Definition

• Pollution is an undesirable change in physical, chemical and biological characteristics of our land, air or water caused by excessive accumulationof pollutant (i.e. Substances which cause pollution).

Kinds of Pollution

• Air pollution, water pollution, land pollution and noise pollution.

Air pollution

• Degradation of air quality and natural atmospheric condition constitute air pollution.
• The air pollutant may be a gas or particulate matter.

Air pollutants and their effects

1. Particulate matter

• Soot, dust, pesticide, etc., and biological agents such as spores, pollen and dust mites.
• Causes respiratory ailments such as asthma, chronic bronchitis, etc.,

2. Carbon monoxide

• Carbon monoxide is a product of incomplete combustion of fossil fuels in automobiles
• It is highly poisonous to moist animals. When inhaled, carbon monoxidereduces the oxygen carrying capacity of blood.

3. Hydrocarbons

• Hydrocarbons such as methane, axe evolved from soil microbes(methanogens) in flooded rice fields and swamps. They are also generated during the burning of coal and petroleum products.

4. Sulphur dioxide

• Sulphur dioxide is released from oil refineries and ore smelters which usethesulphur containing fuels.
• It causes chlorisis (loss of chlorophyll) and necrosis (localized death of tissues.
• In human,it causes health problems such as asthma, bronchitis andemphysema.

5. Nitrogen oxides

• It causes reddish brown haze (brown air) in traffic- congested city airwhich contributes to heart and lung problems.

Secondary effects of air pollution

Photochemieal smog

• Smog is a mixture of smoke and fog.
• Resulting in the formation of PAN (Peroxy acetyl nitrate)PANdamagesthe chlorophyll and thus reduces photosynthesis and growth
• It also causes acute irritation of eyes and throat .Visibility of thesurrounding is reduced due to smog

Acid rain

• Gases such as Sulphur di oxide Nitrogen oxides are oxidized to form sulphuric and along with water, and precipitate as acid rain.
• It damages building materials, plants and animals. It also makes the soilacidic.

BHOPAL GAS TRAGEDY (2^nd&3^rd Dec 1984) refers to the industrial disaster which killed thousand of people and animals due to the inhaling of methyl isocyanate (MIC)

Control of air pollution

• The particulates devices such as scrubbers, precipitators and filters.
• Use of unleaded or low sulphurfule
• Shifting to non-conventional sources of energy.
• Smoking in public places should be prohibited
• Planting of trees

Water Pollution

                       Water pollution is delined as the adding of unwanted substances orchange of physical and chemical characteristics of water.

Sources and effects of water pollution

Industrial wastes

                 Heavy metals and chemicals such as cadmium, copper;chromium, mercury, zinc, nickel, etc

The surface run off

                       The surface run off from agricultural land is contaminated with pesticidesand residues of  inorganic fertilizers

Oil spills

Domestic Sewage

• It is rich in organic matter and detergents.
• Availability of excess nutrients results in algal bloom on the surface ofwater resulting in the deficiency of oxygen content (BOD – Biological Oxygen Demand)
• This in turn leads to the death of aquatic organisms.
• This process is known as Eutrophication
• Mercury poisoning clue to the consumption of fish captured from mercurycontaminatedMinamata Bay in Iapan was detected in 1952.

Control of water pollution

1. Sewage treatment plants
2. Excessive use of pesticides, herbicides and fertilizers should be avoided.
3. Biological control of insect pests and organic farming is to be followed.

Reverse osmosis (RO)

• It is the most efficient way of obtaining purified drinking water.
• It is best suited for desalination of sea watee(removal of salt)

 Soil Pollution

• Soil pollution is the unfavourable alteration of soil by the addition orremoval of substances which decrease soil productivity and ground waterquality.

Causes and effects

• The industrial solid waste and sludge contain toxic organic and inorganiccompounds as well as heavy metals.
• The radioactive waste from nuclear power plants and nuclear explosionsalso contaminate the soil.
• Fly ash contains fine particulates,
• The domestic waste is rich in organic matter and undergo decomposition.
• Agricultural chemicals such as pesticides, insecticides and inorganicfertilizers may pollute drinking water and can change the chemical properties of the soil adversely affecting the soil organisms.

Control of soil pollution

• Categorizationof wastes. Recovery of resources like scrap metals, plastics etc., for recycling and reuse and safe disposal.

Radioactive pollution

• The emission of protons, electrons and electromagnetic radiations released by the disintegration of radioactive substances auch as radium,thorium, uranium, etc., cause air, water and land pollution.

Effects

• The ionizing radiations can cause mutations
• Strontium – 90 aecumulates in bones causing bone cancer
• Iodine -131 can damage bone marrow,spleen, lymph nodes and can cause leukemia(Blood cancer)

Preventive measures

• Care should be taken to prevent the leakage of radioactive substances.
• Radioactive wastes should be disposed off safely.
• Control or prevention of nuclear tests.

Chernobyl disaster (Ukraine)

• The ‘inhabitants of Chernobyl were exposed to radioactivity which was hundred times greater than Hiroshima bomb.
• Babies were born with infirmities and people suffered from seriousdiseases like thyroid cancer.

Noise pollution

• Noise level above 120 db is considered harmful to human beings.

Sources

• Industrial machinery, road, rail and air transport, loudspeakers,constructionequipments

Effects

• Heartbeat, breathing and can cause constriction of blood vessels
• Loud noises (above 130 db) can cause damage to the ear drum, hair cells of cochlea.

Control Measures

• The industrial should be established away from residential areas.

Various laws and rules

1974 – Water (prevention, control of pollution)Act

1981 – Air (prevention, control of pollution) Act

 1986- Environment Pollution Act

1988 – Motor vehicle Act

Global Warming

• July 1998 was the hottest month world over
• In 1998 India has the hottest period in 50 years.
• Since 1988 nine of the hottest years in more than a century have beenrecorded
• There is a rapid melting of snow and subsequent rise in sea level.
• Global warming which refers to an average increase in the temperature of the atmosphere or simply it is the warming of the earth.
• The root cause of this adverse climatic change is the greenhouse effect caused by greenhouse gases

Green House Effect

• The trapping of energy from the sun by green house gases in the atmosphere leading to rise in earth’s temperature is known as the green house effect
• The green house gases such as carbondioxide ,nethane,nitrous oxide , chlorofluro carbons, etc., absorb and reflect infra red waves radiated bythe earth causing increase in temperature as in a green house

Green House

• A green house is a structure primarly of glass or plastic in which temperature and humidity can be controlled  for the cultivation or  production of plants

Green House gases

Carbondioxide

• Most abundant greenhouse gas released by burning of fossil fuels, deforestation,respiration of animals ,decaying of organic matter
• At present there is an increase of 31 % of carbondioxide

Methane

• Produced by the incomplete decomposition of organic compounds bymethanogenic bacteria under anaerobic condition.
• It is also produced by the enteric fermentation in the cow and from theflooded rice fields.

Nitrous oxide

• Is released by burning of fossil fuels, industrial processes.

Chlorofluro carbons

                       Chlorofluro carbons are coolant gases used in refridgerators, aerosols solvent etc

Global Warming

• The level of the sea rises, due to the melting of glaciers and thermal expansion of water which will submerge many parts of countries
• Due to global warming the rise in temperature could create unexpected changes in weather conditions making some regions hotter and others colder
• The rainfall pattern could also change causing drought in some areas and flooding in others
• Crops and forests may be affected by insect pests and plant diseases resulting in severe damage
• Water borne and insect borne diseases such as malaria and dengue could spread to temperate countries
• It can also result in the loss of bio diversity due to the extinction of coral reefs and other key species.

Control Measures

• By reducing the use of fossil fuels, reforestation ,carbon sequestration(trapping CO2 ),shifting of renevable sources of energy such as solar,power,wind power ,hydel power etc

To reduce global warming

• Use CF(Compact Fuorescent Light) bulbs

El Nino Effect

• It causes erratic weather patterns which occur due to the interaction of unusually warm or cold sea surface temperature in the eastern and centralpacific oceans

Compact fluorescent light

• CFLs are a great way to save energy eventhough they coast a little more and are slower to brighten up than an ordinary bulb. They produce less amount of heat

Ozone Depletion

• The ozone layer in the stratosphere is protective in function as it filters the harmful ultraviolet rays of the sun.
• This ozone is continuously broken down reformed; these two processes perfectly balance each other
• But due tohuman activity this balance is upset leading  to the thinning of ozone layer (ozone holes)
• The decrease m the amount of ozone in the stratosphere is called ozone depletion

Reasons

• The ozone is due to chlorine and bromine formed in the atmosphere.The common ones are chloroflurocarbons , methyl bromide,  nitrogen oxides ,etc
• Which are released from freezers, air conditioners,aerosol products ,industrial solvents etc.

Effects

• In humans skin cancer cateracts and poor immune response
• The UV radiation can also cause the death of phytoplanktons (producers)young fishes and larval forms

Control measures

• Controlling the production use and emission of ozone depletingsubstances recycling of chemicals
• Adoption of protection measures from sun’s radiation

Oil Spill

• An oil spill is a release of liquid petroleum hydrocarbons into the environment, mainly due to human activities

Environmental impacts

• Oil spill affects the physical chemical and biological characteristics of water and land
• The oil floating on top of the water
• The oil also drenches ability to fly and escape from predators
• The oil which covers the coats of aquatic animals such as seals can reduce their heat insulation capacity, resulting in hypothermia.

Control and preventive measures

• The oil spills can be controlled by preventing the release of oil or hydrocarbons during transit exploration of accidents
• The seafood should be thoroughly tested for contaminants
• The oil spills may be cleared by using certain micro organisms such as bacteria.
• This process of clearing the oil spills by using bacteria is known as bio-remediation.

Dr. Ananda Mohan Chakraborty

• Invention of Pseudomonas putida, a genetically engineered bacterium an Indian American scientist Dr. Ananda Mohan Chakraborty.
• It is a rod shaped saprotrophic soil bacteria with a diverse metabolism to degrade hydrocarbons and organic solvents like octane and toluene.

Recent episodes of Oil spills

Deep water horizon oil spill

• It is a massive oil spill in the Gulf of Mexico and is the largest offshore spill in US history.
• It stemmed from a sea floor oil gusher that resulted from the April 2010deep water horizon drilling rig explosion

Mumbai oil spill (August 2010)

• The spill occurred due to the collision of two oil tankers MSC Chitra and MV Khalija off the coast of Mumbai

Agenciesof Environmental Management

• P.R. Environmental Centre, Chennai
• Madras naturalists Society
• MSSRF (MS. Swaminathan Research Foundation)