ENVIRONMENTAL ISSUES

ENVIRONMENTAL ISSUES

 

ENVIRONMENTAL ISSUES

·         Pollution: is any undesirable changed in physical chemical or biological characteristics of air, land, water or soil.

·         Pollutant: Any solid, liquid or gas released into the environment in such a huge quantities that make our environment unhealthy is called pollutant.

·         Environment (protection) Act, 1986 to protect and improve the quality of our environment (air, water and soil)

AIR POLLUTION AND ITS CONTROL:

Effect of air pollution:

·         Cause injury to all living organisms.

·         Reduce growth and yield of crops.

·         Cause premature death of plants.

·         Affects the respiratory system of human being.

·         Particulate size 2.5 micrometers or less are responsible for breathing and respiratory symptoms like irritation, inflammations and damage to the lungs and premature death.

Pollution caused by thermal power plant:

·         Sources of particulate matter: thermal power plant, smelters

·         These plants release particulate matter and gaseous air pollutant.

·         A harmless gas released by these plants is Nitrogen and Oxygen.

Prevention of air pollution: ways to remove particulate matter:

·         Electrostatic precipitator

o    Widely used to remove particulate matter in the exhaust from a thermal power plant.

o    Electrode wires that are maintained at several thousand volts, which produce a corona that release electrons.

o    Electron binds with particulate matter giving them a net negative charge.

o    Positively charged collecting plates attract the charged dust particle.

 

·         Scrubber:

o    Removes gases like sulphur dioxide.

o    The exhaust is passed through a spray of water or lime.

 

·         Methods to reduce vehicular pollution:

o    Use of lead free petrol or diesel can reduce vehicular pollution.

o    Catalytic converter:

§  Having expensive metals namely platinum, palladium and rhodium as the catalyst.

§  These metals reduce emission of poisonous gases.

§  The unburnt hydrocarbons are converted into CO₂ and H₂O.

§  Carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas respectively.

§  Motor vehicle equipped with catalytic converter should use unleaded petrol because lead in the petrol inactivates the catalyst.

Controlling Vehicular pollution: A case study of Delhi:

·         Use of CNG (compressed natural gas):

Advantages of CNG

·         CNG burns most efficiently.

·         Very little remain unburnt.

·         Cannot be siphoned

·         Cannot be adulterated like petrol or diesel.

·         CNG is cheaper than petrol and diesel.

Problem of use of CNG:

·         Difficulty in laying down pipelines to deliver CNG

·         Non-assurance of uninterrupted supply.

Other parallel steps taken in Delhi:

·         Phasing out old vehicles.

·         Use of unleaded petrol.

·         Use of low-sulphur petrol and diesel.

·         Use of catalytic converter in vehicle.

·         Application of strict pollution level norms for vehicle.

New auto fuel policy to cut down vehicular pollution.

·         Steadily reducing the sulphur and aromatic content in petrol and diesel fuels.

·         Euro-II norms

o    Sulphur reduced to 350 ppm in diesel.

o    Sulphur reduced to 150 ppm in petrol

o    Aromatic hydrocarbon to be reduced to 42 %.

o    Up gradation of vehicle engines.

 

·         Due to above steps taken by Delhi Govt. there is substantial fall in CO₂ and SO₂ level between 1997 and 2005.

NOISE POLLUTION:

• Undesirable high level of sound is called noise pollution.

Harm full effect of noise pollution:

• Psychological and physiological disorder in humans.
• High sound level, 150dB or more may damage ear drums.
• Noise causes sleeplessness
• Increased heart rate.
• Altered breathing pattern.

Prevention of Noise Pollution:

•   Use of sound absorbent materials or by muffling noise in industries 
•    Demarcation of horn free zones around hospitals and schools. 
•    Permissible sound levels of crackers, 
•    Timings after which Loudspeakers cannot be played 

WATER POLLUTION AND ITS CONTROL:

Domestic sewage and industrial effluents:

• A mere 0.1 percent impurities make domestic sewage unfit for human use
• Sewage contains dissolve salts like nitrates, phosphates, and other nutrients, and toxic metal ions and organic compounds.
• The amount of organic matter in water is estimated by BOD.
• Biochemical oxygen demand: the amount of Oxygen required oxidizing all organic matter present in one liter of water.
• Changes take place on discharge of sewage into the river.
• Micro-organism involved in biodegradation of organic matter in the receiving water body consume a lot of oxygen, hence there is sharp decline in dissolved oxygen downstream from the point of discharge.
• Due to low DO there is mortality of fish and other aquatic animals.

 

• Presence of large amount of nutrients in water also causes excessive growth of Planktonic (free floating) algae, called algal bloom.
• Algal bloom imparts distinct color to water bodies.
• Deterioration of water quality and fish mortality.
• Some bloom-forming algae are extremely toxic to human and animals.

 

• The world’s most problematic aquatic weed is water hyacinth (Eichhornia crassipes) called ‘Terror of Bengal’.
• Introduced to India for their lovely flowers.
• Excessive growth causes blocks in waterways.
• They grow abundantly in eutrophic water bodies.
• Causes imbalance in ecosystem and dynamics of water body.

 

• Sewage  associated with diseases:
• Sewage from home and hospital contain pathogenic microbes.
• Discharge of such sewage without proper treatment causes diseases like dysentery, typhoid, jaundice, cholera etc.

 

• Toxic heavy metals (defined as elements with density > 5g/cm3), released from:-
• Petroleum industry.
• Paper manufacturing.
• Metal extraction and processing.
• Chemical manufacturing industries.

 

• Biomagnifications: increase in concentration of the toxicant at successive trophic level is called biological magnification or biomagnifications.
• Toxic substance accumulated by an organism cannot be metabolized or excreted.
• The accumulated toxic passed to the next trophic level.
• This phenomenon is well known for mercury and DDT.

 

• Bio magnification of DDT in Aquatic food chain.

• Eutrophication: The process of nutrient enrichment of water and consequent loss of species diversity is referred to as Eutrophication.
• Natural Eutrophication:
• Streams draining into the lake increase nutrients like nitrogen and phosphorus.
• Increase in nutrient encourages growth of aquatic organisms.
• Over centuries, as silt and organic debris pileup the lake grows shallower and warmer.
• Warm-water organisms dominate over that thrive in a cold environment.
• Marsh plants take root in the shallows and begin to fill in the original lake basin.
• Eventually the lake gives way to large masses of floating plants (bog), finally converting into land.

 

 Cultural or Accelerated Eutrophication:

o    Pollutants from man’s activities like effluents from the industries and homes can radically accelerate the aging process. This phenomenon is called Cultural or Accelerated Eutrophication.

Causes:

·         Sewage and agricultural and industrial wastes.

·         Prime contaminants are nitrates and phosphates.

Effects:

·         Unsightly scum and unpleasant odors.

·         Robbing the dissolved oxygen form water.

·         Pollutant inflow kills the fish.

·         Decomposition of dead fish causes further depletion of DO.

·         Finally a lake can literally choke to death.

Thermal pollution:

Cause:

·         Heated (thermal) waste waters flowing out of electricity-generating units. E.g. thermal power plants.

Effects:

·         Thermal wastewater eliminates or reduces the number of organism sensitive to high temperature.

·         Enhance the growth of plants and fish in extremely cold areas but only after causing damage to the indigenous flora and fauna.

 

 

A case study of integrated waste water treatment:

·         Wastewater including sewage can be treated in an integrated manner, by utilizing a mix of artificial and natural process.

·         It has been done in town of Arcata, in the northern coast of California.

·         The treatment is done in two stages:-

o    The conventional sedimentation, filtering and chorine treatment are given.

o    The biologist developed a series of six connected marshes over 60 hectares of marshland.

o    Appropriate plants, algae, fungi and bacteria were seeded into this area, which neutralize, absorb and assimilate the pollutant

o    The water flows through the marshes, it get purified naturally.

 

·         The marshes also constitute a sanctuary, with high level of biodiversity in the form of fishes, animals and birds that now reside there.

·         A citizens group called Friends of the Arcata Marsh (FOAM) is responsible for the upkeep and safeguarding of this project.

Ecological sanitation:

·         Ecological sanitation is a sustainable system for handling human excreta, using dry composting toilets.

·         This is a practical, hygienic, efficient and cost-effective solution to human waste disposal.

·         With this composting method human excreta can be recycled into are source (as natural fertilizer).

·         ‘EcoSan’ toilets are being used in Kerala and Srilanka.

SOLID WASTES:

·         Solid wastes refer to everything that goes out in trash.

·         Municipal solid wastes are wastes from homes, offices, stores, schools, hospitals etc. It comprises paper, food wastes, plastics, glass, metals rubber, leathers, textiles etc.

·         Open damp of these wastes serve as the breeding ground for rats and flies.

·         Sanitary landfills were adopted as substitute for open-burning dumps.

Sanitary landfills:

·         Wastes are dumped in a depression or trench after compaction and covered with dirt everyday.

Disadvantages:

·         Shortage of space for huge garbage’s.

·         Danger of seepage of chemicals, polluting the ground water resources.

Solution to solid wastes:

·         All solid wastes are categorized into three types:

o    Bio-degradable.

o    Recyclable.

o    Non-biodegradable.

 

·         All the garbage generated is sorted first.

·         Recyclable material to be separated and send for recycles.

·         Biodegradable wastes can be put into deep pits in the ground and be left for natural breakdown.

·         Only Non-biodegradable wastes are left and required to be disposed.

Prevention:

·         The need to reduce our garbage generation should be a prime goal.

·         Reduction in use of plastics and use of eco-friendly packaging.

·         Carrying cloth or other natural fiber carry bags when we go shopping.

·         Refusing polythene bags.

Case study of Remedy for Plastic wastes: (Ahmed Khan)

·         Polyblend, a fine powder of recycled modified plastic, was developed by his company.

·         Polyblend is mixed with bitumen that is used to lay roads.

·         It increases the water repelling property of bitumen, and helped to increase road life by a factor of three.

·         The raw material used for polyblend is plastic film waste.

Hospital wastes:

• Hospitals generate hazardous wastes that contain disinfectants and other harmful chemicals, and also pathogenic organisms.
• The use of incinerators is crucial to disposal of hospital wastes.

Electronic wastes (e-wastes):

• Irreparable computers and other electronic goods are known as electronic wastes (e-wastes).
• E- Wastes are buried in landfills or incinerated.
• Metals like copper, iron, silicon, nickel and gold are recovered during recycling process of e-wastes.
• Manual recycling process exposes workers to toxic substances present in e-wastes.
• Recycling is the only solution for the treatment of e-wastes.

 

AGRO-CHEMICAL AND THEIR EFFECTS:

• Use of inorganic fertilizers and pesticides has increased manifold for enhancing crop production.
• Pesticides, herbicides, fungicides etc., are being increasingly used.
• These are toxic to non-target organisms that are important components of the soil ecosystem?
• Increasing amounts of artificial fertilizers causes eutrophication.

Case study of organic farming: (Ramesh Chandra Dagar of Sonipat)

• Integrated organic farming is a cyclical, zero waste procedure, where waste products from one process are cycled in as nutrients for other processes.
• Maximum utilization of resource and increase the efficiency of production.
• He includes bee-keeping, diary management, water harvesting, composting and agriculture in a chain of processes, which support each other and allow an extremely economical and sustainable venture.

Advantages:

• There is no need of use of chemical fertilizers for crops
• Cattle excreta are used as manure.
• Crop waste used to create compost, which can be used as a natural fertilizer or can be used to generate natural gas for energy need.

RADIOACTIVE WASTES:

• Nuclear energy was hailed as a non-polluting way for generating electricity.
• Later on it was realized that it has two very serious inherent problem:-
• Accidental leakage, as occurred in Three Mile Island and Chernobyl.
• Safe disposal of radioactive wastes.

 

• Radiation from radioactive waste causes mutation at very high rate.
• High dose of nuclear radiation is lethal, but lower doses create genetic disorders and also cause cancer.

Disposal of nuclear wastes:

• Storage of nuclear waste, after sufficient pre-treatment, should be done in suitably shielded containers buried within the rocks about 500 m deep below the earth’s surface.

GREEN HOUSE EFFECT AND GLOBAL WARMING:

• The term “Greenhouse effect” has been derived from a phenomenon that occurs in greenhouse.
• In a greenhouse the glass panel lets the light in, but does not allow heat to escape. Therefore the greenhouse warms up, very much like inside a car that has been parked in the sun for a few hours.
• The greenhouse effect is a naturally occurring phenomenon that is responsible for heating of Earth’s surface and atmosphere.
• Without greenhouse effect the average temperature at surface of earth would have been a chilly -18^o C rather than the present average of 15^o C.
• Clouds and gases reflect about one-fourth of the incoming solar radiation and absorb some of it but half of incoming solar radiation falls on Earth’s surface heating it, while a small portion is reflected back.
• Earth’s surface re-emits heat in the form of infrared radiation but some part of this does not escape into space because of atmospheric gases (e.g. carbon dioxide, methane etc.).
• The molecule of these gases radiate heat energy and a major part of which again comes to Earth’s surface, thus heating it up once again.
• Carbon dioxide and methane – are commonly called as greenhouse gases because they are responsible for greenhouse effect.
• Increase in the level of greenhouse gases has led to considerable heating of Earth leading to global warming or enhanced green house effect.
• During the past century, the temperature of Earth has increased by 0.6^o C.

Effect of global warming:

• Deleterious changes in the environment and resulting in odd climatic changes (e.g. El Nino effect).
• Increased melting of polar ice caps as well as of other places like the Himalayan snow caps.
• Rise in sea level that can submerge many coastal areas.

Control of global warming:

• Reduce use of fossil fuel.
• Improving efficiency of energy usage.
• Reducing deforestation.
• Promoting afforestation programme.
• Slowing down growth of human population.
• International initiative to be taken to reduce emission of greenhouse gases.

OZONE DEPLETION IN THE STRATOSPHERE:

• ‘Bad’ ozone formed in the lower atmosphere (troposphere) that harms plants and animals.
• There is ‘good’ ozone also; this ozone is found in the upper part of the atmosphere called stratosphere, and it acts as a shield absorbing ultraviolet radiation from the sun.
• The thickness of ozone layer is measured in terms of Dobson units (DU)
• Ozone (O₃) gas is continuously formed by the action of UV rays on molecular oxygen, and also degraded into molecular oxygen in the stratosphere.
• There should be proper balance of formation and degradation of ozone.

Ozone depletion:

• Balance of ozone in stratosphere is disrupted due to enhancement of ozone degradation by chlorofluorocarbons (CFCs).
• CFCs find wide use as refrigerants.
• CFCs discharged in the lower part of atmosphere move upward and reach stratosphere.
• In stratosphere, UV rays acts on CFCs and release active Cl atoms.
• Cl degrades ozone releasing molecular oxygen.
• Cl acts as catalysts and not consumed during reaction.
• Whatever CFCs are added to the stratosphere, they have permanent and continuing affects one Ozone levels.
• The depletion is marked particularly over the Antarctic region. This has resulted in formation of a large area of thinned ozone layer, commonly called as the ozone hole.

 

Effects of UV rays:

• UV radiations shorter than UV-B are almost completely absorbed by Earth’s atmosphere, if the ozone layer is intact.
• DNA and proteins of living organisms are damaged by UV rays as they potentially absorb it.
• The high energy of UV rays breaks the chemical bond in these molecules.
• UV – B damages DNA and mutation may occur.
• It causes ageing of skin.
• Damage skin cells and causes skin cancers.
• In human eye cornea absorb UV – B radiation and high dose of UV – B causes inflammation of cornea called snow-blindness, cataract etc.
• Such exposes may damage cornea.

Prevention:

• Montreal Protocol was signed at Montreal (Canada) in 1987 to control emission of ozone depleting substances.
• Many efforts are being made to reduce emission of ozone depleting substances.

DEGRADATION BY IMPROPER RESOURCE UTILIZATION AND MAINTENANCE:

Soil erosion 

• The removal of top fertile layer due to human activities 

Reasons: - 

•   Over cultivation 
•   Unrestricted  grazing 
•   Deforestation 
•   Poor  irrigation practices 

Water logging and soil salinity:

• Irrigation with proper drainage, leads to water lodging in the soil.
• Draws salt to the surface of the soil.
• The salt starts collecting at the roots of the plants.
• The salt damages the roots and crop productions.

Deforestation:

• Conversion of forested areas to non-forested one.

 

How deforestation does occurs:

• Slash and burn agriculture/jhum cultivation 
• Farmers cut down the trees of the forest and burn the plant remains. 
• Ash is used as fertilizer and land is used for farming or cattle grazing 
• Later, Land is left uncultivated for several years for replenishment of minerals 

Effects of deforestation 

• Leads to global warming due to excess carbon-dioxide 
• Loss of biodiversity 
• Damage to hydrological cycle 
• Leads to soil erosion 
• Desertification of land 

Reforestation 

• Restoring forest that was existing earlier    E.g. Observing Van-Mahotsavas 
•  It also occurs naturally 
• Afforestation Developing a forest in a new area where no such forest existed in that area.

A case study of people‘s participation in forest conservation

• A king of Jodhpur wanted to arrange wood for his new palace in 1731.
•  Few Bishnois hugged the trees and asked to cut them first rather than cutting trees. 
• 365 persons lost their lives in this act 
• A small temple is now present there in remembrance of this act 
• Amrita Devi Bishnois Wild Life Protection Award is instituted for individuals of rural areas who take keen interest in protecting wild life.
• Chipko movement
• It was started by local women of Garhwali; they hugged the trees to protect them from the axes of contractors.
• Joint forest management (jfm)
• Strategy Government of India in 1980 
• Local communities worked with the government to save the forest. 
• Communities get forest products for encouragement.

CPCB:     Central Pollution Control Board
BOD:        Biological Oxygen Demand
CNG:       Compressed Natural Gas
FOAM:      Friends of Arcata Marsh
JFM:         Joint Forest Management.