/1 34/1

he Group 1 metals are: Au, Hg, Sn, Ag, Zn, Pb, W, U,u, and Sb whereas the Group 2 metals are: Mo, Mn, Al, Co,

Ni, Ti, Fe, Cr and K.Non-metal Resources

he major non-metal resources include asbestos, carbonates,l2, granite, O2, phosphate, potash, sand and gravel, Na

ompounds and H2O.sbestos (silicate minerals), the carbonates—principallyhose of Ca and Mg—sand and gravel, together with granite,onstitue the common and most widely used building

materials. As in the case of metals, the environmental aspectsf many of these minerals are quite important..5 NATURAL/BIOGEOCHEMICAL CYCLES

Within an ecosystem (see next Chapter) there areynamic relations between the living forms and their physical

Natural Resources 39nvironment, i.e., rocks, air and soil of the earth (geo-). Theseelations are found as natural or biogeochemical cycles which



nvolve continuous circulation of the essential elements andompounds required for life from environment to organismsnd back to environment. The natural cycles and ecosystemsunction in a balanced manner which stabilises biospherend sustains the life processes on earth..5.1 The Hydrological Cyclehis cycle helps in the exchange of water among air,

and, sea, living plants and animals. About one-third of he solar energy absorbed by the earth is used to drive the

ydrological cycle—massive evaporation of water from theceans, cloud formation and rainfall which supplies oureserves with freshwater.loud Sunranspiration Evaporation

Oceanlantloudrecipitation

Runoff ake Ground waterig. 2.2: The hydrological cycle

t freezing temperature rainwater freezes into snow andorms hail in the presence of strong wind. Water as rain, snownd hail is precipitated on land and water surfaces. On landurfaces water seeps into the soil and is stored as groundwater.he natural water level or water table exists below the ground.0 Environment and Ecologyhe water table is supported by the underlying clay and rock trata. Groundwater does not remain static but moves inarious directions. It moves up and reaches soil surface whereis drawn by plant roots.nother important groundwater resource is the aquifers.hese exist above the impermeable rock strata—water

ercolates through porous rocks and forms thesenderground lakes or reservoirs. From the latter water cane pumped by digging tube wells and extracted by sinking

wells.When there is good rainfall, all the rainwater on land do

ot percolate into the soil. Surface water (run-off) flows intotreams, rivers, seas, lakes and reservoirs. Normal evaporationrom the oceans exceeds precipitation by 10 per cent. Thisxcess 10 per cent moves as water vapour over land surfacend balances the hydrological cycle. Plants absorbroundwater by root pressure and transpirational pull butive off excess water through leaves by the process of

anspiration. Thus, water vapour level in the atmosphere isalanced and at the same time ensures conduction of waternd dissolved mineral salts throughout the plants.hus, the hydrologic cycle consists of a balancedontinuous process of evaporation, transpiration,recipitation, surface run-off and groundwater movements..5.2 Nitrogen Cycle

Nitrogen and its compounds are essential for life processesn the biosphere. There is continuous exchange of nitrogen

within the ecosystems operating the nitrogen cycle. Proteinsroduced by plants and animals in their metabolic processesre organic compounds of nitrogen. The major load of



itrogenous organic residue in soil originates from death andecay of plants and excreta of animals. These organic residuesn soil are taken up by various soil micro-organisms for their

metabolism which give products such as ammonia, nitratesNatural Resources 41nd nitrites. Plants absorb nitrates from soil which re-enterhe nitrogen cycle. Some soil micro-organisms break downoil nitrate into nitrogen by denitrification process whilethers transform nitrogen into soluble nitrogen compounds

see Fig. 2.3).hemical andtmosphericynthesis

Denitrificatorhemicalxation

NitrobacterNitrosomonas

acteriaNitrogen fixation

y micro-organisms

Microbialecaytmospheric

NitrogenNitrogen

xideNitrateNitrate

mmoniaig. 2.3: The nitrogen cycle.5.3 Carbon Cycles carbon is the backbone of biological chemistry, the

arbon cycle is a very important chemical cycle. Thetmosphere is the minor reservoir of carbon dioxide whilehe oceans are the major reservoir, containing as much as 50mes more as that of air where it is stored as bicarbonate

mineral deposit on the ocean floor. The latter regulates thearbon dioxide level in the atmosphere. The cycle operatesn the form of carbon dioxide exchanging among thetmosphere, biosphere and the oceans (Fig. 2.4). The Carbonioxide balance sheet per year is given:) emissions by fossil fuel 20 billion tonnes,i) emissions by deforestation and changes in land use.5 billion tonnes,

ii) uptake in the oceans 5.5 billion tonnes,v) uptake by carbon dioxide fertilization, i.e., photo-synthesis,.3 billion tonnes.2 Environment and Ecologyhus there is a net increase of carbon dioxide in thetmosphere of 11 billion tonnes per year. This can be reducedy 50 per cent if we can stop deforestation (Fig. 2.5).he atmosphere contains 2700 billion tonnes of carbonioxide; biosphere, vegetation and soil about 6600 billiononnes and the oceans about 1,36,000 billion tonnes of arbon dioxide.

HCO3



O2O2O2O2O2O3–

HCO3

O2O3–

Oceanlantshotosynthesis

Uptake byOcean

ptakelantsBiomass)

tmosphereOrganicarbon Mineral deposituto FactoriesxhaustCarbon dioxideBicarbonateCarbonateig. 2.4: Sources and sinks of carbon dioxidetmosphere700hotosynthesis

Ocean.7–7.4uel0ertilization.7–11.1

Deforestation.7–7.4ig. 2.5: Important fluxes of carbon dioxide (in billion tonnes)

Natural Resources 43.5.4 Phosphate Cyclehosphates are necessary for the growth and maintenance

f animal and human bones and teeth while organophosphatesre required for cell division involving productionf nuclear DNA (deoxyribonucleic acid) and RNA ribonucleic acid).hosphate minerals exist in soluble and insoluble forms

n rocks and soil. Plants absorb inorganic phosphate saltsrom soil and change them into organic phosphate. Animalsbtain their phosphate by eating plants. After death andecay, plants and animals return phosphates to the soil. Bulk f the phosphate in soil is fixed or absorbed on soil particlesut part of it is leached out into waterbodies.he natural phosphate cycle is affected by pollution,



mainly from agricultural run-off containing superphosphatend also from domestic sewage. Phosphate pollution of riversnd lakes is the cause of algal bloom (eutrophication) whicheduces dissolved oxygen in water and disrupts the foodhain. The phosphate cycles on land and in water are shownn Figs. 2.6 and 2.7.nimals

Dead organicesidues

Micro-organismsRocksPhosphates)oilhosphates

Run-off o riverslantsig. 2.6: The phosphate cycle on land4 Environment and Ecology

River dischargesoluble

hosphateshytoplanktonDead organicesidues

Microorganismlants Animalsooplanktonig. 2.7: The phosphate cycle in water.5.5 Sulphur Cycleulphur and its compounds are required by plants andnimals for synthesis of some amino acids and proteins. Someulphur bacteria act as the media for exchanges of sulphur

within the ecosystems. The sulphur cycle (Fig. 2.8) illustrateshe circulation of sulphur and its compounds in thenvironment.he sulphur oxidation process is shown in the upperalf of the cycle. The lower section shows the conversion of ulphate into plant and cellular proteins and the decay of ead plant and animal material by bacterial action. In polluted

waters under anaerobic conditions hydrogen sulphide isroduced by bacteria giving deposits of iron sulphide. Innpolluted waters under aerobic conditions the sulphuracteria transform sulphides into sulphates for furtherroduction of proteins.

nergy 45tmosphereOXulphides Sulphateslants andnimals (proteins)

Organic residuesproteins)

Micro-organismsnaerobic Aerobicig. 2.8: The sulphur cycle. ENERGY



.6 CONVENTIONAL ENERGY RESOURCEShe invention of steam engine in 1780 brought about

ndustrial Revolution in Britain. In 1799, Volta invented theattery, the first source of electric current. In 1820, Michaelaraday demonstrated a device—dynamo, for production of lectricity using “dynamo” (electro-magnetic induction).lectricity generation using heat of steam marked the beginningf thermal power production in the middle of 19th century.he demands on energy are increasing with progress in

uman civilization. The quality of life or standard of livings linked with the quantum of energy consumption. In USA,6 Environment and Ecologyer capita energy consumption is 200 million British Thermal

Units, BTU (1 BTU = energy required to raise theemperature of 1 lb. of water by 1°F), 125 million BTU in

UK, 50 million BTU in Japan and only 5 million BTU inndia. But generally much of the energy (about 60 per cent)s wasted. Maximum wastage is observed in power plants andehicles.he conventional energy resources are fossil fuel (coal,etroleum and diesel), wood, natural gas, hydroelectricity

nd nuclear energy. The energy, as consumed by man, is: 33er cent from petroleum and diesel, 27 per cent from coalnd 5 per cent from nuclear fuels..6.1 Coaloal is substantially more abundant than oil or gas, the

otal reservoir being 7×1012 metric tonnes, which isquivalent to 5×1022 calories. This is 1000 times more thanhe total global energy consumption from all fuels. The stock f coal is likely to last several centuries.he natural defect of coal is that it is a dirty fuel to burn.

On combustion, it emits sulphur dioxide which is an offensiveas, forms sulphuric acid in air and causes acid rain in faraway

laces. Thus, it poses environmental hazards (see acidain in previous chapter). Excavation of coal from mines isollowed by soil subsidence (depression) which endangers theesidential areas above the coal mines. Moreover, flyash arisingrom combustion of coal is a nuisance as solid waste whichrings about environmental problems. Also being a solid, coals less convenient to handle than petroleum or natural gas.n order to overcome these problems, the developedountries use less polluting forms of coal by transforming itnto gaseous, liquid or low sulphur, low-ash solid fuel. In aypical case, high-grade ash-free coal is produced as solventrefinedoal (SRC) by suspending pulverized coal in a solvent

nd treating with 2 per cent of its weight of hydrogen at aressure of 1000 pounds per sq. inch and 450°C.nergy 47he product is a semi-solid, m.p. 170°C having a calorificalue of 16,000 BTU per pound. This compares well withhe best-grade anthracite coal..6.2 Thermal Powerlectricity is generated by combustion of coal in a furnace.his heat is utilised to produce steam at high temperaturend pressure. The latter is then used to run a steam turbine

which is linked with the generator producing electricity.hermal power stations are operated on the above



rinciple by combustion of coal in a furnace.oallectricity

HeatGenerator

teamteam turbine

MechanicalRotation

urnacehermal power contributes about 65,000 megawattsMW) of electricity i.e., 70 per cent of India’s power supply.ome of the major thermal power stations of the Nationalhermal Power Corporation (NTPC) of India are at Singraulind Rihand in U.P., Talchar in Orissa, and Farakka in Westengal. They are the sources of severe air pollution..6.3 Methanol, CH3OHis a convenient liquid fuel which can be produced from

oal. On a commercial scale, it is produced by the reaction of arbon monoxide (CO) and hydrogen (H2) at 50 atmosphereressure and 250°C in the presence of copper-based catalyst.

he reactants (CO and H2) are obtained from coal, oxygennd steam:O + 2H2 CH3OH

methanol)5 per cent methanol makes an excellent additive toasoline which improves fuel economy and also cuts downhe emission of practically all automobile pollutants.8 Environment and Ecology.6.4 Petroleum or Mineral Oilhe consumption of petroleum and natural gas is

maximum in the developed countries and has become thetatus symbol of a country. USA is the largest consumer of

etroleum in the world (about 80 per cent of total energyonsumption in USA).he Industrial Revolution (1780) was initially fuelledy coal but later on preference was given to oil and gas whichrovide cleaner fuels and easy transportation. The worldeserve of petroleum is about 800 billion barrels (1 barrel =1.5 gallons = 120 litres) which will last for less than 100ears.

000

0uelwood Coal Petroleumnd

Natural gas00860

Major Energy Sources (%)900 1940 1980ig. 2.9: Energy consumption patterns in USA .6.5 Hydroelectricityhe output from hydroelectricity (electricity from water)



ccounts for 21 per cent of total electricity generation, whichs less than that from thermal power but greater than thatrom nuclear power. In Venezuela, South America, 10,000

mega-watts of hydroelectricity is produced which isquivalent to the production of electricity from 10 thermalower plants. In India, if water resources are properly utilised,may be possible to generate more than 10,000 megawattsnergy 49f electricity. But at present, only 16 per cent or 6,500

megawatts of hydroelectricity is generated.or generation of electricity from hydel project, it is necessaryo utilise energy produced from the descent of waterrom higher to lower level. In practice, a water reservoir isonstructed by means of dam in a river for storage of water.ubsequently the stored water is released from upper level

nto a water-driven turbine placed at a lower level (Fig. 2.10)whereby electricity is generated. The hydel projects of Maithon, Panchyet and Jaldhaka are typical examples.

urbinelectricity

River

WaterReservoirDamWater

ig. 2.10: Hydroelectricity from hydel projecthe merits of hydroelectricity are: (1) clean source of nergy; (2) no emission of greenhouse gases; (3) noonsumption of fuel; (4) no need of high technology. Buthere are several environmental issues—flora and fauna inhe region are disturbed due to construction of dam; localeople become refugees as they are uprooted from theirouses; the capacity of the reservoir gets reduced due to

iltation; occurrence of floods in the area when surplus wateras to be discharged in monsoon season. Hydroelectric damsre costly and take a long time for construction. In order to

make hydroelectricity generation viable, it is necessary todopt a long-term programme of afforestation, environmental0 Environment and Ecologyonservation, housing, public health and transport andnsure close co-ordination among these departments..6.6 Nuclear Powercontributes only 5 per cent of total electricity

eneration. Nuclear power plants do not emit polluting gasesuch as carbon dioxide, sulphur dioxide, like thermal power

lants. But they have some severe drawbacks, viz. they areostly and release large quantities of radioactive fissionroducts.he radioactive wastes remain lethal (deadly) for

housands of years and for this no foolproof disposal methodas been devised. That is why big nuclear power projectsave not succeeded in the long run.n India, the production target was fixed at 10,000

megawatts by 2000 AD, but the actual production is muchess in the nuclear power stations at Tarapur, Rajasthan andhennai. Nuclear power plants cannot match thermal powerlants at present but in future, its unlimited resources will



llow it to dominate the energy scenario when other energyesources are exhausted.irconium–94aesium–140

NeutronNeutronNeutron

nergyUranium–235

ig. 2.11: Nuclear fissionnergy 51t present, nuclear fission is used to produce nuclearower. Heavy large atoms like Uranium and Plutonium splitp into smaller atoms when bombarded by neutrons (nucleararticles with mass 1 and charge 0). This splitting or fissionberates vast amounts of energy, which throughonventional techniques is converted into electricity. Thusuclear power is generated.has been calculated that 1 kg of Uranium-235 on a

omplete fission by slow neutrons releases energy equal to.7 × 1013 calories. This means energy-wise, 1 lb. of Uranium-

35 ≡ 5 million lbs. of coal ≡ 20 million lbs. of T.N.T. (highlyxplosive chemical).his is the secret of nuclear energy/power..6.7 Wood

Wood is a major renewable natural resource. The majormportant products are wood, paper, cellophane, rayon,lywood, plastic, particle board, turpentine, methanol, etc. In

USA, the production of wood and wood products is the fifthargest industry. Ideally, as in USA forests cover 38 per cent.f the total land area; in India it has come down to about l5er cent at present from 80 per cent, 2000 years ago.is interesting to compare between India and USA in

espect of deforestation. In USA, the Sunday issue of theeading newspaper, New York Times consisting of 500 pagesequires 25 hectares (1 hectare = 2.5 acres = 7.5 bighas) of forest.ccording to an estimate, an American destroys as much forest

or his needs for paper as an Indian for his domestic fuel. Thealue of a 50-year-old tree has been estimated as about morehan Rs 20 lakhs—the various functions of a 50-year-old treere roughly evaluated as follows:) Oxygen production (for 50 years) Rs. 2,50,000i) Transformation into protein Rs. 20,000ii) Control of soil erosion Rs. 2,50,000nd soil fertility

2 Environment and Ecologyv) Recycling of water and control Rs. 2,50,000f humidity and atmosphericemperaturev) Habitat for birds and other animals Rs. 2,50,000nd insects, etc.vi) Control of air and heat pollution Rs. 5,00,000otal Rs. 15,20,000his estimate excludes the value of timber/wood for furniture, fuels,

medicines, etc. which will be an extra Rs. 3–4 lakhs.Rayon

ellophane



aper Methanollywoodlasticsarticleoard

Wood/urpentineig. 2.12: Trees—sources of many important productshus the tree, with its 50-year services as above, costs

bout Rs. 20 lakhs (1980 estimate) which at present marketrices will be around Rs. 40 lakhs. The public should bemade aware of the value of a tree and its services to man andnvironment during its life time.n India, 76 per cent of population lives in villages—lmost all of them use wood as fuel for cooking. This is the

main reason for extensive deforestation in rural areas: eachnergy 53ear we are losing about 1.3 million hectares forests.

Deforestation helps increase in greenhouse gas, carbonioxide concentration. Hence for the welfare of the countrys a whole, it is essential to minimise deforestation by adopting

lternative resources of afforestation on a large scale to meethe needs of domestic fuel..6.8 Natural Gasis a better fossil fuel than coal and petroleum since

n burning, it produces less carbon dioxide. For productionf one unit of energy, mineral oil, coal and wood, on burning,roduces respectively 35 per cent, 75 per cent and 80–90er cent more carbon dioxide than natural gas. Hence, naturalas is the obvious choice as a cleaner fuel. Its reserves,owever, are limited and can continue to feed only for theext 70–80 years. At present, in India the exploitable reservef natural gas is about 700 billion cubic metres.

.7 NON-CONVENTIONAL ENERGY RESOURCES.7.1 Solar Energyndia, being a tropical country, is blessed with abundantunshine, 2,000 kilowatt hour/sq. metre (kWh/m2) per yearor about 200–300 days in a year. The daily sunshine isetween 5–7 kWh/m2. This is an enormous and model energyesource, which is clean, pollution-free and inexpensive. Itequires to be converted into other forms of energy by suitableechniques—it can meet our energy demands forever. Theolar energy, incident on earth in one week, is equivalent tohe energy from the entire coal reserve of the world. Againhe solar energy available on earth for 45 minutes is enough

o meet our energy demand for one year.However, the major problem is that sunlight is diffusedwidespread) in nature and difficult to be stored and utilized.ut with advanced technology, the present high costs maye cut down so that solar energy can be utilized on a large4 Environment and Ecologycale in future. At present, solar energy is ten times morexpensive than thermal power. But with advancedechnology, it will be cheaper and will hold the key to meetur energy demands in future.unlight may be directly converted into electricity throughhotovoltaic cell. The latter is a device for conversion of light



nergy into electrical energy. The efficiency of conversion of ght into electricity is only 18 per cent and it is expensive aturrent prices. We can use solar energy in two ways: (1) usef solar heat and (2) use of solar electricity. Use of the formerermits one to boil water or dry foodgrains. Accordingly,everal gadgets have been produced such as solar cooker (forooking), solar dryer (for drying grains), solar water heaterfor heating water), solar distillation (for water purification),tc. Recently there have been extensive use of these solar

quipments in rural and semi-urban areas. By using the secondmethod, i.e., solar cell, sun rays are converted into electricity.ince these solar cells are made of silicon, these are calledilicon cells.he advantages of solar photovoltaics are that they can

eplace systems which use diesel and they are free fromhemical and noise pollutions. They could be installed inemote areas in forests and deserts where installation of lectric cables are cost-prohibitive.olar power, with government subsidy (Department of

Non-conventional Energy Source (DNES), Government of ndia) is being used in remote rural areas in West Bengal in

he forms of solar lanterns, solar streetlights and solar pumpsfor irrigation). Solar powered small pumps are being usedn Delhi, Haryana and Himachal Pradesh. It is desirable tose solar cookers in villages on a large scale so that extensiveeforestation can be prevented. About 1 tonne of wood peread per year can be saved by this process.igure 4.5 illustrates a detailed design for a solar heatedouse during winter in developed countries like USA. In theseountries, 20–25 per cent of fuel is consumed for providingot water to houses and buildings. Sunlight is collected onnergy 55lates in the roof and the heat is transferred to a circulating

water system. An average house with roof area about 1300q. ft. in central USA can get its energy supply for heating andot water supply in December by this method. This may wellpply to hill station houses in India in Jammu & Kashmir,

Nainital, Mussoorie, Darjeeling, etc. in December–January.Hot waterupply at 65°Co hot watereating system000 gallon

water tank rom

eatingystemold watert 25°Cump on whenun shinesump onrom water for heat

main

Env & Eco New Age_Par1

Documents

Transcript of Env & Eco New Age_Par1