Biology Chapter 16 Environmental Issues

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Particulate size 2.5 micrometers
or less in diameter (PM 2.5)

CFCs are released by refrigerators and air conditioners.  CFCs are very harmful to the atmosphere as they deplete the ozone layer. They are discharged in the lower layer of the atmosphere from where they move upwards towards the stratosphere. In the stratosphere they release chlorine atoms on reaction with UV rays. This Cl act as catalysts and degrade ozone releasing molecular oxygen.  Cl atoms are not consumed in the reaction and thus have permanent and cotinuing effect on ozone levels.

(1) Increase in the carbon dioxide concentration of the atmosphere beacuse of the loss of trees.

(2) Loss of biodiversity due to habitat destruction.

(3) Disturbance of the hydrological cycle.

(4) Soil erosion which may lead to desertification in extreme cases.

2.The Water (Prevention and Control of Pollution) Act, 1974. This act deals with the preservation of water quality and the control of water pollution with a concern for the detrimental quality of water pollutants on human health and also on the biological world.

3. The Air (Prevention and Control of Pollution) Act, 1981. It deals with the preservation of air quality and the control of air pollution with a concern for the detrimental effects of air pollutants on human health and also on the biological world.

Differences between biodegradable and non-biodegradable pollutants

(a) The gaseous pollutants of air come from automobiles and industries. These include CO, CO₂, NO, NO₂, SO₂, SO₃, hydrocarbons, fluorides and photochemical oxidants, such as peroxyacyl nitrate (PAN), ozone (O₃), and aldehydes. .

(b) The particulate contaminants of air also come from industries and automobiles. These include fly-ash, soot, metal dust, cotton fibres, asbestos, fibres, lead, aerosols (chlorofluorocarbons or CFCs), polychlorinated biphenyls (PC_Bg), tobacco smoke, smog, pollen, spores, cysts and bacteria.

(c) Radioactive substances are released by nuclear explosions and war explosives.

Acid rain damages forests, especially those at higher elevations. It robs the soil of essential nutrients and releases aluminum in the soil, which makes it hard for trees to take up water. Leaves are also harmed by acids. The effects of acid rain, combined with other environmental stressors, leave trees and plants less able to withstand cold temperatures, insects, and disease. They also decrease the productivity of the plants.

(1) Use of efficient engines to reduce the amount unburnt hydrocarbons emission .

(2) Use of catalytic converter filter in the vehicle that reduce the amount of toxic gases.

(3) Use of good quality of fuel.

(4) Use of unleaded petrol to reduce the load of lead in the exhaust.

(5) Use of CNG (compressed natural gas) to  lower the toxic contaminants in the exhaust.

1. Construction of sound-proof rooms for noisy machines in industries.

2. Radios and transistors should be kept at low volume.

3. Use of horns with jarring sound should be banned.

4. Noise producing industries, aerodromes, railway stations, etc. should be shifted away from the inhabited areas.

5. Proper laws should be enforced to check the misuse of loudspeakers and public announcement systems.

6. Need to enforce silence zone around institutions like educational institutes, residential areas, hospitals, etc.

7. Sound absorbing techniques like acoustical furnishing should be extensively employed.

8. Noise should be deflected away from the receiver by using mechanical devices.

9. Green muffler scheme that involves growing green plants along roadsides to reduce noise pollution should be followed and encouraged.

10. Stringent laws for permissible sound-levels of crackers should be made and followed.

Classification of Water pollutants:
 

Sanitary landfills are used to dispose solid wastes. In this method a depression or trench is made in the ground and wastes are dumped into it after compaction and covered with dirt everyday. The waste then left for decomposition.

Sanitary Landfills are also not really much of
a solution because the amount of garbage has increased so much that these landfills are getting filled and there is no space for the new ones. Since the waste is buried in the ground there is danger of seepage of chemicals and pollution of underground water.

1. Burning of municipal solid wastes to reduce their volume. 

2. Use of sanitary landfills instead of open-burning dumps.

3. Incineration of municipal wastes and using the heat emitted to generate electricity.

4. Recycling of various components of e-waste.

5. Categorisation and sorting of wastes into three categories called (a) bio-degradable, (b) recyclable and (c) the non-biodegradable.

6. Reducing the amount of garbage and the use of non-biodegradable materials like plastic.

The measures that need to be taken to control global warming are:
(i) Reducing the use of fossil fuels.
(ii) Reforestation or planting of more and more trees.
(iii) Use of Bio-fuels.
(iv) Improving efficiency of energy usage.
(v) Reducing the emission of greenhouse gases in the atmosphere.

1. The two measures taken to reduce the vehicular traffic in Delhi were:
(i) All the buses of Delhi were converted to run on CNG by the end of 2002. CNG being a better fuel than diesel burns more efficiently and has very little left behind.

2. Phasing out of old vehicles and use of unleaded petrol.

(ii) Euro II norms imposed that Sulphur should be controlled at 350 ppm in diesel and 150 ppm in petrol. Aromatic hydrocarbons need to be at 42 per cent in the concerned fuel. The goal was to reduce sulphur to 50 ppm in petrol and diesel and bring down the level to 35 per cent. The vehicles had to be upgraded too.

(b) Water becomes unfit for aquatic fauna because of less oxygen, scum and unpleasant odour.

(c) Eutrophication.

Effects of Sewage discharge on a river : 
(i) The micro-organisms in the sewage consume alot of oxygen and this pose a problem for other organisms in the river.
(ii) The Biochemical oxygen demand (BOD) of the river increases.
(iii) Presence of large amount nutrients causes excessive growth of planktonic algae or Algal bloom which imparts distinct color and degrades the quality of water and fish mortality. Some bloom-forming algae are extremely toxic to human beings and animals.
(iii) Various disease causing microbes  may cause outbreak of serious diseases, such as, dysentery, typhoid, jaundice, cholera, etc

(a) Eutrophication. The process of natural aging oflake because of the presence of excessive nuttrients. The excess of nutrients result in the increase in the population of aquatic organisms and thus decrease in the level of oxygen. The quality of the water is depleted and the temperature also increases.

(b) Biological magnification (Bio-magnification). The phenomenon in which the harmful pollutants (such as pesticides) enter the food chain and get concentrated more and more at each successive trophic level of organisms is called biological magnification.

This phenomenon is well known for mercury and DDT. Zooplankton (tiny floating animals) in the food chain, accumulated moderate levels of DDT. However, small fish, forming the next level of the food chain, must eat zooplankton several times their own weight and thus they accumulate more of DDT. In this manner, the concentration of DDT is magnified at successive trophic levels, starting with 0.003 ppb (ppb = parts per billion) in water it ultimately reached 25 ppm (ppm = parts per million) in fish-eating birds.

(c) Ground water depletion and ways for its replenishment.
The level of ground water has decreased in the recent years. The source of water supply is rapidly diminishing each year because of an increase in the population and water pollution. To meet the demand of water, water is withdrawn from water bodies such as ponds, rivers etc. As a result, the source of ground water is depleting. This is because the amount of groundwater being drawn for human use is more than the amount replaced by rainfall. Lack of vegetation cover also results in very small amounts of water seeping through the ground. An increase in water pollution is another factor that has reduced the availability of ground water.

Measures for replenishing ground water:-

i. Preventing over-exploitation of ground water

ii Optimizing water use and reducing water demand

ii Rain water harvesting

iv Preventing deforestation and plantation of more trees

1. In 1731, Bishnoi community led by women Amrita Devi obstructed the cutting of trees by hugging the tree and asked the workers of king to cut her before cutting the tree. Her three daughters and hundreds of other Bishnois lost their lives in saving trees.

2. Chipko movement started by Chandi Prasad Bhatt and Sunder Lai Bahuguna of Silyara in Tehri region, when workers of contractor were not allowed to cut the trees by village people by hugging  them.

To reduce environmental pollution one can take the following measures:
1. Use of unleaded petrol or CNG in vehicles as fuel.
2. Use of catalytic converters in automobiles.
3. Avoiding the use of chloroflurocarbons to save ozone in the atmosphere.
4. Recycling and reuse of plastic and paper.
5. Plantation of more and more trees.
6.  Optimizing the use of water.
7. Use of biodegradable material should be used.
8. Avoid burning crackers on Diwali.
9. Keeping radio, transistors, T.V., music system at low volume to control noise pollution.
10.Practising organic farming and avoiding excessive use of agro-chemicals.

(b) Defunct ships and e-wastes. Defunct ships are a kind of solid waste requiring proper disposal. Such ships are broken down in developing countries for scrap metal. They often contain toxic substances such as asbestos, polychlorinated biphenyls, tributyltin, lead and mercury.

E-waste are irreparable computers and electronic goods . Most of them are shipped to developing countries for metals like copper, nickel, silicon, gold, that are recovered by recycling. E-wastes are buried and incinerated.

(c) Municipal Solid Wastes. Municipal solid wastes are wastes generated  from homes, offices, stores, schools, etc. and they are collected and disposed by the municipality. The municipal solid wastes generally comprise paper, food wastes, glass, metals, rubber, leather, textile, etc. Burning reduces the volume of the wastes, although it is generally not complete and open dumps often serve as the breeding ground for rats and flies.

1. Use of CNG (Compressed Natural Gas) for its public transport system.

2. Phasing out of old vehicles.

3. Use of unleaded petrol.

4. Use of low sulphur petrol and diesel.

5. Use of catalytic converter in vehicles.

6. Application of Euro II norms for vehicles.

Because of above mentioned steps taken up by the Government, the air quality of Delhi  improved with a substantial fall in carbon monoxide, oxides of sulphur and nitrogen level between 1997-2005.

(b) Catalytic converter is a device that uses a catalyst to convert the harmful compounds in car exhaust into harmless compounds. They are fitted into the automobiles and have expensive metals namely platinum-palladium and rhodium as the catalysts. As the exhaust passes through the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water and carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively. 

(c) Ultraviolet-B radiations. These are high energetic UV-radiations which are mostly blocked by the ozone layer. UV-B damages DNA  and causes mutations in it. UV-B radiation is very harmful for eyes. It leads to aging of skin and causes skin cancers. When cornea absorbs UV-B, it leads to the inflammation of cornea and may cause diseases like snow blindness cataract. Exposure may even permanently damage cornea.

Causes for Deforestation

(i) Conversion of forests into agricultural land to feed the growing human population.

(ii) Clearing of forests for making homes and establishing industries.

(iii) Excessive cutting of trees for trees for timber, fire wood, etc.

(iv) Practising of agricultural methods like Jhum cultivation in the north-eastern states which involves cutting down of trees and burning its remains to form fertilizers.

(v) Natural calamities like fire, floods and droughts that lead to destruction of the forest.

Wastes generated at home include waste paper, plastic bags, paper napkin, toiletries, kitchen wastes (such as peelings of vegetables and fruits, tea leaves), domestic sewage, glass, etc.
Wastes generated at schools include waste paper, plastics, vegetable and fruit peels, food wrappings, sewage etc.
Wastes generated at trips or picnics include plastic, paper, vegetable and fruit peels, disposable cups, plates, spoons etc.
Yes, these wastes can be easily reduced by the judicious use of the above materials. Wastage of paper can be minimized by writing on both sides of the paper and sending it for recycle. Plastic and glass waste can also be re-used. Substituting plastics bags with biodegradable jute bags can reduce wastes generated. Domestic sewage can be reduced by optimizing the use of water while bathing, cooking, and other household activities.
The reduction of non- biodegradable wastes such as plastic, metal, broken glass, etc, prove to be difficult as they are not decomposed by the micro-organisms in the soil. Thus, they persist in the environment for long and cause harm to it. 

Water hyacinth (Eichhornia crassipes) is referred to as the 'Terror of Bengal'.

Causes of accelerated eutrophication:

i) Industrial wastes which are a great source of nitrogen and phosphorous that over-stimulate the algal growth.

ii) Sewage and agricultural wastes also lead to increase in temperature and BOD of the water body thereby leading to algal blooms.

Biological Oxygen Demand (BOD) is a measure of the quantity of oxygen used by microorganisms (e.g., aerobic bacteria) in the oxidation of organic matter. Determining the BOD of the water body help in suggesting the quality of the water body. Presence of more organic waste increases the biological activity which uses up a large amount of oxygen and thus results in deficiency of oxygen. Thus the oxygen demand of the water body increases, high BOD value indicates that the water body has more organic wastes and microbial activity, indicating that the water body is polluted and it is poor in quality.

(a) 'Swachh Bharat Abhiyan' is an initiative started by India's Prime Minister, Narendra Modi on October 02, 2014. It is India's biggest cleanliness drive since independence. On a personal note, I am completely in support for the movement. It is our primary duty to clean our nation because wastes and garbage are the biggest problems that play havoc on the progress and the development of a country. An unclean surrounding leads to lots of problems like health issues and may cause diseases. On a large scale, it is responsible for the pollution, be it air and water, which creates problem both on development and economic aspects of the country.

(b) As a biologist, two problems might be faced while implementing the programme in my locality are as follows:
i. Problem of proper sanitation and disposal.
ii. Separation of biodegradable and non-biodegradable wastes.

(c) Two suggested remedial methods are:

1. To overcome sanitation problems, we should provide awareness regarding the advantages of proper sanitation and encourage people of the locality to make proper toilets and dispose their garbage in dustbins or garbage bags and not throw them on the road.

2. There should be separate bins for both biodegradable and non-biodegradable wastes so that the non-biodegradable waste like plastic items can be used and recycled accordingly.

The two sources of e-waste are:

Irreparable computers and electronic goods.
Two different ways for their disposals are

(i) They can be buried in landfills.

(ii) They are incinerated.

Human activities like over- cultivation, unrestricted grazing, deforestation and poor irrigation practices, resulting in arid patches of land.  The open lands without any cover of vegetation is prone to soil erosion. The soil erodes and becomes incapable of providing nutrition to the plants. The land become barren over the years These large barren patches extend and meet over time to create a desert.Rapid urbanisation has led to the desertification.

Presence of large amounts of nutrients in water causes excessive growth of planktonic (freefloating) algae, and such condition is called an algal bloom. It imparts a  distinct colour to the water bodies and cause deterioration of the water quality and fish mortality. Some algal blooms are extremely toxic to human beings and animals.

Eichhornia crassipes is nicknamed Terror of Bengal because they caused havoc by their excessive growth by causing blocks in the waterways. They grew at a very high rate such that it was nearly impossible to remove completely. They caused imbalance in the ecosystem dynamics of the water body.

The public transport of Delhi switched over to new fuel - CNG (COMPRESSED NATURAL GAS). It is considered better due to following reasons

i. CNG is a clean fuel and it burns more efficiently.  Very little of it remains unburnt on combustion. It is eco-friendly and causes less pollution.

ii. CNG is cheaper than petrol or diesel and thus is economical.

Dobson units (DU) is used to measure the ozone thickness.

Following are the two advantages of using unleaded petrol as fuel in automobiles:

i. Unleaded petrol does not have lead compounds therefore does not inactivate the catalytic converter.

It is desirable to use unleaded petrol in the automobiles fitted with catalytic converter because lead in the petrol inactivates the catalyst.

Ahmad Khan of Bangalore , solved the ever-increasing problem of accumulating plastic waste came up with a remedy for efficient use of plastic waste by developing Polyblend, a fine powder of recycled modified plastic. In collaboration with R.V. College of Engineering and the Bangalore City Corporation, Ahmed Khan proved that blends of Polyblend and bitumen, when used to lay roads, enhanced the bitumen’s water repellant properties, and helped to increase road life by a factor of three. Thus the plastic wastes were used to make polyblend and lay road.

Two advantages for preferring CNG over diesel as an automobile fuel are:
(i) CNG is cheaper than diesel.
(ii) CNG burns efficiently as compared to diesel and causes less of air pollution. 

CFCs find wide use as refrigerants. CFCs discharged in the lower part of atmosphere move upward and reach stratosphere. In stratosphere, UV rays act on them reacting with the Cl atoms. Cl atoms acts as catalysts and degrades ozone releasing molecular oxygen. Cl atoms are not consumed in the reaction. Hence whatever CFC are added to stratosphere, have permanent and continuing effects on ozone level. 

The presence of large amounts of nutrients in the water bodies lead to excessive growth of algae and cause Algal bloom. The algal blood leads to deterioration of the quality of water, reduces dissolved oxygen and the hence leads to fish mortality.

(a) Two places where it is essential to install electrostatic precipitators are automobile vehicles and thermal power plants. This is so because these produce toxic gases and need an electrostatic precipitator to remove particulate matter from their exhaust.

(b) One of the major limitations of the electrostatic precipitator is that it cannot remove particulate matter that are very small particles that are less than 2.5-micrometre in diameter). The PM 2.5 or smaller are the one which causes various respiratory problems and can pose the greatest harm to human health.

Algal bloom imparts a distinct colour, diminishes the water quality, increases fish mortality and is extremely toxic to human beings and animals.

a. Development of embryo depends upon the amount of endosperm present in the nucleus, as the embryo obtain its nutrition from the endosperm only. The cells of the endosperm tissue are filled with reserve food materials and provide nourishment to the developing embryo.
b. Utilization of the endosperm vary among plants, in some plants endosperm, gets exhausted or used up and produce exalbuminous seeds e.g groundnut.
In plants like castor some part of the endosperm persist in the seeds and are used during seed germination, these seeds are termed as albuminous
c. Seeds are covered by a hard covering called as integument, except at the top part of seed called as micropyle. Mycropyle helps in the entry of O₂ and H₂O during seed germination. Pollen tube enters the ovary through the micropyle. 
d. Maturation of seed is preceded by reduction in water content and increase hardening of integuments. Reduced content of water makes the seed metabolically slow and dry. Then embryo enters into dormancy stage. When seeds are subjected to adequate moisture, oxygen and suitable temperature they start to grow.
e. Maturation of ovules into seed and development of ovary into fruit occur simultaneously. When fruit develops from thalamus rather than from ovary are termed as false fruit.

(a) The presence of large amounts of nutrients in water leads to algal bloom. These nutrients (nitrogen and phosphorus) are added to water bodies from fertilisers that get issolved in soil and are washed off by water bodies. Algal bloom affects the quality of water in the
following ways:
(i) It causes deterioration of water quality making it unfit to use.
(ii) Eutrophication (natural ageing of water bodies) is accelerated, resulting in hypoxic conditions (i.e. low oxygen), killing off the aquatic diversity.
(b) To prevent the algal bloom, the farmers instead of using chemical nutrients must start using natural products like manures produced using vermicomposting. Biodegradable materials should be used, that are readily decomposed and are phosphate free. Awareness should be created among people about the effects of dumping waste in water bodies.

(a) The three states through which the annuals and biennial angiosperms pass during their life cycle are:
(i) Vegetative or Juvenile phase
(ii) Reproductive phase
(iii) Senescent phase
(b) Vegetative propagules are the parts/units of a plant which can be used for vegetative propagation, e.g. roots, stems, leaves, etc. Root propagules include the production of a new plant via roots, e.g. fleshy roots in case of sweet potato, tapioca and Dahlia. Vegetative propagation through leaves, many plant leaves have adventitious buds which help in the development of a new plant, e.g. Begonia, Bryophyllum, etc.

Roles of ‘flocs’ and ‘activated sludge’ in sewage treatment are as follows: Flocs These are masses of bacteria held together by slime and fungal filaments to form mesh-like structures. Flocs are used during the secondary sewage treatment in the aeration tank to increase the rate of decomposition. The microbes digest a lot of organic matter, converting it into microbial biomass and releasing a lot of minerals. As a result, BOD of the sewage reduces. As the BOD of waste is reduced to 10-15% of raw sewage, it is passed into settling tanks. In these tanks, flocs are allowed to undergo sedimentation. Activated Sludge The sediment of settling tank is called activated sludge. A part of it is used as inoculum in aeration tanks. The remaining part is passed into a large tank called anaerobic sludge digester. In these tanks, anaerobic microbes are present that digest the organic mass as well as aerobic microbes of activated sludge. The remaining sludge is used as manure or compost.

(a) Restriction Endonucleases These are the bacterial enzymes that cut dsDNA into fragments after recognising and binding to the specific nucleotide sequences, known as recognition site. These enzymes are used to form recombinant molecules of DNA, composed of DNA from different sources.

(b) Gel-Electrophoresis is the technique which allows the visualisation of separated fragments of DNA on an agarose gel matrix.
Since, the DNA fragments are negatively charged molecules, they separate and move towards the anode (+ ve) under the influence of an electric field. DNA fragments are separated on the basis of their size through the sieving effect provided by the gel.
(c) Selectable Markers in pBR322, an E. coli cloning vector has two antibiotic resistance genes, i.e. for ampicillin and tetracycline. Antibiotic resistance is used as selectable marker, i.e. it helps in identification and selection of transformants. For example, when a foreign DNA is ligated at the site of tetracycline resistance (tet r ,) gene in pBR322, the recombinant plasmid will lose tetracycline resistance due to insertional inactivation of foreign DNA, but can still be selected out from non-recombinants by placing the transformants on ampicillin containing medium. The transformants growing on ampicillin containing medium, are then transferred on tetracycline containing medium. The recombinants will grow on ampicillin containing medium but not on tetracycline one whereas non-recombinants grow on both.

(a) Following arguments can be put forward to promote burying and discourage burning:
(i) When we burn wastes, pollutants such as carbon dioxide,NO2 , SO2 , etc. are released in the atmosphere. These
pollutants damage the environment. Due to burning, smoke is released into atmosphere which causes
problems like asthma, emphysema, etc.
(ii) Burying the waste does not have any harmful effect in fact when we bury organic wastes, the soil becomes
enriched with nutrients.
(b) The solid wastes are of two types:
Biodegradable wastes These can be degraded by the microbes, e.g. organic waster paper, etc.
Non-biodegradable wastes These cannot be degraded by the microbes and can remain as such for long periods,
e.g. plastic.
Flow charts depicting effects of burying and burning are:

(1) Ozone depletion will be prevented.
(2) Green house effect will be controlled
(3) Global warming will be controlled.
(4) It will prevent old climatic changes that takes place due to rise in temperature.

Secondary treatment or Biological treatment :
* Primary effluent is passed into large aeration tanks with constant mechanical agitation and air supply. * Useful aerobic microbes grow rapidly and form flocs.
* Flocs are masses of bacteria and consumes organic matter and thus reduce the biochemical oxygen demand (BOD).
* When BOD of sewage has reduced, the effluent is passed into Settling tank.
* Here, the bacterial flocs settle and sediment is called activated sludge.
* A small part of the sludge is used as an inoculum in the aeration tank and the remaining part is passed into large tanks called anaerobic sludge digesters.
* In the digesters, heterotrophic microbes anaerobically digest bacteria and fungi in sludge producing mixture of gases such as methane, H2S, CO2 which forms the biogas.

Wastewater including sewage can be treated in an integrated manner, by utilising a mix of natural and artificial processes.

1. The conventional sedimentation, filtering and chlorine treatments are given. After this stage, lots of dangerous pollutants like dissolved heavy metals still remain.
2. To combat this, an innovative approach was taken and the biologists developed a series of six connected marshes over 60 hectares of marshland.
3. Appropriate plants, algae, fungi and bacteria were seeded into this area, which neutralises, absorb and assimilate the pollutants. Hence, as the water flows through the marshes, it gets purified naturally.
4. The marshes also constitute a sanctury, with a high level of biodiversity in the form of fishes, animals and birds.

a)Two causes of air pollution

(1) The burning of fossil fuels.
(2) Smoke released from vehicles.
(3) Industrial effluents
(4) Smoke stacks of thermal power plants.

(b) Harmful effects of air pollution.
(1) It affects respiratory system of humans and of animals.
(2) It also reduces growth and yield of crops & causes premature death of plants.

(c)
(1) Encouraging public transport i.e. buses & using CNG instead of diesel.
(2) Planting more trees to curb pollution.

A.

ozone

Ozone is found in the stratosphere acts as a shield absorbing ultraviolet radiation from the sun. So, its depletion can lead to an incidence of skin cancers. 

B.

1980s

The Joint Forest management Concept was introduced in 1980s by the Government of India to work closely with the local communities for protection and management of forests.

C.

death of fish due to lack of oxygen

A river with sewage increases the organic waste and decreases the dissolved oxygen.

A.

CoP-3

Kyoto protocol climate change conference (CoP-3) held at Kyoto, Japan in 1997. The developed countries agreed to specific targets for cutting their emissions of green- house gases. A general framework was defined for this, with specifics to be detailed over- the next few years. This became known as the Kyoto protocol.

A.

Reducing deforestation, cutting down use of fossil fuel

Global warming can be controlled by the reducing deforestation, cutting down the use of fossil fuel, which results in reduction into one of the greenhouse gas.i.e, CO₂.
The other ways of reducing global of warming are slowing down. The growth of human population, improving efficiency fo energy usage.

B.

1981

Air prevention and control of pollution protection act come into force in 1981. Environment protection act in 1986 and water (prevention and control of pollution) act in 1974.

B.

Doha

The UN conference of Parties (COP-18) was the UN framework convention on climate change (UNFCC) was held in Doha, Qatar from 26th Nov, to the 8th Dec 2012.

A.

biomagnification

Biomagnification is the sequence of processes in an ecosystem by which higher concentrations of a particular toxicant, such as the pesticide or heavy metal are reached in higher organisms of the food chain, generally through a series of prey-predator relationships. 

A.

Acid rain is caused by increase in the atmospheric concentration of SO₂ and NO₂. These mix with water vapour to form sulphuric acid (H₂SO₄) and nitric acid (HNO₃) respectively which falls on earth in the form of acid rain. 

D.

oxygen

Eutrophication is a process where water bodies receive excess nutrients that stimulate excessive plant growth. This can lead to overcrowding and competition for sunlight, space and oxygen.
This condition creates the lacking of essential nutrients for fishes due to which they die. 

D.

many of the birds eggs laid, did not hatch

DDT, its breakdown products and other chlorinated hydrocarbon pesticides posed an insidious threat to birds. These persistent poisons enter the food chain and they accumulate in the fatty tissues of organisms at lower trophic level and then tend to concentrate as they move through the food chain. This is called biomagnification or bioconcentration.  The insidious aspect of this phenomenon is that large concentrations of chlorinated hydrocarbons do not usually kill the bird out right. Rather, DDT and its relatives alter the bird's calcium metabolism in a way that results in thing egg shells which are unable to support the weight of incubating bird. So, many of the birds eggs laid are not hatched. This causes a significant decline in the population of birds.

D.

Eutrophication is a natural phenomenon in freshwater bodies

Ozone (O₃) is an isotope of oxygen which exists is so-called ozone layer at a height of about 15-60 km in the middle and upper stratosphere and lower mesosphere. This ozone layer absorbs UV-rays of longer wavelength and protects life on Earth from damaging effects of these radiations.
Ozone in the lower atmosphere (troposphere) is regarded as a pollutant. 

C.

Measuring the activity of Saccharomyces cerevisae in producing curd on a commercial scale

Decomposition of organic matter by microbes requires oxygen. The degree of impurity of water due to organic matter is measured in terms of BOD  (Biochemical Oxygen Demand) or BOD is the oxygen in milligrams required for five days in one litre of water at  for the microorganisms to metabolise organic waste.

C.

stratosphere

The ozone layer is mainly found in the lower portion of the stratosphere, i.e., approximately 20-30 km above the earth, though its thickness varies seasonally and geographically ozone layer acts as a shield absorbing UV rays from the sun.

B.

IUCN

IUCN is international Union for conservation of Nature, which publishes the Red List of threatened species or Red Data List which assesses the conservation status of species. It is an international organisation founded in October 1948. Its head quarter is in Gland Switzerland.
ICFRE is Indian Council of Forestry Research and Education which conduct forestry research, imparts forestry education, etc.
UNEP is United Nations Environment Programme that coordinate its environmental activities, assisting developing countries in implementing environmental sound policies and practices.
WWF is World Wide Fund for nature (WWF) which works on issues regarding the conservation, research and restoration of the environments.

A.

Gases like sulphur dioxide

Scrubber is an electrostatic precipitator in which the dirty air is cleaned by capturing the gas like SO₂ and other oxides in water/lime spray

B.

is processed by aerobic and then anaerobic bacteria in the secondary treatment is Sewage Treatment Plants (STPs)

Sewage is waste water having food residue, animal and human excreta, detergents, discharges from commercial and industrial establishments. The domestic sewage is processed first by aerobic and then by anaerobic bacteria in secondary treatment in Sewage Treatment Plant (STPs).

B.

South Africa

THE UN conference of parties on climate change in the year 2011 from 28th November to 1st December was held at Durban, South Africa.

B.

water is highly polluted

BOD is the measure or oxygen required for chemical breakdown of organic pollutants or wastes. High value of BOD in a water source indicates, high level of pollutants. Highly polluted water bodies has increased demand of BOD.

A.

pesticide pollution

Silent spring documents the determental effect of indiscriminated use of pesticides, on the environment and both its components.
The book spurred the authorities and caused a reversal in pesticide usage policies also, ensuring a nationwide ban on DDT use in agricultural fields.
Environmental protection agencies and acts were created as the result of jarring awareness caused by the book.

D.

Increased liver cancer

Depletion of stratospheric ozone, UV radiation is able to reach earth's surface. The exposure to these radiations has increased the occurrence of skin cancer, snow blindness (damage to eyes), herpes and deficient functioning of immune system, etc.
Live cancer is not a consequence of UV exposure it is a pathogen-induced, health or life - style induced disease.

C.

CO₂ and N₂O

The phenomenon of keeping the earth warm due to presence of certain radiatively gases in the atmosphere is called green house effect (Fourier, 1827). The name is based after a similar warmer interior in a glass-enclosed green house where glass panes, CO₂ and water vapour allow the solar radiations to enter but prevent the escape of long wave heat radiations. CO₂ and N₂O are the major causes of 'green house effect'. CO₂ contributes 60% of total global warming. N₂O contributes 6% to green house effect.

C.

IUCN = International Union for Conservation of Nature and Natural Resources

IUCN OR IUCNNR (International Union for Conservation of Nature and Natural Resources) is now known as WCU (World Conservation Union). Its headquarters are at Morges, Switzerland. It studies the threat to biodiversity in all parts of the world by gathering information about the geographical distribution, population size and population changes of various taxa. It prepares a red list or red data book.

B.

Radioactive fallout engulfed Bhopal

Bhopal gas Tragedy (Bhopal disaster) the world's worst industrial catastrophes. It occurred on the night of December 2/3, 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh. A leak of methyl isocyanate gas and other chemicals from the plant resulted in the exposure of hundreds of thousands of people. The official immediate death toll was 2,259 and the government of Madhya Pradesh has confirmed a total of 3,787 deaths related to the gas release. A government affidavit in 2006 stated the leak caused 5, 58125 injuries.

B.

Ocean

Eutrophication is a nutrient enrichment of water body resulting in increased growth of algae, other plants and animals. It is often seen is fresh water lakes. Actually, it is the natural ageing of a lake by biological enrichment of its water.

C.

stratosphere

The stratosphere is the second major layer of earth's atmosphere, just above the troposphere and below the mesosphere. It is the layer of ozone (O₃). The ozone absorb high-energy UV-B and UV-C energy waves and breakdown into atomic Oxygen (O) and diatomic oxygen (O₂).

C.

Biogas, commonly called gobar gas, is pure methane

Activated sludge is a process dealing with the treatment of sewage and industrial waste waters. Atmospheric air on pure oxygen is introduced to a mixture of primary treated or screened sewage (or industrial waster water) combined with organisms to develop a biological flock, which reduces the organic content of the sewage. Sediment is settlement tanks of sewage treatment plant is a rich source of aerobic bacteria because small amounts are used as inoculum in secondary treatment of biological treatment stage of sewage treatment.

A.

(2) and (3)

When a person moves to higher altitudes, the P_O2 and total atmospheric pressure decrease. Hypoxia stimulates the JG - cells of the kidney to release erythropoietin hormone, which stimulates erythropoiesis in bone marrow causing polycythemia. Hypoxia will also increase breathing rate. Initially, the size of RBCs will also increase but with an increase in number of RBCs, the size of RBCs becomes normal.