Samacheer Kalvi 12th Bio Zoology Solutions Chapter 12 Environmental Issues

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Tamilnadu Samacheer Kalvi 12th Bio Zoology Solutions Chapter 12 Environmental Issues

Samacheer Kalvi 12th Bio Zoology Text Environmental Issues Book Back Questions and Answers

Question 1.
Right to Clean Water is a fundamental right, under the Indian Constitution ________
(a) Article 12
(b) Article 21
(c) Article 31
(d) Article 41
Answer:
(c) Article 31

Question 2.
With which of the following, the Agenda 21 of Rio Summit, 1992 is related to?
(a) Sustainable development
(b) Combating the consequences of population
(c) Mitigation norms of Green House Gases (GHGs) emission
(d) Technology transfer mechanism to developing countries for ‘clean energy’ production
Answer:
(a) Sustainable development

Question 3.
Which among the following awards instituted by the Government of India for individuals or communities from rural areas that have shown extraordinary courage and dedication in protecting Wildlife?
(a) Indira Gandhi Paryavaran Puraskar
(b) Medini Puraskar Yojana
(c) Amrita Devi Bishnoi Award
(d) Pitambar Pant National Award
Answer:
(c) Amrita Devi Bishnoi Award

Question 4.
The ‘thickness’ of Stratospheric Ozone layer is measured in/on _________
(a) Sieverts units
(b) Dobson units
(c) Melson units
(d) Beaufort Scale
Answer:
(b) Dobson units

Question 5.
Which among the following is the most abundant Green-House-Gas (GHG) in the Earth’s atmosphere?
(a) Carbon dioxide
(b) Water Vapour
(c) Sulphur Dioxide
(d) Tropospheric Ozone
Answer:
(a) Carbon dioxide

Question 6.
As per 2017 statistics, the highest per capital emitter of Carbon dioxide in the world is _________
(a) USA
(b) China
(c) Qatar
(d) Saudi Arabia
Answer:
(b) China

Question 7.
The use of microorganism metabolism to remove pollutants such as oil spills in the water bodies is known as __________
(a) Biomagnification
(b) Bioremediation
(c) Biomethanation
(d) Bioreduction
Answer:
(b) Bioremediation

Question 8.
The Ozone Day is observed every year on September 16 as on this day in 1987 the __________ was signed for launching efforts to arrest the depletion of the fragile ozone layer in the stratosphere that prevents the harmful ultra-violet rays of the Sun from reaching the Earth.
Fill the correct word in blank:
(a) Montreal Protocol
(b) Geneva Protocol
(c) Kyoto Protocol
(d) Nagoya Protocol
Answer:
(a) Montreal Protocol

Question 9.
Which among the following always decreases in a Food chain across tropic levels?
(a) Number
(b) Accumulated chemicals
(c) Energy
(d) Force
Answer:
(c) Energy

Question 10.
In the E-waste generated by the Mobile Phones, which among the following metal is most abundant?
(a) Copper
(b) Silver
(c) Palladium
(d) Gold
Answer:
(a) Copper

Question 11.
The Hydro chlorofluorocarbons (HCFCs) are the compounds which have the following molecules _________
(a) Hydrogen
(b) Carbon
(c) Chlorine
(d) Fluorine
Answer:
(c) Chlorine

Question 12.
SMOG is derived from _________
(a) Smoke
(b) Fog
(c) Both A and B
(d) Only A
Answer:
(c) Both A and B

Question 13.
Excess of fluoride in drinking water causes _________
(a) Lung disease
(b) Intestinal infection
(c) Fluorosis
(d) None of the above
Answer:
(c) Fluorosis

Question 14.
Expand

1. CFC
2. AQI
3. PAN

Answer:

1. CFC: Chlorofluorocarbons
2. AQI: Air Quality Index
3. PAN: Peroxyacetyl nitrate

Question 15.
What is SMOG and how it is harmful to us?
Answer:
Smog is a type of air pollution caused by tiny particles in the air. The word comes from a mixture of the words smoke and fog. Today, smog generally refers to photochemical smog, which is created when sunlight reacts with nitrogen oxides and volatile organic compounds found in fossil fuel emissions from automobiles, factories, and power plants. These reactions create ground-level ozone and particulate matter, reducing visibility. Smog ’ can make breathing more difficult, especially for people with asthma.

Smog also affects plants and animals. It damages crops as well as causes health problems in pets, farm animals and human beings. Smog has also been known to cause corrosive damage to buildings and vehicles.

Question 16.
List all the wastes that you generate, at home, school or during your trips to other places. Could you very easily reduce the generation of these wastes? Which would be difficult or rather impossible to reduce?
Answer:

Yes, we can reduce the generation of daily wastes in our life. For example, using jute/cloth bags instead of plastic bags, using the plastic drum as flower pots, etc.
E-wastes and plastic wastes are generally difficult to biodegrade.

Question 17.
Discuss the causes and effects of global warming. What measures need to be taken to control global warming?
Ozone layer depletion can be controlled by
Answer:
Ozone layer depletion can be controlled by

• Phase down or ban the use of CFCs (CFC free refrigerants).
• Minimizing the use of chemicals such as halons and halocarbons.
• Creating awareness about ozone-depleting agents.
  UV rays may penetrate deep into the skin and can lead to premature skin aging and wrinkling of the skin; suppression of the immune system, skin cancer (melanoma), and chronic effects leading to eye damage.
• DNA damage can result from free radicals and reactive oxygen and photons can damage the DNA itself.

Question 18.
What would Earth be like without the greenhouse effect?
Answer:
The greenhouse effect is vital for the sustenance of life. Greenhouse gases like CO₂, water vapour etc absorb some of the reflected sun’s radiation and radiate back it to the Earth’s surface, thus maintaining the Earth’s warm condition. Without this effect, life on Earth would be difficult or rather impossible for existence or become hostile to most living organisms.

Question 19.
Write notes on the following:

1. Eutrophication
2. Algal Bloom

Answer:

1. Eutrophication refers to the nutrient enrichment in water bodies leading to a lack of oxygen and will end up in the death of aquatic organisms.
2. Algal Bloom is excess growth of algae due to abundant excess nutrients imparting distinct color to water.

Question 20.
What effect can fertilizer runoff have on an aquatic ecosystem?
Answer:
When run-off from land containing nutrients’ reaches water bodies like lakes, it results in a dense growth of plant life. This phenomenon is called Eutrophication.

Question 21.
How can we control eutrophication?
Answer:
Eutrophication can be controlled by reducing the use of fertilizers in agricultural lands, checking the runoff from fields, planting vegetations along the stream beds there by the nutrients will be uptaken by plants.

Question 22.
Why does an ozone hole form over Antarctica?
Answer:
Ozone hole in Antarctica is due to special atmospheric and chemical conditions that existed there and nowhere else on the globe.

Question 23.
Mention the causes of enhanced ultraviolet radiation.
Answer:
UV rays may penetrate deep into the skin and can lead to premature skin aging and wrinkling of skin; suppression of the immune system, skin cancer (melanoma) and chronic effects leading to eye damage. DNA damage can result from free radicals and reactive oxygen and photons can damage the DNA itself.

Question 24.
Discuss the role of women in the protection and conservation of forests.
Answer:
Women and communities have played a crucial role in environmental conservation programmes.
Example 1: Chipko movement was started in 1974 in India. In this women from the village hugged the trees and prevented the felling of trees by contractors.

Example 2: Amrita Devi, from Khejarli village of Jodhpur district, Rajasthan sacrificed her life to maintain Bishoni Dharma. Here the King of Jodhpur ordered his men to get the wood of Khejri trees by cutting them to construct his new palace. On hearing this Amrita Devi and many others had hugged the trees to save them from cutting. But her effort went in vain. Amrita Devi and others were killed by King’s men. This resistance by the people of the village forced the King to give up the idea of cutting trees.

Question 25.
Discuss the role of an individual to reduce environmental pollution.
Answer:

1. Decrease waste generation
2. Use efficient transportation
3. Reduce energy consumption
4. Planting trees

Question 26.
How does recycling help to reduce pollution?
Answer:
Recycling prevents the emission of many greenhouse gases which are the major cause of global warming. It also reduces water pollutants and saves energy.

Question 27.
What is the primary purpose of the Kyoto Protocol?
Answer:
The primary purpose of Kyoto Protocol is to reduce the onset of global warming by reducing the concentration of greenhouse gases in atmosphere.

Question 28.
In what way Peyang conserves the forest?
Answer:
The ‘Forest man of India Jadav Payeng who created 1,360 acres of dense and defiant forest was bom in Arunasapori (a river island on the Brahmaputra). He had just completed his Class X exams in 1979 when he started-to sow the seeds and shoots on the eroded island covered with sand and silt.

Thirty-six years later he had converted the once unproductive land into a forest. Payeng’s forest is now home to five Royal Bengal tigers, over a hundred deer, wild boar, vultures, and several species of birds. For his remarkable initiative, the Jawaharlal Nehru University invited Payeng in 2012 on Earth Day and honoured him with the title of the ‘Forest Man of India’.

Question 29.
Discuss briefly the following:
Answer:
(a) Catalytic converter
(b) Greenhouse gases
(c) Ecosan
Answer:
(a) A catalytic converter is a device that converts toxic gases and pollutants into less toxic pollutants by catalyzing redox reaction.

(b) Gases that trap the heat within the atmosphere are called Green house gases.
Example: CO₂ and CO

(c) About 150 liters of wastewater at an average is generated by an Indian individual daily, and a large amount of it is generated from toilets. Ecological sanitation (EcoSan) is a sustainable system for handling human excreta by using dry composting toilets. EcoSan toilets not only reduce wastewater generation but also generate the natural fertiliser from recycled human excreta, which forms an excellent substitute for chemical fertilisers. This method is based on the principle of recovery and recycling of nutrients from excreta to create a valuable supply for agriculture.

Question 30.
What are some solutions to toxic dumping in our oceans?
Answer:
Reducing energy usage, Eat sustainable sea foods, use reusable plastic products, proper dispose of hazardous materials. Avoid littering on beach and buying ocean friendly products.

Question 31.
Describe how deforestation might contribute to global warming.
Answer:
Deforestation refers to cutting down of trees. Trees are one of the major sources of CO₂ uptake. CO₂ is a major green house gas. If there is a large scale destruction of forests, the level of CO₂ will be increased leading to global warming.

Question 32.
How does forest conservation help to reduce air pollution?
Answer:
Forests decreases the CO₂ level and increase the oxygen level of atmosphere. Particulate matters in air will settle down on leaves. Thus they help to reduce water pollution.

Samacheer Kalvi 12th Bio Zoology Environmental Issues Additional Questions and Answers

1 – Mark Questions

Question 1.
The gaseous envelope which surrounds the Earth is called as ________
(a) Stratosphere
(b) Atmosphere
(c) Troposphere
(d) Ozonosphere
Answer:
(b) Atmosphere

Question 2.
are the major causes of CO polution in large cities and towns ________
(a) Fossil fuels
(b) Ocean
(c) Deforestation
(d) Automobiles
Answer:
(d) Automobiles

Question 3.
and are the major cause for acid rain ________
(a) Sulphur di oxide and Hydrogen peroxide
(b) Hydrogen peroxide and Sulphuric acid
(c) Hydrochloride and sulphur dioxide
(d) Sulphur dioxide and Nitrogen oxide
Answer:
(d) Sulphur dioxide and Nitrogen oxide.

Question 4.
What is the name of the app published by Central Pollution Control Board that provides updates on AQI
(a) Hamear
(b) Jhoan
(c) Sameer
(d) Industan
Answer:
(c) Sameer

Question 5.
PAN stands for ________
(a) Peroxy acetic nitrogen
(b) Perchloro acetate
(c) Peroxyacetyl nitrate
(d) Peractyl nitroxide
Answer:
(d) Peroxyacetyl nitrate

Question 6.
Average human consumption of oxygen per day is ________
(a) 280 L
(b) 550 L
(c) 620 L
(d) 730 L
Answer:
(b) 550 L

Question 7.
Name the famous flagship programme of Central Government launched to achieve pollution abatement and rejuvenation of River Ganga.
Answer:
Namami Gange

Question 8.
The intensity of noise is measured in ________
(a) Dobson
(b) Hertz
(c) Decibel
(d) Frequency
Answer:
(c) Decibel

Question 9.
According to noise pollution rules 2000, the permissible level of noise in commercial area is during day and during night
(a) 55 db, 65 db
(b) 65 db, 55 db
(c) 70 db, 60 db
(d) 75 db, 65 db
Answer:
(b) 65 db, 55 db

Question 10.
Which is not a physical method of waste water treatment ________
(i) Floatation
(ii) Filtration
(iii) Phydro remediation
(iv) Oxidation
(a) i and iii
(b) ii and iv
(c) i and ii
(d) iii and iv
Answer:
(d) iii and iv

Question 11.
Match List I with List II

Answer:
a – iv, b – i,b c – ii, d – iii

Question 12.
Which is not a method of disposal of radioactive waste.
(a) Dilute and dispense
(b) Delay and decay
(c) Recycle and reuse
(d) Limit generation
Answer:
(c) Recycle and reuse

Question 13.
E-Wastes are basically ________
(a) Poly iodinated biphenyl based compounds
(b) Poly chlorinated biphenyl based compounds
(c) Poly hydroxy biphenyl based compounds
(d) Poly acetyl biphenyl based compounds
Answer:
(c) Poly hydroxy biphenyl based compounds

Question 14.
Identify the correct statement indicating 4Rs of treating water.
(a) Regenerate, Reduce, Reuse and Recycle
(b) Refuse, Reduce, Rejenuvate and Reuse
(c) Redeem, Refuse, Rejenuvate and Reduce
(d) Refuse, Reduce, Rescue and Recycle.
Answer:
(d) Refuse, Reduce, Rescue and Recycle.

Question 15.
UN conference on Sustainable development in 2012 was held at ________
(a) Ruanda
(b) Rio de Janeiro
(c) Geneva
(d) Stockholm
Answer:
(b) Rio de Janeiro

Question 16.
The molecular formula for ozone is ________
(a) O₂
(b) O₄
(c) O₃
(d) O₇
Answer:
(c) O₃

Question 17.
World Ozone Day was observed on ________
(a) September 16th
(b) October 12th
(c) December 1st
(d) August 18th
Answer:

Question 18.
Who is the leader of Chipko Movemet?
Answer:
Sunderlal Bahuguna

Question 19.
I am called as the Forest Man of India? Who am I?
Answer:
JadavPayeng

Question 21.
Identify the incorrect statement.
(i) EcoSan toilets is a sustainable way for handling human excreta by using dry composting toilets
(ii) It reduces waste water generation
(iii) It is based on recovery and recycling of nutrients from excreta
(iv) EcoSan toilets are used in several parts of India and Srilanka.
(a) i and ii only
(b) iii and iv only
(c) all the above
(d) none of the above
Answer:
(d) none of the above

Question 22.
What is the name of the action plan for sustainable development framed in Rio conference in in 1992?
(a) Action 21
(b) Declaration 21
(c) Protocol 21
(d) Agenda 21
Answer:
(d) Agenda 21

Question 23.
Eutrophication is a result of ________
(a) Agricultural and sewage waste
(b) Vehical emission
(c) Pesticides
(d) Indutrial effluent
Answer:
(c) Pesticides

Question 24.
BOD stands for ________
(a) Biological Oxidation Demand
(b) Biotic Oxygen Deficient
(c) Biological Oxygen Deficit
(d) Biochemical
Answer:
(a) Biologoical Oxidation Demand

Question 25.
Stratosphere is mainly depleted by ________
(a) Excess CO
(b) CFC’s
(c) Ozone
(d) Exess CO
Answer:
(b) CFC’s

Question 26.
Treatment of sewage involves
(a) Floatation, Filtration and Sedimentation of suspended particles
(b) Aerating it for bacterial action
(c) Removal of nitrates and phosphates
(d) All of the above
Answer:
(d) All of the above

Question 27.
Assertion (A): Ozone layer protects the UV rays entering the Earth.
Reason (R): UV rays may cause melanoma
(a) A is right R is wrong
(b) A is wrong R is right
(c) Both A and R are correct
(d) R explains A
Answer:
(d) R explains A

Question 28.
Assertion (A): Evolution of Greenhouse gases leads to Global warming
Reason (R): The energy released by the greenhouse gases move away from the atmospheric surface
(a) A is right R is wrong
(b) A is wrong R is right
(c) Both A and R are correct
(d) R explains A
Answer:
(a) A is right R is wrong

Question 29.
Statement (1): Incomplete combination of fossil fuels release CO
Statement (2): CO is a GHG
(a) Statement 1 is true, statement 2 is false
(b) Statement 1 is false, statement 2 is true
(c) Both Statements 1 and 2 are true
(d) Both statements 1 and 2 are false
Answer:
(c) Both statements 1 and 2 are true.

Question 30.
Statement (1): The intensity of noise is measured in dobson (dB) unit.
Statement (2): Noise provides immense bliss.
(a) Statement 1 is true, statement 2 is false
(b) Statement 1 is false, statement 2 is true
(c) Both Statements 1 and 2 are true
(d) Both statements 1 and 2 are false
Answer:
(d) Both statements 1 and 2 are false.

Question 31.
The threshold of noise level is ________
Answer:
120db

Question 32.
Chemicals used in agriculture as fertilizer and pesticides are generally called as ________
Answer:
Agrochemicals

2 – Mark Questions

Question 1.
Define pollution.
Answer:
Pollution is any undesirable change in the physical, chemical and biological characteristics of the environment due to natural causes and human activities.

Question 2.
What is air pollution?
Answer:
The alterations or changes in the composition of the Earth’s atmosphere by natural or human activities (anthropogenic factors) are referred as Air Pollution.

Question 3.
Classify air pollutants.
Answer:
Air pollutants can be

• discharge of dusts or particulate matter (PM: 2.5 and 10)
• discharge of gases (SO_x, NO_x, CO and CO₂)

Question 4.
What are particulate matters? Give examples.
Answer:
Particulate matters are tiny particles of solid matter suspended in a gas or liquid. Combustion of fossil fuels, fly ash produced in thermal power plants, forest fires, asbestos mining units and cement factories are the main sources of particulate matter pollution.

Question 5.
Name the secondary pollutant in photochemical smog. Mention its adverse effect.
Answer:
Peroxyacetyl nitrate (PAN) is a secondary pollutant present in photochemical smog. It is thermally unstable and decomposes into peroxyethanol radicals and nitrogen dioxide gas causing eye irritation.

Question 6.
How ozone hole is developed?
Answer:
Ozone depletion: Thinning of the stratospheric ozone layer is known as ozone depletion. Such depletion causes the ‘ozone hole’, resulting in poor screening of the harmful UV rays and increase in incidences of skin cancer. Some of the common agents that deplete ozone are CFCs.

Question 7.
List out the green house gases.
Answer:
(a) CO₂
(b) CFCs
(c) Methane
(d) Nitrous oxide

Question 8.
What is Acid rain?
Answer:
Acid rain is a form of precipitation that contains acidic components, such as sulfuric acid or nitric acid. It damages trees, crops and harms marine animals (coral reefs) and induces corrosion.

Question 9.
Point out any two non-point sources of water pollution.
Answer:

1. Agriculture chemical run off.
2. Dumping of plastics in water bodies.

Question 10.
How will you define noise pollution?
Answer:
Sound that is unwanted and undesirable or can disrupt one’s quality of life is called as Noise. When there is lot of ‘noise’ in the environment, it is termed as Noise Pollution.

Question 11.
Expand USEPA and MOEFCC.
Answer:

1. USEPA : United States Environmental Protection Agency.
2. MOEFCC : Ministry of Environment, Forest and Climate Change.

Question 12.
What are agrochemicals?
Answer:
Chemicals which are used in agriculture for growth of plants and pest control are called agrochemicals or agrichemicals.

Question 13.
Which organism is affected by colony collapse syndrome? What will be the impact?
Answer:
Colony collapse syndrome in Honey bees due to pesticides/herbicides can lead to destruction of hives and lower agricultural productivity.

Question 14.
Define the term eutrophication.
Answer:
When run-off from land containing nutrients reaches water bodies like lakes, it results in dense growth of plant life. This phenomenon is called Eutrophication.

Question 15.
What is meant by accelerated eutrophication?
Answer:
Pollutants from anthropogenic activities like effluents from the industries and homes can radically accelerate the aging process. This phenomenon is known as Cultural or Accelerated Eutrophication.

Question 16.
List out the chemical methods of wastewater treatment.
Answer:
Chemical methods of wastewater treatment include:

1. Generation of insoluble solids.
2. Produce an insoluble gas.
3. Produce biologically degradable substances from a non-biodegradable substance.
4. Oxidize or reduce to produce a non-objectionable substance.

Question 17.
Expand RZWT and DEWATS.
Answer:

1. RZWT : Root Zone Wastewater Treatment
2. DEWATS : Decentralized Wastewater Treatment System

Question 18.
What are medical wastes?
Answer:
Any kind of waste that contains infectious material generated by hospitals, laboratories, medical research centers, Pharmaceutical companies and Veterinary clinics are called medical wastes.

Question 19.
What does 4R stands for?
Answer:
‘4R’ refers to Refuse, Reduce, Reuse and Recycle methods to manage plastic waste.

Question 20.
Define deforestation.
Answer:
Deforestation is the destruction of forests in order to clear the land and make it available for other uses.

3 – Mark Questions

Question 21.
Classify degradable pollutants.
Answer:
Based on the time taken to breakdown into their ingredients, degradable pollutants are classified as rapidly degradable (non-persistent) and slowly degradable (persistent).

1. Rapidly degradable or non-persistent pollutants: These can be broken down by natural processes. Domestic sewage and vegetable waste are examples of such pollutants.
2. “Slowly degradable or persistent pollutants: These are pollutants that remain in the environment for many years in an unchanged condition and take decades or longer to degrade, as in the case of DDT.

Question 22.
What are the main sources of air pollution?
The main sources of air pollution are:

1. Transport sources – cars, buses, airplanes, trucks and trains.
2. Stationary sources – power plants, incinerators, oil refineries, industrial facilities, and factories.
3. Area sources – agricultural – wood / stubble burning and fireplaces.
4. Natural sources – wind-blown dust, wildfires and volcanoes.

Question 23.
Define AQI. What will be the air quality if AQI is between 0-50?
Answer:
Air Quality Index (AQI) is a number used by government agencies to communicate to the public how polluted the air is at a given time. If AQI is between 0-50 then the quality of air is good.

Question 24.
Explain the three main sources of water pollution.
Answer:

1. There are three main types of sources: point sources, non-point sources, leaks and spills.
2. Point sources: Discharge of pollutants at specific locations through pipelines or sewers into the water body. Factory effluents, sewage, underground mines, oil wells, oil tankers and agriculture are common point sources.
3. Non-point sources: Sources that cannot be traced to a single site of discharge like acid rain, dumping of the plastics in water bodies and agriculture chemical run off are common examples.
4. Leaks and Spills: This occurs mostly due to ship collision, off shore oil rigs, oil leakages and discharges into sea.

Question 25.
What will be the impact of water pollution on ecosystem?
Answer:
Destruction of ecosystems: Ecosystems, especially aquatic systems, can be severely affected or destroyed by water pollution.Water pollutants affect existing niches and habitats and the survival of organisms. Soil fertility is affected and the system becomes uninhabitable.

Question 26.
Suggest few ways to control water pollution.
Answer:

1. Regulate or control of pollutant(s) discharge at the point of generation.
2. Wastewater can be pretreated by scientific methods before discharge to municipal treatment sources.
3. Setting up of Sewage Treatment Plants (STP) and Effluent Treatment Plants (ETP).
4. Regulate or restrict the use of synthetic fertilisers and pesticides.
5. Public awareness and peoples’ involvement is essential.

Question 27.
Write a note on ‘Namami Ganga’ programme.
Answer:
Namami Gange (National Mission for Clean Ganga) Programme is an Integrated Conservation Mission approved as the ‘Flagship Programme’ of the Union Government in June 2014 with a budget outlay of 20,000 crores to accomplish the twin objectives of effective abatement of pollution, conservation and rejuvenation of River Ganga.

Question 28.
List out the sources of noise pollution.
Answer:
‘Vehicle engines, air horns, audio video systems, trains, low flying aircrafts, factory machines, sirens, motors, drillers and crushers, compressor machines, crackers, explosives and modem supersonic transports are the common sources of noise pollution.

Question 29.
State the role of Government in controlled Noise pollution.
Answer:
Article 48-A and Article 51-A of the Constitution of India, Noise Pollution (Regulation and Control) Rules 2000, and Tamil Nadu State Environment Policy 2017 are some of the legal relief from noise pollution. According to Noise Pollution (Regulation and Control) Rules, 2000, the permissible limit of noise in areas categorized as commercial is 65 decibels (dB) during day and 55 dB during night.

Question 30.
Comment on Bio-magnification of DDT.
Answer:
When non-degradable substances enter the food chain, they do not get metabolized or broken down or expelled and instead get transferred up the tropic levels of the food chain. During this process, they show an increase in concentration which is referred to as biomagnification. This results in increased toxicity and may even be lethal. This phenomenon is well established for mercury and DDT.

Question 31.
Explain biological methods of waste water treatment.
Answer:
Biological methods of Wastewater treatment:

1. Bioremediation of wastewater includes the aerobic treatment (oxidation ponds and aeration lagoons) and anaerobic treatment (anaerobic bioreactors and anaerobic lagoons).
2. Phytoremediation of wastewater includes constructed wetlands, Root Zone Wastewater Treatment (RZWT), and Decentralized Waste Water Treatment System (DEWATS).

Question 32.
Write a note on organic farming.
Answer:
Organic farming is a method of farming system which primarily aims at cultivating the land and raising crops in such a way, so as to keep the soil alive and in good health by use of organic wastes (crop, animal and farm wastes, aquatic wastes) and other biological materials along with beneficial microbes (biofertilizers) to release nutrients to crops for increased sustainable production in an eco-friendly pollution free environment.

Question 33.
How radioactive wastes are generated?
Answer:
Radioactive wastes are generated during various operations of the nuclear power plant. Radioactive waste can be in gas, liquid or solid form, and its level of radioactivity can vary. The waste can remain radioactive for a few hours or several months or even hundreds of thousands of years. Depending on the level and nature of radioactivity, radioactive wastes can be classified as Exempt Waste, Low and Intermediate Level Waste and High Level Waste.

Question 34.
What are geological repositories?
Answer:
Geological Repositories – A deep geological repository is a nuclear waste repository excavated deep within a stable geologic environment. It is suited to provide a high level of long-term isolation and containment without future maintenance. In India at Tarapur and Kalpakkam, a wet storage facility of Spent Fuel is the main mode of storage.

Question 35.
Give an account on E-waste.
Answer:
Electronic waste or e-waste describes discarded electrical electronic devices as well as any refuse created by discarded electronic devices and components and substances involved in their manufacture or use. Their disposal is a growing problem because electronic equipment frequently contains hazardous substances.

In a personal computer, for example, there may be lead (Pb) in the cathode ray tube (CRT) and soldering compound, mercury (Hg) in switches and housing, and cobalt (Co) in steel components, among other equally toxic substances. E-wastes are basically PCB (Polychlorinated bipheny) based, which are non-degradable.

Question 36.
What will be the impact of global warming?
Answer:
The large-scale global warming will have significant impact on people and nature. As global average temperatures rise, precipitation patterns could be, affected. Extreme wet and dry conditions can be expected (flooding and desertification). Coastal areas shall become more vulnerable to storm surges as sea level rises. Plant and animal species will migrate or disappear in response to climate change.Global warming can directly affect the flora and fauna. This could also result in shortage of food and even lead to food crisis; and affect the health of the people and organisms.

Question 37.
Explain the process of Ozone formation in atmosphere.
Answer:
Ozone is found in the layer of the atmosphere called the Stratosphere. It acts as a protective covering that absorbs ultraviolet (UV) radiation from the Sun. The ozone molecule (O₃) consists of three oxygen atoms. It is formed when atmospheric oxygen (O₂) on exposure to solar radiation breaks into two oxygen atoms; each atom then joins up with a single oxygen atom. The ozone molecule is unstable. It soon decays again to form molecular oxygen. This cycle is a continuous process in the upper reaches of the stratosphere.

Question 38.
How Ozone depletion can be controlled?
Answer:
Ozone layer depletion can be controlled by

1. Phase down or ban the use of CFCs (CFC free refrigerants).
2. Minimizing the use of chemicals such as halons and halocarbons.
3. Creating awareness about ozone depleting agents.

Question 39.
What will be effect of Ozone depletion on Earth?
Answer:
UV rays may penetrate deep into the skin and can lead to premature skin aging and wrinkling of skin; suppression of the immune system, skin cancer (melanoma) and chronic effects leading to eye damage. DNA damage can result from free radicals and reactive oxygen and . photons can damage the DNA itself.

Question 40.
Write a brief note on Chipko movement.
Answer:
The Bishnois, who are known conservators of their forest, were inspiration to many people’s participatory movements for Environmental protection in India. The Chipko movement resisted the destruction of forests of India in the 1970s. Sunderlal Bahuguna was the leader of this movement. People in the movement hugged the trees, and prevented felling of trees by contractors.

Question 41.
What do you mean by Ecosan Toilets?
Answer:
About 150 liters of wastewater at an average is generated by an Indian individual daily, and a large amount of it is generated from toilets. Ecological sanitation (EcoSan) is a sustainable system for handling human excreta by using dry composting toilets. EcoSan toilets not only v reduce wastewater generation but also generate the natural fertiliser from recycled human .excreta, which forms an excellent substitute for chemical fertilisers. This method is based on the principle of recovery and recycling of nutrients from excreta to create a valuable supply for agriculture. ‘EcoSan’ toilets are being used in several parts of India and Sri Lanka.

Question 42.
List out the effects of air pollution.
Answer:

1. Affects all organisms as they depend on the atmosphere for respiration.
2. Causes irritation in the throat, nose, lungs and eyes.
3. It causes breathing problems and aggravates existing health conditions such as emphysema and asthma.
4. Contaminated air reduces the body’s defense mechanism and decreases the body’s capacity to fight other infections in the respiratory system.
5. Frequent exposure to polluted air increases the risk of cardiovascular diseases. Breathing air that is filled with fine particulate matter can induce hardening of the arteries, triggering cardiac arrhythmia or even a heart attack.
6. People who exercise outdoors can sometimes be susceptible to adverse effects of air pollution because it involves deeper and faster breathing. Hence it is advisable to walk or jog in the mornings in places with ample tree cover.
7. Gas leaks can be lethal or affect the quality of air in the affected area.
8. CO in the atmosphere interferes with O₂ transport since haemoglobin has greater affinity. for carbon monoxide. At low concentration it causes headache and blurred vision. In higher concentration, it can lead to coma and death.

Question 43.
How air pollution can be controlled?
Answer:
Certain measures help to remove pollutants, reduce their presence or prevent their entry into the atmosphere.

1. Trees are the best remedy for urban particulate and gaseous pollution.
2. Forests act as carbon sinks and lungs of the planet.
3. Catalytic converters in vehicles help to reduce polluting gases drastically.
4. Diesel exhaust filters in automobiles cuts particulates.
5. Electrostatic precipitators reduce release of industrial pollutants.
6. Cost effective air pollution treatment systems like indoor plants and high performance bio filters can improve indoor air quality.

Question 44.
Point out the effects of Noise pollution.
Answer:

1. According to the USEPA (United States Environmental Protection Agency) there are direct links between noise and health. Heart disease, high blood pressure, stress related illness, sleep disruption, hearing loss (deafness), and productivity loss are the problems related to noise pollution.
2. Increased stress and tension, nervousness, irritability, anxiety, depression and panic attacks.
3. Peptic ulcer, severe head ache and memory loss.
4. Marine animals are affected by noise pollution from offshore activities and port activities.
5. Fire crackers frighten animals. Birds are often affected by increased air traffic.

Question 45.
How agrochemicals affect ecosystem?
Answer:

1. May kill beneficial bacteria and soil organisms.
2. Can cause eutrophication in water bodies.
3.  Afreet aquatic animals and their productivity.
4. Pesticide containing water, even in trace quantities is unfit for human consumption.
5. Particles (aerosols) and residues of these chemicals cause air pollution.
6. Inhalation of contaminated air can cause respiratory problems.
7. Consumption can lead to poisoning, side effects and after effects.
8. Chemicals can cause skin rashes and irritation of eyes.
9. Many of these chemicals are reported to be carcinogenic.
10. They can trigger hormonal disorders and neurotoxicity.
11. Beneficial insects and animals can be affected.

Question 46.
Categorize the soild waste and their sources.
Answer:

Waste category	Source
Residential	Food wastes, plastics, paper, glass, leather, cardboard, metals, yard wastes, ashes, tires, batteries and old mattresses.
Industrial	Packaging wastes, ashes, chemicals, cans, plastics and metal parts.
Commercial	Thin and thick plastics, food wastes, metals, paper, glass, wood and cardboard materials.
Institutional	Wood, paper, metals, cardboard materials and electronics.
Construction and Demolition	Steel materials, concrete, wood, plastics, rubber, copper wires, dirt and glass.
Agriculture	Agricultural wastes, Spoiled food and pesticide containers.
Biomedical	Syringes, bandages, used gloves, catheter, urine bags, drugs, paper, plastics, food wastes, sanitary napkins, diapers and chemicals.
e-waste	Electronic items like used TVs, transistors, tape recorders, computer cabinets, mother boards, CDs, cassettes, mouse, wires, cords, switches and chargers.

Question 47.
How radioactive waste are managed? Suggest few methods of disposal of radioactive waste.
Answer:
Radioactive waste management involves the treatment, storage, and disposal of liquid, airborne, and solid effluents from the nuclear industry.
Methods of disposal of radioactive wastes are:

1. Limit generation – Limiting the generation of waste is the first and most important consideration in managing radioactive wastes.
2. Dilute and disperse – For wastes having low radioactivity, dilution and dispersion are adopted.
3. Delay and decay – Delay and decay is frequently an important strategy because much of the radioactivity in nuclear reactors and accelerators is very short lived.
4. Concentrate and confine process – Concentrating and containing is the objective of treatment activities for longer-lived radioactivity. The waste is contained in corrosion resistant containers and transported to disposal sites. Leaching of heavy metals and radionuclides from these sites is a problem of growing concern.

Higher Order Thinking Skills (HOTs) Questions

Question 1.
Complete the following:
(a) Smoke + ______ = Smog
Answer:
Fog

Question 2.
What is the unit of measuring ozone thickness?
Answer:
Dobson Unit

Question 3.
List any four adverse effect of noise.
Answer:
High blood pressure Stress related ailments Sleep disruption Hearing impairment

Question 4.
Name the scientist who discovered ozone layer
Answer:
Charles Fabry and Henri Buisson