Unit 5: Environmental Pollution

 ENVIRONMENTAL POLLUTION 

5.1. INTRODUCTION 

The air we breathe, the water we drink and the place we live in may be polluted with unwanted toxic  substances. The tremendous increase in industrial activity during the last few decades and the release of  toxic industrial wastes into the environment, have been of considerable concern in the recent years from  the point of view of environmental pollution.  

Composition of air

It is well known that the outcome of the human activity in the last 200 years on nature (after the industrial  revolution) is very damaging and disrupts natural phenomena and ecological balance. Many incidents and  issues like the death of thousands of people in Minamata in Japan after eating fish from the local Bay  (mercury poisoning), Itai-Itai’ disease (due to cadmium pollution), Bhopal gas tragedy(due to poisonous  gas, MIC), London smog in 1952, the emergence of new ocean currents like El-Nino, Global warming,  Depletion in Ozone umbrella, the nuclear accidents of Three mile island, Chernobyl and recently in  Fukushima, Japan have forced mankind to have a second look on the impact of industries on nature.  Thus, environmental pollution on one hand and deforestation and population explosion on the other, are  threatening the very existence of life on earth. Hence to stimulate awareness of the environment and to  enhance political attention and public action United Nations General Assembly in 1972 established June  5th as World Environment Day.  

Pollutants and Contaminants 

The term pollution was derived from the Latin word ‘pollotioneum’ which means to make dirty. A  substance present in the environment in greater proportion than its natural abundance and resulting in  harmful or detrimental effect is called a pollutant and this phenomenon is called pollution. For example,  carbon monoxide, sulphur dioxide, ozone and nitrogen oxide are present in air, but if their percentage  increases because of human activities, they are likely to cause pollution. In addition to this, there are  certain substances which are not present in the environment, but the release of which as a result of  chemical reactions can lead to pollution. They are called as contaminant. Examples: oil spills in sea,  methyl isocyanate (MIC) –the gas responsible for Bhopal gas tragedy.  

The major forms of environmental pollutions, their cause, effects and control measures are discussed  below: 

1 

5.2. AIR POLLUTION 

The atmosphere is a gaseous envelope held to earth by gravity. It extends from earth’s surface to about  1000 km. The composition of the air varies from place to place. The composition is Nitrogen 78%,  Oxygen 21%, Argon less than 1%, and others include carbon dioxide, water vapour, ozone, helium,  methane etc in trace amount.  

The main layers of atmosphere from the surface of earth upwards are troposphere, stratosphere,  mesosphere and thermosphere. As far as atmospheric pollution is concerned, only troposphere and  stratosphere are important. Troposphere extends to a height of about 10 km from the sea level. It contains  air, water vapour, clouds etc. The pollution in this region is caused by poisonous gases, fumes and smog.  Examples include photochemical smog, acid rain*, global warming and green house effect*. 

Stratosphere, which is the seat of ozone is above troposphere. It extends from the height of 10 to 50 km  above the sea level. It is the ozone layer at stratosphere that acts as the protective blanket of the earth  from the injurious effects of the ultraviolet rays from the sun. Ozone layer depletion* is the pollution that  affects the stratosphere.  

[ *refer section 5.5.2, 5.5.3 and 5.5.4 for more details] 

The World Health Organization defines air pollution as “the presence of materials in the air in such  concentration which are harmful to man and his environment.”Or it is the occurrence or addition of  foreign particles, gases and other pollutants into the air which have an adverse effect on human  beings, animals, vegetation, buildings, etc.

Pollutants are classified into primary and secondary pollutants. Primary pollutants: they are emitted into  the atmosphere directly from the source and retains the same chemical form. Examples are carbon  monoxide, sulphur oxides, nitrogen oxides, hydrocarbons, suspended particulate matter(SPM).Secondary  pollutants: they are formed by the inter mingling and reactions of primary pollutants. Examples are  photochemical smog, acid rain, PAN etc. 

The sources of air pollution are classified into two groups: Natural and Man- made sources. Natural  process of air pollution includes dust storms, forest fires, ash from volcanoes, decay of organic matter,  pollen grains floating in air etc. Manmade sources include population explosion, deforestation,  urbanization and industrialization. 

5.2.1. Causes of Air Pollution 

Important causes of air pollution include:  

• Pollutants emitting from vehicles, carbon monoxide formed by improper or incomplete  combustion which are emitted from vehicles is a major pollutant.  

• Pollutants from industries, like sulphur dioxide, oxides of carbon, nitrogen oxide, chlorine,  asbestos dust, hydrocarbons and chemicals deplete the quality of air.  

• Use of fertilizers and pesticides in agriculture. 

• Particulate matter from mining activities. 

• Household cleaning products, carpets, paints emit toxic chemicals into the air and cause indoor  air pollution.  

• Suspended particulate matter (SPM) produced due to burning of coal. 

• Nuclear power plants pollute air by releasing radioactive radiation. 

• Indiscriminate cutting of trees and clearing of forests increases the amount of carbon dioxide in  the atmosphere. 

• Acid deposition due to acid rain may lead to damaged trees, soils and aquatic life. • Use of chlorofluorocarbons in refrigeration, fire extinguishers and aerosol sprayers pollute air by  depleting the ozone layer. 

• Smoking pollutes air by emitting carbon monoxide and nicotine. 

5.2.2. Effects of Air Pollution 

Important effects of air pollution include:  

• It affects respiratory system causing breathing difficulties and diseases such as bronchitis, asthma,  lung cancer, tuberculosis and pneumonia.

• Inhaling carbon monoxide results in respiratory problems, muscular weakness, mental impairment, and dizziness in human beings. At high concentration, it will harmfully affect the plants causing leaf drop, reduction in leaf size, and premature aging. 

• Carbon dioxide causes mild narcotic effects and affects respiratory systems. Increased concentration in the atmosphere causes green house effect and global warming. 

• Air pollution causes acid rain which damages crop plants, trees, buildings, monuments, statues  and metal structures. It also makes the soil acidic. 

• Ozone layer depletion due to which ultraviolet radiations can reach the earth and cause skin cancer, damage to eyes and immune system. 

• Excess nitrogen oxides in the atmosphere results in respiratory problems and bronchitis. It also causes harmful effects on nylon, rayon and causes cracks in rubber. 

• Excess sulphur oxides are extremely harmful to plants and animals. It causes eye irritation, respiratory problems, lung cancer etc. In plants, it kills leaf tissues, reduces plant productivity, and bleaches leaf pigments. 

• Pesticides like DDT which are toxic, enter into our food chain and gets accumulated in the body  causing kidney disorders, problems of brain and circulatory system. 

• Excess pollen and microbes in the atmosphere directly damage the vegetation, food articles and  cause diseases in plants, animals and human beings.  

5.2.3. Control Measures of Air Pollution 

The atmosphere has several built-in self-cleaning processes such as dispersion, gravitational settling,  flocculation, absorption, rain-washout, etc to cleanse the atmosphere. However, control of contaminants  at their source level is a desirable and more effective method. 

• Use of public transportation facilities and using unleaded petrol or using fuels with low sulphur  and ash content. 

• Catalytic converters should be used to help control emissions of carbon monoxide and  hydrocarbons. 

• Planting trees along busy streets remove particulates, carbon dioxide and absorb noise. 

• Renewable and non- polluting sources of energy like solar energy, wind energy etc. should be  used. 

• Automobiles should be properly maintained and adhere to emission control standards.

• Industries and waste disposal sites should be situated outside the city preferably on the downwind  of the city. It should also be fitted with equipment for removal and recycling of wastes.  • Emission rates should be restricted to permissible levels by industries. 

• Tall chimneys should be installed in factories. 

• Better designed equipment and smokeless fuels should be used in houses and industries. 

• Large amount of fossil fuels are burnt to produce electricity. So conserve energy by switching off  fans and lights when not in use. 

• Understand the concept Reduce, Reuse and Recycle. 

• Use energy efficient devices like LEDs, CFL lights etc. 

• Growing plants capable of fixing carbon monoxide. Example: Phaseolus vulgaris, Daucus carota 

• Growing plants capable of metabolizing nitrogen oxides and other gaseous pollutants. Example: Vitis, Pimis, Pyrus etc. 

5.3. WATER POLLUTION 

Water is undoubtedly the most precious natural resource that exists on our planet. It is essential for the  survival of any form of life. Water pollution is a major global problem, both in developed and developing  countries, as more and more wastes are being disposed in oceans, rivers and lakes. This increase in  pollution is harming our food supplies, drinking water and environment. Water pollution is defined as the  “the alteration in physical, chemical and biological characteristics of water which may cause harmful  effects on humans and aquatic life”.  

Point and non-point sources: 

Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without  adequate treatment to remove harmful compounds. Point source pollution refers to contaminants that  enter a waterway through a discrete conveyance, such as a pipe or ditch. Examples of sources in this  category include discharges from a sewage treatment plant to rivers, lakes etc. Non-point source  pollution (NPS) refers to diffuse contamination that does not originate from a single discrete source. NPS  pollution is often the cumulative effect of small amounts of contaminants gathered from a large area.  Run-off and under-drainage from agricultural land into rivers are typical examples.  

5.3.1. Causes of Water Pollution 

Important causes of water pollution include: 

• Sewage and waste water: Raw sewage contaminates water with pathogens. Microorganisms  causing degradation of sewage take up most of the oxygen present in water. Untreated sewage  water is a major problem in developing countries with insufficient sanitation.  

• Industrial waste: Many industrial plants use fresh water to dispose their waste, polluting rivers,  lakes, and oceans. Toxic chemicals, acids, alkalis, metallic salts, phenols, cyanides are released  into water bodies. They also cause thermal pollution of water. 

• Organic contaminants: They include detergents, disinfection byproducts like chloroform,  food processing wastes, insecticides, herbicides, petroleum products, industrial solvents,  cosmetic products etc.  

• Inorganic contaminants: They include industrial discharge, ammonia from food  processing waste, fertilizers containing nutrients like nitrates and phosphates, heavy  metals from motor vehicles, acid mine drainage, runoff from construction sites. The  major inorganic pollutants in water are arsenic, cadmium, lead, chromium, cyanides,  nitrates, phosphates etc. 

• Radioactive waste: Produced during industrial, medical, and scientific processes, and through  mining and refining of nuclear fuels like Uranium and Thorium. Nuclear processing plants give  off wastes that can pollute the marine environment. 

• Oil Pollution: Large oil spill events account for only 12% of total oil pollution. The remaining is  through routine shipping, land run-off, and intentional oil dumping. 

• Eutrophication: It occurs when ocean waters and other aquatic habitats are enriched with excess  nutrients, such as phosphates and nitrogenous compounds caused by agricultural runoff. Excess  nutrients cause algal blooms in the ocean, lakes and other freshwater bodies. 

• Run-off from many different sources (non-point source pollution):Rainfall and snowmelt can  wash natural and man-made pollutants into rivers, lakes, wetlands, and coastal waters. • Agricultural Run-off: Agricultural pollutants include excessive nutrients, ammonia and nitrates,  pathogens, antibiotics and hormones, heavy metals and salts. Manure, animal bedding, wasted  feed, soil, dust, hair and feathers can be mixed together and can end up in waterways. 

5.3.2. Effects of Water Pollution 

Important effects of air pollution include:  

• Organic pollutants like sewage, industrial waste, wastes from slaughtering units, paper mills and  tanneries, run off from agricultural activity etc causes the depletion of oxygen. Low oxygen levels 

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cannot support most marine organisms and hence the natural ecological balance in rivers and lakes is disturbed.

• Groundwater contamination from pesticides causes reproductive damage within the wildlife in ecosystems. Most of the pesticides are non-biodegradable and persistent. They will remain in the water bodies for a fairly long time and results in environmental hazards. Pesticides, show biomagnification* by reaching the food chain. Organophosphorous pesticides cause Eutrophication*resulting in algal bloom and lowering of DO, thereby threatening aquatic life.

• Excess fluoride in water causes defects in teeth and bones called fluorosis, while arsenic can cause significant damage to the liver and nervous system.

• Oil spills in the water cause animals to die when they ingest or encounter it.

• Excess sediments in water cause cloudiness reducing photosynthetic ability, which disrupts the aquatic food chain.

• Drinking contaminated water causes health problems like cancer, reproductive problems, typhoid fever, stomach sickness and skin rashes in humans.

• Excess radioactive materials in water cause genetic mutations, birth defects and cancer.

• Excess of nitrates in drinking water produces Blue baby syndrome, a disease that affects the oxygen carrying capacity of infant's blood, usually resulting from the consumption of high levels of nitrate.

2. Control Measures

• Setting up effluent treatment plants to treat waste water.

• Planting more trees will reduce the amount of sulphur dioxide and nitric oxide.

• Oxidation pond can be useful in removing low level radioactive wastes.

• Sewage pollutants are to be subjected to chemical treatment to convert them into non-toxic substances.

• Laws, standards and practices should be established to prevent water pollution and these laws should be modified from time to time based on current requirements and technological advancements.
  

• No type of waste (treated, partially treated or untreated) should be discharged into any natural water body. Industries should develop closed loop water supply schemes and domestic sewage must be used for irrigation.

• Industrial plants should be based on recycling operations as it helps prevent disposal of wastes into natural waters but also extraction of products from waste.

• Thermal pollution can be reduced by employing techniques like cooling ponds, wet/dry cooling towers etc.

• Water hyacinth (plant) can purify polluted water. It can also filter out heavy metals like cadmium, mercury, lead, nickel as well as other toxic substance from industrial waste.

• The government has undertaken several projects to clean the rivers, the first of which was the Ganga Action Plan.

• Increase public education and awareness around the world concerning the causes and impacts of water pollution.

3. Eutrophication*

Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen and phosphorous and other nutrients from detergents, fertilizers, sewage and agricultural runoff. Eutrophication can be a natural process in lakes, occurring as they age through geological time. The process of eutrophication can be both natural and human-induced.

Steps involved in Eutrophication include:

1. Excess nutrients are applied to soil.

2. Some nutrients leach into the soil where they will remain for years or get drained into the water bed.

3. The excess nutrients result in algal bloom.

4. Algal bloom blocks the sunlight from reaching the bottom of the water body.

5. Plants beneath the algal bloom die due to non-availability of sunlight.

6. Algal bloom dies and sinks to the bottom of lakes.

7. Bacteria decomposes the dead remains, using up the oxygen for respiration.

8. Due to decomposition water gets depleted with oxygen, larger life forms like fish suffocate to death.
   

9. Water body cannot support any forms of life.

Human activities can accelerate the rate at which these nutrients enter the ecosystem. Phosphorous is regarded as the main culprit of eutrophication. With the phasing out of phosphate-containing detergents in the 1970s, industrial/domestic run-off and agriculture have emerged as the dominant contributors to eutrophication.

4. Biomagnification or bioaccumulation*

It is the process by which a pollutant or pesticide moves up the food chain, works their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substances/toxins become concentrated in tissues or internal organs as they move up the chain. Each successive step up in the food chain causes a stepwise concentration of pollutants such as heavy metals like mercury or persistent organic pollutants like DDT. Bioaccumulants are usually accumulated and collected in certain part of living organisms so that their concentration increases because the substances are slowly metabolized or excreted.

Substances that biomagnify include DDT, hexachlorobenzene, polychlorinated biphenyles, monomethyl mercury and heavy metals. For example, DDT is stored up in the fatty tissues of breast so that the breast milk is contaminated by DDT. The shell fish collects and stores heavy metals like cadmium.

Process of Biomagnification includes:

1. Release of toxic chemicals and pollutants into environment.

2. Absorption of toxins by phytoplankton (small plants that float on sea) – once absorbed, the toxin stays in their tissues without being excreted or broken down.

3. Consumption of phytoplankton by zoo plankton (small marine animals that float in sea) – hence they take up the toxin, which stay locked in the organism tissue without being excreted or broken down.

4. Small fish consume the zooplankton.

5. Large fish consume the smaller fish.

6. The top food chain organism consumes the fish – these toxins get accumulated in the liver of sea birds, dolphins, humans etc.
   

Effects of Biomagnification

1. Impact on human health.

2. Reproduction and development of marine creatures. (iii)Destruction of the coral reefs.

(iv)Disruption of the food chain.

5. Water Quality parameters

The parameters for water quality are determined by the intended use. The parameters that are important to drinking water are alkalinity, colour, pH, taste, odour, dissolved metals, microorganisms like fecal coliform, dissolved metals, dissolved organic compounds, heavy metals, pharmaceuticals etc. The water quality parameters important in environmental concerns are salinity, dissolved oxygen (DO), BOD (Biochemical Oxygen Demand), nitrate, orthophosphates, COD (Chemical oxygen demand), pesticides, pH, temperature, total suspended solids (TDS) and turbidity.

(i)        Dissolved Oxygen (DO)

Dissolved oxygen is the amount of gaseous oxygen dissolved in an aqueous solution. DO enter water through the air or as a plant by-product. From air, oxygen can slowly diffuse across the water surface from the surrounding atmosphere.

Dissolved oxygen is essential for aquatic life. It is an important parameter in assessing the water quality because it influences both plant and animal population in water. It is expressed in parts per million (ppm) or mg/L. The optimum value of DO in water is 4-6 ppm. Low value of DO indicates water pollution. Pollutants like sewage, industrial waste, wastes from slaughtering units, paper mills and tanneries, run off from agricultural activity etc reduces DO. All these materials undergo bacterial activity in the presence of DO, converting the carbon in the waste to carbon dioxide, thus deoxygenating the water. Aquatic life is made impossible in water with low DO. Dissolved oxygen should be analyzed immediately after collecting the sample. Hence, this is a field test that should be performed on site.

Consequence of unusual DO level include fish mortality, fish kill, gas bubble disease (bubbles block the flow of blood through blood vessels causing death), creation of dead zone (it is an area of water with little or no dissolved oxygen), water column stratification (which is the separation of water body into layers) etc.

(i) Biological Oxygen demand [BOD] and Chemical Oxygen Demand [COD]

No	Biological Oxygen demand [BOD]	Chemical Oxygen Demand [COD]
1	It is an important parameter used in estimating the degree of organic pollution in wastewater	It is an important parameter used in estimating the degree of organic pollution in wastewater
2	BOD is milligram of oxygen used by microorganism to decompose the organic material in one liter of waste water	COD is an index of inorganic and organic content of water. It is the amount of oxygen required to degenerate all pollution in a chemical way (by adding oxidizing agents and heating).
3	It measures the dissolved oxygen consumed by organisms to oxidize organic compounds	It measures all organic compounds that can be chemically oxidized.
4	BOD will be lower than COD	COD will be higher than BOD
5	BOD is only a measurement of consumed oxygen   by   aquatic microorganisms to decompose or oxidize organic	COD refers the requirement of dissolved oxygen for both the oxidation of organic and inorganic constituents
6	BOD measurements take five days to complete	COD measurements can be made in a few hours
7	Less reproducible results	COD is more scientific, more reproducible and accurate
8	Increased BOD can be due to domestic sewage, petroleum residues and organic wastes etc	Increased COD can be due to industrial waste
9	The determination of BOD is time consuming and depends on biochemical factors	Determination of COD is precise, saves time and is completely chemical in nature

6. Quality of Drinking Water

The following parameters must be followed before water is supplied for drinking

• It must be colourless and free from any odour or smell.

• It must be free from suspended particles and turbidity.

• It must be free from microorganisms.

• Its pH must be between 6 to 9.

• It may have harmless dissolved salt to impart good taste.

• It must be free from harmful chemicals.
  

2. SOIL POLLUTION

Soil is a very important constituent of the lithosphere. It is a complex physio-biological system containing water, mineral salts, nutrients and dissolved oxygen. It is a resource for which there is no substitute. Fertilizers are not a substitute for a fertile soil. Several factors contribute for the formation of soil like weathering of rocks due to temperature changes, abrasion, wind, moving water, glaciers, etc. Climate and time are also important in the development of soil. Soil is a natural body consisting of layers of various thicknesses called soil horizon. Depending upon the type of soil there are different horizons like O, A, B and C.

The top layer or surface layer is called O horizon. It consists mostly of dead leaves, twigs, animal waste, fungi and other organic wastes. Normally it is brown or black in colour. Below the O layer is A horizon, also called surface soil. This layer has maximum fertility because it contains microbes and microorganisms. Below A horizon is B, also called subsoil which contains less organic materials and fewer organisms than surface soil. The parent rock is called C horizon which is below B. It contains inorganic materials and large unbroken rocks.

Soil pollution is defined as the presence of toxic chemicals (pollutants or contaminants) in soil, in high enough concentrations to pose risk to human health and ecosystem. Soil pollution is the adverse alternation in the properties of the soil due to dumping of solid

and semi-solid waste from agriculture, industry and urban areas. It also results because of washing down of pollutants by rain and faulty sanitation in the soil. However, soil pollution is different from air and water pollution in following respects

• Soil pollutants do not get dispersed unlike air and water pollutants.

• The pollution is localized unlike air and water pollution.

• The pollutants remain at a particular place for relatively longer period.

1. Causes of Soil Pollution

Important causes of soil pollution include:

• Agrochemicals:   Agricultural   activities involving   the   diffusion   of herbicides, pesticides, insecticides and fertilizers.
  

• Industrial wastes: Industrial activity has been the biggest contributor to the soil pollution in the last century due to increased mining and manufacturing units. It also includes the release of harmful gases and chemicals.

• Petroleum wastes: Contamination of soil by petroleum products is a current problem in several countries in the world. Oil leakage during transportation and storage of petroleum liquids in underground tanks are the main cause.

• Electronic wastes or E-waste: it is a complex, non-biodegradable waste which is generally dumped in soil. They have large quantities of lead, cadmium, arsenic etc. Electronic waste include cell phones, computers, gadgets, printers, radio, camera, video games, scanners, DVDs, Land phones etc.

• Unfavorable and harmful irrigation practices.

• Indiscriminate dumping of untreated domestic waste on land .

• Improper septic system, leakages from sanitary sewage, underground tanks and underground pipe lines.

• Accidental oil spills which can happen during storage and transport of chemicals.

• Construction and mining activities.

• The storage of waste in landfills, as the waste products may leak into groundwater or generate polluted vapors.

• Radioactive waste from laboratories, nuclear reactors and nuclear explosions.

• Soil erosion results in the loss of topsoil and makes the soil less fertile and reduces it water holding capacity.

2. Effects of Soil Pollution

Some of the serious problems caused by soil pollution are:

• Reduction in soil fertility.

• Soil pollution has major consequences on human health. Consumption of crops and plants grown on polluted soil cause health hazards. This could explain small and terminal illness.

• Imbalance in the flora and fauna of the soil.

• Excess use of chemical fertilizers may result in reducing the ability of plants to fix nitrogen.
  

• Increase in salinity of the soil makes it unfit for cultivation.

• Pollutants in soil cause alteration in soil structure, causing death of many soil organisms which can affect the food chain.

• Decline in the microorganisms found in the soil creating additional problems of soil erosion.

• Emissions of toxic gases and foul odour from the landfills pollute the environment and causes serious health effects.

• Contamination of underground and surface drinking water.

3. Control Measures

• Reducing the use of chemicals and fertilizer and encouraging the use of biopesticides in the place of toxic chemical pesticides.

• Recycling and Reuse of wastes: To minimize soil pollution, wastes such as paper, plastics, metals, glasses, organics, petroleum products and industrial effluents etc should be recycled and reused.

• Prevention of erosion and silting.

• Create dumping ground away from residential area.

• Launching extensive afforestation and community forestry programmes

• Proper treatment of liquid wastes from industries and mines.

• People should be trained regarding proper sanitary practices.

• Effective treatment of domestic sewage by suitable biological, chemical and adopting modern method of sludge disposal.

• Public awareness programmes should be implemented to educate people on health hazards due to soil pollution.

• Ban should be imposed on chemicals and pesticides which are fatal to plants and animals.

• Nuclear explosions and improper disposal of radioactive wastes should be banned.

• Bioremediation: It uses microorganisms (yeast, fungi or bacteria) to breakdown, or degrades hazardous substances into less toxic or nontoxic substances (such as CO2 and H2O).

• Waste water from industries should not be used for irrigation without eliminating toxic chemicals from the effluent. This will also reduce the concentration of unwanted substances in the soil.
  

• Enforcing environmental audit for industries and promoting ecolabelled products.

• Municipal waste should be properly collected, segregated, treated and disposed scientifically in land fills.

3. MARINE POLLUTION

Seas are the unlimited source of water and main source of food and sustenance for persons living in coastal areas. When the marine water is polluted, it affects the animals and other food chain components. Marine pollution can be defined as the introduction of substance to marine environment directly or indirectly by man resulting in adverse effects such as hazards to human health, obstruction to marine activities, and lowering the quality of sea water.

1. Causes of Marine Pollution

While the cause of marine pollution may be similar to that of water pollution, there are some very specific causes that pollutes marine water.

• Toxic chemicals like chemical run-off from industries, industrial wastes, household cleaners, nuclear power stations etc.

• Rivers carry waste in the drainage and joins sea/ocean. The drainage includes sewage effluents, sludge, industrial effluents, agrochemicals, plastics, metal scraps etc.

• Petroleum and oil washed off from roads normally enter sewage system and finally into the seas.

• Oil spillage is usually an accidental form of releasing oils by ships, which can devastate marine life.

• Testing of atomic weapons, space aircrafts, missiles and other radioactive wastes when dumped in seas, cause heavy loss to aquatic life.

• Oil drilling in seas, tourism activities and heat released from industries.

• Plastic bags, aluminium cans, trash and other human waste constitute major marine pollutant.

• Greenhouse gases from human fossil fuel consumption are making sea more acidic.

2. Effects of Marine Pollution

Important effects of marine pollution include:

• Oil is the most dangerous pollutant when afloat on sea or mixed with water, a great threat to marine life specially fish, birds, invertebrates and algae. Oil also affects sensitive flora, fauna, phytoplankton, zoo plankton, and other animals.
  

• Oil slicks damage salt marshes and mangrove ecosystem and liquid oil contaminates birds’ plumage and its water repellant properties diminishes.

• Presence of sewage and other bio-matter in sea will result in oxygen depletion, which destroys marine life.

• Toxic chemicals make the sea/ocean more acidic which harms marine animals, plants and corals.

• Plastic materials are dumped into seas by commercial ships or from drainage. Animals take it through their food in stomach which may cause ulcer or reduced hunger.

• Heavy metals like mercury, lead, factory materials, mineral oils, are also hazard to marine life when mixed with sea water.

• Presence of detergents is responsible for the high mortality of marine animals.

• Marine pollution affects the food chain in seas. Serious diseases like cancer are caused when affected animals are consumed by man from ocean.

3. Control Measures

• Recycling the plastics and proper disposal is our key responsibility to reduce marine pollution.

• Authorities should take effective measures to check oil leakage from ships and tankers.

• Urban and coastline corporations should check the dumping of wastes from human activities and municipalities.

• Introduction of sewage treatment plants to reduce BOD of the final product before discharging into sea.

• Port authorities should take anti-pollutant measures to reduce pollution.

• Cleaning oil from surface water and beaches can be done by spraying chemical dispersants, suction device or by spreading high density powder over oil spill.

• Developmental activities in coastal areas should be minimized.

• Nuclear explosion and nuclear activities in sea should be minimized.

• Drilling should not be allowed in coastal areas.

4. NOISE POLLUTION

Sound that is unwanted, unpleasant or that disrupts the activity of living beings is called noise. When there is lots of noise in the environment, it is called noise pollution. The word noise comes from the Latin word nauseas, meaning seasickness. The unwanted, unpleasant sound which causes irritation to ears and pollution caused by heavy noise is called noise pollution.

The unit of sound intensity is Decibel (dB), which is the standard for the measurement of noise. It is not an absolute physical unit, but it is a ratio expressed as logarithmic scale relative to a reference sound pressure level. People are generally exposed to noise levels ranging from 65 to 80 dB which is the tolerable noise level forthe human ear. Exposure to noise level greater than 80 dB leads to stress and is referred as noise pollution. The sensitivity of the ear is lost if the sound intensity exceeds 150 dB level.

1. Cause of Noise Pollution

There are several sources of noise that contribute to both indoor and outdoor noise pollution.

• Industries/ Factories

• Poor urban planning

• Construction activities

• Household chores

• Transportation/ vehicles

• Playing of loud speakers during festivals/ social events

• Fire crackers

• Microphones

• Television

• Loud music

• Home appliances

• Barking dogs

• Service sirens

2. Effects of Noise Pollution

The most direct harmful effect of excessive noise is the physical damage to our ears causing temporary or permanent hearing loss. People suffering from this condition will be unable to detect weak sounds. 125 dB give the sensation of pain in the ear and 150 dB might kill a human being. The various effects of noise pollution in human beings can be classified as auditory and non-auditory effects.

1. Auditory effects:

The impairment of hearing which may cause immediate auditory fatigue finally leading to deafness is known as auditory effects.

2. Non-auditory effects:

These effects include interference with speech communication, ill-temper, mental disorientation, violent behaviour and a series of health hazards.

In addition to hearing loss, the effect of noise on human being can be physiological or psychological in nature.

The physiological disorders include progressive hearing loss, nausea, dizziness, hypertension, reduced heart beat, variations in blood pressure and breathing problems. The continuous noise can generate resonance in the skull and affect the brain and nervous system. It can have an impact on thinking and coordination of limbs and induce pain and numbness. Moderate noise/ vibration can lead to pain, numbness and cyanosis (blue coloration in fingers). Severe vibrations results in damage to bone, joints with swelling and stiffness. Exposure to low frequency noise can reduce heart beat, variation in blood pressure and breathing difficulties.

It is difficult to assess psychological noise effects on human beings. The psychological effects include sleep disturbances, physical and mental fatigue, lower efficiency, reduced work rate, increased absenteeism, forgetfulness, higher potential for accidents and injuries. Children exposed to excess noise show signs of behavioral disorder in later age. Recent reports suggest that blood is thickened by excessive noise.

The effect on living beings can be summarized as:

• Health issues – Effect psychological health, aggressive behaviour, stress, fatigue, hypertension, work efficiency and behaviour etc.

• Pediatric problems – hearing problems associated with children.

• Gynecological problems – pregnant women are vulnerable to high noise levels.

• Heart problems – hypertension and cardiovascular problems.

• Hearing problems – auditory fatigue caused by noise levels above 80 dB.

• Sleep disorders – exposure to noise reduces duration of sleep, diminish quality of sleep, Psychic disorders.

• Wild life issues - noise bring about changes in the behavioral aptitude of birds and animals. They become inefficient in hunting and hence disturb the balance of ecosystem. For example, noise pollution discourages the annual visit of migratory birds to Alipore Zoo at Kolkata.

3. Control Measures

Noise produced from different sources has created a catastrophe. Hence necessary steps should be taken to minimize the level of noise and protect the living world from detrimental effects.

• Create public awareness.
  

• Antipollution laws should be enacted and enforced.

• Planting coniferous trees (they have pointed leaves which reflect minimum sound).

• Regular servicing and tuning of automobiles.

• Reduction of traffic density in residential areas and giving preference to public transport system.

• Preference to petrol engines over diesel engines.

• The use of microphones should be controlled and regulated.

• Ban on fire crackers.

• Proper lubrication and sound proofing of machineries.

• Minimum use of loudspeakers.

• Creation of green vegetation covers in highway, streets and industrial areas.

• Usage of ear plugs and mufflers.

• Buildings can be designed with noise absorbing materials on walls, windows and ceilings.

5. THERMAL POLLUTION

It is defined as the sudden increase or decrease in temperature of a natural body of water like oceans, lakes, rivers or ponds by human influence. It can also be defined as the degradation of water quality by any process that changes ambient temperature of water. Many industries generate their own power and use water to cool their generators. This hot water is released into the system from where it was drawn, causing a warming trend of surface water. It creates a disturbance in the oxygen level of water bodies. This will disturb the marine life and local ecosystems.

1. Causes of Thermal Pollution

Important causes of thermal pollution include:

1. Nuclear power plants: They emit a large amount of unutilized heat and traces of toxic radio nucleotides into nearby water streams. Emission from nuclear reactors and processing instruments are also responsible for increasing the temperature of water bodies.

2. Industries: Industries generating electricity require large amount of cooling water for heat removal. Industries like textile, paper-pulp and sugar industry also release heat in water, but to a lesser extent.
   

3. Coal- fired power plants: Some thermal power plants use coal as fuel. Coal- fired power plants constitute one of the major sources. Their condenser coils are cooled with water from nearby lakes or rivers and discharges hot water.

4. Hydroelectric power plant: The generation of hydroelectric power may result in the release of warm water into water bodies.

5. Domestic sewage: It is often discharged into rivers, lakes, canals or streams without waste treatment. The municipal water sewage normally has a higher temperature than receiving water.

6. Deforestation and soil erosion: Removal of trees along the shore line increases solar incidence

7. Natural and Geothermal activities: Natural geothermal activities like volcano can stimulate lava and can cause a rise in water temperature, leadingto thermal pollution

8. Chemical pollutants discharged into water: There are factories that discharge their chemical waste directly into natural water bodies.

2. Effects of Thermal Pollution

Important effects of thermal pollution include:

• The concentration of dissolved oxygen decreases with increase in temperature.

• The increase in temperature increases toxicity of poison (pesticides, detergents, chemicals) present in water.

• A rise in temperature changes the physical and chemical properties of water.

• The physiology, metabolism and biochemical process of aquatic organisms are affected with increase in temperature.

• It influences the reproductive cycle, digestion rate, respiration rate and many enzymatic activities of living organisms.

• Economic and environmental damage.

• Thermal pollution may permit the invasion of organisms that are tolerant in warm waters and are highly destructive in nature.

• The egg of fish may hatch early or fail to hatch at all.

• Thermal pollution results in low dissolved oxygen levels thereby perishing aquatic organisms.

3. Control of Thermal Pollution

Heat must be removed from the condenser cooling water prior to their disposal into water bodies

• Cooling ponds: This is the simplest and cheapest method which cools water to a considerably low temperature. Heated effluents on the surface of water in cooling ponds maximize dissipation of heat to the atmosphere and minimize the water area and volume.

• Spray ponds: In spray ponds, the water is sprayed in the cooling ponds with the help of spray nozzles to convert it into fine droplets which provide more surface area to facilitate efficient heat transfer to atmosphere.

• Artificial lakes: Artificial lakes are manmade water bodies that offer once-through cooling. The heated effluents can be discharged into the lake at one end and water for cooling purposes may be withdrawn from the other end. The heat is eventually dissipated through evaporation.

• Plantation of trees upon the banks of rivers, seas and other water bodies: Trees not only help in controlling thermal pollution but also aid in a better environment

• Recycling used water:New ideas to be developed on recycling the used water in factories. Every plant or industry should make it a rule that water used as coolant will not be spilled back into water bodies.

• Co-generation: Co-generation is also a wonderful idea to combat thermal pollution. In the process of co-generation, the useless heat from hot water can be recycled and used smartly in many tasks by industries.

6. NUCLEAR HAZARDS

Nuclear pollution is the pollution that contains radioactive materials. It can spread in air, land or water. It is created by the mishandling and inappropriate storage of nuclear fuels, contaminated tools, insecure transportation of highly radioactive materials, nuclear explosions etc. It is the only type of pollution which “we can’t see, we can’t smell and we can’t touch”. The effect of which may not show up in this decade, this generation or in this century. However, the nuclear impacts on us are far beyond our imagination.

Nuclear energy is both beneficial and harmful depending on the way in which it is used. We use the science of radioactivity in the treatment of cancer, diagnosis of diseases, electricity generation, industrial, commercial, food processing and agriculture applications. Approximately 17 % of electricity generated in the world comes from nuclear power plants. However, on the other hand, it is impossible to forget the hazards caused by the nuclear explosion at Hiroshima and Nagasaki (1945), Three Mile Island accident (1979), Chernobyl disaster (1986), Tokaimura nuclear accident(1999), Fukushima Daiichi nuclear disaster(2010).

The two main sources of nuclear pollution are natural and manmade. Natural sources include cosmic rays from outer space, emission from radioactive materials from earth’s crust. Manmade sources include nuclear waste produced during mining and processing from nuclear power plants, nuclear weapon, use of radioisotopes in medical, industrial and research applications.

1. Causes of Nuclear Pollution

Important causes of nuclear pollution include:

• Nuclear waste comes from nuclear power stations. They release tritium (an isotope of hydrogen) into air and water. Tritium has a half-life of 12.3 years and emits beta particles. Inhalation of tritium can cause mutation.

• Cosmic rays from outer space.

• Mining and refining of radioactive materials like uranium and thorium.

• Nuclear fuel cycle (used in many industrial, medical and scientific processes).

• The advent of nuclear medicines to cure and for precise diagnosis, with the help of radio isotopes.

• Use of various radioactive derivatives to produce nuclear weapons for mass destructions

• Use of radio isotopes in industrial activities and various detectors.

• Nuclear accidents or any leaks.

• Disposal of nuclear wastes.

• Nuclear tests carried out by defense sectors.

• Radioisotopes coming from scientific research institutions contains various radioactive materials which causes water pollution.

• Television set, radiographic equipment’s.

Fallout: The radioactive pollution that will spread through the earth’s atmosphere is called fallout. The best example of fallout is the nuclear bomb attack at Hiroshima and Nagasaki, Japan in 1945 by US during World War II. As a result of these nuclear bomb explosion, more than two lakh people died owing to radiation effect and cancer.

2. Effects of Nuclear Pollution

Important effects of nuclear pollution include:

• The effects of radioactive pollutants depend upon half-life, energy releasing capacity, rate of diffusion and rate of deposition of the contaminant. Various atmospheric conditions and climatic conditions such as wind, temperature and rainfall also determine their effects.
  

• As long as the radiations continue, nuclear wastes are dangerous for living being. The effects may be somatic (individual exposed is affected) or genetic (future generation) damage.

• No physical, chemical or biological process can influence the process of radioactive emissions. The unstable nuclei have to decay and acquire a stable state.

• Exposure of human beings to low doses of radiations, may begin to suffer from fatigue, nausea, vomiting and loss of hair. But recovery is possible.

• Exposure of human beings to medium doses of radiation may result in bone marrow disorder, reduction in blood cells,reduction in natural resistance against germs and failure of blood to clot.

• Higher radiation doses will kill the organisms by damaging tissues, brain etc.

• Radiations may cause skin burns which may lead to skin cancer.

• Radiation at pelvic regions of pregnant ladies, cause damage to the fetus. Infants between eight and fifteen weeks of pregnancy who were exposed to the atomic attack at Hiroshima and Nagasaki during World War II were reported to have a greater incidence of brain damage with side effects including lower Intelligent Quotient (IQ) and severe mental retardation in some cases.

• The radiation weakens the immune system of the body.

• Delayed effects of radiation include cataracts, leukaemia, malignant tumours, cardiovascular disorders, premature ageing and reduced life span.

• In spite of all these hazards, nuclear reactors and tests are still continuing and increasingly large amounts of radioactive wastes are accumulated every day while no solution to the problem of their safe disposal is in sight till date.

3. Control Measures

Control of natural radioactive pollution may not be possible. On one hand, the peaceful uses of radioactive materials are so wide and effective that modern civilization cannot go without them; on the other hand, there is no cure for radiation damage. The only option against nuclear hazards is to check and prevent radioactive pollution. For this:

• Waste disposal must be careful, efficient and effective. Low level wastes should be subjected to treatment for the removal of radioactivity and then discharged to water bodies or landfills.
  

• Medium level wastes (e.g., filters, reactor components, etc.,) are solidified and mixed with concrete in steel drums before being buried in deep mines or below the sea bed in concrete chambers.

• High level wastes should be concentrated, contained (ceramics) and stored out of the reach of human environment or buried deep into earth or stored in deep salt mines.

• Leakages from nuclear reactors, careless handling, transport and use of radioactive fuels, fission products and radioactive isotopes have to be totally stopped.

• There should be regular monitoring and quantitative analysis through frequent sampling in the risk areas.

• Prevention of erosion of radioactive waste disposal sites.

• Prevention of any drilling activity in and around the waste disposal site.

• Laboratory generated nuclear wastes should be disposed off safely and scientifically.

• Appropriate protection against occupational exposure.

• Nuclear medicines and radiation therapy should only be applied when absolutely necessary.

• Nuclear tests should be banned.

• Nuclear reactor should be perfectly maintained to avoid accidental leakage.

• High chimney and ventilations should be used at working places where radioactive contamination is high.

• Protective garments must be worn by the workers who work in the nuclear power plants.

• The nuclear power plants must follow all the safety instructions.

• Production of radio isotopes should be minimized.

• In nuclear mines, wet drilling may be employed along with underground drainage.

7. SOLID WASTE MANAGEMENT

Industrialization across the world has brought a lot of good as well as bad things as well. One of the negative effects of industrialization is the creation of solid waste and consequent environmental degradation.

According to Britannica, “Solid-waste management is the collecting, treating and disposing of solid material that is discarded because it has served its purpose or is no longer useful. Improper disposal of municipal solid waste can create unsanitary conditions, and these conditions in turn can lead to pollution of the environment and to the outbreaks of vector-borne disease”

Human and animal activities generate different kinds of wastes. These wastes are generally in solid form, and may cause pollution of land, water and air unless treated and disposed off. The process of collection, transportation, treatment and disposal can be grouped under solid waste management. The increase in the quantity of solid waste is due to overpopulation, affluence and technological advancement.

1. Causes of formation of solid waste

Sources	Waste generators	Types of solid waste
Urban / Residential wastes	Single and multifamily dwellings	Food wastes, cloth, waste paper, cardboard, plastics, textiles, leather, yard wastes, wood, glass, metals, ashes, special wastes like consumer electronics, batteries, used oil, tires and household hazardous wastes.
Industrial	Light and heavy manufacturing, fabrication, power and chemical factories.	Packaging, food wastes, hazardous chemical wastes, ashes, medical wastes and special wastes.
Commercial / institutional	Stores, hotels, restaurants, markets, office buildings, schools, hospitals etc.	Paper, cardboard, plastics, wood, food wastes, glass, metals, medical wastes, hazardous wastes.
Construction and demolition	New construction sites, road repair, renovation sites, demolition of buildings	Wood, steel, demolition materials, concrete, dirt, metals etc.
Municipal services	Street cleaning, landscaping, parks, beaches, other recreational areas and wastewater treatment plants.	Street sweepings, tree trimmings, general wastes from parks, beaches, plastics and other recreational areas.
Process (manufacturing, etc.)	Heavy and light manufacturing units, refineries, chemical plants, power plants, mineral extraction and processing.	Industrial process wastes, scrap materials.
Agriculture	Crops, dairies, feedlots, farms.	Spoiled food wastes, agricultural wastes, hazardous wastes (e.g., pesticides).

2. Effects of Waste Pollution

• Due to improper disposal of municipal solid waste on the roads and immediate surroundings, biodegradable materials undergo decomposition and may create unsanitary conditions. This may lead to the outbreak of epidemic, producing foul smell and becoming a breeding ground for disease vectors.

• Burning of industrial and domestic wastes (plastics, batteries) produce furans and dioxins which are harmful to human beings.

• Toxic substances may percolate into the ground and contaminate the groundwater.

• Solid waste from industries like toxic metals, hazardous wastes and chemicals, when released to the environment can cause biological and physicochemical problems to the environment and may affect the productivity of the soil in that particular area.

• Direct dumping of untreated waste in rivers, seas, and lakes results in the accumulation of toxic substances in the food chain through the plants and animals that feed on it.

• Waste treatment and disposal sites can also create health hazards for the neighborhood. Improperly operated incineration plants cause air pollution.

• Improperly managed and designed landfills attract all types of insects and rodents that spread disease. Ideally these sites should be located at a safe distance

from all human settlements.

• Recycling wastes also carries health risks if proper precautions are not taken.

• Eye and respiratory infections resulting from exposure to infected dust, especially during landfill operations.

• Intestinal infections that are transmitted by flies feeding on the waste.

• Skin and blood infections resulting from direct contact with waste and from infected wounds.

• Incineration operators are at risk of chronic respiratory diseases including cancer and skin diseases.

3. Control Measures

1. Sanitary Landfill: This is the most popular solid waste disposal method used today. Disposing of waste in a landfill involves burying the waste, in abandoned or unused places. In this method garbage is spread out in thin layers, compacted and covered with clay, sand or plastic liner. The liners protect the
   

ground water from being contaminated. When the landfill is full, it is covered with layers of sand, clay, top soil and gravel to prevent seepage of water.

Advantages: Simple, economical, cheap equipment, no residue or by-products, skill labour not required, segregation of waste not required, natural resources are returned to soil and recycled.

Disadvantages: Large area is required, continuous evolution of foul smell from the site, use of insecticide is required, may cause ground water pollution, cause fire hazard due to formation of methane gas in wet weather.

2. Incineration: It is the hygienic way of disposing solid waste. It is a thermal process (controlled combustion) in which the waste material is converted to heat, gas, steam and ash, which can be used for electrical generation and domestic heating. It is suitable for hazardous, organic and medical wastes. Combustible substance should be separated and removed before incineration process. Wet municipal waste should be preheated before incineration process. It reduces the volume of waste up to 20 or 30% of the original volume.

Advantages: Safest and hygienic method, requires very little space, residue is only 20-30% of the original amount and can be used as cement clinker after treatment, an incinerator plant of 3000 tones per day capacity can generate 3MW of power.

Disadvantages: Its capital and operating cost is high, operation needs skilled personnel, formation of smoke, dust and ashes needs further disposal and that may cause air pollution, ordinary incinerators cannot be used for radioactive wastes.

3. Composting: It is a popular method by which bulk organic matter is converted into fertilizer by biological action. Microorganisms like fungi, bacteria convert degradable organic waste into broken, odourless mass called humus, which is a good fertilizer. Separated compostable waste is dumped in underground trenches in layers of 1.5m and finally covered with soil of 20 cm and left for decomposition. Sometimes, actinomycetes are introduced for active decomposition. Biological action will start within two to three days. Good quality environmental friendly manure is formed from the compost and can be used for agricultural purpose.

Advantages: Environmentally effective than landfill and incineration, manure can be sold thereby reducing cost of disposing wastes, recycling can be done, this method can be used to treat several industrial solid wastes, controls growth of weeds in garden, make soil easier to cultivate.

Disadvantages: Non-consumables have to be disposed separately; the technology has not caught-up with the farmers and hence does not have an assured market.

4. Vermi Composting:It has become very popular in the last few years. In vermi composting, earthworms are added to the compost. These help to break the waste and the added excreta of the worms makes the compost rich in nutrients. It is very useful biofertilizer and soil conditioner.

4. Reduce, Reuse, and Recycle is the new answer to the problem of environmental pollution

The aim of waste management is to collect, treat, utilize and dispose solid waste in an economic manner protecting public health. Its major consideration, apart from health, is to adopt three R’s-reduce, reuse and recycle strategy.

1. Reduction in use of raw materials:

This will correspondingly decrease the production of waste. Reduced demand of any metallic product will decrease the mining of their metal and cause less production and less waste.

2. Reuse of waste materials:

Reuse of paper, cardboard, glass, metal, plastic, discarded cycle tubes, auto-parts of vehicles considerably reduces the waste of generation.

3. Recycling of materials:

Recycling is the reprocessing of discarded materials into new useful products. Examples include formation of new cans, bottles from broken aluminium cans and glass, fuel pellets from kitchen waste, cellulose from waste paper etc.

5. Green Chemistry

Green Chemistry, also known as sustainable chemistry, is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances. Green chemistry is a powerful approach to pollution prevention, waste minimization and hazard reduction.

The focus of Green Chemistry is on

1. Source reduction/prevention of chemical hazards

2. Reuse or Recycle chemicals

3. Treat chemicals to render them less hazardous

4. Dispose chemicals properly
   

ENVIRONMENTAL POLLUTION

ROLE OF AN INDIVIDUAL IN THE PREVENTION OF POLLUTION

Pollution is a man-made disease that can be cured only by man and remedies adopted by them. Incomplete and inefficient technology coupled with increased population is the main cause of man-made pollution. In fact, the role of individuals in prevention of pollution is of critical importance because it is the individual that makes a community or country.

Environment awareness programme should be organized and individuals should be encouraged to modify the life style and living habit, if that are not healthy for environment. Over population and pollution are potent ecological forces impinging upon man by affecting the quality of the environment.

The main causes of pollution in developing countries

1. Increasing population

2. Illiteracy and poverty

3. Rapid industrialization

4. Failure in pollution management

Ways in which an individual/NGO can help in prevention of pollution

• Development of nonpolluting sources of energy.

• Effective use of water resources.

• Usage of cloth bags instead of plastics.

• Usage of rechargeable batteries.

• Avoid burning plastics.

• Switch off electrical appliance when not in use.

• Make use of public transport system.

• Periodic pollution check should be done for vehicles by approved authorities.

• Reuse items whenever possible.

• Use renewable source like solar heaters, solar cookers etc.

• Cells, batteries, pesticide containers should be disposed properly.

• Quit smoking.
  

• Reduce the use of air conditioners, refrigerators etc.

• Reduce deforestation.

• Use handkerchief instead of paper tissues.

• Purchase recyclable, recycled and environmentally safe products.

• Organize environmental awareness programme.

• Implement environment protection law.

• Use unleaded gasoline in your cars.

• Never use open fires to dispose of wastes.

• Do not litter in public places.

• Organic waste should be dumped in places far from residential areas.

• Use of chemical pesticides, weedicides, insecticides etc. should be minimized. Promote the use of bio-pesticides, bio-fertilizers etc.

• Non -biodegradable waste should be collected and disposed for recycling processes.

• Start individual or community vermin-composting plant in your neighborhood and motivate people to join.

• Advocate organic farming.

• Develop respect for all forms of life.

POLLUTION CASE STUDIES

Case study 1: Love Canal incident [New York]

It was the most widely quoted example for ground water pollution. In 1978, residents of love canal neighborhood in New York city noticed high rates of cancer and alarming number of birth defects. This was found to be due to the organic solvents and dioxins from an industrial land fill. These contaminants have infiltrated into water supply and evaporated in basements to further contaminate air. During 1930- 53, New York city municipal waste and industrial waste was dumped in love canal dumping site. Later this site was filled up with soil and sold to build an elementary school and residential area. Survey of air sample around the area showed the presence of 26 different organic compounds including chloroform, benzene, toluene, perchloroethylene etc. Eight hundred families were reimbursed for their homes and moved, after extensive legal battles and media coverage.

Case study 2: Minamata Tragedy [Japan]

A case of human mercury poisoning which occurred in May 1956 in the Minamata in Japan, which is a typical example of the pollution related health damage. A large plastic plant located near the Minamata Bay used a mercury containing compound in a reaction to produce polyvinyl chloride (PVC), a common plastic material. The left-over mercury was dumped into the Bay along with other waste from the plant. Though mercury was in its inorganic state when dumped, the microorganism at the bottom of the bay converted the mercury into its organic form. This organic mercury entered into the tissues of fish which were in turn consumed by the people living in the

area. The contaminated fish thus caused an outbreak of poisoning, killing and affecting several people. Mothers who had eaten the contaminated fish gave birth to infants who showed the signs of mercury poisoning. Mercury poisoning is thus called ‘Minamata Diseases’.

Case study 3: Exxon Valdez oil spill- worst oil spill disaster [Alaska, US]

On March 24, 1989 Exxon Valdez, a tanker in an attempt to avoid iceberg, ran aground and released 11 million gallons of crude oil into a wide channel in Prince William Sound near Valdez in Alaska. It was the worst environmental disaster in Alaska history, and occurred in a very sensitive coastal ecosystem. It contaminated 1300

miles of shoreline and stretching over 470 miles from the crash site. The site was in a remote location and lack of oil skimming equipment and ineffective chemical dispersants made a speedy response very difficult. The cleaning operation involved 11,000 people and 1000 boats. The fast spreading oil proved deadly for wild life in the region. Countless fishes, along with more than 2,50,000 sea birds and thousands of otters and seals perished. Exxon spent more than $2 billion for cleaning up the spill, but some oil still remains. In a civil case Exxon was hit with a $ 5 billion civil judgment for its role in the accident.

Case study 4: Kuttanadu Wetland [ Kerala, India]

It is a low-lying area near the coast and is known as the rice bowl of Kerala. Kuttanadu is a wetland ecosystem located in the southern coastal part of Kerala State, and spread across the districts of Alappuzha, Kottayam and Pathanamthitta; that is in an extreme state of ecological decay and environmental degradation. Wetlands are one of the most productive ecosystems and play a significant role in the ecological sustainability of a region.

Kuttanadu is a complex system of brackish lagoons, marshes, mangroves, reclaimed land and a network of canals. Vembanadu Lake is identified as an important bird area, which supports the third largest wintering waterfowl of the country. It is also one of the 15 mangrove areas. The most significant eco- system services of Vembanadu include fishery, agriculture, navigation, port facility, tourism and coir industries. The environmental conditions of this lake are in a steady state of decline due to various anthropogenic activities which leads to severe livelihood crisis for the dependent communities. The major ecological consequences in this region is the fall in soil fertility, increased incidence of pest and diseases, use of large quantities of pesticides, and extinction of mangroves that used to function as favoured nursery areas of fishery resources.

All this makes water pollution the major environmental problem of Kuttanadu region. The residues of pollutants such as fertilizers and pesticides, animal and human wastes etc accumulate in water. Pollutants from industrial and agro-chemical residues, municipal sewage, effluents from motor boats, and coir retting to open water bodies, deteriorates the quality of the lake ecosystem. Kuttanadu area is found to have very high occurrence of cancer of the lip, stomach, skin and brain, lymphoma, leukemia, vision and multiple myloma. The other health problems include breathing problems, dehydration, vomiting, cramps and diarrhea.This intense pollution and environmental degradation is adversely affecting the flora and fauna of the area. For example, many of the fish varieties that were common in the area are already extinct.

DISASTER MANAGEMENT

The Indian subcontinent is traditionally vulnerable to natural disaster on account of its unique geo- climatic conditions. Floods, cyclones, earthquakes and landslides have been recurrent phenomena. About 60% of the landmass is prone to earthquakes of various intensities; over 40 million hectares are prone to floods; about 8% of the total area is prone to cyclones and 68% of the area is susceptible to drought. Among all the disasters that occur in the country, floods are the most frequently occurring natural disaster due to the irregularities of the Indian Monsoon. The term disaster management includes all aspects of preventive and protective measures, preparedness and organization of relief operations for mitigating the impact of disaster on human beings and socioeconomic aspects of the disaster-prone areas. At the

global level, there has been considerable concern over natural disasters. Even as scientific progress is made, loss of lives and property due to disaster is increasing. Disaster management occupies an important place in our country’s policy framework as it is the poor and under-privileged who are the worst affected on account of calamities and disaster.

Flood

India is one of the most flood prone countries in the world. Floods occur in almost all rivers basins in India. Most of the flood affected areas lie in the Ganga basin,   Brahmaputra   basin,the northwestern river basin, peninsular river basin and the coastal regions of Andhra Pradesh, Tamilnadu, Orissa, Kerala, Assam, Uttar Pradesh and Bihar. Twenty-three of the 35 states and union territories in the country are subject to floods and it affects an average area of around 7.5 million hectares per year. According to the National Commission on Floods, the area susceptible to floods was estimated in 1980 to be around 40 million hectares and it is possible to provide reasonable degree of protection to nearly 80 per cent.

Flood is a state of high-water level reaching land in a short span of time, causing land surface to be submerged under water. Floods may happen gradually and also may take hours or even happen suddenly without any warning due to spill over, heavy rains etc. There are different types of floods namely: flash flood, river line flood, urban flood, etc.

Causes

There are several causes of floods and they differ from region to region. The causes may vary from a rural area to an urban area. Some of the major causes are:

• Heavy rainfall and deforestation.

• Heavy siltation of the river bed reduces the water carrying capacity of the rivers/stream.

• Blockage in the drains leads to flooding of the area.

• Landslides blocking the flow of the stream.

• Construction of dams and reservoirs.

• In areas prone to cyclone, strong winds accompanied by heavy down pour along with storm surge leads to flooding.

Adverse Effects

• The most important consequence of floods is the loss of life and property. Structures like houses, bridges, roads etc. get damaged. There is huge loss to life and livestock caused by drowning.
  

• Lack of proper drinking water facilities, contamination of water (well, ground water, municipal water supply) leads to outbreak of epidemics, diarrhoea, viral infection, malaria and many other infectious diseases.

• Flooding also leads to huge crop loss. This results in shortage of food, and animal fodder. Floods may also affect the soil characteristics. The land may be rendered infertile due to erosion of top soil or may turn saline if sea water floods the area.

• 121 people were killed due to floods across the state of Kerala during August 2019. Over 2 lakh people have been directly affected by flood and were shifted to 1318 relief camps in different parts of Kerala.

Control measures:

• Mapping of flood prone areas using Satellite and remote sensing-based imageries are found to be the best tool.

• As soon as the information of a flood event is obtained, the earliest available satellite is programmed to collect the required data for the explanation of flooded areas. Both optical and microwave satellites data can be used.

• Land use control will reduce danger of life and property when water enters the flood plains and the coastal areas.

• Construction of engineered structures in the flood plain will strengthen the structures to withstand flood forces like flood walls, flood levees, coastal protection works, etc.

• Reforestation will help in flood control by decreasing the amount of run-off.

• Diversion of flood water and improvement in drainage facilities.

• The National Flood Control Programme was launched in 1954. Since then, sizeable progress has been made in the flood protection measures.

• Flood insurance, public health awareness, and disaster relief.

Cyclones

The major disaster that affects the coastal region of India is cyclone. India has a coastline of about 7516 Km and it is exposed to nearly 8% of the world’s tropical cyclones. About 71% of this area falls in ten states (Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Puducherry, Andhra Pradesh, Orissa and West Bengal). The islands of Andaman, Nicobar and Lakshadweep are also prone to cyclones.

Cyclone is a region of low atmospheric pressure surrounded by high atmospheric pressure resulting in swirling atmospheric disturbance accompanied by powerful winds blowing in anticlockwise direction in the Northern Hemisphere and in clockwise direction in the Southern Hemisphere. They generally move

300-5000 Km per day over the ocean. They occur mainly in the tropical and temperate regions of the world. The main dangers from cyclones are very strong winds, torrential rains and high storm tides. The development of a cyclone covers three stages namely formation and initial development state, fully matured and weakening/decay. Although one cannot control cyclones, the effect can be mitigated through effective mitigation policies and strategies.

Adverse effect:

• Major damage to infrastructure and housing

• Causalities due to flooding and flying elements in air

• Contamination of water supplies may lead to diarrhea, malaria etc

• Contamination of ground and pipe water

• Loss of crops and food supplies

• Disruption of communication towers, electricity, telephone cables etc

• Roads and rails may be damaged

Control measures:

• Hazard mapping/ early warning system - Using appropriate models and satellite data, ISRO is supporting the efforts of India Meteorological Department to predict the tropical cyclone track, intensity and landfall. After the formation of cyclone, its future tracks are regularly monitored and predicted by ISRO. These experimental track predictions are regularly posted on departmental web portal (http://www.mosdac.gov.in/scorpio/) as part of information dissemination.

• Using the wind pattern generated by the Oceansat-2 Scatterometer, data models have been developed for predicting the formation of a cyclone even before the depression turns into a cyclone.

• Coastal belt plantation and land use control.

• Engineered structures which can withstand high wind forces.

• Protect river embankment.

• Construction of permanent houses.

• Communication lines should be installed underground.

• Provide strong halls for community shelter in vulnerable locations.

• Land use control and settlement planning.

• Public awareness programme /training /education.
  

Earthquakes

Earthquake is one of the most destructive natural hazards. They may occur at any time of the year with sudden impact and little warning and involves violent shaking of the ground. An earthquake struck Gujarat on 26 January 2001 on a massive scale. Remote Sensing and GIS provide a database from which the evidences left behind by disaster can be combined with other geological and topographical database to arrive at hazard map. The areas affected by earthquakes are generally large, but they are restricted to well- known regions (Plate contacts).

Earthquakes results from the release of accumulated stress of the moving lithospheric or crustal plates. The earth's crust is divided into seven major plates, that are about 50 miles thick, which move slowly and continuously over the earth's interior and several minor plates. Earthquakes are tectonic in origin; that is the moving plates are responsible for the occurrence of violent shakes.

Cause:

India's increasing population and extensive unscientific constructions mushrooming all over, including multistoried luxury apartments, huge factory buildings, gigantic malls, supermarkets as well as warehouses and stonework buildings keep - India at high risk. During the last 15 years, the country has experienced 10 major earthquakes that have resulted in over 20,000 deaths.

Adverse Effects

• Damage to structures, human life.

• The occurrence of an earthquake in a populated area may cause numerous casualties and injuries as well as extensive damage to property.

• Sea activity-water level in the sea could rise suddenly.

• Landslides will be caused due to impacts, changed topography, blocked roadways etc.

Control measures:

• Satellite data gives a synoptic overview of the area affected by the disaster. These data can be made use to create a very large scale base information of the terrain for carrying out the disaster assessment and for relief measures.

• Community preparedness.

• Construction of buildings should be based on the guidelines of the Bureau of Indian standards to with stand ground shaking.

• Public education through sensitization and training programme for community, architects, engineers, builders, masons, teachers, government functionaries, teachers and students.
  

Landslide

Landslides are downward and outward movement of slope materials such as rock debris and earth, under the influence of gravity. Landslides are one of the natural hazards that affect at least 15 per cent of the land area of our country—an area which exceeds 0.49 million Km2. They are recurring phenomena in Himalayan region.

Cause:

• Earthquake

• Volcanic eruption

• Weakness in the composition of the structure of rock or soil

• Erosion

• Intense rainfall

• Human excavation

Adverse effects:

• For a long time, landslides have had disastrous consequences causing enormous economic losses and affecting the social fabric. In 2005 alone, more than 500 human lives were lost due to this hazard in our country.

• Loss of buildings, roads, communication lines etc.

• On August 2019 in Kerala, incessant rainfall triggered major landslides at Ipadi, Puttupala, Wayanad, Neelambur and Mallapuram, which trapped several people under debris. 64 land slides happened in the state in the recent disastrous spell. Unlike in 2018, where around 400 people were killed, mostly due to floods, in 2019, majority of the 103 deaths have happened due to landslides.

Control measures

• Remote sensing data have been proved to be useful for landslide inventory mapping both at local and regional level.

• Engineered structures with strong foundations.

• Strong vegetation cover.

• Department of Space has prepared Landslide Hazard Zonation maps (LHZ) along tourist and pilgrim routes.

• Hazard mapping will locate areas prone to slope failures. These maps will also serve as a tool for mitigation planning.
  

• The surface drainage control works are implemented to control the movement of landslides accompanied by infiltration of rain water and spring flows.

5. Role of public/community participation in disaster management

The government of different countries, international, national and local (also voluntary) agencies have adopted comprehensive disaster management plans and programs, emphasizing on public participation with an intention of reducing the pains and sufferings of victims, shorten the number of loss of human lives and livestock. As it is the public which is going to face the disaster, it is very important that community should be part of the complete disaster management process in all three phases- rescue, relief, and post-disaster recovery. Communities are the first responders in case of a disaster. Therefore, community-based disaster risk reduction (CBDRR) should be the core of any risk reduction approach.

Public is a largely untapped resource in the emergency management field. Engaging the public dialogically in early policy stages and emergency management phases is essential to successful inclusion for both administrators and communities. Public inclusion creates expanded knowledge, shared learning, personal responsibility, and increased social capital. Faced with the growing threat from disasters, emergency management can create communities that are both more resilient and sustainable by increasing public participation.

QUESTIONS

Part A (2 marks)

1. Define pollutants. Give example.

2. What are contaminants? Give example.

3. List the main segments of atmosphere.

4. Define air pollution. List two important causes of air pollution.

5. What is blue baby syndrome? What are the causes

6. What is photochemical smog? Why it is dangerous?

7. Why is CFCs dangerous?

8. What are indoor air pollutants? Give examples.

9. Name two inorganic pollutants in water

10. What is noise pollution? Name the unit formeasuring noise pollution.

11. Outline BOD
    

12. What is primary pollutant? Give examples

13. Define water pollution

14. What is secondary pollutant? Give examples.

15. Differentiate point and non-point sources

16. What is greenhouse effect. How can it be reduced?

17. Suggest two control measures for marine pollution

18. What are the essential qualities of drinking water?

19. Discuss two factors responsible for nuclear pollution

20. What is Eutrophication

21. What is dissolved oxygen. What does it indicate?

22. How can you reduce water pollution?

23. Which region of soil has maximum biological activity? Why?

24. What is meant by COD?

25. Outline Love canal incident

26. Discuss the cause of soil pollution

27. What is marine pollution. How can it be reduced?

28. How isthermal pollution different from marine pollution?

29. What is nuclear fallout. How is it dangerous

30. Why solid waste management is essential?

31. What is vermin-composting?

32. Define bioaccumulation.

33. Why is disaster management necessary?

34. What are earthquakes? How is it caused?

35. List four important causes of noise pollution

36. What are landslides? How can it be prevented?

37. Solid waste management is an essential perquisite for a healthy living. Discuss.

38. Name any two nuclear accidents

39. What is the effect of biomagnification?

40. How can noise pollution be prevented?

41. What are water quality parameters?

42. Reduce, Reuse and Recycle is a new answer to environmental pollution. Explain.
    

Part B (5 marks)

1. What are the control measures adopted to minimize air pollution?

2. Discuss global warming and greenhouse effect.

3. What are the adverse effects of water pollution?

4. How can we control water pollution?

5. Differentiate between BOD and COD.

6. What is soil horizon? Explain.

7. How can soil pollution be reduced?

8. What are the causes of land degradation/soil pollution? Suggest few techniques to reduce soil pollution.

9. Discuss the preventive measures which can be adopted for nuclear pollution

10. Comment on the Love canal incident –a case study of ground water pollution.

11. What are the different types of water pollution? What are the major sources?

12. What is pollution? Explain the different sources of air pollution

13. Write briefly on marine pollution

14. What is biomagnification? What the effects?

15. What is noise pollution? How can it be controlled?

16. What are the health effects of noise pollution?

17. What are nuclear hazards? How can you control nuclear pollution?

18. Comment on the environmental degradation of Kuttanadu wetland

19. Write briefly on solid waste disposal.

20. Discuss following methods adopted for waste management a) sanitary landfills b/ incineration c) composting

21. What is thermal pollution? How can it be controlled?

22. What are causes and effects of nuclear pollution?

23. Discuss the important methods adopted for solid waste disposal

24. Write notes on Minamata tragedy

25. What is disaster management? What the measures opted for the prevention of landslides.

26. Discuss the cause, effects and control measures for flood

27. How can cyclone be prevented? What are its adverse effects?

28. Discuss the role of community in disaster management

29. Write a note on nuclear pollution, its source and impact on environment

30. Outline the role of individual in the prevention of pollution.
    

Part C (15 marks)

1. Analyze critically the factors responsible and remedial measures for a) air pollution b) noise pollution

2. Explain the cause, effects and control measures of a) water pollution b) soil pollution

3. Outline the cause, effects and control measures of thermal pollution. How is it different from marine pollution?

4. What is nuclear pollution? Briefly describe its causes, effects and control measures

5. Write an essay on the causes, effects and control measures employed for solid waste management.

6. What is pollution? Which are the different types? Explain the role of NGO/individual in the protection of environment.Outline the role of public/community participation in disaster. management

7. What is disaster management? Write explanatory note on the cause, effects and control measures adopted for a) floods b) earthquakes

8. Discuss the cause, effects and control measures adopted for a) landslides b) cyclone c) earthquakes

9. What is water pollution? What are it causes? How can it be controlled? Explain with the help of a case study.

10. Discuss the factors responsible and remedial measures for a) nuclear pollution b) solid waste management.

QUESTIONS

Part A (2 marks)

1. Define pollutants. Give example.

2. What are contaminants? Give example.

3. List the main segments of atmosphere.

4. Define air pollution. List two important causes of air pollution.

5. What is blue baby syndrome? What are the causes

6. What is photochemical smog? Why it is dangerous?

7. Why is CFCs dangerous?

8. What are indoor air pollutants? Give examples.

9. Name two inorganic pollutants in water

10. What is noise pollution? Name the unit formeasuring noise pollution.

11. Outline BOD
    

12. What is primary pollutant? Give examples

13. Define water pollution

14. What is secondary pollutant? Give examples.

15. Differentiate point and non-point sources

16. What is greenhouse effect. How can it be reduced?

17. Suggest two control measures for marine pollution

18. What are the essential qualities of drinking water?

19. Discuss two factors responsible for nuclear pollution

20. What is Eutrophication

21. What is dissolved oxygen. What does it indicate?

22. How can you reduce water pollution?

23. Which region of soil has maximum biological activity? Why?

24. What is meant by COD?

25. Outline Love canal incident

26. Discuss the cause of soil pollution

27. What is marine pollution. How can it be reduced?

28. How isthermal pollution different from marine pollution?

29. What is nuclear fallout. How is it dangerous

30. Why solid waste management is essential?

31. What is vermin-composting?

32. Define bioaccumulation.

33. Why is disaster management necessary?

34. What are earthquakes? How is it caused?

35. List four important causes of noise pollution

36. What are landslides? How can it be prevented?

37. Solid waste management is an essential perquisite for a healthy living. Discuss.

38. Name any two nuclear accidents

39. What is the effect of biomagnification?

40. How can noise pollution be prevented?

41. What are water quality parameters?

42. Reduce, Reuse and Recycle is a new answer to environmental pollution. Explain.
    

Part B (5 marks)

1. What are the control measures adopted to minimize air pollution?

2. Discuss global warming and greenhouse effect.

3. What are the adverse effects of water pollution?

4. How can we control water pollution?

5. Differentiate between BOD and COD.

6. What is soil horizon? Explain.

7. How can soil pollution be reduced?

8. What are the causes of land degradation/soil pollution? Suggest few techniques to reduce soil pollution.

9. Discuss the preventive measures which can be adopted for nuclear pollution

10. Comment on the Love canal incident –a case study of ground water pollution.

11. What are the different types of water pollution? What are the major sources?

12. What is pollution? Explain the different sources of air pollution

13. Write briefly on marine pollution

14. What is biomagnification? What the effects?

15. What is noise pollution? How can it be controlled?

16. What are the health effects of noise pollution?

17. What are nuclear hazards? How can you control nuclear pollution?

18. Comment on the environmental degradation of Kuttanadu wetland

19. Write briefly on solid waste disposal.

20. Discuss following methods adopted for waste management a) sanitary landfills b/ incineration c) composting

21. What is thermal pollution? How can it be controlled?

22. What are causes and effects of nuclear pollution?

23. Discuss the important methods adopted for solid waste disposal

24. Write notes on Minamata tragedy

25. What is disaster management? What the measures opted for the prevention of landslides.

26. Discuss the cause, effects and control measures for flood

27. How can cyclone be prevented? What are its adverse effects?

28. Discuss the role of community in disaster management

29. Write a note on nuclear pollution, its source and impact on environment

30. Outline the role of individual in the prevention of pollution.
    

Part C (15 marks)

1. Analyze critically the factors responsible and remedial measures for a) air pollution b) noise pollution

2. Explain the cause, effects and control measures of a) water pollution b) soil pollution

3. Outline the cause, effects and control measures of thermal pollution. How is it different from marine pollution?

4. What is nuclear pollution? Briefly describe its causes, effects and control measures

5. Write an essay on the causes, effects and control measures employed for solid waste management.

6. What is pollution? Which are the different types? Explain the role of NGO/individual in the protection of environment.Outline the role of public/community participation in disaster. management

7. What is disaster management? Write explanatory note on the cause, effects and control measures adopted for a) floods b) earthquakes

8. Discuss the cause, effects and control measures adopted for a) landslides b) cyclone c) earthquakes

9. What is water pollution? What are it causes? How can it be controlled? Explain with the help of a case study.

10. Discuss the factors responsible and remedial measures for a) nuclear pollution b) solid waste management.