Thermal Pollution

 

THERMAL POLLUTION

“It is defines and the undesirable changes in the temperature of the water body”.

          The temperature change can be upwards or downwards.  Thermal pollution refers to release of warm water into the water body where desirable organisms are adversely affected or otherwise causes significant departures from the normal activities of aquatic communities in water.

 

Sources of Thermal pollution

·       Thermal power stations

·       Nuclear power plants

·       coal-fired power plants

·       Oil refineries

·       Steel factories

 

Effects of Thermal pollution

·       Concentration of dissolved oxygen decreases with increase in temperature of water.

·       The rising temperature increases the toxicity of the poison present in water.

·       Fishes move away from their natural habitat polluted by warm water.

·       Blue green algae and other plants grow more rapidly in warm water than in cold, but they also die more rapidly.

·       The dead and decaying algae make the water look, taste, and smell unpleasant.

·       It affects the biodiversity.

 

Control of Thermal pollution

          Thermal pollution may be controlled by the following methods.

Cooling ponds

          Discharge the heated water into shallow ponds or canals, allow it to cool, and reuse it as cooling water.

Cooling Towers

          A large cooling tower is designed to control the temperature of water.  Here, the hot water is allowed to run through a coiling pipe from top of the cooling tower;  The cool air is passed to flow up from the bottom of the tower.  After cooling, the water is drained into water bodies.

Spray ponds

          The hot water coming from the industries are allowed to pass through several sprayers.  Heat is dissipated through evaporation.

 

Cogeneration

          The Excess heat energy from generating electricity can be used in another manufacturing process that needs such energy.   Where homes or other buildings are located near industrial plants, waste hot waste can be used for heating the materials the require energy.

Noice Pollution

 

NOISE POLLUTION

The word “noise” comes from the Latin word “nausea” meaning “seasickness”.  The undesirable sound or unwanted sound is called noise.  Noise is a disturbance to the human environment.  Noise is an inescapable part of modern life.  Noise pollution is the major pollutant in developing India.

 

Definition

“Noise pollution is defined as the undesirable or unwanted sound that causes discomfort all the living beings”

 

Sources of noise pollution

          The source of noise is either natural or man made.  The natural noise comes from volcanic eruptions, stroms, sea wave, thunder and animal sound.  The main sources of man made noises are from industry (Textile mills, generators and bore well drillers), Transport (Motor cycle, buses, rail noise) and neighbourhood (radio, TV, religious functions, kitchen appliances) in developing countries.  Aircraft noise is the largest (after roadway noise) source of environmental noise.

          Noise is measured in decibel.  One dB is equal to the faintest sound, a human can hear.  A noise dosimeter or noise dosemeter is a specialized sound level meter, used to measure the noise exposure of the person integrated over a period of time.

1.  The ambient noise levels recommended by central pollution control board

Zone	Day 6am-10pm	Night 10pm-6am
Industrial	70	70
Commercial	65	55
Residential	55	45
Silence	50	40

 

Effects of Noise pollution

·       It damages physiological and psychological health

·       It causes annoyance and aggression

·       It increases the rate of heart bead and blood pressure

·       It causes headache, mental fatigue and lack of concentration

·       It causes hearing loss, deafness

·       Ultrasonic sound can affect semicircular canals of the internal ear and cause nausea and dizziness

·       Noise disturbs sleep.

 

Control of Noise pollution

1.   Source control

The sources that generate unwanted sound should be reduced.  This may include source modification such as acoustic treatment to machine surfaces, design changes, limiting the operational timings and so on.  Wheels of the machines must be oiled properly.  The loud speakers should be set at low sound.

 

2.   Transmission path intervention

This may include containing the source inside a sound insulating enclosure, construction of noise barrier or provision of sound absorbing materials along the path.  Trees absorb pollution.  So, plantation of tree in public places, around industries, cities and on the sides of roads is to be encouraged.

 

3.   Receptor control

This include protection of the receiver by altering the work schedule.  having a ear plug or cotton plugs to protect the ear drum from noise pollution.

 

4.   Preventive measure

·       Residential area, hospitals, school, etc may be constructed far away from city.

·       Declaration of “no horn zone” in residential, hospital and school areas.

·       Restriction should be on the use of loud speakers/utility address system.

·       Immediate steps to be taken to control manufacturing and selling of fire crackers exceeding the prescribed limits.

·       Noise limits must be prescribed for automobiles, domestic appliances and construction equipment at the manufacturing stage.

·       Noise can be reduced by prescribing noise limits for vehicles traffic.

·       Honking of horns should be banned.

·       Noise proof building should be constructed.

·       Education and awareness should be taught about the consequences of noise

Pollution in massive scale though media.

 

Marine Pollution

MARINE POLLUTION

The undersirable change occurring in the sea is called marine pollution.

 

Causes of Marine pollution:

Marine pollution is caused by the following factors:

1.   Industries pass the effluents into the sea through pipes.

2.   Municipal wastes and garbages are dumped into the sea.

3.   Discarding of old and useless fishing nets from fishing boats and ships into the marine water.

4.   The passengers of ships and the fish farmers throw the plastics into the sea.

5.   The pesticides and fertilizers applied on agricultural fields are washed into the sea by surface run off.

6.   Oil spilling, due to leaks in the oil tanker ships, cause oil pollution.

7.   Oil leaks from oil refineries and pipelines.

8.   Accident of cargo ships carrying toxic substances such as oil, gas, pesticides, fertilizers etc causes marine pollution.

9.   Petrol and oil washed off from the roads cause oil pollution.

10.                     Gulf war created much marine pollution.  During gulf war about 750 oil wells in Kuwait were set of fire.

The undesirable charges in the characteristics of marine water around the gulf countries due to oil in 1991 gulf war is an example of ecoterrorism.

 

Effects of Marine pollution

1.   The rich amount of nutrients in the sewage water facilitate the thick growth of phytoplankton and algae.  It is called eutrophication.

2.   Heavy amount of nutrients bring about the thick growth dinoflagellates causing plankton bloom.  They emit red light in the tides and it is called red tide.  They toxic to fishes.

3.   The thin film of oil on the surfaces of water is called oil slick.  It damages the mangrove plants.

4.   The desalinated drinking water is contaminated with oil.

5.   coral reefs, the gardens of the sea are damaged by oil slick.

6.   The sea birds and sea cows are much affected by oil pollution and die.

 

Control of Marine Pollution

1.   Sewage treatment: It includes a number of steps such as screening sedimentation, decomposition etc.

2.   Large sewage materials can be removed by screening.

3.   Dissolved particles can be removed by sedimentation.

4.   The sewage is allowed to decompose by micro-organisms.

5.   The volatile part of oil can be removed by evaporation.

Water Pollution

WATER POLLUTION

          Water pollution refers to the undersirable change occurring in water which may harmfully affect the life activities of man and domesticated species.

Water pollutants:  The common water pollutants are as follows.

·       Domestic sewage

·       Industrial effluents

·       Pesticides

·       Fertilizers

·       Micro organisms

·       Plankton blooms

·       Heavy metals

·       Temperature

·       Silt

·       Radioactivity

·       Oil

 

Causes of Water Pollutants

1.   Domestic sewage:  The sewage is released into the river.  It consists of human face, urine and dirty particles used up in houses.  It contains large number of pathogenic bacteria and virus.

2.   Industrial effluents:  The non-usable organic and inorganic chemical waters released from the industries are get into water bodies.  These wastes includes heavy metals, detergents, petroleum, carbonates, cyanides, chlorine

3.   Thermal pollution:  Many industries use water for cooling.  The resultant warm water is discharged into rivers.  It brings about thermal pollution.

4.   Pesticides:  These are chemicals used to control pests in crop fields and houses.  They include DDT,  BHC, Endrin etc.

5.   Fertilizers:  The fertilizers used for crops are washed into ponds and rivers.

6.   Radioactive wastes:  Liquid radioactive wastes released into the sea around nuclear installations.  The oceanic currents carry the radioactive contamination every where.

7.   Oil pollution:  Oil is a source of pollution in sea water.  Oil pollution is due to ship accidents, loading and discharging of oil at the harbor and oil refineries.

8.   Retting:  The process of decaying coconut just to get fibre for making coir is called retting.  Retting releases h2s.  It is toxice and makes water polluted.

Ecological effects of water pollution

1.  Minamata disease:  This disease is caused by mercury poisoning.  It is characterized by crippling and death.  This disease appeared in a coastal town, Minamata in Japan,  Mercury, a by product released from plastic industry was disposed into  the sea.  The accumulation of mercury leads to crippling and death.  The initial symptoms of minamata disease includes numbness of limbs, lips and tongue, impairment of motor control deafness and blurring of vision.  Finally it affects the brain.

2.  Diarrhoea:  It is caused by micro organisms and metals like mercury, cadmium and cobalt.  Some of the diseases caused by microbes and metals found in water are as follows.

·       Typhoid fever

·       dysentery

·       hookworm disease

·       whooping cough

·       methamoglopinema

·       jaundice

·       poliomyelitis

·       pneumonia

·       influenza

·       handy code syndrome

3.  Mortality of plankton and fish:  Chlorine which is added to water to control the growth of algae and bacteria in the coding system of power stations may persist in streams to cause the mortality of plankton and fish.  Plankton is a small aquatic plant or animal that live in the surface water.

4.  Reduction in productivity:  Intensive agriculture increases the amount of silt in lakes and rivers.  Silt reduces transparency of water and prevents the penetration of light to depths and reduces primary production.

5.  Siltation:  Siltation is a phenomenon by which the gills of fishes are deposited with silt.  This causes heavy mortality among fishes.

6.  Poor oxygenation:  Oil present on the surface of water prevents water oxygenation.  This reduces respiration and metabolism in aquatic organisms.

7.  Poor photosynthesis:  Oil pollution prevents photosynthesis in phythoplankton.

8.  Red tide:  When coastal waters are enriched with nutrients of sewage, dinoflagellates multiply rapidly and form bloom.  These blooming dinoflagellates produce toxic metabolic by products which can result in a large scale death of marine fishes.  This is called red tide.

9.  Biochemical oxygen demand:  Sewage enriches the water with nutrients.  This causes growth of plankton and algae.  This leads to oxygen depletion in water.  This depletion causes the death of algae.  The decay and decomposition of algae consume more oxygen from water.  Biological oxygen demand is the amount of oxygen required by the microorganisms in water.  BOD is higher in polluted water and lesser in drinking water.

10.  Water-borne diseases:   Diseases like jaundice cholera, typhoid, diarrhea are transmitted through water contaminated with sewage.

11.  Methacmoglobinema:  The nitrate used in fertilizers enters the intestine of man through drinking water,  In the intestine, it is converted into nitrite,  Nitrite is absorbed into the blood where it combines with haemoglobin to form met haemoglobin.  Met haemoglobin cannot transport oxygen.  This leads to suffocation and breathing troubles,  especially in infants.  This disease is called methaemoglobinema.

12.  Eutrophication:  The increased productivity of lakes and ponds brought about by nutrient enrichment is known as eutrophication.  Domestic sewage and fertilizers add large quantities of nutrients such as nitrates and phosphates to the fresh water ecosystems.  The rich supply of these nutrients make blue green algae, green algae and other phytoplankton to grow abundantly.  As the algae use O2 of the water for respiration, the O2 is depleted from the water.  Thus eutorphication leads to the complete depletion of the flora and fauna from the ecosystem.

Soil Pollution

 

SOIL POLLUTION

 

“ It is the introduction of substances, biological organisms into the soil, resulting in a change of the soil quality, which is likely to affect the normal use of the soil”

The soil is a resources for which there is no substitute.  It is a thin covering over the land consisting of mixture of minerals of minerals, organic material, living organisms, air and water.  Several factors like mechanical weathering of rocks due to temperature changes, wind, moving water, glaciers and chemical weathering activities contribute to the soil formation.  Mature soils are arranged in a series of zones called ‘soil horizons’.  Soils vary in their content of clay, silt, sand and gravel.  Soil with equal mixtures of clay, sand, silt, and humus are called loams.

SOIL POLLUTANTS

Crop residues, ashes, garbage, paper, plastics, rubber, leather, cloth, bricks, sand, broken glasses, demolished buildings, dead animals, and discarded furniture, automobiles, insecticides, oil spillage and herbicides.

PESTICIDES:

They are chemical used to kill pests like insects, rats, fungi, herbs etc.  They are of the following types.

1)  Insecticides: chemicals used to kill insect pests

2)  Rodenticides: kill rats

3)  Fungicides:  kill fungi

4)  Herbicides:  kill weeds

5)  Helminthicides:  Kill helminth worms

 

CHEMISTRY OF PESTICIDES

Based on chemical composition, pesticides are divided into three main groups.  They are 1. chlorinated hydrocarbons.  2.  Organic phosphorus insecticides and 3.  Inorganic insecticides

1.  Chlorinated hydrocarbons:

DDT, aldrin, dieldrin, endrin form chlorinated hydrocarbon.  They are very poisonous, very persistent,hightly mobile and highly capable dissolving in fat.  They are non degradable pollutants

2.  Organic phosphorus insecticides:  These are alkyl or organic phosphates.  Parathion and malathion are well known organic phosphates.  They are biodegradable

3.  Inorganic insecticides:  These include arsenic and sulphur compounds.  They are much less in use.

ECOLOGICAL EFFECTS OF PESTICIDES

1. Mutation:  Insecticides induce gene mutation in human beings

2.  Cancer:  DDT produces cancer in human tissues

3.  Congenital birth defects:  Certain herbicides like dioxin increase birth defects in both human and cattle.

4.  Sex hormones:  DDT affects sex hormones in mammals and birds.

5.  Calcium metabolism:  DDT interferes with calcium metabolism resulting in delayed ovulation and inhibition of gonad development

6.  Biomagnification:  As the pesticides are non degradable the accumulate in the tissues of higher organisms through food chain and food web.  It is called biomagnifications or biological amplification.

 

CONTROL OF PESTICIDE POLLUTION

a)  Minimal use:  Pesticides should be used at minimum rates and that too when required

b)  Sterilization:  Juvenile hormones prevent metamorphosis maturation in insects.  They can be used to control insect pests.

c)  Biological control:  Pests should be killed either by rearing predator or parasites.  For e.g Mosquito larvae can be eradicated by culturing fishes as they feed these larvae as effective food materials

d)  Integrated pest management:  It promotes the use of biopesticides,  Biopesticides are derived from three sources

1)  Microbial pesticides are microorganisms such as bacteria, fungus, virus or protozoa.  They produce toxins specific to the pests and produce disease in them.  The most commonly used biopesticide is bacillus thuringiensis

2)  Biochemical pesticides:  Contain several chemicals that affect the reproductive and digestive mechanisms of the pests

3)  Botanical pesticides:  Plant products like azardiractin from nee, Azardiracta indica is used as an effective pesticide.

Air Pollution

 

AIR POLLUTION

Air pollution refers to the undesirable change inn the quality of air due to contamination of chemical and particulate matter or biological agents.

 

HISTORY OF AIR POLLUTION

·       The origin of air pollution on the earth can be traced back to the time when man started using firewood for cooking and heating.

·       It was noticed as a problem 700 years ago in London in the form of smoke pollution.  The major disaster ‘London smog’ occurred in 1952 caused more than 4000 deaths due to accumulation air pollution over the city for five days.

·       The severe air quality problems due to petrochemical smoke from vehicles were observed for the first time in los angels.

·       The air pollution control act in India was passed in 1981.

·       The greatest industrial disaster took place in Bhopal on the night of 2^nd December, 1984 due to the leakage of poisonous methyl isocyanate gas from the union carbide company.  It caused the death of 3000 of human beings.

 

THE ATMOSPHERE:

Composition of the air:  The atmosphere is made up of a mixture of gases.  Normally the air consists of 78.08% if nitrogen, 20.95% oxygen and 0.93% argon.  Other gases like carbon dioxide, hydrogen, neon, helium, methane and ozone are also present in very small quantities.

 

Structure of atmosphere:  The atmosphere is divided into four different layers.

1)  Trophosphere:  It is the lower most layer.  It extends 18km above the sea level at the equator.  It contains 75% of the mass of the earth’s air.  Temperature decreases with height in this layer.

 

2)  Stratosphere:  It is the second layer of the atmosphere.  It extends to a height of 48km above the sea level.  The volume of water vapour here is about 1000 times less, while the volume of ozone is about 1000 times greater.  The presence of ozone in the stratosphere prevents about 99% of the sun’s harmful ultra radiation reaching the earth.  Hence, it protects human from cancer and damage to immune system.  It provides flying conditions for jet air crafts.

 

3)  Mesosphere:  It extends to height of 82km above the sea level temperatue of this layer decreases with increasing height, reaching upto -110*c at the top.

4)  Thermosphere:  It extends to a height of 82 to 400 km.  This layer contains electrically charged particles called ions.  Hence, this layer is also called as Ionosphere.  Temperature starts increasing with height in the layer because of radiation from the sun.

 

AIR POLLUTANTS

Air pollutants are directly emitted from identifiable sources.  They are produced both by natural events and human activities.  These are called Primary pollutants.  They are five primary pollutants that together contribyte to about 90% of global air pollution.  These are carbon oxides, nitrogen oxides, sulfur oxides, volatile organic compounds and suspended particulate matter.

Carbon Monoxide is a colorless, odorless and toxic gas produced from the incomplete burning gas, coal or wood.  Vehicular exhausts are the single largest source of carbon monoxide.

Sulphur oxides are produced when sulfur containing fossil fuels are burnt

Nitrogen oxides are found in vehicular exhausts.

Hydrocarbons are group of compounds consisting of carbon and hydrogen atoms.  They are washed out of the air when it rains.

Particulates are small pieces of solid materials.

The following are the different types of particulates.

1.  Aerosol: It is a general term for particles in air.

2.  Mist:  Aerosal consisting of liquid droplets.

3.  Dust:  Aerosal consisting of solid particles.

4. Smoke:  Aerosal consisting of mixture of solid and liquid particles produced by chemical reaction.

5.  Fume: It is similar to smoke but produced from condensation of hot vapors of metals

6.  Fog:  Aerosal constisting of water droplets

7.  Smog:  Term used to describe a mixture of smoke and fog

 

The primary pollutants by chemical reaction produce secondary pollutants.

Lead is major air pollutant emitted by vehicles.  The use of unleaded petrol is one way of reducing this pollutant.

EFFECTS OF AIR POLLUTION ON HUMAN HEALTH

Continuous smoking or exposure to air pollutants can cause lung cancer, asthma, chronic bronchitis and pulmonary edema

1.  Carbon monoxide:  Cigarette smoking is responsible for the greatest exposure to carbon monoxide. Exposure to air containing even 0.001% carbon monoxide for several hours can cause coma and death.  It also reduces the oxygen carrying capacity of hemoglobin in the blood which leads to headaches, drowsiness, nausea and blurred vision.

2.  Sulfur dioxide:  produces irritation of the respiratory tissues and in long term exposure causes bronchitis and lung cancer.

3.  Nitrogen oxides:  Affect the respiratory tract leading to bronchitis and asthma.  Particles from asbestos, ash can cause cancer in lungs

5.  Volatile compounds:  Benzene and formaldehyde and toxic particulates can cause mutation, reproductive problems and cancer.  Repeated inhalation of ozone can cause coughing chest pain, breathlessness and irritation eyes, nose, and throat.

 

EFFECTS OF PLANTS

Long term exposure of plants to air pollutants cause the following effects

1.  Disappearance of chlorophyll by sulphur di oxide affects photosysthesis

2.  Less carbohydrate production

3.  Damage of leaf tissue, buds, flowers and fruits

4.  Reduction in growth rate or suppression of growth

5.  Increases possibility to disease and pest attack

6.  Decrease in crop yield, smaller fruits and less nutritious products

7.  Leaves turn to yellow, brown

 

EFFECTS ON MATERIALS

The air pollutants can also break down the exterior paint on cars and houses.  All over the world,  air pollutants have discolored irresplaceable effects to monuments, historic buildings, marble statues and natural beauty sites

 

EFFECTS ON THE STRATOSPHERE

The upper stratosphere consists of ozone which acts as an effective screen for uv light.  Ozone is a form of ozygen with three atoms instead of two.  The small changes in ozone oncentration produce drastic effects on the life on earth.  The accumulation of air pollutants can accelerate the breakdown of ozone.  In 1985, large scale destruction of ozone called ‘ozone hole’ was created by chlorfluro carbons.

Chlorofluoro carbons causes depletion of ozone.  They are stable, non flammable, nontoxic and harmless to handle.  But they are used in air conditioners, refrigerators and fire extinguishers.

Halons are similar in structure to CFC’s but contain bromine instead of chlorine.  They are most dangerous than CFC ad used as fire extinguishing agents.  Ozone depletion is prevailing in south poles due to extreme ice crystals.

Effects of ozone depletion

1) Depletion on human health:

Sunburn, cataracts, aging of the skin, skin cancer are caused by uv radiation.  It weakens the immune system which leads to measles, chickenpox and other viral diseases.

2) Zoophanktons:

They are damaged by UV radiation.  In zooplankton the breeding period is shortened.  Changes in total number and species compositon disrucpt the food fish production.

3) Food production:

The UV radiations affects photosynthsis, reduces and nutrient content and decreases the growth in legumes and cabbage.

4) Materials:

Increased UV radiation damages paints and fabrics leading them to fade faster

5) Effect on climate:

Global warming a phenomenon by which earth is warming up due to the increased concentration of certain gases like nitrogen oxides, carbon di oxide, methane and CFCs.  They absorb the heat in the form of infra red radiation near the earth’s surface as in a glass green house which allows solar radiation to enter which is absorbed by the objects inside.  Hence, this is known as “Green house effect”.

There could be several adverse effects of global warming

1.  With a warmer earth, the polar ice caps will melt causing rise in sea level and flooding of coastal area.

2.  If sea level rises by 3 metres, the Maldives will disappear completely beneath the waves

3.  Rise in temperature will affect agricultural production

4.  Temperature rise by global warming also affects changes in species of plants, insects, live stock and microorganisms.

AIR POLLUTION IN INDIA

The world health organization rater new delhi as the fourth 4^th most polluted city In the world.  According to central pollution control board (2003), Ahmedabod’s air is the most noxious followed by Kanpur, shalapur and lucknow.  Nitrogen dioxide level increases in Kolkata and delhi due to heavy vehicular traffic and density.  Implementation of compressed natural gas program has improved the quality of air.

Marble cancer to Taj mahal:  Increased level to sulfur dioxide and suspended particulate matter caused a fungal growth that corroded the surface to taj mahal giving a yellow tinge called ‘ Marble cancer’.  The supreme court of India ordered 292 industries in the vicinity to either adopt pollution control measures or shut down.

CONTROL OF AIR POLLUTION

1.  The emission of exhaust from automobiles can be reduced by devices such as ventilation valve and catalytic converter

2.  Electrostatic precipitators can reduce the smoke and dust from industries.

3.  Certain gases can be removed by filtration or absorption through activated carbon

4.  Greater emphasis should be given on the pollution prevention rather than control

5.  The quality of vehicular fuel should be improved

6.  At the Government level pollution can be controlled by farming legislations