Environmental Pollution [Environmental Studies Notes BCOM/BA/BSC 2nd SEM CBCS Pattern]

Unit 5: Environmental Pollution (8 lectures)

Environmental Studies Notes For BA, B.Com and BSC CBCS Pattern

Environmental pollution: types, causes, effects and controls; Air, water, soil and noise pollution

• Nuclear hazards and human health risks

• Solid waste management: Control measures of urban and industrial waste.

Pollution case studies – Bharalu river, Deepor Beel, Kolong river



Soil Pollution

Land is an important component of environment because soil is vital for the substances of life on earth. An inch of soil takes about 500 to 1000 years to be build. It is estimated that the total surface area of earth is 3,15,14,640 square km out of which only about one third is land surface. It is a resource for which there is no substitute. So, it becomes necessary to protect soil from

Soil pollution can be more dangerous than other types of pollution. 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.

Sources of Soil Pollution

a) Agrochemicals: The application of inorganic fertilisers to crop lands and the use of toxic insecticides, pesticides, fungicides etc. for controlling diseases have an adverse impact of soil.

b) Industrial waste: The rapid growth of industries has resulted in the release of a lot of industrial waste on the land surface. The quality of those wastes depends on the types of raw materials and chemicals used in the industries. The toxic chemicals are absorbed by the green plants along with the nutrients and enter into the food chain and finally reaching the human being causing health hazards.

c) Domestic Garbage: Plastics are mainly used as packing materials which are normally thrown away as garbage. This garbage is pile up at public places which creates disposal problem.

d) Petroleum wastes: Contamination of soil by petroleum products is a major cause of soil pollution in several countries in the world.

e) Electric Waste: Electronic waste like cell phones, computers, gadgets, printers, radio, camera, video games, scanners, DVDs, Land phones etc. are non-biodegradable waste which is generally dumped in soil.

Measures to Control Soil Pollution

Since soil is vital for life, these should be protected from pollution. Some important measures to control soil pollution are:

a) Agro-chemicals should be used with caution in the field. Organic manure should be used instead of agro-chemicals.

b) Use of bio-fertilizers should be encouraged instead of chemical fertilizers.

c) Industrial effluents should be properly treated before discharging them on the soil. The effluents released should be subjected to proper treatment before their release into land mass.

d) The garbage produced should be dumped in closed chamber.

e) Adequate latrine facility should be provided in rural and urban areas.

f) Public awareness programmes should be implemented to educate people on health hazards due to soil pollution. Prevention of erosion and silting.

g) People should be trained regarding proper sanitary practices.

h) Application of pesticides should be controlled.

i) Bioremediation can be adopted for degradation of toxic chemicals present in soil.

Effects of Soil Pollution

a) Industrial wastes consist of a variety of chemicals which are extremely toxic. Chemical like acids, alkalis, pesticides, heavy metals etc. affect soil fertility and ultimately affect human health.

b) Nitrogen and phosphorus from the fertilizers in soil reach nearby water bodies with agricultural run-off and cause eutrophication.

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

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

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

f) Contamination of underground and surface drinking water.

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. Lakes, rivers, seas and groundwater are the main source of water. Water pollution is the pollution of bodies of water, such as lakes, rivers, seas, the oceans, as well as groundwater. It occurs when pollutants reach these bodies of water, without treatment. Waste from homes, factories and other buildings are main pollutant of the water bodies.

Sources of Water Pollution: 

a) Domestic wastes if they are not properly treated and released into water bodies cause serious water pollution.

b) Industrial wastes such as Toxic chemicals, acids, alkalis, metallic salts, phenols, cyanides are released into water bodies causes thermal pollution of water.

c) Agricultural pollutants such as excessive nutrients, ammonia and nitrates, pathogens, antibiotics and hormones.

d) Run off from urban areas such as rainfall and snowmelt can wash natural and man-made pollutants into rivers, lakes, wetlands, and coastal waters.

e) Oil pollution

f) Radioactive waste produced during industrial, medical and scientific processes.

Effects of Water Pollution

Domestic and hospital sewage contain many undesirable pathogenic microorganisms, and its disposal into a water without proper treatment may cause outbreak of serious diseases, such as, amoebiasis dysentery, typhoid, jaundice, cholera, etc. Metals like lead, zinc, arsenic, copper, mercury and cadmium in industrial waste waters adversely affect humans and other animals. Some of the serious effects of water pollution are listed below:

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

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

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

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

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

Control of water pollution

a) The first and most important step in controlling water pollution is to Increase public education and awareness around the world concerning the causes and impacts of water pollution.

b) Government initiatives like Swachh Bharat Mission helps in reducing domestic wastes.

c) Setting up effluent treatment plants to treat waste water.

d) 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.

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

f) 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.

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

Air Pollution

We all breathe in air, we can feel, and even smell the air and say whether it is fresh or stale. The pollution in air may not be noticed until we see smoke coming out from some source. All human activities from cooking at home to activities in highly mechanized industries contribute to air pollution.

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.”

In Simple words, 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.

Air Pollutants

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.

Sources and causes of Air Pollution

The sources of air pollution are classified into two groups: Natural and Man- made sources.

(a) Natural sources:

1)    Volcanic eruption: releasing poisonous gases like SO2, H2S, CO etc.

2)   Forest fires: Very large quantities of smoke and particulate matter are liberated during their breakout.

3)    Decomposition of organic and inorganic substances: Methane gas, carbon dioxide is released into the air.

4)    Dust: Dust is always present in the atmosphere in varying amount.

(b) Manmade sources:

1)   Deforestation.

2)   Burning of fossil fuels.

3)   Emission from vehicles.

4)   Rapid industrialization.

5)   Modern agricultural practices.

Effects of Air Pollution

Air pollution is very dangerous for health. Some of the adverse effects of air pollution are given below:

1. Air pollution affects our respiratory system and causes breathing difficulties.

2. Diseases such as bronchitis, asthma, lung cancer, tuberculosis and pneumonia caused due to air pollution.

3. Increased concentration of carbon dioxide in atmosphere causes global warming.

4. Air pollution causes acid rain which damages crop plants, trees and buildings. It also makes the soil acidic.

5. Ozone layer depletion due to air pollution which allows ultraviolet radiation to reach the earth. Such radiation causes various skin and eye diseases.

6. Excess nitrogen oxides in the atmosphere results in respiratory problems and bronchitis.

Measures to Control Air Pollution

Air pollution can control from the following points:

1. A raw material for feedstock should be renewable rather than depleting.

2. Better designed equipment and smokeless fuels should be used in houses and industries. Less polluting fuels should be used.

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

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

5. Use of non-conventional sources of energy should be encouraged.

6. Use of public transport to control fuel consumption.

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

8. Proper Environmental Impact Assessment for any developmental work must be done.

Environmental Studies  MCQs  Multiple Choice Questions and Answers

Top 100 Environmental Studies MCQs

Environmental Studies  Chapterwise  Notes

Unit 1: Introduction to Environmental Studies

Unit 2: Ecosystems

Unit 3: Natural Resources: Types, Renewable and Non-renewable Resources

Unit 4: Biodiversity and Conservation (Available in DTS App – Only for Members)

Unit 5: Environmental Pollution

Unit 6: Social Issues and the Environment

Unit 7: Environmental Policies & Practices

Unit 8: Human Communities and the Environment

Unit 9: Field work

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Noise Pollution

Noise is one of the most pervasive pollutant. A musical clock may be nice to listen during the day, but may be an irritant during sleep at night. Noise by definition is “sound without value” or “any noise that is unwanted by the recipient”.

Noise in industries such as stone cutting and crushing, steel forgings, loudspeakers, shouting by hawkers selling their wares, movement of heavy transport vehicles, railways and airports leads to irritation and an increased blood pressure, loss of temper, decrease in work efficiency, loss of hearing which may be first temporary but can become permanent in the noise stress continues. It is therefore of utmost importance that excessive noise is controlled.

Noise level is measured in terms of decibels (dB). W.H.O. (World Health Organization) has prescribed optimum noise level as 45 dB by day and 35 dB by night. Anything above 80 dB is hazardous.

Causes and Sources of Noise Pollution

There are several sources of noise that contribute to both indoor and outdoor noise pollution which are listed below:

a) Cutting and Crushing in Industries/ Factories.

b) Movement of heavy transport vehicles, railways and airports etc.

c) Sound generated during Construction activities.

d) Household chores such as washing and cleaning.

e) Playing of loud speakers during festivals/ social events and also hearing loud music in home.

f) Fire crackers burning during festivals and celebrations.

g) Microphones, Television and radio run in loud voice.

h) Loudspeakers in religious places.

h) Some noises are also caused by nature which are called atmospheric noise which arises due to spurious radio frequency waves due to lightning and other natural disturbances occurring in the atmosphere. Natural phenomena like lightning, thunder, volcanic eruption, earthquake, sound of the ocean waves, etc.

Effects of Noise Pollution

a) Hearing Problems: Exposure to noise can damage one of the most vital organs of the body, the ear.

b) Poor Cognitive Function: With regular exposure to loud noise, the ability to read, learn and understand decreases significantly over time.

c) Serious diseases: High noise pollution can cause high blood pressure and loss of temperament.

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

e) Wild life issues – noise bring about changes in the behavioural aptitude of birds and animals. They become inefficient in hunting and hence disturb the balance of ecosystem.

Thermal Pollution

The excessive heat dissipated into air or water from the industries increases the temperatures of the entire ecosystem and hence causes thermal pollution. Industrial waste and heat not only causes widespread climatological changes but also it can cause the damage of aquatic and terrestrial life. The effect of thermal pollution is more prominently marked in aquatic system.

The industries like iron and steel plants, petroleum refineries, nuclear reactor, electronic power plants etc. use large amount of water for cooling purposes. The water carries a lot of heat which when released into nearby bodies leads to thermal power pollution. Such an increase in temperature of the aquatic bodies by 8 to 10 degree celcius becomes injuries to the aquatic life.

When an increase in temperature of the aquatic body affects and disrupts the normal activities of the aquatic living organisms, the process is known as thermal pollution.

Sources of Thermal Pollution

a) Nuclear reactor

b) Industrial Wastes

c) Hydro-electric Power Plant

d) Thermal Power

e) Domestic Sewage

Effects of thermal pollution

Thermal pollution affects the living organism in the following ways:

a) It reduces the dissolved oxygen content of water.

b) It changes the characteristics properties of water.

c) It influences reproductive cycle, digestion rate, respiration rate and many enzymatic activities of living organism.

d) It favours the growth of certain bacteria and pathogens.

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

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

Measures to Control Thermal Pollution

1. Colling of Pond’s water is the simplest and cheapest method to control thermal pollution.

2. 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.

3. Creating artificial lakes for cooling of ponds.

4. Recycling of used water of factories.

5. Co-generation of heat from hot water and used in different tasks of industries.

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.

Bad effects of solid wastes

a) Open dumps are malodorous places in which disease carrying vermins such as rats and files proliferate.

b) Methane gas is released into the surrounding air due to decomposition of solid wastes by the micro-organisms.

c) Hazardous materials dissolved in this liquid contaminate underground water and solid strata.

d) The leachate consisting of a variety of chemical constituents’ seeps and pollute the ground water.

e) Absence of landfill lingers aggravate the problem furthermore.

Types of Solid Waste

Solid wastes (waste which are neither liquid nor gaseous) can be classified into:

a) Urban or municipal wastes

b) Industrial wastes

Sources of Urban Waste

– Domestic wastes: It includes a variety of materials thrown out from homes.

– Food waste, Cloth, Waste paper, Glass bottles, Polythene bags, Waste metals, plastic containers, scrap, paints etc.

– Commercial wastes: It includes wastes coming out from shops, markets, hotels, offices, institutions, etc.

– Waste paper, packaging material, cans, bottle, polythene bags, etc.

– Construction wastes: It includes wastes of construction materials. • Wood, Concrete, Debris, etc.

– Horticulture waste and waste from slaughter houses include vegetable parts, residues and remains of slaughtered animals, respectively.

– Biomedical wastes: It includes mostly waste organic materials

– Anatomical wastes, Infectious wastes, glass bottles, plastic, metal syringe, etc.

– Mining waste: A large amount of solid waste is released from the mining activities. The increase in solid waste is due to overpopulation, affluence and technological advancement.

Sources of Industrial Waste

The main source of industrial wastes are chemical industries, metal and mineral processing industries.

– Nuclear plants: Generate radioactive wastes

– Thermal power plants: Produce solid waste in the form of fly ash 3

– Chemical Industries: Produce large quantities of hazardous and toxic materials.

– Other industries: Other industries produce packing materials, rubbish, organic wastes, acid, alkali, scrap metals, rubber, plastic, paper, glass, wood, oils, paints, dyes, etc.

Measures to Control Solid Waste

i) 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.

ii) 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.

iii) 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.

iv) 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.

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