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AR - 78897889

B.Sc. (Second Semester) Examination, 2013

FORESTRY

(Environmental Science)

Time Allowed: Three hours

Maximum Marks: 60

Note: Section - A is compulsory. Attempt any four questions from section - B

Section-A 10x1=10

(Objective type questions)

1. (a) Multiple Choice Questions :

Write the correct option:

(i) The region of atmosphere adjacent to the earth is called as

(a) Troposphere

(b) Ionosphere

(c) Exosphere

(d) Mesopause

Ans. (a) Troposphere

(ii) Which type of food chain has Bull-Kelps as a producer?

(a) Marine

(b) Fresh water

(c) Grassland

(d) Desert

Ans. (a) Marine

(iii) Hydro carbons released in to the atmosphere from plants are

(a) Natural pollutants

(b) Fuels

(c) Useful chemicals

(d) Bleaching agents

Ans. (a) Natural pollutants

(iv) The size of smoke particles usually remains

(a) 0.50 to 1 micron

(b) 1 to 10 micron

(c) 0.08 to 1 micron

(d) 40 to 500 micron

Ans. (a) 0.50 to 1 micron

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(v) The increasing pollution of marine waters is causing death of molluscs as the waters of seas

are turning

(a) Dirty

(b) Acidic

(c) Alkaline

(d) Saline

Ans. (b) Acidic

(vi) The radioactive substances join food chain after falling on the earth as nuclear fall out I131

is one such substance which enters into human bodies and is deposited in

(a) Bones

(b) Heart

(c) Thyroid gland

(d) Brain

Ans. (c) Thyroid gland

(vii) Chlorine atom can react with ozone molecule to convert it into

(a) Oxygen

(b) Methane

(c) Carbon dioxide

(d) CFC

Ans. (a) Oxygen

(viii) Most poisonous pollutant in water is

(a) Dead body

(b) Sewage

(c) Arsenic

(d) Industrial pollutants

Ans. (c) Arsenic

(ix) Accumulation of nutrients in a lake or pond due to human intervention or natural process is

(a) B.O.D

(b) Pollution

(c) Sewage

(d) Eutrophication

Ans. (d) Eutrophication

(x) The internal pattern of distribution of a particular population is called as

(a) Natality

(b) Dispersion

(c) Population growth

(d) Variation

Ans. (b) Dispersion

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B. Write Whether True / False 5x1=5

(i) Blasting and transport does not cause noise disturbance to local people. False

(ii) Sky diving and even aviation of passenger air crafts are done in troposphere. True

(iii) Depletion of ozone layer, global warming and climate change are local issues. False

(iii) Air conditioners contribute to ozone depletion. True

(iv) Oil is the major cause of marine pollution. True

C. Fill in Blanks with appropriate words : 5x1=5

(i) The density of air in the atmosphere is ________ by increasing altitude.

(ii) Streams, rivers, seas, oceans, lakes, ponds and ditches and other water bodies are

collectively known as _________ .

(iii) _________consists of liquid droplets (size smaller than 10 µm) formed by the condensation

of vapours in the atmosphere or are released from industrial operations.

(iv) The total of rock material present on the crust of the earth and floor of oceans is called

_________.

(v) _________damages leafy vegetables causing premature fall, discoloration and curling of

sepals.

Ans: C

(i) Decreased (ii) Hydrosphere (iii) Mist (iv) Lithosphere

(v) PAN (Peroxyacetylnitrate)

Section-B 4x10=40

Note: Attempt any four questions. Each question carries 10 marks.

2. What are the effects of noise at the physical, physiological and psychological level?

Ans: Effects of noise at the physical level

The physical manifestation of noise pollution is the effect on hearing ability. Repeated

exposure to noise may result in temporary or permanent shifting of hearing threshold of a person

depending upon the level and duration of exposure. The immediate and acute effect of noise

pollution is impairment of hearing (i.e. total deafness).

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Human ears have sensory cells for hearing. If these cells are subjected to repeated sounds

of high intensity before they have an opportunity to recover fully they can become permanently

damaged leading to impairment of hearing. Beside the sensory cells, the delicate tympanic

membrane or the ear drum can also be permanently damaged by a sudden loud noise such as an

explosion.

Effects of noise at the physiological level:

The physiological manifestations of noise pollution are several as mentioned below

(a) Headache by dilating blood vessels of the brain

(b) Increase in the rate of heart-beat.

(c) Narrowing of arteries.

(d) Fluctuations in the arterial blood pressure by increasing the level of cholesterol in the blood.

(e) Decrease in heart output.

(f) Pain in the heart.

(g) Digestive spasms through anxiety and dilation of the pupil of the eye, thereby causing eye –

strain.

(h) Impairment of night vision.

(i) Decrease in the rate of colour perception.

(j) Lowering of concentration and effect on memory.

(k) Muscular strain and nervous breakdown.

Effect of noise at Psychological level

The psychological manifestation of noise pollution are :

(a) Depression and fatigue which considerably reduces the efficiency of a person

(b) Insomnia as a result of lack of undisturbed and refreshing sleep.

(c) Streaming of senses and annoyance as a result of slow but persistent noise from motorcycles,

alarm clocks, call bells, telephone rings etc.

(d) Affecting of psychomotor performance of a person by a sudden loud sound.

(e) Emotional disturbance

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For a talkative person, the most important effect of noise pollution would invariably be that

noise interferes with our conservation.

So noise is annoying and the annoyance depends on many factors not merely the intensity of

the sound but also repetition, because even a sound of small intensity of (e.g. dripping tap or

clicking of clock) may become annoying, simply by repetition.

3. What role an individual can play for prevention of pollution. Discuss.

Ans: Over Population and pollution are potent ecological forces impinging upon man by

affecting the quality of the environment. All efforts aimed at bringing more and more people

above the poverty line actually increase the pressure on natural resources. Careless management

of natural resources is disrupting the ecological processes so much so that earth‟s life supporting

capacity is being substantially threatened. Unmindful exploitation of the finite resources of the

biosphere has a severe ecological backlash because no development is sustainable unless it is

environmentally compatible.

Environmental compatibility demands that the economic and social development should

be linked with environmental management.

Artcle 48. A and 51.A of our constitution provide for environmental protection.

According to the National committee of Environment-Planning and Co-ordination, the

framework for environmental protection aims at:

(a) Control of environmental pollution

(b) Conservation of natural resources

(c) Land management

(d) Development of non-polluting sources of energy

(e) Environmental education

(f) Environmental laws

Pollution is the burning issue of the day at the global level. A combined effort to control

pollution has to be made by all government agencies, technologists, industrialists,

agriculturalists and last but not the least the common man.

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An international conference on “Human Environments” was held in Stockholm in 1971

to emphasise the need to control Pollution. Several measures were recommended by the

scientists participating in the conference, e.g.,

(a) The first step should be to identify those causes of pollution that have global implications and

to devise protective measures to be adopted.

(b) The second step should be to find out carrying capacity of the environment and reduce the

emission of the major sources of pollution.

(c) The third step should be to find a neutralizer for each type of pollutant.

(d) The fourth step should be to ensure that anti- pollution measures are adopted by all

industries.

(e) The fifth step should be the identification of areas where the cause of pollution is poverty and

lack of environmental education. Contamination of food and water are the basic causes of

pollution in such areas.

(f) Most important is initiation of adequate research to devise measure for controlling pollution.

Environmental monitoring is urgently required for controlling pollution. This involves.

(a) Careful scruitinisation of the environmental characteristics.

(b) Laying down the standards of environmental quality

(c) Regular assessment of the above mentioned environmental characteristics.

(d) Keeping track of changes in the environmental characteristics and educating people about

the pollution due to these changes.

(e) Devising measures to combat the menace of pollution.

(f) Enacting environmental laws and taking legal action against environmental offenders.

Efforts are required to made by each individual to control pollution

These efforts include:

(a) Installation of proper sewage disposal methods.

(b) Dumping of non-biodegradable wastes in low lying areas.

(c) Installation of gober gas plants in areas of high availability of cow dung.

(d) Reduction of smoke emission and treatment of chimney smoke to remove solid carbon

particles.

(e) Judicious use of fertilizers, pesticides and detergents (Detergents of low level phosphate

content are less harmful).

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(f) Growing plants like Pyrus (apple), Pinus (chir) and Vitis (grapes) is advocated because of

their capability of metabolizing gaseous nitrogenous pollutants like nitrogen dioxide etc. and

plants like coleus, Ficus (banyan) can fix carbon monoxide.

Skilled personnel with know-how to tackle the problems arising from pollution and for

devising environmental pollution control measures are working in many institutions in India.

Important ones amongst them are:

(a) National Environmental Engineering Research Institute (NEERI), Nagpur.

(b) Bhaba Atomic Research Centre (BARC), Mumbai

(c) National committee of Environmental Planning and Co-ordination (NCEPC), New Delhi.

(d) Central Drug Research Institute (CDRI), Lucknow

(e) Councils of Scientific and Industrial Research (CSIR).

(f) Central Public Health Engineering Research Institute (CPHERI), Nagpur

Scientists have rightly said that, „in the course of our progress from one age to another, we have

simply passed from a sav-age to sew-age‟.

What is important is the query- „Will there be any salvage‟?

4. What are the reasons behind depletion of ozone layer in the atmosphere? Explain the ill-

effects of ozone depletion.

Ans: Ozone is a unstable blue gas having pungent odour. Chemically, it is an allotrope of

Oxygen which is an element in the gaseous form. It has three oxygen atoms in its single

molecule and its molecular formula is O3 . It is used as a powerful oxidant, bleach, and water

purifier. It is also used to treat industrial wastes.

If found in the troposphere; ozone acts as a powerful pollutant. But when found in the

Stratosphere, it acts like a friend of the earth because it shields most of the ultra violet radiations

and does not allow them to pass on towards the same. In stratosphere it is found in the form of

dense layer called as ozone layer or the Ozone Belt. Thus the Ozone Belt in the stratosphere acts

like a protective Umbrella of the earth.

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Ozone is formed in the stratosphere when oxygen molecules Photo dissociate after

absorbing an UV Photon of shorter wavelength (less than 240 nm) to produce two oxygen atoms.

It can be represented as below-

O2 → O + O or ½ O2 + ½ O2

The atomic oxygen combines with O2 to create O3 -

O + O2 → O3

Ozone is mainly produced from oxygen containing molecules such as Sulphur dioxide, Nitrogen

Oxides, etc. also when these molecules are exposed to ultraviolet radiations.

A large number of ozone molecules assemble around the earth to form the Ozone

Layer which extends from 13 to 48 km above the earth surface. On an average, it is about 230

dobson units (DU) in thickness. DU is the unit which measures thickness of the ozone layer. It

equals to 0.01 mm.

Substances that cause depletion of the Ozone Layer

Cholorofluorocarbons (CFCs or Freons), Methane, Nitrous Oxide (N2O), Carbon

Tetracholoride (CCl4), Methyl Bromide (a soil fumigant and insecticide), aircraft emissios,

n-propyl bromide and Halon- 1202 are major agents that cause depletion of ozone layer. Hence,

these are called as Ozone Depleting Substances (ODS).

Reasons behind depletion of Ozone layer in the atmosphere

Use of Air conditioner and Refrigerator which emits chlorofluorocarbons is one of the

reason behind the Ozone depletion.

Chlorofluorocarbons or freons get accumulated in greater amounts at high altitudes and

gradually reach to the stratosphere. Under the influence of intense short wave ultraviolet

radiations they release chlorine atoms. A single chlorine atom can react with more than, 100,000

molecules of ozone and can convert them into oxygen. Other ozone depleting substances like

methane, nitrous oxide, methyl bromide etc. too, pass through a series of reactions under the

influence of UV-Radiations of sunlight and catalysts found in the air and help in the depletion of

ozone layer.

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Ozone molecule absorbs UV light between 310 and 200 nm. The ozone molecule absorbs

oxygen atom to form two molecules of Oxygen, and the Ozone cycles continues.

O + O3 → 2O2

Ozone is destroyed by a number of free radicals catalysts- like Hydroxyl radical, Nitric oxide

radical, and Bromine through natural and anthropogenic sources-

CFCl3 + UV → CFCl2 + Cl

Cl + O3 → ClO + O2

ClO + O → Cl + O2

Finally we can write it as-

CFCl3 + UV + O3 + O → Cl + CF Cl2 + 2 O2

Ill effects of Ozone layer Depletion

Some of the remarkable effects of the UV radiations or the effects of depletion of the Ozone

layer are mentioned below.

(1) UV radiation causes sun-eye-diseases (cataract), Skin diseases, skin cancer and damage to

immune system in our body.

(2) It damages plants and causes reduction in crop productivity.

(3) It damages embryos of fish, shrims, crabs and amphibians. The population of salamanders is

reducing due to UV- radiations reaching to the earth.

(4) UV-radiations damage fabrics, pipes, paints and other non –living materials on this earth.

(5) It contributes in the global warming. If the ozone depletion continues, the temperature around

the world may rise even up to 5.5 degree celsius.

The specific effects of depletion of Ozone layer have been observed on Human Society,

agriculture and animals etc.

Effects of ozone depletion on Human society:

(i) The flux of ultra violet radiation in the biosphere is increased due to ozone depletion. It has

seriously harmful effects on human societies like formation of patches on skin and

weakening of the human immune system.

(ii) It may cause three types of skin cancer like basal cell carcinoma, squamous cell carcinoma

and melanoma. A 10 per cent decrease in stratospheric ozone has been reported to cause 20

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to 30 per cent increase in cancer in human society. Each year about 7000 people die of such

diseases each year in USA. About 10 percent increase in skin cancer has been reported in

Australia and New Zealand.

(iii) Exposure to UV radiations damages skin of the sun bathing people by damaging

melanocyte-cells or by causing sun-burns due to faster flow of blood in the capillaries of

exposed areas.

(iv) Exposure of UV radiations due to Ozone depletion may cause leukemia and breast cancer.

(v) The ambient Ozone Exposure may cause Emphysema, bronchitis, asthma and even

obstruction of lungs in human beings.

(vi) Exposure to radiation due to ozone depletion has been reported to cause DNA breakage,

inhibition and alteration of DNA replication and premature ageing in human beings.

Effect of Ozone Depletion on Agriculture:

(i) Radiations reaching to earth due to ozone depletion cause severe damage to plants including

crops. As per reports, ultra violet radiations reaching to the earth cause losses up to 50 per

cent in European countries.

(ii) The radiation reaching to the earth due to the depletion of the ozone layer excuse visible

damages in plants. They adversely affect the rate of photosynthesis that finally results into

decrease in the agricultural productions.

(iii) The UV radiation enhances the rate of evaporation through stomata and decrease the

moisture content of the soil. This condition adversely affects the growth and development of

crop plants and reduces the crop yield.

(iv) The ozone reduction adversely affects the weather pattern which in turn affects the crop

production by encouraging plant injuries and disease development.

(v) The UV radiation reaching to the earth surface alters the global balance between radiation

and energy. This condition of imbalance causes seasonal variations that further reduce the

crop production.

(vi) A number of economically important plant species such as rice, depend on cyanobacteria

residing in their roots for the retention of nitrogen. These bacteria are sensitive to UV light

and they are hence, are killed instantly.

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Effect of Ozone Depletion on animals

(i) The ozone layer depletion causes climatic alterations that cause physiological changes in

plants and animals. The change in the energy balance and radiation may affect the survival

and stability of living organisms.

(ii) The depletion of ozone layer may cause changes in thermal conditions of the biosphere. It

may affect type density and stability of vegetation which in turn may affect different bio-geo-

chemical cycles operating in nature. Interruption in these cycles damages important process

of ecosystem leading to dangerous conditions for plants and animals.

(iii) The depletion of ozone layer causes death of plankton- populations in fresh as well as

marine waters. This condition seriously affects the transfer of materials in ecosystems. The

recent researches gave analyzed a widespread extinction of planktons 2 million years ago that

coincided with the nearby supernova. Planktons are particularly susceptible to effects of UV

light and are vitally important to the marine food webs.

5. Write short notes on any two of the following:

(i) Environmental Impact Assessment

(ii) Acid rain

(iii) Biological magnification

Ans: (i) Environmental Impact Assessment (EIA):

An environmental impact assessment (EIA) is an assessment of the possible positive or

negative impacts that a proposed project may have on the environment, consisting of the

environmental, social and economic aspects.

The purpose of the assessment is to ensure that decision makers consider the ensuing

environmental impacts when deciding whether or not to proceed with a project. The International

Association for Impact Assessment (IAIA) defines an environmental impact assessment as "the

process of identifying, predicting, evaluating and mitigating the biophysical, social, and other

relevant effects of development proposals prior to major decisions being taken and commitments

made. " EIAs are unique in that they do not require adherence to a predetermined environmental

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outcome, but rather they require decision makers to account for environmental values in their

decisions and to justify those decisions in light of detailed environmental studies and public

comments on the potential environmental impacts of the proposal.

EIAs began to be used in the 1960s as part of a rational decision making process. It

involved a technical evaluation that would lead to objective decision making. In 1969, EIA was

made legislation in the US in the National Environmental Policy Act (NEPA). It has since

evolved as it has been used increasingly in many countries around the world.

EIAs have often been criticized for having too narrow spatial and temporal scope. At

present no procedure has been specified for determining a system boundary for the assessment.

The system boundary refers to „the spatial and temporal boundary of the proposal‟s effects‟. This

boundary is determined by the applicant and the lead assessor, but in practice, almost all EIAs

address the direct, on-site effects alone.

However, as well as direct effects, developments cause a multitude of indirect effects

through consumption of goods and services, production of building materials and machinery,

additional land use for activities of various manufacturing and industrial services, mining of

resources etc. The indirect effects of developments are often an order of magnitude higher than

the direct effects assessed by EIA. Large proposals such as airports or ship yards cause wide

ranging national as well as international environmental effects, which should be taken into

consideration during the decision-making process.

Broadening the scope of EIA can also benefit the conservation of threatened species.

Instead of concentrating on the direct effects of a proposed project on its local environment some

EIAs used a landscape approach which focused on much broader relationships between the entire

population of a species in question. As a result, an alternative that would cause the least amount

of negative effects to the population of that species as a whole, rather than the local

subpopulation, can be identified and recommended by EIA.

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There are various methods available to carry out EIAs, some are industry specific and

some general methods:

Industrial products - Product environmental life cycle analysis (LCA) is used for identifying

and measuring the impact of industrial products on the environment. These EIAs consider

technological activities used for various stages of the product: extraction of raw material for

the product and for ancillary materials and equipment, through the production and use of the

product, right up to the disposal of the product, the ancillary equipment and material.

Genetically modified plants - There are specific methods available to perform EIAs of

genetically modified plants. Some of the methods are GMP-RAM, INOVA etc.

Fuzzy Arithmetic - EIA methods need specific parameters and variables to be measured to

estimate values of impact indicators. However many of the environment impact properties

cannot be measured on a scale e.g. landscape quality, lifestyle quality, social acceptance etc.

and moreover these indicators are very subjective. Thus to assess the impacts we may need to

take the help of information from similar EIAs, expert criteria, sensitivity of affected

population etc. To treat this information, which is generally inaccurate, systematically, fuzzy

arithmetic and approximate reasoning methods can be utilized. This is called as a fuzzy logic

approach.

At the end of the project, an EIA should be followed by an audit. An EIA audit evaluates the

performance of an EIA by comparing actual impacts to those that were predicted. The main

objective of these audits is to make future EIAs more valid and effective. The two main

considerations are:

scientific - to check the accuracy of predictions and explain errors;

management- to assess the success of mitigation in reducing impacts.

Some people believe that audits be performed as a rigorous scientific test of the null

hypotheses, while some believe in a simpler approach where you compare what actually

occurred against the predictions in the EIA document.

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Ans: (ii) Acid Rains:

The oxides of sulphur and nitrogen are important gaseous pollutants of air. These oxides

are produced mainly by combustion of fossil fuels, smelters, power plants, automobile exhausts,

domestic fires etc. These oxides swept up into the atmosphere and can travel thousands of

kilometers. The longer they stay in the atmosphere, the more likely they are to be oxidized into

acids. Sulphuric acid and Nitric acid are the two main acids, which then dissolve in water in the

atmosphere and fall to the ground as acid rain or may remain in atmosphere in clouds and fogs.

Acidification of of environment is man-made phenomenon. The acid rain is in fact a cocktail of

H2 SO4 and HNO3 and the ratio of the two may vary depending on the relative quantities of

oxides of sulphur and nitrogen emitted on an average 60-70% of the acidity is ascribed to H2SO4

and 30-40 % to HNO3. The acid rain problem has increased due to industrialization. Burning of

fossil fuel for power generation contributes to almost 60-70 % of total SO2 emitted globally.

Emission of NOx from anthropogenic sources ranges between 20-90 million tonnes annually

over the globe. Acid rains have assumed global ecological problem, because oxides travel a long

distance and during their journey in atmosphere they may undergo physical and chemical

transformation to produce more hazardous products.

Acid rain creates complex problems and their impacts are far reaching. They increase soil

acidity, thus affecting land flora and fauna; cause acidification of lakes and streams thus

affecting aquatic life, affect crop productivity and human health. Beside these they also corrode

buildings, monuments, bridges, fences railing etc. British Parliament building also suffered

damage due to H2 SO4 rains. The Taz Mahal in Agra, Delhi also suffered from acid rain

problems. Due to acidity levels of heavy metals as aluminium, manganese, zinc , cadmium, lead

and copper in water increase beyond the safe limits. Over 10,000 lakes in Sweden have become

acidified. Thousands of lakes in USA, Canada, Norway have become unproductive due to

acidity. Fish population has decreased tremendously, and there are deaths of salmon, trout etc.

Many bacteria and blue- green algae are killed due to acidification, thus disrupting the

ecological balance. In West Germany nearly 8% of the forests died and nearly 18 million acres

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of forests are critically affected by acid rains. Nutrients as calcium, magnesium and potassium

have been leached away from soil by acids.

Acid rains are carried away by prevailing winds to other areas where precipitation takes

place. Thus oxides may be produced at one place, and these affect elsewhere by turning into

acids. Two such victims are Canada and Sweden. Canada gets acid rains from petro chemical

units in north America. Heavy wind pick up acid rains from factories in Britain and France to

Sweden Equally grim are the acid rains in Norway, Denmark and W. Germany. It is said that

90% of the acid rains of Norway and 75% of Sweden are due to drifted acid rain oxides. Acid

rains are thus becoming a major political issue.

Though acidity of rain water is yet to be adequately monitored, developing countries like

ours may soon have to face the acid rain problem. Acid rain is fast spreading to developing word

where tropical soils are even more vulnerable than those in Europe. It appears that acid rain

problem is on the anvil in India. Industrial areas with the pH value of rain water below or close

to the critical values have been recorded in Delhi, Nagpur, Pune, Mumbai and Kolkata. This is

due to sulphur dioxide from coal based power plants and petroleum refinery.

There is urgent need for proper regulatory monitoring to provide timely warnings about

acidification of our environment.

(iii) Biological magnification

Biological Magnification, also called bioaccumulation -- is the process whereby certain

substances such as pesticides or heavy metals move up the food chain.

These substances work their way into rivers or lakes, and are eaten by aquatic organisms such as

fish, which in turn are eaten by large birds, animals or humans. The substances, called

bioaccumulants, become concentrated in tissues or internal organs as they move up the chain.

Occurs when compounds are poorly excreted by an organism thereby leading to a buildup of said

compound as the organism consumes more and more organisms/substances containing the

compound.

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Biological magnification often refers to the process whereby certain substances such as

pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are

eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or

humans. The substances become concentrated in tissues or internal organs as they move up the

chain. Bioaccumulants are substances that increase in concentration in living organisms as they

take in contaminated air, water, or food because the substances are very slowly metabolized or

excreted.

Although sometimes used interchangeably with bioaccumulation

Bioaccumulation occurs within a trophic level, and is the increase in concentration of a

substance in certain tissues of organisms' bodies due to absorption from food and the

environment. Bio magnification occurs across trophic (food chain) levels.

Non-degradable Pollutants are the substances that either do not degrade or degrade very

slowly in the natural environment. These include mercury salts, long chain phenolic

chemicals, DDT and Aluminium cans etc. Such non degradable pollutants accumulate and

are biologically magnified as they move in the biogeochemical cycle and along food chains

in the ecosystem. For example, DDT, when washed from the ground goes to the streams

where it is absorbed by the phytoplanktons which are eaten by the fishes. So the initial dose

of DDT which was harmless in the phytoplanktons becomes very harmful as it accumulates

in the fish day by day, with the result that large population of fish dies or become sterile and

same is the case with the birds feeding on such fishes.

6. Differentiate between noise and sound. Mention the causes and effects of noise pollution

in brief.

Ans: Sound a normal feature of our life is the means of communication and entertainment in

most animals, including human beings. It is also a very effective alarm system. A low sound is

pleasant whereas a loud sound is unpleasant and commonly referred to as „noise‟. Noise can be

defined as an unpleasant and unwanted sound.

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Whether a given sound is as pleasant as music or as unpleasant as noise depends on its

loudness, duration, rhythm and the mood of the person. But loudness is definitely the most

significant criterion which converts sound into noise. Exposure to loud noise is indeed annoying

and harmful too.

Noise is a physical form of pollution and is not directly harmful to the life supporting

systems namely air, soil and water. Its effects are more directly on the receiver i.e. man. Noise

pollution is the result of modern industrialized urban life and congestion due to over population.

Even though noise pollution is not fatal to human life, yet its importance cannot be

overlooked because repeated exposure to noise reduces the sleeping hours and productivity or

efficiency of a human being. It affects the peace of mind and invades the privacy of human

being. The importance of noise pollution as environmental pollution is being recognized as the ill

effects of noise on human health and environment are becoming evident with each passing day.

Sources of Noise pollution:

Major causes and sources of noise pollution are:

(i) Industrial Sources

Progress in technology (industrialization) has resulted in creating noise pollution. Textile

mills, printing presses, engineering establishments and metal works etc. contribute heavily

towards noise pollution. In industrial cities like Kolkata, Ludhiana, Kanpur etc. often the

industrial zones are not separated from the residential zones of the city especially in the case of

small scale industries. These operate from workshops located on the ground floors of the

residential areas and cause annoyance, discomfort and irrigation to the residents exposed to the

noise that is inevitably produced. The situation is much better in modern planned cities like

Chandigarh where the industrial area is kept away from the residential areas and both are

separated from each other by a sufficiently wide green belt.

(ii) Transport Vehicles

Automobile revolution in urban centres has proved to be a big source of noise pollution.

Increasing traffic has given rise to traffic jams in congested areas where the repeated hooting of

horns by impatient drivers pierce the ears of all road users. Noise from airplanes constitutes an

increasing serious problem in big cities like Delhi & Mumbai. Airport situated in the vicinity of

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population centers and the air lanes pass over residential areas. Heavy trucks, buses, trains, jet-

planes, motor -cycles, scooters, mopeds, jeeps- the list of vehicles is endless but the outcome is

same –noise pollution.

(iii) Household

The household is an industry in itself and is a source of many indoor noises such as the

banging of doors, noise of playing children, crying of infants, moving of furniture, loud

conversation of the inhabitants etc.

Beside these are the entertainment equipment in the house, namely the radio record

players and television sets.

Domestic gadgets like the mixer- grinders, pressure cookers, desert coolers, air

conditioners, exhaust fans, vacuum cleaners, sewing and washing machines are all indoor

sources of noise pollution.

(iv) Public address system

In India people need only the slightest of an excuse for using loud speakers. The reason

may be a religious function, birth death, marriage, election, demonstration, or just commercial

advertising. Public system, therefore, contributes in its own way towards noise pollution.

(v) Agricultural Machines

Tractors, thrashers, harvesters, tube wells, powered tillers etc. have all made agriculture

highly mechanical but at the same time highly noisy. Noise level 90 dB to 98 dB due to running

of farm machines have been recorded in the state of Punjab.

(vi) Defense Equipment

A lot of noise pollution is added to the atmosphere by artillery, tanks, launching of

rockets, explosions, exercising of military airplanes and shooting practices.

Screams of jet engines and sonic booms have a deafening impact on the ears and in

extreme cases have been known to shatter the window panes and old dilapidated buildings.

(vii) Miscellaneous sources

The automobile repair shops, construction-works, blasting buildings, stone crushing etc. are

other sources of noise pollution.

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Effects of Noise

Noise is generally harmful and aserious helth hazard. It has far-reaching cosequences and has

many physical , physiological as well as psychological effects on human beings.

(i) Physical Effects

The physical manifestation of noise pollution is the effect on hearing ability. Repeated

exposure to noise may result in temporary or permanent shifting of hearing threshold of a person

depending upon the level and duration of exposure. The immediate and acute effect of noise

pollution is impairment of hearing (i.e. total deafnes

Human ears have sensory cells for hearing. If these cells are subjected to repeated sounds

of high intensity before they have an opportunity to recover fully, they can become permanently

damaged leading to impairment of hearing. Beside the sensory cells, the delicate tympanic

membrane or the ear drum can also be permanently damaged by a sudden loud noise such as an

explosion.

Physiological Effects

The physiological manifestations of noise pollution are several as mentioned below:

(a) Headache by dilating blood vessels of the brain

(b) Increase in the rate of heart-beat.

(c) Narrowing of arteries.

(d) Fluctuations in the arterial blood pressure by increasing the level of cholesterol in the blood.

(e) Decrease in heart output.

(f) Pain in the heart.

(g) Digestive spasms through anxiety and dilation of the pupil of the eye, thereby causing eye –

strain.

(h) Impairment of night vision.

(i) Decrease in the rate of colour perception.

(j) Lowering of concentration and effect on memory.

(k) Muscular strain and nervous breakdown.

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Psychological Effects

The psychological manifestation of noise pollution are:

(a)Depression and fatigue which considerably reduces the efficiency of a person

(b) Insomnia as a result of lack of undisturbed and refreshing sleep.

(c) Straining of senses and annoyance as a result of slow but persistent noise from motorcycles,

alarm clocks, call bells, telephone rings etc.

(d) Affecting of psychomotor performance of a person by a sudden loud sound.

(e) Emotional disturbance

For a talkative person, the most important effect of noise pollution would invariably be that

noise interferes with our conservation.

So noise is annoying and the annoyance depends on many factors not merely the intensity of

the sound but also repetition, because even a sound of small intensity of (e.g. dripping tap or

clicking of clock) may become annoying, simply by repetition.

7. What do you mean by hazardous wastes? How is land filling an important method for

the disposal of hazardous wastes? What are its disadvantages?

Ans: Any dangerous condition or event that threatens or has the potential for causing damage to

life, property or environment is called as hazard. Substances that can cause hazard on exposure

are called as hazardous substances. A waste is a discarded substance as it is considered to be

expired and useless. A solid, liquid or gaseous substance that can cause illness, injury, abnormal

body function and even death to people or destruction of the environment if treated, stored,

transported or discarded improperly- is called as a hazardous Waste. Beside the above mentioned

characteristics, a hazardous waste may be ignitable, corrosive and reactive or toxic. Different

forms of substances like mixtures, residues or materials containing hazardous pollutants are also

considered as hazardous wastes. These also include toxic chemicals, reactive substances, and

industrial wastes from chemical plants or nuclear reactors, agricultural wastes like pesticides and

fertilizers, medical wastes, household hazardous wastes like toxic paints and solvents etc.

Land Filling:

Land filling is a process of disposing solid waste in low or into trenches through proper

sanitary methods. It involves- collection, transport, compaction, etc. process along with proper

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management for gas- outlet etc. For land filling the thing to be taken into account is the distance

of waste collection site to the waste dumping site, because it involves cost of transportation.

The process of land filling is similar to dumping in very general sense. However, it is

different from dumping as it involves scientific method of disposal of wastes into low land sides,

without creating hazards to the community health or safety.

The overall process of land filling involves following methods- Area Method, Trench

Method, and Ramp Method. In Area Method, Solid waste are pulverized and spread over the

entire area. Then the waste is compacted by rolling of bull dozers. The same process is repeated

a number of times.

In the Trench Method, trenches measuring 10x 5x 20 feet are dug and heaps of solid

wastes are filled into them. These trenches are compacted by rolling of bull dozers. The top and

side of trenches are covered with soils. This method needs at least one acre of land top handle the

solid waste generated by about 10,000 people in a time period of one year.

In Ramp method, a number of gullies, ravines or quarries are dug for land filling.

Natural gullies made by soil erosion may also be selected for filling. Solid wastes are filled

along the slopes, then covered with soil and pressed properly.

The selection of site for land filling is done on the basis of following considerations-

(i) Availability of land and area.

(ii) Accessibility of the land site.

(iii)Availability of soil for the use as covered material.

(iv) Climate of the area in which the land fill site is located.

(v) The topography of the area selected for land filling.

The process of land filling has following advantages-

(i) Flies, rats and other pests cannot breed in landfills.

(ii) Chances of fire hazards are reduced through this method.

Therefore land filling is an important method for the disposal of hazardous wastes.

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Land Filling has following disadvantages-

(i) It may cause ground water pollution by leaching down of liquefied wastes during rains.

(ii) A landfill may cause water pollution if located near a water source.

(iii)The land fill site becomes unfit for human settlement due to release of gases like methane,

carbon dioxide and sometimes radon, within the period of first few years. These gasses are

produced due to the decomposition of filled-in wastes.

8. What is global warming? Describe its impacts on human society’s agriculture and

animal communities.

Ans: Global warming is the phenomenon whereby average temperature of the earth is rising

due to the increases in the amounts of greenhouse such as CO2 in the atmosphere.

The heat absorbing gases accumulate in high concentration in the upper atmosphere

around the earth extending up to 100km above its surface and act as glass panels of a green

house. They allow much of the short wave solar radiation to reach the earth surface but stop

much of the long wave infrared rays against escaping out as heat. They absorb these infrared

radiations and then re-radiate most of them back to the earth surface. Thus, the temperature of

the atmosphere rises gradually causing an unnatural heating effect which is called as the Global

warming. Global warming is the enhanced greenhouse effect due to greater accumulation of

GHGs in the upper atmosphere.

The warming of the earth‟s atmosphere attributed to a buildup of greenhouse gasses in

high concentration in the atmosphere is called as the Global warming.

Impact Global warming in Human Society :

Any adverse change in the weather pattern or in the environment on the whole, is sure to

affect adversely the lives of human beings. We can easily understand that a warmer climate is

sure to change the patterns of rain fall and snow fall. It is sure to cause increase in the frequency

and severity of drought and floods also. The increasing heat will cause the air to expand and

develop more capacity of holding moisture. In turn this is sure to affect our resources like water,

forests and different ecological systems. These conditions will affect the conditions of power

generation, infrastructure, tourism and healthy living.

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The changes in temperature have already caused a number of disasters like cyclones,

hurricanes, and other forms of storms across the world. In a nut shell we may conclude that

changing climate due to global warming will damage natural resources, together with causing

spread of deadly diseases, displacement of human populations, hunger loss of economy and

shortage of human resources, in case the problem of global warming is not averted properly.

The Global warming has various types of impacts on the whole earth, its systems and the

whole human society. Global warming may cause frequent natural disasters like cyclones, storms

and hurricanes, floods and droughts. Thus it may claim lives of large sections of human society,

it may also cause cloud bursts, avalanches, landslides, mud-flows and earthquakes. A very large

number of men, women and children are killed in these disasters. Thousands of people become

homeless and migrate elsewhere to take shelter as refugees. Global Warming is causing melting

of ice and glaciers which is leading to a rise in sea level. As a result, the creeping up oceans

swallow low laying islands, coastal areas, people and their property etc. Such is the case of

SATBHAYA village of Orissa State of India.

According to the fourth assessment Report, Brussels, April 2007 of Intergovernmental

Panel on climate change causes following adverse impacts on human health-

Increase in malnutrition and consequent disorders, with implication for child growth and

development;

Increased deaths, diseases and injury due to heat waves, floods, storms, fires and droughts;

The increased burden of diarrheal diseases;

Increased frequency of cardio-respiratory diseases due to higher concentrations of ground

level ozone related to climate change; and

The altered spatial distribution of vectors of some diseases.

Impact of Global warming on Agriculture:

Our demands for more and more food are rising on day by day due to increasing human

population. The supply of food mainly comes from agriculture. But the increasing temperature

followed by changes in climatic conditions due to global warming is sure to damage it.

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Global warming may cause drought and outbreak of insects. Both of these conditions are

damaging to agriculture. Higher temperature accelerates the malnutrition of earlier disease

causing agents and their vectors. All these conditions cause damage and failure of crops.

Climatic factors like temperature, wind, relative humidity, rain fall etc. have direct effects

on agriculture. Since global warming is changing the global climates, adverse changes in

agriculture and its production is bound to occur. On the other hand changing frequencies of

natural disasters such as floods, cyclones, hurricanes, landslides, mud-flows etc. tend to vanish

out our crops besides causing great losses to life and property. Hail storms, wind storms and also,

fog and mist cause serious damage to our crops each year. In many parts of India, farmers go on

demonstration and road jams demanding compensations from the government whenever their

crops are damaged due to any of these reasons. In a democratic Country the government is

formed by the people themselves. On the other hand, climate change is global tragedy the

responsibilities of which go in everyone‟s share. However since the climate is changing

agriculture is sure to be damaged and such incidents are bound to follow because everyone wants

to live.

Impact of Global warming on Animals:

Since the animals depend on a favorable climate, suitable habitats, food and appropriate

breeding conditions for survival and development, the global warming followed by the climate

change is sure to impose disastrous effects on them. The animal population in arctic region is

declining fast due to rising temperature across the region. The disproportionate warming in this

region has had detrimental effects on many arctic species including the Arctic Gull, Emperor

Penguins, Arctic fox, and the polar bear. The total area of the arctic sea ice has declined by 6 per

cent over the last twenty years. Since 1979 damage to the coral reefs and events of coral

bleaching on a large scale has increased considerably.

So far vast varieties of birds, reptiles, insects, bacteria, fungi, rodents etc. have vanished

out due to these effects. The golden toads in the mountains of Costa Rica are believed to have

gone extinct in recent years. The population of Salamanders and similar species are at the brink

of extinction as their embryos do not develop properly under the conditions of rising temperature

due to global warming.

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In Central South America many of the mountain amphibians including the golden toads

have been vanished due to global warming. According to the WWF (Worldwide fund for nature)

with the doubling of carbon dioxide, climate change could eventually destroy 35 per cent of the

worlds‟ existing terrestrial habitats. Bird‟s habitats will be altered through changes in sea level,

fire regimes, vegetation and land use etc. Due to the Climate anomaly caused by global warming,

the population of the Emperor Penguins declined by 50 per cent during 1970s due to reduced

adult survival caused by prolonged abnormally warm temperatures with reduced sea ice.

The population of Siberian Crane, Which is a critically endangered species, has reduced

considerably up to few thousand individuals. It demonstrates the vulnerability of a wet land

migratory bird to the climate change. Some populations of migratory birds have been declining

sharply because of unfavourable variations in climatic conditions. The increasing deposits of

carbon dioxide in oceanic waters due to global warming and other incidents are damaging

mollusks due to which their population in marine waters has declined sharply.

The global warming is damaging various ecosystems like mangrove-swamps, coral reefs

and coastal lagoons etc. due to various reasons like reduction in pH of oceanic water and

increasing deposits of acids. The migration time of spring butterflies in Britain has become

earlier than it was 30 years ago. It has been observed that the behaviours of some bird species

have changed due to climatic variations in the Indian state of Orissa. Some birds like Black

Headed Oriole and Open Billed stork have changed their times of migration where as some birds

like Bronze Winged Jacana and Indian Small Skylark have changed their nesting behaviours.

The change in climate due to rise in global temperature is causing migration of species of wild

animals towards poles and high altitudes. Since those areas are already inhabited by animals of

different species receive the status of refugee species.