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Environmental Issues

1. Environmental Issues

Environmental Issues

Pollution Any undesirable change in natural resources is termed as pollution. Though pollution at times, occurs naturally due to volcanic eruptions, forest fibres, etc., it is mainly man-made (anthropogenic), due to the enormous growth in the human population size.

Environment (Protection) Act, 1986 To control environmental pollution and to protect and improve the quality of environment the Government of India, has passed the Environment (Protection) Act, 1986.

Types of Pollution: (i) Air Pollution (ii) Water Pollution (iii) Soil Pollution

POLLUTANTS y Substances that reduce the physical and chemical qualities of natural resources are pollutants.

Types of Pollutants Whether microbes can decompose any pollutant or not, pollutants are of two types: Biodegradable and non-biodegradable pollutants.

Biodegradable Pollutants Non-biodegradable Pollutants

Pollutants which can be broken into simpler and harmless substances by the action of decomposers or microbes.

Pollutants which cannot be broken into simpler and harmless substances by the action of decomposers or microbes.

For example, sewage, paper, leather goods, animal refuse, dead plants and animals, etc.

For example, pesticides, polythene bags, plastics, aluminium cans, e-wastes, etc.

Definition

Pollution: Any undesirable change in the physical, chemical and biological characteristics of air, water and soil that adversely affect the living organisms.

3. Environmental Issues

Causes of Air Pollution y Smokestacks of thermal power plants, smelters and other industries. y Burning of fossil fuels in automobiles, industries and households. y Smoke from forest fires, volcanic eruptions, etc. y Release of unwanted gases into the atmosphere due to the decompositiobn of garbage.

Air Pollutants y Thermal power plants, smelters, oil refineries automobiles, etc., release: ○ Particulate pollutants, e.g., metallic particles, dust particles, soot, aerosol, etc.

Definition

Pollutants: These are those substances or agents which bring about undesirable changes in the properties of air, water and soil, that adversely affect the living organisms.

Environmental Issues 4.

○ Gaseous pollutants like carbon monoxide (CO), sulphur dioxide (SO 2 ) and nitrogen oxides (NOx).

CONDITIONS THAT CAUSE HARMFUL EFFECTS OF AIR POLLUTION y Concentration of pollutants. y Duration of exposure to the pollutants.

HARMFUL EFFECTS OF AIR POLLUTION IN ANIMALS y Respiratory problems in humans and other animals. y Skin problems like rashes, acne, skin ageing, etc.

HARMFUL EFFECTS OF AIR POLLUTION IN

PLANTS

y Injury to plants y Premature death of plants y Reduced growth y Delayed flowering and reduced yield.

FINDINGS OF CENTRAL POLLUTION CONTROL

BOARD (CPCB)

y As per Central Pollution Control Board (CPCB), particulate size 2.5 micrometres or less in diameter (PM 2.5μm) cause greatest damage to human health. y These particles cannot be exhaled as they settle down deep inside the lungs. y These particles cause inflammation and damage of lungs, severe respiratory problems, irritation in respiratory tract and premature deaths.

Note: Air (Prevention and Control of Pollution) Act came into force in 1981.

CONTROL METHODS

To reduce harmful gases and particulate matter from the exhausted air of automobiles and industries following are the control methods:

Suspended Particulate Matter (SPM) It includes solid but small sized pollutants which remain suspended in the air. It is formed of dust particles which may be silica, cement, coal, etc. It is known to cause respiratory diseases like bronchitis, asthma, pneumoconiosis, asbestosis, silicosis, etc.

Previous Year’s Question

Automobile exhaust gas that causes major respiratory problem is (1) CO (2) CH (3) NO 2 (4) Chlorine

Previous Year’s Question

Acid rain is secondary effect of (1) sound pollution (2) water pollution (3) air pollution (4) soil pollution

Environmental Issues 6.

y Scrubber ○ It is used to remove gases like sulphur dioxide (SO 2 ) from the industrial exhaust. ○ The exhaust is passed through a spray of lime water. ○ Water dissolves the gases while lime reacts with sulphur dioxide to form precipitate of calcium sulphate or sulphite.

Note: Wet scrubbing

Wet scrubbing primarily uses magnesium-enhanced lime (containing 3-8% magnesium oxide) because it provides high alkalinity to increase SO (^2) removal capacity from industrial exhaust.

y Catalytic Converters ○ Used in vehicles for reducing emission of harmful and poisonous gases. ○ Platinum-palladium and rhodium as catalysts. ○ Through chemical reactions catalytic converters convert:  Unburnt hydrocarbons into carbon dioxide (CO 2 ) and water vapour (H 2 O).  Carbon monoxide and nitric oxide (NO) , nitrogen dioxide (NO 2 ) get changed into carbon dioxide (CO 2 ) and nitrogen gas (N 2 ).

Caution: Unleaded petrol to be used in vehicles

Unleaded petrol should be used in vehicles with catalytic converters as lead in the petrol inactivates the catalyst

Previous Year’s Question

Carbon monoxide is a pollutant because it (1) inactivates nerves (2) inhibits glycolysis (3) combines with oxygen (4) combines with haemoglobin

7. Environmental Issues

AUTO FUEL POLICY

y The Government of India has laid down a road map to cut down the vehicular air pollution in many cities of India through the auto fuel policy. y The goal of this policy is to reduce sulphur at 50 ppm in petrol and diesel, and reduce it further to 35 per cent. y According to Euro II norms, sulphur is to be controlled at 350 ppm in diesel and 150 ppm in petrol; aromatic hydrocarbons are to be contained at 42 per cent. y Upgradation of vehicle engines.

Rack Your Brain

Leaded gasoline contains lead (1) peroxide (2) tetramethyl (3) tetraethyl (4) oxide

Table: Mass Emission Standards in India

Note:

In 13 megacities (Delhi and NCR, Mumbai, Kolkata, Chennai, Bengaluru, Surat, Kanpur, Agra, Lucknow and Solapur) Bharat Stage IV emission norms have been in place since April 2010 and it has been enforced for entire country since April 2017

CONTROL OF VEHICULAR AIR POLLUTION IN

DELHI

y The switching over of public transport from diesel to Compressed Natural Gas (CNG) from the end of 2002.

9. Environmental Issues

HEARING FREQUENCY RANGE OF HUMAN BEINGS

y Human beings can hear sound in a frequency range of 20 hertz to 20 kilohertz (1kHz = 1000 Hz). y In decibels (dB) the hearing range is 0 dB (threshold) to 120–130 dB. y All sounds above 90 dB harm the inner ear and do irreversible damage above 120 dB. y Extremely high sound level of 150 dB or more generated by take-off of a jet plane or rocket and can cause damage to the eardrum and permanent loss of hearing. y Chronic exposure to low level noise ( 80 dB ) can also cause permanent damage to hearing abilities.

Previous Year’s Question

Pollution is controlled by: (1) Banning atomic blasts (2) Use of electrically operated automobile (3) Sewage treatment (4) All the above

Previous Year’s Question

Noise pollution is measured in: (1) Hertz (2) Fathoms (3) Nanometres (4) Decibles

NOISE AS AIR POLLUTANT

y The Air (Prevention and Control of Pollution) Act was amended in 1987 to include noise as an air pollutant.

Harmful Effects of Noise on Human Beings: y Sleeplessness (insomnia) y Increased rate of heartbeat or racing pulse.

Environmental Issues 10.

y Altered breathing pattern. y Stress (Physical and mental) y High blood pressure y Anxiety y Hearing impairment y Tinnitus

Control of Noise: ○ Establishment of horn-free zones (silent zones) around schools and hospitals. ○ Use of sound absorbent materials or mufflers in industries. ○ Use of acoustic material in the wall of homes located in high sound zones. ○ Machines with low noise emission should be used. ○ Silencers are fitted in automobiles and industrial gadgets. ○ Use of crackers and loudspeakers with permissible sound levels. ○ Laws are framed to enforce timings like loudspeakers, etc., cannot be used after 10 pm till 6 am.

PERMISSIBLE NOISE LEVEL y Central Pollution Control Board (CPCB) has laid down the permissible noise level for different areas or zones in India:

Zone

Permissible Noise Level Standards

Day (dB) Night (dB)

Silent Zone 50 dB 40 dB

Residential Zone 55 dB 45 dB

Industrial Zone 75 dB 70 dB

Previous Year’s Question

Maximum permissible noise as per Noise Pollution Rules 2000 is (1) 75 dB (2) 65 dB (3) 55 dB (4) 45 dB

Previous Year’s Question

Noise becomes uncomfortable above (1) 180 dB (2) 140 dB (3) 100 dB (4) 80 dB

Environmental Issues 12.

EFFECTS OF WATER POLLUTION ON LIVING

ORGANISMS

Domestic Sewage y Domestic sewage mainly contains biodegradable wastes, they are decomposed by microorganisms; the decomposers use oxygen of the water body and hence many aquatic organisms die due to lack of oxygen. y Biochemical Oxygen Demand (BOD) is used to measure the amount of biodegradable organic matter in sewage water. y Higher BOD reflects more is the presence of biodegradable wastes in sewage water. y Domestic sewage contains nutrients like nitrogen add phosphorus, which trigger excessive growth of algae and aquatic plants; this may result in algal bloom which in turn causes the following: ○ Deterioration in water quality ○ Fish mortality ○ Secretion of chemicals that are highly toxic to human and other animals.

Definition

Biochemical Oxygen Demand (BOD): It is a measure of oxygen required by aerobic decomposers for the biochemical degradation of biodegradable organic wastes.

Definition

Algal Bloom: The excess or profuse proliferation of planktonic algae imparting distinct colour to the water, is called algal bloom.

Previous Year’s Question

Treatment of polluted water is carried with the help of (1) Lichens (2) Fungi (3) Ferns (4) Phytoplanktons

13. Environmental Issues

y Domestic sewage may also contain pathogens and cause diseases like typhoid, jaundice, dysentery, etc.

Industrial Chemical Wastes ○ Industrial wastes often contain heavy metals like cadmium, mercury, lead, copper, etc., and a variety of organic compounds; many industrial chemicals are toxic to humans and other animals. ○ Mercury and DDT ( Dichloro Diphenyl Trichloroethane ) cause biological magnification. ○ For example, the concentration of DDT increases from 0.003 ppb (parts per billion) in water to 5 ppm (part per million) in fish- eating birds. ○ The concentration of DDT increases at successive trophic levels because it is neither metabolised nor excreted; instead, it accumulates in the tissues of the organisms. Note: Maize is the sensitive indicator of fluoride pollution.

FACT!!!

A mere 0.1 percent impurities make domestic sewage unfit for human consumption.

Definition

Biological Magnification : The phenomenon in which harmful chemicals get accumulated in the tissues of organisms in increasing concentrations at successive trophic levels, as they travel along the food chain.

15. Environmental Issues

EUTROPHICATION

y Natural ageing of a lake by nutrient enrichment such as nitrogen and phosphorus of its water. y Nutrients of lake’s water promote growth of aquatic organisms. y Over the time bottom of the lake is piled up with debris that makes it shallower and warmer which promotes marsh like plants. y Thus, aquatic succession continues for thousands of years.

ACCELERATED OR CULTURAL EUTROPHICATION

y Overloading of a lake with domestic, agricultural and industrial wastes speeds up the eutrophication termed as accelerated or cultural eutrophication. y The prime contaminants are nitrates and phosphates which act as plant nutrients. y Growth of algae is over stimulated.

Definition

Cultural or Accelerated Eutrophication: It is man-induced nutrient enrichment of water bodies which accelerate algal growth and dissolved oxygen is reduced.

Definition

Eutrophication: It refers to the nutrient enrichment in the water bodies leading to lack of oxygen and deadening of life-supporting conditions.

Environmental Issues 16.

y Unpleasant odours are generated, dissolved oxygen (DO) is used up by the algae resulting in suffocation and eventually death of other aquatic organisms. y Reduced dissolved oxygen slows down the decomposition of debris and further addition of sewage, etc., chokes the lake to death.

Note : Eichhornia crassipes grows very fast in eutrophicated lakes and other such water bodies causing imbalance in the ecosystem dynamics. It is world’s most problematic aquatic weed and in India it is called ‘ Terror of Bengal’.

Thermal Wastewater ○ Thermal (heated) wastewater flowering out from thermal power plants (electricity- generating units), eliminates or reduces many organisms that are sensitive to high temperature (indigenous flora and fauna) and it may enhance the growth of plants and fish in extremely cold areas.

SOLID WASTES y Solid wastes refer to all that goes out in trash. y Types of solid wastes:

Municipal solid wastes ○ These are wastes from homes,schools,offices, etc., that are collected and disposed by the municipality and generally consists of paper, glass,waste food materials, leather, textile, rubber, etc. ○ When they are dumped in the open, they provide breeding ground for flies and other insects which may be vectors.

Fly ash ○ Thermal power plants generate fly ash. It is composed of oxides of silica, iron and

Rack Your Brain

Why is Eichhornia crassipes known as the world’s most problematic aquatic weed?

Gray Matter Alert!!!

Consumption of large amount fish and shellfish contaminated with mercury can cause a disease of central nervous system known as Minamata disease or Chisso-Minamata disease.