Lecture # 5 & 6 Environmental Pollution Objectives 1.To Define Environmental Pollution 2.To Discuss the Types of Environmental Pollution 3.To Discuss the.

Lecture # 5 & 6 Environmental Pollution

Objectives1. To Define Environmental Pollution2. To Discuss the Types of Environmental

Pollution3. To Discuss the Sources and Causes of

Environmental Pollution

Presented by Abul Kalam Azad

Senior Lecturer, GEDNorthern University Bangladesh

E-mail: [email protected]

Introduction

For a few decades, environmental scientists have been much more concerned about environmental degradation. With a rapid population growth, unplanned urbanization and industrialization, the present world is observing different kinds of environmental pollutions such as air pollution, water pollution, soil pollution etc. Let’s, first of all, define the concept environmental pollution, secondly, classify the concept and finally, detect the sources and causes of such pollutions

Definition of Environmental Pollution

Pollution is the addition of extraneous materials (whether chemical substances, or energy such as noise, heat, or light) to water, air or land.

So, environmental pollution is “the addition of any substance or form of energy e.g., heat, sound, radioactivity (energy produced by atom-breaking) to the environment at a rate faster than the environment can accommodate it by dispersion, breakdown, recycling, or storage in some harmless form (Encyclopedia Britannica).”

A pollutant need not be harmful in itself. Carbon dioxide, for example, is a normal component of the atmosphere and a by-product of respiration that is found in all animal tissues; yet in a concentrated form it can kill animals.

However, as regards the nature of pollutants, pollution may be caused by different categories of wastes as evident from the table below:

Fig: Environmental pollution

Table: Categories of Wastes and Example

Categories of Wastes

Examples

Solid Wastes Garbage, Rubbish, Ashes, Dead Animals, Industrial Chemicals, Paints, Sand, Mining Wastes, Pesticides, Insecticides, Crop residues etc.

Liquid Wastes Sewage

Gaseous Wastes

Carbon Monoxide, Hydrogen Sulphide, Nitrogen dioxide, Smog

Wastes without Weight

Radioactive substances, Heat, Noise etc.

Types of Environmental Pollution

There are many kinds of environmental pollution. Most important of these are: 1. Water pollution, 2. Air pollution 3. Soil pollution

4. Sound and Noise pollution Now, water and air pollutions will

be discussed below.

1. Water Pollution Undoubtedly, water is the basic need for

the survival of living organisms. Water is called another name of life. But due to water pollution, water is being redefined from life giver to threat for human survival.

Water pollution is the contamination

of water bodies such as lakes, rivers, oceans, and groundwater caused by human activities, which can be harmful to organisms and plants which live in these water bodies

Symbol of Water Pollution

1. point-source pollution If the pollution comes directly from

a single source, such as an oil drop or a pipe from industry, factory, mills etc. into water bodies, it is called point-source pollution.

2. Nonpoint-source pollution If the pollution is not come from

point-sources e.g., when fertilizer from a farm field is carried into a river or ground water due to rain (i.e. run-off).

Two Types of Water Pollution

The main causes of water pollution are as follows:

1. Pesticides 2. Fertilizers 3. Oil and Gasoline 4. Mining 5. Sediment 6. Chemical and Industrial Processes 7. Plastic 8. Personal Care Products, Household Cleaning Products, and Pharmaceuticals 9. Sewage 10. Arsenic contamination

Causes of Water Pollution

Air pollution is a serious problem for human health, fauna and also environment.

Air pollution may be defined as “the accumulation in the atmosphere of substances that, in sufficient concentrations, endanger human health or produce other miserable effects on living matter and other materials.”

[Grolier Encyclopedia of Knowledge,

Vol # 15, PP-110-11]

2. Air Pollution

There are many sources/ causes of air pollution as narrated by many scholars:

“Burning fossil fuel; Industrial activities and transportation;Agricultural activities; Industrial process;Burning of wastes and crops in the field;Natural sources such as dust storms and

volcanic eruptions; and Transported by the wind.”

[Nasreen Alam, Simple Fcats about Environmental Pollution, 2000:13-14]

Causes of Air pollution

Gaziur Rahman et.al mentioned the following causes:

“Emitting gases and particulates particularly from fossil fuel combustions, domestic and industrial sources and transports;

Burning forest and grassland fires;Ploughing, overgrazing and other human activities releasing dusts that rise in dry windy weather;

Releasing particulates that act as condensation and freezing nuclei.”

[Bangladesh States of Environment Report -1999, 2000:71 ]

There are also some other sources of air pollution as follows:

Motor vehiclesAircraftRailway enginesIndustrial plantsPower plantsBrick fields.

Impact of Air Pollution

• Air pollution causes many problems and affects so much on –

1. Environment 2. Human Health and 3. Fauna.

1. Impact on Environment Air pollution affects the

environment by the depletion of Ozone Layer, acid rain, and global warming.

Depletion of Ozone Layer Ozone is a blue colored gas. The

presence of Ozone in the stratosphere is beneficial because it protects the world from the ultra violet rays emitted from the sun. But, recently it has been discovered that CFCs are continuously damaging this important Ozone Layer. When refrigerator, air conditioner or spray leaks or breaks, CFCs are released into the atmosphere and can’t break down at once rather than they can move around atmosphere for years.

• They float up and reach the upper atmosphere where the ultra violet rays break the CFCs into Chlorine, Florin, and Carbon atom. The released chlorine atoms react with the Ozone Layer and destroy it. One atom of Chlorine can destroy thousands of atoms of Ozone molecules. As a result, the ultra violet rays directly comes to the earth and ultimately Green House Effect is noted.

Acid Rain When fossil fuel is burned, Sulfur

dioxide and oxides of nitrozen form and pass into the atmosphere. When these chemicals combine, they become heavy and return to the earth. Other chemical combinations become absorbed by water vapor in the atmosphere and form a weak sulfuric and nitric acid solution. These acid solutions then return to the earth in the form of rain or hail. These are called acid rain.

acid rain actually changes the PH of water in the rivers or ponds, and affects fish population. Also it affects ground water and trees.

Global warming Sunlight is the source of life, no

doubt. During the day time, sunlight comes to the earth and some of its hit is absorbed by the earth and the rest goes back into the atmosphere.

After entering the atmosphere part of this hit is absorbed by Carbon dioxide and water vapor present in the atmosphere and the rest is absorbed into the universe.

During the night, when there is no sunlight, Carbon dioxide and water vapor release this hit to the earth. Otherwise the earth would be cooled and the survival of life would be impossible. Carbon dioxide and water vapor, thus, balances the temperature. However, due to relatively recent increase of the concentration of CFCs, methane, nitrous oxide, the temperature is rising gradually that may jeopardize our lives and as a result over rainfall and drought is noted.

Impact on Human Health

Air pollution causes various dideases as Kamrul Islam Chowdhury states:

“ public exposure to air pollution in Dhaka city is estimated to cause 15000 premature deaths and several million cases of sickness every year, said a recent World Bank Report.” [Air Pollution in Asian Cities, 2000:6]

Air pollution causes different kinds of diseases such as Asthma, birth-defects, blood pressure, hypertension, cancer, damage of brain & Kidney, renal damage, headache, irritation, fatigue etc.

Impact on Fauna

Fauna refers to all those animals that live wild in a particular area. Air pollution also affects fauna as acid rain affects the fish population of ponds or rivers by changing pH of water.