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What is water pollution?
What are the sources of water pollution?
How do farmers pollute water?
How do mills and factories pollute water?
How do ignorant people pollute water?
How do water vehicles pollute water?
How does polluted water affect us?
How can we minimize water pollution?
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Bài 1: When water becomes undrinkable and harmful for our existence, we call it polluted. Water is polluted in many ways. Firstly, farmers often use chemical fertilizer and insecticides in the corn fields. When rain and flood water wash away these chemicals into the rivers, canals or ponds and water gets polluted thereby. Secondly, mills and factories throw their waste into the rivers and canals and thus pollute water. Thirdly, ignorant people pollute water by throwing human waste and filth from drains and unsanitary latrines. Water vehicles also pollute water by dumping oil, food waste and human waste. By drinking polluted water, we suffer from fatal diseases-and die. Water pollution may cause serious environmental disaster. To minimize water pollution, various measures may be taken. However, making people aware of the dangers of pollution is the best measure to reduce water pollution to an optimum level. Bài số 2 Water pollution is one of the most serious environmental problems. It occurs when water is contaminated by such substances as human and animal wastes, toxic industrial chemicals, agricultural residues, oil and heat. Most of our water bodies— rivers, lakes, seas, oceans, estuaries and underground water sources (i.e., tubwells, bore wells) are gradually becoming polluted. In the course “Covered so far, you have seen how deforestation, urbanization, intensive agriculture and industrialization have caused pollution of water bodies. You are familiar with various aspects of air pollution, including harmful effects of acid rain. In this unit we will summaries various types of water pollution caused by different pollution sources, and also explain some important concepts such as point and non-point sources, biological oxygen demand (BOD), eutrophication, self-purification capacity of natural waters, infiltration of pollutants to groundwater, thermal pollution and pollution caused by accidents in oil tanker ships. In the next unit you will read about the degradation of land resources and terrestrial features of earth. Polluted water may look clean or dirty, but it invariably contains germs, chemicals or other materials that can cause inconvenience, illness or death.
