Associate Professor

Zoology

Narain College

Shikohabad, Firozabad  Uttar Pradesh, India 

Abstract

Environment protection  and  sustainability are pleasant and sustainability can be achieved by protecting our natural resource. This chapter presents an overview of the different types of problems affecting the environment and recent advances in environmental protection strategies. Environmental protection can be defined as the prevention of unwanted changes to ecosystems and their constituent parts. As human population size has grown enormously over the last hundred years. This means increase in demand for food, water, home, electricity, roads, automobile and numerous other commodities. These  demands are exerting  tremendous  pressure on our natural resource, and are  also contributing to pollution of  air, water and soil. The need of hour is to check the degradation and depletion of our precious natural resource and pollution without  halting  the  process  of development. In order to control environmental pollution, the government of  india  has passed the  Environment  protection  Act, 1986 to  protect and  improves the quality of our environment (air,water,and soil). 

Introduction 

The environment is  our  abrupt  surroundings, which  include both  animate and inanimate elements. It can refer to the social, natural, or constructed environment. The environment has a significant  influence on a person’ behavior and cognition. Any change in a living entity is tied to a change in his immediate surroundings, whether directly or indirectly. The term  environment  refers to everything  that  surrounds, including  animate and inanimate object like soil, water, plants, animals that adapt to their environment.

Types of Environment 

The environment is divided into two parts which are as follows :

1. Geographical Environment

2. Man-made Environment

Pollution: Being aware of pollution is quite mandatory for citizens these days. In order to become a responsible citizen of the world for future generation, how human activities are leaving an impact on the nature. “Pollution is any undesirable change in physical, chemical, or biological characteristic of air water and land which  is harmful to the man directly or indirectly through his animals,plants,industrial units or raw materials .”

Pollutants: Any material or act on the part of man, or nature which lead pollution is called pollutant. The majority of these pollutant are emitted through human activities like burning fossil fuel, vehicle exhaust fumes and emissions from agriculture and industry.

 Usually Pollution are divided into following categorise:

1) Non degradable pollutants: Many of these pollutants are usually not degraded partially in environment. Such as aluminium pecks, mercury compound, iron compound of phenols,  DDT, benzene, BHC, pesticides, etc., They are collected in the environment and causes pollution. These pollutants are harmful even in low concentration and its effect increases with their increasing concentration. There is no treatment found in nature for their recycling. There are two methods by which we can stop the pollution caused by pollutants:-

(a)  Such type of substances should be banned by law.

(b)  Usage of alternative substances.

2 ) Biodegradable pollutants:  If entities such as domestic sewage papers, wood, garbage, livestock wastes, etc., are easily degraded completely by micro- organism, then it becomes useful. But  if these materials enter the environment in such large quantities, than they cannot be degraded completely, then the addition of these materials severe as a causative agent for environment pollution.

1) Primary pollutants: They persist in the form in which they are added to the environment. example: DDT, CO etc.,

2)  Secondary pollutants : These pollutants are formed by chemical reaction amongst primary pollutants. Example : Photochemical smog, London smog, PAN, O3.

Synergism : Formation of secondary pollutants is known as synergism. The secondary pollutants are more toxic than primary pollutants.

1. Quantitative pollutants : These substances occur in nature but are transformed into a pollutant when their concentration reaches beyond a thresold value in the environment. Example : carbondioxide , nitrogen oxide.

2. Qualitative pollutants : These are substances which do not occur in the environment but is passed through daily human activity. Example : fungicides, herbicides, DDT, etc.,

Other type of pollution

· Natural pollution : It is caused by natural sources like , methane from paddy fields and cattle, marsh, forest fire.

· Anthropogenic pollution: It is extremely caused by human activities.

1)  Negative pollution : It results in the loss of soil productivity. Example : Overgrazing, soil erosion. The removal or absence of desirable substances at the right place always results in the loss of soil productivity.

2)  Positive pollution : The presence or addition of undesirable substances at wrong places which results in the reduction of soil fertility. Example : comprehensive use of biofertilizers, land filling by wastes.

Main sources of pollution

1. Point source pollution : It is the places where effluent discharge occurs at a specific sites. Example : Factory outlets and municipal sewage.

2. Line source pollution : It is passed along a narrow belt.  Example : Roads, Railway track

3. Diffuse source pollution : It occurs over a large area. Example: Spraying fertilizers or pesticides through run off.

4. Area source pollution : It occurs over industrial estate and mining area.

How environment became polluted :  The rapidly growing human population, rapid urbanization , intensive agriculture and industrialization together with human activities resulted in the environmental pollution  This has become a global problem .All the countries of the world feel concerned about it and interacting with each other to tackle it in appropriate ways. The splendid plentifulness of nature is a heritage that should be conserved for future generation and not be spoiled. Such activities of mankind had adverse effect on all forms of living organism in the biosphere. The earth planet alongwith the atmosphere (air, land, water) that substains life is called biosphere. Biosphere extends into about 7 km, of the earth surface itself, downward into the oceans to depths of about 10.67km, and vertically into the air to about 10km., where life is found to exist. It is very common to find warning at public places, reading as “Air unfit for breathing “, Water unfit drinking , “Do not eat fish caught here, and so on. India today is among  the leading industrialized countries of the world. Mining activites also added to this problem particularly as solid waste. Thus, pollution is a gift of industrial development. Due to lack of a culture of pollution control, there has resulted a heavy backlog of gasesous, liquid and solid pollution in our country.

 Environmental Pollutants : The principal pollutants which pollute our air, water, and land are as follows:

1. Deposited matter :  Smoke, tar, dust, grit etc

2. Aerosols

3. Suspended particulate matter (SPM)

4. Respirable suspended particulate matter (RSPM) or PM10( thoracic fraction)

5. Gases: oxides of nitrogen (NO, NO2), sulphur (SO2), carbon monoxide, halogens, halogenated carbons like CFCs and chlorine, bromine, iodine, ozone, ammonia, benzene.

6. Acid droplets : Sulphuric acid, nitric acid etc.,

7. Fluorides

8. Metals : Mercury, lead, iron, zinc, nickel, tin, cadmium, chromium arsenic etc.

9. Agrochemicals : Biocides (pesticides, herbicides, fungicides, nematicides, bactericides, weedicides etc.,) and fertilizers.

10. Complex organic substances : Benzene, ether, acetic acid, benzpyrenes etc.

11. Photochemical oxidants : Photochemical, smog, ozone, peroxyacetyl nitrate(PAN), peroxybenzol nitrate (PB2N), nitrogen oxides, aldehydes, ethylene etc.,

12. Solid wastes

13. Radioactive waste

14. Noise

Different  Kinds of Pollution

Air Pollution : We are dependent on air for respiratory needs. Air Pollutants causes injury to all living organisms. They reduce growth and yield of crops and causes premature death of plants. Air pollutant also deleteriously affect the respiratory system of human and of animals. Harmful effect depends on the concentration of pollutants, duration of exposures and the organism.The air pollution is mainly caused due to the addition of unwanted substances or gases. The atmospheric pollution is mainly caused by the activities of man and concentrated to the inhabited and industrial complexes in cities. There are two main categories of air pollutants:

1) Gases

2) Particulate

1)  Gases : The gaseous materials include various gases and vapours of volatile substances or the compound with a boiling point below 200 celsius.

Major Air Pollutant and their Effects

1) Carbon monoxide (CO)

Source : It is the main air pollutant which is released as smoke from automobiles.

Effect: Carbon monoxide is a highly toxic gas, it combines with haemoglobin of the blood and blocks the transportation of oxygen . Thus it impairs respiration and causes death due to asphyxiation when inhaled in large amount .

2)  Unburnt Hydrocarbon –(3,4 Benzopyrine , methane , benzene)

Source: These are mainly released from automobiles and burning of fossil fuel ( petrol, diesel).  Methane (CH4) is the most abundant hydrocarbon in atmosphere and its main source is from marshy area and paddy field .

Effect:  Hydrocarbon causes lung cancer.

3) Ethylene –(C2H4)

Source : It main source are petroleum/ natural gases.

Effect : Falling of leaves without any particular reason, falling of flowering bud before time.

4)  Nitrogen Oxide (NO, NO2)

Source  : Burning ( combustion ) of fossil fuel in automobiles.

Effect    :  These nitrogen oxide from photochemical smog in atmosphere and release ozone. Nitrogen oxide ia also responsible for acid rain. The entry of this nitrogen oxide causes respiratory troubles such as emphysema, bronchitis, swelling of lungs and lung cancer etc.,

5) Sulphur oxide (SO, SO2)

Source : It is one of the most harmful gaseous pollutants, the main source of sulphur oxides are coal burning, smelters, oil refineries.

Effect: Lichen and mosses don not grow in SO2 polluted area. Lichen and mosses is an  indicator of SO2 pollution. Oxides of sulphur produces acid rain and smog in atmosphere, due to its adverse effect Taj Mahal also get polluted

6)  Smoke : (SO2, SO3, NO2. NO, CO, CO2)

Secondary pollutants

Smog (Smoke + Fog ) : This word was given by Des Voeux. Smog/Smoke  is measured by Ringelmann method. Smog is two types :

1) Los Angeles smog or Photochemical Smog : It was first observed in Los Angeles. In this processes, smoke ,fog, nitrogen oxide, hydrocarbons, oxygen, UV light and high temperature are essential. These components react with each other and forms reddish brown smog (PAN+ O3+ Nitrogen oxide) or brown haze/ brown air. Los Angeles smog is light induced smog.

Effect: (a) Photochemical smog causes irritation in eyes and harms the lungs. Due to smog, the elastic substance ( rubber /tyres) are also affected.

( b) Ozone causes harm to mucous membrane.

( c) During smog peroxyacteyl nitrate (PAN) is formed.

2) London Smog or Sulphur smog :  It was first observed in London. In this process, coal, smoke, fog, sulphur oxide and low temperature is essential . These components reacts with each other and forms vapours ( fog) of H2SO4 which is known as London smog .

Effect: Due to inhalation of H2SO4 vapour with fog 4000 people died in London in 1952.

Acid Rain : This term acid rain was given by Robert August . NO2 and SO2 are released from different sources in the form of smoke and it is dissolved in atmosphere water vapour to form sulphuric acid and nitric acid ( H2SO4+ HNO3). These acids that pours down with rain water on earth is called acid rain. The pH of acid rain is lesser than 5.6, In acid rain the ratio of H2SO4+HNO3 is 7:3 ( 70% of H2SO4 + 30% HNO3)

Effect:  (a) Due to acid rain, the acidity of soil and water increases

(b)  Acid rain also causes invetiable damage to historical monuments such as Taj Mahal, Red Fort.,etc.,

Global Warming : Global warming is also called as “climate changes”.It refers to rise in average temperature of the earth’s atmosphere. The natural causes such as greenhouse effect, volcanic eruption, wild fire etc., while anthropogenic causes are industrial revolution, mining  Drought, heavy rainfall with floods, heavy snowfall ,ocean acidification, species extinction etc.,

Control of Air Pollution

Control of Particulate Matter : Two devices are used to remove the particulate air pollutants .

1)  Arresters

2)  Scrubbers

1) Arresters : These are used to separate particulate matter from contaminated air . Arresters are of different types :

(a)  Cyclonic separator and trajectory separators : these are commonly used to separate out particulate matter from industrial emission with minimum moisture content. These separators work on the principle of dust separation by centrifugal force.

(b)  Electrostatic precipitator : It is used as the most efficient device to remove fine particulate pollutants. The electrostatic precipitation device works on the principle of electrical charging of the dust particles and collects it on a differently charged platform. These are several ways to removing particulate matter; the most widely used of which is the electrostatic precipitators, which can remove over 99 % particulate matter present in the exhaust from a thermal power plant. It has electrode wires that are maintained at several thousand volts, which produce a corona that release electrons. These electrons attach to dust particle giving them a net negative charge. The collected plates attract the charged dust particles. The velocity of air between the plates must be low enough to allow the dust to fall.

2) Scrubbers: It is used to clean air for both dust and gases. There are two types of scrubbers such as wet and dry that is used for dust separation.

A scrubbers can remove gases like sulphur dioxide. In a scrubber, the exhaust is passed through a spray of water or lime.

Control of Gaseous Pollutants : Combustion, absorption and adsorption technique is used to control gaseous pollutants.

Water pollution :  Water pollution refers to the introduction of harmful &dangerous substances into water bodies which make the water unusable for drinking, cooking, cleaning, swimming etc., This  pollution is caused by the addition of organic and inorganic chemicals as well as biological materials which change the physical and chemical properties of water. This harmful process is called water pollution. Realising the importance of maintaining the Cleanliness of the water bodies, the Government of India has passed the Water (Prevention and Control of Pollution) Act 1974 to safeguard our water resources. Water Pollution is caused by many source such as sewage matter, industrial wastage, agricultural wastage, domestic wastage,hot water of thermal plant and nuclear reactors etc.

Component of water pollution –

(a) Domestic effluent & sewage – It contain faeces, urine, laundry water etc. In our country , there is no proper measure to control water pollution. People disposed all their domestic water in rivers, seas & other water bodies. They do not take proper measure to control all this pollution. Untreated sewage is considered as the largest source of water pollution in rivers of India.

(b) Industrial effluent : Industries produce large amount of water, which contain toxic chemicals & pollutants like lead, sulphur, Mercury, aebestos etc. So many industries do not have a proper water management system, drainage system etc.

Note: A mere 0.1 % impurities make domestic sewage unfit for human use .

Biochemical oxygen Demand (BOD): The water pollution by organic wastes  is increased in terms of biochemical oxygen demand. It is the amount of dissolved oxygen (DO= Dissolved oxygen) needed by bacteria in decomposing the organic wastes present in water.

BOD is increased = Water is polluted

If BOD is increased then dissolved oxygen is decreased in water . Higher amount of organic waste increase the rate of decomposition in water. O2 is rapidly consumed by microbes, thereby causing drop in DO content in water .

Note :  Daphnia is the indicator of BOD

Chemical Oxygen Demand (COD) : It is the oxygen requirement by chemical for oxidation of total organic matter (biodegradable + non biodegradable) in water .

Note :  The COD value is always higher than BOD value .

Biological Magnificaton : The non biodegradable pollutant like Al, Hg, Fe, DDT, pesticides, phenolic compound ABS (Alkyl benzene sulphonate) are not decomposed by microorganisms. They get accumulated in tissue in increasing concentration alon the food chain, it is called biological magnification.The highest concentration occurs in tops consumers.

 Water (DDT=0.003ppb) – Phytoplankton ( 0.003ppm) – ZP (0.04ppm)

Small fish (0.5ppm) – Large fish(2ppm) – Fish eating birds (25ppm)

NOTE : Higher concentration of DDT distrubs calcium metabolism in birds, which causes thinning of egg shell and their premature breaking , eventually causing decline in birds population.

Example :  Minamata disease is caused in human in japan by biomagnification of mercury(Hg).

Eutrophicaton : The process of nutreint enrichment of water and consequent loss of species diversity (or death of aquatic animals ) is referred to as eutrophication  and  the lake is known as eutrophic lake . In this process, the presence of nutrient in lake stimulate the growth of algae (algal bloom) increase, organic loading and brings about reduction in the oxygen content of water causing death of aquatic animals. Eutrophication  can be caused by the following man-made source :

(a)  Household

(b) Industrial waste

( c) Sewage

Types of Lakes

1) Eutrophic lake : They are shallow water lakes which contain high amount of organic materials and nutrients.They have little O2 because decomposer rapidly use it up. Chironomus larvae are commonly present in it. example., Dal lake of Kashmir

2) Oligotrophic lakes : These are deep lakes which have less amount of organic materials and nutrient.

Sound Pollution : Increase in the noise in the atmosphere is called noise pollution or sound pollution. Noise is a loud and unwanted or unpleasant sound. The common things which are responsible for noise pollution are industries and mills, means of transportation, television stereo, loud speaker and jet planes etc.,

Intensity :The intensity of sound is measured in bel or decibel (1 bel= 10 decibel). Normally at 25 decibel, the atmosphere may be peaceful. Above 80 decibel , the intensity of sound is called noise pollution .

Radioactive Pollution : As per the international atomic energy agency (IAEA), Radioactive contamination is the deposition of or presence of radioactive substances on surface or within solids, liquid or gases where their presence is unintended or undesirable. A large amount of nuclear waste is generated from nuclear power many harmful & dangerous diseases like typhoid, Cholera, paratyphoid, fever, dysentery, jaundice.etc., The government & people of country would take major steps to clean water bodies & people should have awareness to clean the water bodies.

Electromagnetic Pollution : The technology we use today from cell phone to our laptops to the wi-fi that connect them generate an electromagnetic field .At certain frequencies and exposure levels, this energy can be considered toxic to environment.

Some other informations :

 1) Third pollution or land scape pollution :  To make fertile land barren by dumping wastes. Example : Ash, industrial waste, etc.,

2) Incineration : Solid waste burning in the presence of oxygen.

3)  Pyrolysis : solid waste burning (combustion) in the absence of oxygen.

4) Flu gas : The gas which is released from chimneys .

5)  Plume : The smoke which is released from chimneys.

NOTE: (1)  In india , the Air (prevention and control of pollution) Act came into force in 1981 but was amended in 1987 to induce noise as an air pollutant.

(2) The 3R initiative aims to promote the “3Rs” (reduce,reuse,recycle) helps in reducing the amount of carbon di-oxide in the atmosphere.