1.Growing human population –> Exerting tremendous pressure on natural resources, pollution of air, water and soil.
2. POLLUTION is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil.
3. Agents that bring about such an undesirable change are called as POLLUTANTS.
4. Environment (Protection) Act, 1986 to control environmental pollution & to protect and improve the quality of our environment (air, water and soil).
o Air pollutants cause injury to all living organisms.
o They reduce growth and yield of crops and cause premature death of plants.
o Air pollutants also deleteriously affect the respiratory system of humans and of animals.
o Harmful effects depend on
●the concentration of pollutants,
●duration of exposure and
o ●Smokestacks of thermal power plants, smelters and other industries
▪︎release particulate and gaseous air pollutants together with harmless gases, such as nitrogen, oxygen, etc.
▪︎These pollutants must be separated/ filtered out before releasing the harmless gases into the atmosphere.
▪︎There are several ways of removing particulate matter; the most widely used of which is the ELECTROSTATIC PRECIPITATOR, which can remove over 99 per cent particulate matter present in the exhaust from a thermal power plant.
A SCRUBBER can remove gases like sulphur dioxide.
Recently we have realised the dangers of particulate matter that are very very small and are not removed by these precipitators.
o According to Central Pollution Control Board (CPCB), particulate size 2.5 micrometers or less in diameter (PM 2.5) are responsible for causing the greatest harm to human health. These fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, irritation, inflammations and damage to the lungs and premature deaths.
o AUTOMOBILES ARE A MAJOR CAUSE FOR ATMOSPHERIC POLLUTION
atleast in the metro cities.
Proper maintenance of automobiles along with use of lead-free petrol or diesel can reduce the pollutants they emit.
Catalytic converters, having expensive metals namely platinum-palladium and rhodium as the catalysts, are fitted into automobiles for reducing emission of poisonous gases. 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. Motor vehicles equipped with catalytic converter should use unleaded petrol because lead in the petrol inactivates the catalyst.
In India, the Air (Prevention and Control of Pollution) Act came into force in 1981, but was amended in 1987 to include noise as an air pollutant.
6. Noise is undesired high level of sound.
o 150 dB or more generated by take off of a jet plane or rocket, may damage ear drums thus permanently impairing hearing ability.
o Even chronic exposure to a relatively lower noise level of cities may permanently damage hearing abilities of humans.
o Noise also causes sleeplessness, increased heart beat, altered breathing pattern, thus considerably stressing humans.
o Reduction of noise in our industries can be affected by use of sound absorbent materials or by muffling noise.
o Stringent following of laws laid down in relation to noise like delimitation of horn-free zones around hospitals and schools, permissible sound-levels of crackers and of loudspeakers, timings after which loudspeakers cannot be played, etc., need to be enforced to protect ourselves from noise pollution.
o Delhi leads the country in its levels of air-pollution
o In the 1990s, Delhi ranked fourth among the 41 most polluted cities of the world.
o Air pollution problems in Delhi became so serious that a public interest litigation (PIL) was filed in the Supreme Court of India.
o To tackle this within a specified time period, appropriate measures were taken by the government
Switching over the entire fleet of public transport, i.e., buses, from diesel to compressed natural gas (CNG).
All the buses of Delhi were converted to run on CNG by the end of 2002.
1. CNG burns most efficiently, unlike petrol or diesel
2. CNG is cheaper than petrol or diesel,
3. CNG cannot be adulterated like petrol or diesel.
●Phasing out of old vehicles,
●Use of unleaded petrol,
●Use of low-sulphur petrol and diesel,
●Use of catalytic converters in vehicles,
●Application of stringent pollution-level norms for vehicles, etc.
o More stringent norms for fuels means steadily reducing the sulphur and aromatic content in petrol and diesel fuels.
o The goal, according to the roadmap, is to reduce sulphur to 50 ppm in petrol and diesel and bring down the level to 35 per cent.
9. WATER POLLUTION AND ITS CONTROL
o Water bodies are our lifeline as well as that of all other living organisms.
o Due to human activities the ponds, lakes, stream, rivers, estuaries and oceans are becoming polluted in several parts of the world.
o WATER (PREVENTION AND CONTROL OF POLLUTION) ACT, 1974
to safeguard our water resources.
Domestic Sewage and Industrial Effluents
Even 0.1 per cent impurities make domestic sewage unfit for human use
Solids are relatively easy to remove, what is most difficult to remove are dissolved salts such as nitrates, phosphates, and other nutrients, and toxic metal ions and organic compounds.
Domestic sewage primarily contains biodegradable organic matter, which readily decomposes due to bacteria and other micro-organisms
These microbes multiply using these organic substances as substrates and hence utilise some of the components of sewage.
It is possible to estimate the amount of biodegradable organic matter in sewage water by measuring Biochemical Oxygen Demand (BOD).
Micro-organisms involved in biodegradation of organic matter in the receiving water body consume a lot of oxygen, and as a result there is a SHARP DECLINE IN DISSOLVED OXYGEN downstream from the point of sewage discharge.
This causes mortality of fish and other aquatic creatures.
Presence of large amounts of nutrients in waters also causes excessive growth of planktonic (free-floating) algae, called an ALGAL BLOOM which imparts a distinct colour to the water bodies. ALGAL BLOOMS CAUSE DETERIORATION OF THE WATER QUALITY AND FISH MORTALITY. Some bloom-forming algae are extremely toxic to human beings and animals.
o WATER HYACINTH (Eichhornia crassipes),
World’s most problematic aquatic weed, also called ‘TERROR OF BENGAL’.
They grow abundantly in EUTROPHIC WATER BODIES, and lead to an imbalance in the ecosystem dynamics of the water body.
o Sewage polluted water may cause outbreak of serious diseases, such as, dysentery, typhoid, jaundice, cholera, etc.
o WASTE WATER FROM INDUSTRIES often contain toxic substances,
heavy metals -mercury, cadmium, copper, lead, etc.
a variety of organic compounds.
A few toxic substances
These material can undergo BIOLOGICAL MAGNIFICATION (BIOMAGNIFICATION) IN THE AQUATIC FOOD CHAIN.
o BIOMAGNIFICATION refers to increase in concentration of the toxicant at successive trophic levels. This happens because a toxic substance accumulated by an organism cannot be metabolised or excreted, and is thus passed on to the next higher trophic level. This phenomenon is well known for MERCURY and DDT.
o Biomagnification of DDT in an aquatic food chain.
the concentration of DDT is increased at successive trophic levels;
if it starts at 0.003 ppb (ppb = parts per billion) in water, it can ultimately reach 25 ppm (ppm = parts per million) in fish-eating birds, through biomagnification.
High concentrations of DDT disturb calcium metabolism in birds, which causes thinning of eggshell and their premature breaking, eventually causing DECLINE IN BIRD POPULATIONS.
Natural aging of a lake by nutrient enrichment of its water.
Depending on climate, size of the lake and other factors, the natural aging of a lake may span thousands of years.
However, pollutants from man’s activities like effluents from the industries and homes can radically accelerate the aging process.
This phenomenon known as Cultural or Accelerated Eutrophication.
The prime contaminants are nitrates and phosphates, which act as plant nutrients.
They overstimulate the growth of algae, causing unsightly scum and unpleasant odors, and robbing the water of dissolved oxygen vital to other aquatic life.
In such fashion, a lake can literally choke to death.
o HEATED (THERMAL) WASTEWATERS
flowing out of electricity-generating units, e.g., thermal power plants
Thermal wastewater eliminates or reduces the number of organisms sensitive to high temperature, and may enhance the growth of plants and fish in extremely cold areas but, only after CAUSING DAMAGE TO THE INDIGENOUS FLORA AND FAUNA.
10. A Case Study of Integrated Waste Water Treatment
o Wastewater including sewage can be treated in an integrated manner, by utilising a mix of artificial and natural processes.
o Townspeople of Arcata, California & Humboldt State University Created an integrated waste water treatment process within a natural system.
o A citizens group called Friends of the Arcata Marsh (FOAM) are responsible for the upkeep and safeguarding of this wonderful project.
o Sustainable syECOLOGICAL SANITATIONstem for handling human excreta, using dry composting toilets. Practical, hygienic, efficient and cost-effective solution to human waste disposal.
o The key point to note here is that with this composting method, human excreta can be recycled into a resource (as natural fertiliser), which reduces the need for chemical fertilisers. THERE ARE WORKING ‘ECOSAN’ TOILETS IN MANY AREAS OF KERALA AND SRI LANKA.
o Solid wastes refer to everything that goes out in trash.
o Municipal solid wastes
Generally comprise paper, food wastes, plastics, glass, metals, rubber, leather, textile, etc.
Burning reduces the volume of the wastes, although it is generally not burnt to completion and open dumps often serve as the breeding ground for rats and flies.
o SANITARY LANDFILLS were adopted as the substitute for open-burning dumps. In a sanitary landfill, wastes are dumped in a depression or trench after compaction, and covered with dirt everyday.
danger of seepage of chemicals, etc., from these landfills polluting the underground water resources.
o A solution to all this can only be in human beings becoming more sensitive to these environment issues.
o All waste categorised into three types –
o The need to reduce our garbage generation should be a prime goal, instead, we are increasing the use of non-biodegradable products.
o State Governments across the country are trying to push for reduction in use of plastics and use of eco-friendly packaging
o Hospitals generate hazardous wastes that contain disinfectants and other harmful chemicals, and also pathogenic micro-organisms. Such wastes also require careful treatment and disposal.
The use of INCINERATORS is crucial to disposal of hospital waste.
o Irreparable computers and other electronic goods are known as ELECTRONIC WASTES (E- WASTES). E-wastes are buried in landfills or incinerated.
o Recycling is the only solution for the treatment of e-waste, provided it is carried out in an environment friendly manner.
o CASE STUDY OF REMEDY FOR PLASTIC WASTE
A plastic sack manufacturer in Bangalore Ahmed Khan
Polyblend, a fine powder of recycled modified plastic, was developed by his company. This mixture is mixed with the bitumen that is used to lay roads.
In collaboration with R.V.College of Engineering and the Bangalore City Corporation
Polyblend and bitumen increase road life by a factor of three.
The raw material for creating Polyblend is any plastic film waste.
o During green revolution, use of inorganic fertilisers and pesticides has increased manifold for enhancing crop production.
o Pesticides, herbicides, fungicides, etc., are being increasingly used.
o These incidentally, are also toxic to non-target organisms, that are important components of the soil ecosystem.
o Integrated organic farming is a cyclical, zero-waste procedure, where waste products from one process are cycled in as nutrients for other processes. This allows the maximum utilisation of resource and increases the efficiency of production.
o Ramesh Chandra Dagar, a farmer in Sonipat, Haryana, is doing just this. He includes bee- keeping, dairy management, water harvesting, composting and agriculture in a chain of processes, which support each other and allow an extremely economical and sustainable venture.
o There is no need to use chemical fertilisers for crops, as cattle excreta (dung) are used as manure.
o Crop waste is used to create compost, which can be used as a natural fertiliser or can be used to generate natural gas for satisfying the energy needs of the farm.
o Enthusiastic about spreading information and help on the practice of integrated organic farming, Dagar has created the Haryana Kisan Welfare Club.
o Use of nuclear energy has two very serious inherent problems.
The first –> Accidental leakage,
1. Three Mile Island tragedy and
2. Chernobyl disaster
●The second –> Safe disposal of radioactive wastes
o Radiation –> causes mutations at a very high rate –> extremely dangerous
o Nuclear waste is an extremely potent pollutant and has to be dealt with utmost caution.
o It has been recommended that 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.
o The greenhouse effect is a naturally occurring phenomenon that is responsible for heating of Earth’s surface and atmosphere.
o Carbon dioxide and methane – are commonly known as greenhouse gases because they are responsible for the greenhouse effect.
o Increase in the level of greenhouse gases has led to considerable heating of Earth leading to global warming.
o During the past century, the temperature of Earth has increased by 0.6 oC, most of it during the last three decades.
o This rise in temperature is leading to deleterious changes in the environment and resulting in odd climatic changes (e.g. EL NINO EFFECT) , thus leading to increased melting of polar ice caps as well as of other places like the Himalayan snow caps.
o Over many years, this will result in a rise in sea level that can submerge many coastal areas.
o Control of global warming
●cutting down use of fossil fuel,
●improving efficiency of energy usage,
●planting trees and slowing down the growth of human population.
●International initiatives are also being taken to reduce the emission of greenhouse gases into the atmosphere.
o ‘bad’ ozone, formed in the lower atmosphere (troposphere) that harms plants and animals.
o ‘good’ ozone also; this ozone is found in the upper part of the atmosphere called the stratosphere, and it acts as a shield absorbing ultraviolet radiation from the sun.
o UV rays are highly injurious to living organisms –> Skin Cancer & Mutations
o The thickness of the ozone in a column of air from the ground to the top of the atmosphere is measured in terms of DOBSON UNITS (DU).
o Ozone gas is continuously formed by the action of UV rays on molecular oxygen, and also degraded into molecular oxygen in the stratosphere.
o Ozone degradation enhanced by chlorofluorocarbons (CFCs).
o CFC used in refrigerators & airconditioners.
o CFCs discharged in the lower part of atmosphere move upward and reach stratosphere.
o In stratosphere, UV rays act on them releasing Cl atoms.
o Cl degrades ozone releasing molecular oxygen, with these atoms acting merely as catalysts; Cl atoms are not consumed in the reaction.
o Hence, whatever CFCs are added to the stratosphere, they have permanent and continuing affects on Ozone levels.
o Although ozone depletion is occurring widely in the stratosphere, the depletion is particularly marked over the Antarctic region. This has resulted in formation of a large area of thinned ozone layer, commonly called as the ozone hole.
o UV radiation of wavelengths shorter than UV-B, are almost completely absorbed by Earth’s atmosphere, given that the ozone layer is intact.
o But, UV-B damages DNA and mutation may occur. It causes aging of skin, damage to skin cells and various types of skin cancers.
o In human eye, cornea absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called snow-blindness, cataract, etc. Such exposure may permanently damage the cornea.
•Montreal (Canada) in 1987 (effective in 1989)
•to control the emission of ozone depleting substances.
o The degradation of natural resources also by improper resource utilisation
•Due to human activities like over-cultivation, unrestricted grazing, deforestation and poor irrigation practices, resulting in arid patches of land.
•When large barren patches extend and meet over time, a desert is created.
•Internationally, it has been recognised that desertification is a major problem nowadays, particularly due to increased urbanisation.
o Waterlogging and soil salinity
•Irrigation without proper drainage of water leads to waterlogging in the soil.
•Besides affecting the crops, waterlogging draws salt to the surface of the soil.
•The salt then is deposited as a thin crust on the land surface or starts collecting at the roots of the plants.
•This increased salt content is inimical to the growth of crops and is extremely damaging to agriculture.
•Waterlogging and soil salinity are some of the problems that have come in the wake of the Green Revolution.
o Deforestation is the conversion of forested areas to non-forested ones.
o According to an estimate, almost 40 per cent forests have been lost in the tropics, compared to only 1 per cent in the temperate region.
o In India –> At the beginning of the twentieth century, forests covered about 30 per cent of the land of India. By the end of the century, it shrunk to 19.4 per cent,
o National Forest Policy (1988) of India has recommended 33 per cent forest cover for the plains and 67 per cent for the hills.
o Reasons for deforestation
•the conversion of forest to agricultural land
•Trees are cut for timber, firewood, cattle ranching and for several other purposes.
•Jhum cultivation in the north-eastern states of India
o consequences of deforestation
•enhanced carbon dioxide concentration in the atmosphere
•loss of biodiversity due to habitat destruction,
•disturbs hydrologic cycle,
•causes soil erosion, and
•may lead to desertification in extreme cases.
20. Reforestation is the process of restoring a forest that once existed but was removed at some point of time in the past. Reforestation may occur naturally in a deforested area.
21. Case Study of People’s Participation in Conservation of Forests
o In 1731, the king of Jodhpur in Rajasthan constructing a new palace. cut down trees.
The Bishnoi community Opposes cut down trees by the kings –>A Bishnoi woman Amrita Devi –> hugging a tree and daring king’s men to cut her first before cutting the tree –>Sadly, the king’s men cut down the tree along with Amrita Devi–>Her three daughters and hundreds of other Bishnois followed her, and thus lost their lives saving trees. –> Nowhere in history do we find a commitment of this magnitude when human beings sacrificed their lives for the cause of the environment.
o Amrita Devi Bishnoi Wildlife Protection Award –>for individuals or communities from rural areas that have shown extraordinary courage and dedication in protecting wildlife.
o In 1974, local women showed enormous bravery in protecting trees from the axe of contractors by hugging them.
o People all over the world have acclaimed the Chipko movement.
●Realising the significance of participation by local communities
●The Government of India launched in 1980s to work closely with the local communities for protecting and managing forests.
●In return for their services to the forest, the communities get benefit of various forest products (e.g., fruits, gum, rubber, medicine, etc.), and thus the forest can be conserved in a sustainable manner.