Any change in the physical, chemical, or biological characteristics of the air, water, or soil that can affect the health, survival, or activities of human beings or other forms of life in an undesirable way is called pollution. Pollution does not have to cause physical harm; pollutants such as noise and heat may cause injury but more often cause psychological distress, and aesthetic pollution such as foul odors and unpleasant sights offend the senses. People, however, may differ in what they consider to be a pollutant, on the basis of their assessment of benefits and risks to their health and economic well-being. For example, visible and invisible chemicals spewed into the air or water by an industrial plant might be harmful to people and other forms of life living nearby. However, if the installation of expensive pollution controls forced the plant to shut down, workers who would lose their jobs might feel that the risks from polluted air and water are minor weighed against the benefits of profitable employment. The same level of pollution can also affect two people quite differvently - some forms of air pollution might be a slight annoyance to a healthy person but life-threatening to someone with emphysema. As the philosopher Georg Hegel pointed out, the nature of tragedy is not the conflict between right and wrong but between right and right.
As long as they are not overloaded, natural processes or human-engineered systems (such as sewage treatment plants) can biodegrade, or break down, some types of pollutants to an acceptable level or form. Pollutants can be classified as being rapidly biodegradable (such as animal and crop wastes), slowly biodegradable (such as DDT and PCBs), and nonbiodegradable (such as toxic mercury and lead compounds and some radioactive substances). Polluting substances can enter the environment naturally or through human activities. Most natural pollution is dispersed over a large area and is often diluted or degraded to harmless levels by natural processes. In contrast, the most serious human pollution problems occur in or near urban and industrial areas, where large amounts of pollutants are concentrated in relatively small volumes of air, water, and soil. Furthermore, many pollutants from human activities are synthetic (human-made) chemicals that are slowly biodegradable or nonbiodegradable.
Determining the amount of a particular pollutant that can cause
a harmful or undesirable effect in human beings or other organisms is
a difficult scientific problem. The amount of a chemical or pollutant in a given volume of air, water, or other medium is called its concentration. Concentrations of pollutants are often expressed as parts per million (ppm) or parts per billion (ppb) - the number of parts of a chemical or pollutant found in 1 million or 1 billion parts of air, water, or other medium. Although 1 ppm and 1 ppb represent very small concentrations for some organisms, with some pollutants they represent dangerous levels. During a lifetime an individual is exposed to many different types and concentrations of potentially harmful pollutants. The scientific evidence correlating a particular harmful effect to a particular pollutant is usually statistical or circumstantial - as is most scientific evidence. For example, so far no one has been able to show which specific chemicals in cigarette smoke cause lung cancer; however, smoking and lung cancer are causally linked by an overwhelming amount of statistical evidence from more than 32,000 studies. Another complication is that certain pollutants acting together can cause a harmful effect greater than the sum of their individual effects. This phenomenon is called a synergistic effect. For example, asbestos workers, already at a higher-than-average risk of lung cancer, greatly increase that risk if they smoke, because of an apparent synergistic effect between tobacco smoke and tiny particles of asbestos inhaled into the lungs. Testing all the possible synergistic interactions among the thousands of possible pollutants in the environment is prohibitively expensive and time-consuming, even for their effects on one type of plant or animal.
Підберіть відповідний заголовок до кожного абзацу.
What is Pollution?
Determining Harmful Levels of Pollutants.
Types and Sources of Pollutants.
Виберіть з тексту Pollution 10-15 ключових слів. Які з Ваших припущень виправдалися?
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Physical, biological, characteristics, forms, psychological, basis, risk, economic, industrial, installation, person, philosopher, process, classify, urban, effect, concentration, million, organism, statistical, sum, individual, type, radioactive.
Складіть 5 загальних питань до 1 абзацу тексту Pollution.
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|1. The device enables temperatures to be monitored, ... improving the safety margin.||a. therebyb. neverthelessc. namelyd. e.g.|
|2. A new technique, ... the infra-red camera, means that dust surrounding new stars can be penetrated.||a. whereasb. namelyc. besidesd. for instance|
|3. Superconducting, ... when materials lose all resistance, will boost computer performances.||a. thusb. obviouslyc. besidesd. that is to say|
|4. Programmable electronic systems are more reliable ..., they can be used to handle radio-active material.||a. whereasb. such asc. moreoverd. in other words|
|5. Computers can process data extremely fast. ... This, they have several serious drawbacks.||a. in spite ofb. whereasc. howeverd. moreover|
|6. The new engine is far more efficient. ... More work is required to reduce noise levels.||a. neverthelessb. whereasc. i.e.d. besides|
|7. The presence of high concentrations of elements that are rarely found on Earth, ... iridium, suggests there was a meteorite impact at that spot.||a. on the wholeb. moreoverc. such asd. that is to say|
|8. The data is stored on hard disk, ... it is easily accessible.||a. actuallyb. whereasc. e.g.d. hence|
|9. Applicants for the job should speak at least one other European language ... French.||a. obviouslyb. besidesc. moreoverd. actually|
|10 ..., in the initial stages there were minor problems to be overcome, but from then on, the prototypes were perfectly reliable.||a. besidesb. as a rulec. namelyd. despite|
Вправа 9. Прочитайте текст і знайдіть відповіді на наступні питання (Контрольний час 10 хвилин):
1. Від чого залежить загальне забруднення обраної області?
2. Що означає перенаселеність?
3. До чого призводить перенаселеність в слаборозвинених країнах?
4. Де зустрічається перенаселеність 2 типу та що це таке?
Vegetation | Deforestation | Carbon and Oxygen Cycles | Biogeochemical Cycles | Phosphorus Cycle | Nitrogen Cycle | Energy Flow in the Biosphere | Biosphere | Nuclear fusion | Types and Sources of Outdoor Air Pollution |