Fertilizers and pesticides from agriculture and forestry
Polluted ground and surface water
Livestock waste from farming
Hazardous wastes from industry
Runoff from mining and quarrying
Leaks from landfill sites
Pict. 9. Substances that Pollute Drinking Water Sources
4. There are also some nonpathogenic microorganisms in water. The most important microbiological measure of is a group of bacteria called coliforms. Escherichia coli (E. coli) is a bacterium used as an indicator that water has beenwith faeces.
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12. Translate the words and word combinations in brackets.
Water is called the "universal (растворитель)" because of its strong tendency to dissolve other (вещества). Since pure water is not found in nature (i.e., outside chemical laboratories), any distinction between clean water and polluted water (зависит от) the type and (концентрация) of impurities found in the water as well as on its intended use*. Water is said to be polluted when it contains enough (примеси) to make it (не- пригодный) for a particular use, such as drinking, swimming, or fishing. Although the (качество) of water is affected by natural conditions, the word “pollution” usually implies human activity as the source of (за- грязнение). Water pollution is caused primarily by the drainage of con- taminated waters into (поверхностные воды) or (грунтовые воды).
Water pollution control, therefore, primarily involves the (удаление) of impurities before they reach natural (водоемы) or aquifers.
*intended use – использование по назначению; предполагаемое использование
Match the terms and their definitions.
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a. (chiefly of environmental pollution and pollutants) originating in hu- man activity
b. (of a substance) able to be dissolved, esp. in water
c. (of a substance) incapable of being dissolved, esp. in water
d. a contaminant (contaminating material or agent) in water; in a broad sense, any physical, chemical, biological or radioactive matter in wa- ter
e. a thing or constituent that impairs the purity of something
f. being in suspension; not dissolved
g. free from dirt, pollutants or unpleasant substances; free from any con- tamination
h. the presence in or introduction into the environment of a substance or thing that has harmful or poisonous effects
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i. the standard of something as measured against other things of a simi- lar kind; the degree of excellence of something
j. the use of a chemical, physical, or biological agent to preserve or give particular properties to water
Choose the correct word.
Coagulation / coagulants / to coagulate
is clumping together of very fine particles into larger particles using chemicals ( ) that neutralize the electrical charges of the fine particles and destabilize the particles. During, different chemical additives cause particles and thus to settle.
2. flocculation / flocculants / to flocculate
is the process in which small particles clump together through gentle stirring.
3. filtration / filters / to filtrate
is the process in which particulate matter in water is removed by passage through porous media.through beds of fine sand or through crushed anthracite coal can trap the suspended matter.
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