observation on study of types of pollution 2 page
Answers
Answer:
Introduction
You were introduced to wastes and pollutants in Study Session 1, where we discussed the interactions between humans and our environment. Pollution was defined as the introduction into the environment of substances liable to cause harm to humans and other living organisms. Many human activities pollute our environment, adversely affecting the water we drink, the air we breathe, and the soil in which we grow food.
In this and the next study session we will look more closely at pollution. In this session you will learn about the different types and sources of pollution and the various human activities that can cause pollution. We will also describe the ways pollution can affect different sectors of the environment: water, air and soil. Study Session 8 describes some of the significant effects of pollution on the environment and on human health. It also discusses options for preventing and controlling pollution.
Learning Outcomes for Study Session 7
When you have studied this session, you should be able to:
7.1 Define and use correctly all of the key words printed in bold. (SAQs 7.1, 7.2, 7.3 and 7.4)
7.2 Describe the main types of pollution. (SAQ 7.3)
7.3 Describe the sources of pollution and the way pollutants reach the environment. (SAQ 7.4)
7.4 Describe the main characteristics of water, air and soil pollution. (SAQ 7.5)
7.1 What is pollution?
If you hold up a glass of water in front of you, how can you tell if it’s polluted? You would expect drinking water to be colourless, odourless and transparent (not turbid with suspended particulates). If it was not all of these things, then it could be polluted. If you were looking at water in a river, it is unlikely to be as clear as drinking water in a glass, but you could deduce it was probably not polluted if you observed that the water did not look dirty or smell bad. You might also observe that animals were drinking the water without ill effects and fish were swimming in it. However, if the water was discoloured or had an unpleasant odour, or you could see dead fish floating on the surface you could conclude that pollution was the problem.
Let us consider the human activity that could have caused the pollution. Imagine a river that flows through an area of land on the edges of a town. The water is used by the community for drinking and other domestic uses and also for vegetable farming. Several residents use this water to irrigate small areas of land where they cultivate vegetables and many of the farmers use fertiliser and pesticide to improve productivity (Figure 7.1). Fertilisers are made of chemicals such as nitrogen, potassium and phosphorus, which are essential plant nutrients. Pesticides are chemicals that destroy pests but can be harmful to other forms of life – including humans.