Free Study Materials of Pollution and Pollutants

(People and Environment)

Pollution and Pollutants

 

The addition of unwanted substances in a concentration that has an adverse effect on organisms and the environment is called pollution.

An undesirable change in the physical, chemical and biological characteristics of the environment especially air, water and land that may adversely affect human population and the wildlife, industrial processes, cultural assets (building and monuments), is called pollution.

The agents that pollute the environment or cause pollution are called Pollutants.

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TYPES OF POLLUTION

• Air pollution
• Water pollution
• Land (Soil) pollution
• Noise pollution

Air Pollution

 

Sources of Air Pollution

The sources of air pollution can be divided into two categories (i) natural, and (ii) human-made

(i)    Natural sources

• Ash from burning volcanoes, dust from the storm, forest fires
• Pollengrainsfromflowersinairarenaturalsourcesofpollution

(ii)  Anthropogenic (human-made) sources

• Power stations using coal or crude oil release CO2 in the air
• Also, furnaces using coal, cattle dung cakes, firewood, kerosene, etc.
• Steam engines used in railways, steamers, motor vehicles, etc. give out CO2.
• Sodo Motor and internal combustion engines which run on petrol, diesel, kerosene, etc. Vegetable oils, kerosene, and coal as household fuels
• Sewers and domestic drains emanating foul gases
• Pesticide residues in air

 

Major Air Pollutants

• Carbon Dioxide

Carbon dioxide is one of the major gases which contribute towards air pollution. It is mainly produced during the combustion of fuel in factories, power stations, household etc. The increasing CO2 in the atmosphere is likely to have the following effects:

1.  A rise in atmospheric temperature or global warming due to Green House Effect. Also, causes climate change.
2. Reduced productivity of the marine ecosystem. This is due to the fact that water in the oceans would be more acidic due to increased concentration of CO2 in the air, which dissolves in the water.
3. Due to Global warming, the increased surface temperature would cause melting of continental and mountain glaciers and thus would cause flooding of coastal areas of some countries.

 

• Sulphur Dioxide

It is produced by the burning of coal in powerhouses and automobiles (car, trucks  etc.). It causes chlorosis and necrosis of plants, irritation in eyes and injury to the respiratory tract (asthma, bronchitis) in humans responsible for discolouration and deterioration of buildings. High concentration of sulphur dioxide in the atmosphere dissolves in raindrops to form sulphuric acid which causes acid rain.

 

• Carbon Monoxide

Carbon monoxide is produced as a result of incomplete combustion of fossil fuels like coal, petroleum and wood charcoal. Automobiles using diesel and petroleum are the major sources of carbon monoxide which get added to the atmosphere. Carbon monoxide is more dangerous than carbon dioxide. It is a poisonous gas which causes respiratory problems. When it reaches the bloodstream, it replaces oxygen due to its high affinity for haemoglobin. It also causes giddiness, headache and interferes with normal function of the heart.

• Fluorides

Upon heating, rocks, soils, and minerals that contain fluorides, give out hydrogen fluoride gas. This is an extremely toxic gas, which causes serious injury to livestock and cattle.

• Oxides of Nitrogen

A few oxides of nitrogen, such as nitric oxide (NO), nitrous oxide (N2O) and nitrogen dioxide (NO2) are produced by natural processes as well as from thermal power stations, factories, automobiles, and aircraft (due to burning of coal and petroleum). They reduce the oxygen carrying capacity of blood, may cause eye irritation and skin cancer in human beings.

• Smog

Smog is a mixture of smoke, dust particles and small drops of fog. Smog may cause necrosis and develop a white coating on the leaves(silvering) of plants. In human beings and animals, it may cause asthma and allergies.

• Aerosol Spray Propellants

Suspended fine particles in the air are known as aerosols. Aerosols contain Chlorofluorocarbons (CFCs) and fluorocarbons used in refrigerants and aerosol cans. They cause depletion of the ozone layer.

Domestic Air Pollutants

Smoke from cigarettes, biri, cigar and other such objects using burning tobacco, burning of coal, firewood, cow dung cakes, kerosene oil and liquefied gases are major domestic pollutants. The common pollutant gases emitted during the domestic burning of coal, kerosene oil, firewood, cow dung cakes, etc. are carbon monoxide (CO), carbon dioxide (CO2), sulphur dioxide (SO2), etc.The pollution due to these pollutants causes suffocation, eye and lung diseases and low visibility.

Effects of Air Pollution

Major effects of air pollution on human health, plants and other animals are given below –

Some major air pollutants, their sources and effects –

Pollutant	Source	Harmful effect
Carboncompounds	–       Automobile	Ÿ Respiratory problems Ÿ Greenhouse effect global warning  and  climate change     Ÿ Respiratory  problems  in humans Ÿ loss of chlorophyll in plants   (chlorosis) Ÿ Acid rain     Ÿ Irritation  in  eyes  and lungs Ÿ Low  productivity  in plants Ÿ Acid rain damages material (metals and stone) Ÿ Respiratory problem Ÿ Cancer  causing properties
(CO  andCO2)	exhausts
	burningof
	wood  and coal
Sulphur	powerplants
compounds	andrefineries
(SO2  andH2S)	Volcanic
	eruptions
NitrogenCompound	–       Motorvehicle
(NO  andN2O)	exhaust,
	atmospheric
	reaction
Hydrocarbons	–       Automobiles
(benzene,ethylene)	andpetroleum
	industries

SPM (Suspended Particulate matter) (Any Solid or liquid particles  suspended in the air, (fly ash, dust, lead)   Fibres (Cotton, wool)

Thermal power plants. construction activities, metallurgical processes and automobiles Textile and carpet weaving industries

Ÿ Poor  visibility,  breathing problems Ÿ Lead interferes with the development of red blood cells and causes lung diseases  and cancer Ÿ Smog (smoke+fog) formation leads to poor visibility  and  aggravates  asthma inpatients Ÿ Lung disorders

 

 

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Water Pollution

Sources of Water Pollution

Therearetwosourcesofwaterpollutiononthebasisoforiginofpollutants:

(i)   Point sources. and(ii) non-pointsources.

• Point sources – Those sources which discharge water pollutants directly into the water are known as point sources of water pollution. Oil wells situated near water bodies, factories. power plants, underground coal mines, etc. are point sources of water pollution.
• Non-point sources – Those sources which do not have any specific location for discharging pollutants, in the water body are known as non-point sources of water pollution. Run-offs from agricultural fields, lawns, gardens, construction sites, roads and streets are some non-point sources of water pollution.

Water Pollutants

River, lake and sea water may be polluted in many ways.

• Domestic sewage discharged into rivers from areas located on its banks.
• Industrial wastes effluents from urban areas containing high concentration of oil, heavy metals and detergents
• Minerals, organic wastes and crop dusting from agricultural fields with phosphate and nitrogen fertilizers that reach lakes, rivers and sea (waterbecomes deoxygenated and poisonous, thus, cannot support aquatic life)
• Chemical fertilizers, pesticides, insecticides, herbicides and plant remains

• Industrial waste water containing several chemical pollutants, such as calcium, magnesium, chlorides, sulphide, carbonates, nitrates, nitrites, heavy metals and radioactive waste from nuclear reactor.
• Excretory wastes of humans and animals in water bodies

• Disposal of urban and industrial waste matter into water bodies

 

Some major disturbances in the ecosystem due to water pollution

Pollutant	Sources	Cause	Effect
Nitrates, phosphates, ammoniumsalts	Agricultural fertilizers, sewage, manure	Plant nutrients	Eutrophication
Animalmanure and  plantresidues	Sewage,  papermills, foodprocessing wastes	Oxygen deficiency	Death  ofaquatic animals
Heat	Power  plants and industrial cooling	Thermal discharge	Death  of fish
Oil slick	Leakage  from oil ships	Petroleum	Death  of  marine life due  to  non-availability of  oxygen  dissolved in water

Fertilizers and pesticides are widely used in agriculture. Their excessive use for increasing agricultural yield has led to the phenomenon of eutrophication and biomagnification.

Sources of Industrial Pollution

Type of Industry	Inorganic pollutants	Organic pollutant
Mining	Chlorides,  various  metals, ferrous
	sulphate,  sulphuric  acid,hydrogen
	sulphide,  ferric  hydroxidesurface
	wash offs, suspended solid,  chlorides
	and  heavymetals
Iron  andSteel	Suspended  solids,  ironcyanides,	Oil,  phenoland
	thiocyanate,  sulphides,oxides	naphtha.
	of  copper,  chromium.,cadmium
	andmercury.
Chemical Plants	Various  acids  and  alkalies, chlorides,	Aromatic
	sulphates,  nitrates  ofmetals,	compounds
	phosphorus,  fluorine,  silicaand
	suspendedparticles
Pharmaceuticals		Protein,carbohydrates,
		organic solventsintermediate
		products,  drugsand
		antibiotics.

Soap and Detergents	Tertiary ammonium compound alkalies.	Fats and fatty
		acids, glycerol,
		phosphates,
		polysulphonated
		hydrocarbons.
Food processing		Highly putrescible
		(easily rots) organic
		matter  and pathogens.
Paper  andPulp	Sulphides  and  BleachingLiquors	Cellulosefibre,
		bark,  wood sugars
		organic acids,

 

                           Some water pollutants, their sources and effect on human health

Pollutant	Source	Diseases  in humans
Lead	Industrialwaste	Nervous disorders,
		Kidney failure.
		blood poisoning
Tin	Industrial dust	Affects central nervous system  (CNS)
		Affects, vision
Mercury	Industrial discharge	Affects central nervous system  and
		peripheral  nervoussystem,
		kidney failure,
		Numbness of lips, muscles and   limbs,
		Blurred vision
Arsenic	Industrial discharge	Respiratory  and  skincancer.
		Nervous disorder
Nickel	Aerosols,  industrialdust	Pulmonary  disorders, dermatitis
Cadmium	Industrial discharge	Kidney disorders,
		Pulmonary  and  skeletal diseases
Uranium, thorium	Radioactivewaste	Leucoderma,  skin cancer
cesium

 

Major Water Pollutants their Sources and Effects

 

  Water Borne Diseases

  A. Bacterial Diseases

Disease	Causative organism	Mode of spread	Symptoms
Typhoid	Salmonellatyphi	Contaminated food, water, milk, unwashed raw vegetables andflies	Continuous fever which increases day by day Temperature higher in evening than morning, body ache, headache and constipation. Haemorrhagefromanulcerationin small intestine
Cholera	Vibriocholerae	Water or food con- taminated by bacteria from tools of cholerapatient	Painless diarrhoea, vomiting, 30-40 stools per day which soon becomes typically watery and colourless with flakes of mucous floating in them
Bacterial Diaorhoea	Shigella spp.	Contaminated food, water and by direct personal contact	Diarrhoea, with blood and dysentry mucous in the stools along with severe gripping pain in the abdomen. Stools not too frequent (4-10 per day), faecal matter scanty. Patient looks ill
Leptospirosis	Leptospira	Rodents primary hosts-carry organisms in kidneys. Infection by wading or swimming in water contaminated with rodent urine	Fever, pain in legs, nausea, vomiting are common, congestion of the conjunctival blood vessels around corneas of the eyes

  B. Viral diseases:

Infective Hepatitis	Hepatitisvirus	Food and water contaminated with virus instools	Loss of appetite, nausea, vomiting, and diarrhea, accompanied with fever. Urine dark coloured. Eye and skin appear yellow
C.  Protozoan diseases:
Amoebic dysentery	Entamoeba histolytica	Ingestion of cysts in food andwater	Abdominal discomfort and diarrhoea, with or without blood or mucous in stools, fever, chills and gripping pain in abdomen
Diarrhoea	Giardia (=Lamblia) intestinalis	Food or water con- taminated withfae- ces havingcysts	Intestinaldisordersleadingtoepigastric pain, abdominal discomfort, loss of appetite, headache and loosebowels
D.  Helminth diseases:
Bilharzia	Schistosomaspp	Cercaria larvaeof flukes inwater penetrate skin of persons  wading in water	Allergy-like itch, rash, aches,fever, eosinophiliaetc.Wheninfectionheavy, eggs may block arterioles oflungs cardio-pulmonary watercausing schistosomiasis and may  leadto congestive heart failure
Guinea  worm    Dracunculus medinensis		Unfilteredwater	Blister near the ankle, causing allergy and aches

 E. Vector-borne diseases related to water:

Diseases transmitted by mosquitoes-

Disease	Causative Organisms	Vector	Hosts	Symptoms
Malaria	Plasmodiumsp	Female Anopheles (primary or final hosts)	Man(intermediate hosts)	Shivering, chills and sweating. Aschillssubside body temperature rises as high as 106ºF. When temperature comes down patient sweats profusely and becomes chills subside body temperature rises as high as 106ºF. When temperature comes down patient sweats profusely and becomes as high as 106ºF. When temperature comes down patient sweats profusely and becomes comfortable until next attack which takes place at regular intervals.
Filaria (Elephantiasis)	Wuchereria(=filaria)	Culexfatigans	Man (final hosts)	Enlargement of limbs and scrotum
Dengue	Barbo-virus	Aedesaegypti	Man (reservoir)	Sudden on set of moderately high fever, excruciating joint pain, intense pain behind eyes, a second rise in temp following brief remission, reduction in neutrophilic white blood cells

 

GREENHOUSE EFFECT AND GLOBAL WARMING

 

A greenhouse is an enclosure usually made of glass in which temperature inside is higher than outside. An increase in the percentage of greenhouse gases which prevent the escape of heat from the earth, would increase the average temperature on earth worldwide known as greenhouse effect.

Greenhouse gases in the atmosphere behave much like the glass panes in a greenhouse. Theyallowsunlighttoentertheatmosphereofearth.When the sunlight enters the surface of the earth, sun’s energy is absorbed by land, water and biosphere. Some of this energy is reflected back to the atmosphere by earth.Some of this energy passes back into space. However, most of the energy remains trapped in the atmosphere by the greenhouse gases causing global warming on earth.

Causes Of Global Warming

Carbon dioxide (CO2), Chlorofluorocarbons (CFCs), Methane (CH4) and Nitrous oxides(N2O) are the main greenhouse gases that cause global warming. An increase in the concentration of these greenhouse gases leads to an increased trapping of longwave radiation resulting in an increase in earth’s temperature causing global warming.

 

Greenhouse Gases: Their sources and Causes

Gas	Sources and Causes
Carbon dioxide (CO2)	Burning of fossil fuels, deforestation
Chlorofluorocarbons(CFCs)	Refrigeration, solvents, insulation foams, aero propellants, industrial and commercial uses
Nitrogen oxides (N2O)	Burning of fossil fuels, fertilizers; burning of wood and crop residue.
Methane (CH4)	Growing paddy, excreta of cattle and other livestock, termites,

 

The Ozone Hole: Depletion Of The Ozone Layer

The ozone layer present in the earth’s atmosphere prevents the entry of sun’s harmful ultraviolet(UV) radiation reaching the Earth’s surface. Industrial use of chemicals called chlorofluorocarbons (CFCs) in refrigeration, air conditioning, cleaning solvents, fire extinguishers and aerosols (spray cans of perfumes, insecticides, medicines,etc.) damage the ozone layer.The ozone hole is formed as follows:

Chlorine contained in the CFCs on reaching the ozone (O2) layer splits the ozone molecule to form oxygen (O2) Amount of ozone, thus, gets reduced and cannot prevent the entry of UV radiation. There has been a reduction by 30-40% in the thickness of the ozone umbrella or shield over the Arctic and Antarctic regions.

 

Important Ozone Depleting Chemicals and their uses.

Name of the compound	Used in
CFCs	Refrigeration, aerosol, foam, food freezing, warming devices, cosmetics, heat detectors solvents, cosmetics, refrigerants, firefighting
Halon	firefighting
HCFC-22	Refrigeration, aerosol, foam, firefighting
Methyl chloroform	Solvent
Carbon tetrachloride	Solvent

Acid Rain

Acid rain occurs when Sulphur dioxide (SO2) and oxides of Nitrogen (NOx) are emitted into the atmosphere, undergo chemical transformations and are absorbed by water droplets in clouds. This causes the formation of sulphuric and nitric acids in rain clouds. The droplets then fall to earth as rain, snow or mist. If rain falls through polluted air it picks up more of these gases and increases its acidity. This is called acid rain. This can increase the acidity of the soil, and affect the chemical balance of lakes and streams. Thus, acid rain is defined as any type of precipitation with a pH that is unusually low. A pH of less than about 5 is used as a definition of acid rain. Acid rain is a serious environmental problem that affects large parts of the world.

Sources of Acid Rain

Sulphur dioxide (SO2) is generally a byproduct of industrial processes and burning of fossil fuels. Ores melting, coal-fired power generators and natural gas processing are the main contributors to sulphur dioxide in the atmosphere.

The main source of oxides of nitrogen (NOx) emissions is the combustion of fuels in motor vehicles, residential and commercial furnaces, industrial and electrical- utility boilers and engines, and other equipment.

 

Effects of Acid Rain

It causes acidification of lakes and streams and contributes to the damage of trees any many sensitive forest soils. In addition, acid rain accelerates the decay of building materials and paints, including heritage buildings, statues, and sculptures that are part of our nation’s cultural heritage. Prior to falling to the earth, suphur dioxide  (SO2)  and nitrogen  oxide  (NOx)  gases and  their particulate matterderivatives— sulphates and nitrates- contribute to visibility degradation and harm public health.

RADIATION–AN ENVIRONMENTAL POLLUTANTS

 

Radiation is one of the chief forms of energy consisting of high energy particles. Radiation could be natural (solar and cosmic) or and human (nuclear). Radiation has also become a major factor causing environmental  pollution.

Radiation may have both short term or long term effects.They can further be divided functionally into:

• Ionising and
• Non Ionising radiations

Ionizing and Non Ionising Radiations

 

Type	Ionizing	Non ionizing
Examples Properties Effects   Harmful Effects	Alpha,  Beta,  Gamma  and X-Ray Short wavelengths,  high energy. Causes ionisation in cells photoproducts Ÿ Deep penetrating power effects both external & internal organs	Ultraviolet radiation Higher wave lengths, low energy Damage  through toxic   Ÿ Only superficial tissues are damaged
	Ÿ Breakage of chromosomes   Ÿ Gene mutation and genetic variations Ÿ Cancer of bone marrow (Leukaemia)   Ÿ Loss hair Ÿ Male sterility	Ÿ Kills  micro-organism and egg  of  fish  & amphibians     Ÿ Prevents synthesis of DNA  and RNA, Cell division   Ÿ Skin  cancer  in humans

Nuclear Radiation and its harmful effect

Radiations emitted by nuclear substances or wastes(fallout) or from an atomic power plant or an atomic explosion cause nuclear radiation. Nuclear wastes continue to emit radiation for a very long period.

Radioactive Iodine (131I) and Strontium (90Sr) are two nuclear wastes from an atomic explosion and may cause cancer of thyroid and cancer of bone narrow respectively. By entering food chain they also get accumulated in high concentration in the body of the top consumer causing harmful effect on the health of both humans and animals.

Soil Pollution

 

Addition of substances that change the quality of soil by making it less fertile and unable to support life is called soil pollution.

 

Sources of soil pollution

Soil pollution is caused due to :

• Domestic sources: plastic bags, kitchen waste, glass bottles, and paper
• Industrial sources: chemical residue, fly ash, metallic waste, and
• Agricultural residues: fertilizers and pesticides.

 

Harmful effects of soil pollution

• Decrease in irrigated land thereby reduction in agricultural production.
• Decrease in soil productivity.
• Carry over of pollutants into the food chain.
• Damage to landscape

 

Control of Soil Pollution

• Judicious use of chemical fertilizers and pesticides.
• Proper and appropriate irrigation practices
• Conversion of farm wastes into compost and much use of biofertilizers and manure in farming.
• Ensure use of pollution-free or treated wastewater only for irrigation.
• Recycling of waste material for example plastic, metal and glass are recyclable and incineration of non-recyclable, wastes.

 

Soil Erosion

The process of detaching and removal of loosened soil particles by water (running water, ground water, rain, sea waves) and the wind is known as soil erosion.

 

Soil may be eroded by water and wind, each contributing towards a significant amount of soil loss every year in our country.

 

Types of soil erosion

 

Wind erosion

Erosion of large quantity of fine soil particles and sand from deserts by wind is known as wind erosion. It is spread over the cultivated land and thus, destroys the fertility of that land.

 

Sheet erosion

When water moves over the land surface as a sheet, it takes away the topmost thin layer of soil. This phenomenon occurs uniformly on the slopes of hilly areas, riverbeds and areas affected by floods. This type of erosion is known as sheet erosion.

 

Gully erosion

When water moves down the slope as a channel, it scoops out the soil and forms gullies which gradually multiply and spread over a large area. This type of soil erosion is known as gully erosion.

 

NOISE POLLUTION

Any unwanted sound is defined as noise. You know that the noises come from traffic, vehicles, especially at peak hour every day, loudspeakers and building construction work. Industries expose their workers to

a high level of noises for a long period of work every day.

Prolonged exposure to the high level of noise is harmful. Noise is measured in terms of ‘decibel’ (dB) – a scale expressing the intensity of the sound.

Noise has harmful effects on the human body. The noise of 70-80 dB causes annoyance and irritation. Above this level, breathing rate may be affected, blood vessels may constrict, movement of the digestive canal is disturbed, glandular secretions may be affected. Long exposure to high noise levels can impair hearing.

 

Pollution control Legislations in India

Acts	Year
Indian Forest Act	1927
Wildlife Protection Act	1972
The water (Prevention and control of Pollution) Act	1974
The air (Prevention and control of Pollution) Act	1981
The Environmental (Protection) Act	1986
The National Environmental Tribunal Act	1995

 

The pollution related laws like the Water Act (1974), Air Act(1981), and the Environmental Protection Act (1995) do not give the right to individuals to move the court under the environmental laws for damages caused to them by pollution. The right has been vested only in the agencies of the State Government.

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