1. The problem of water pollution in a global context.
2. The categories of surface water pollution. The differencies in their definition.
3. The problems of groundwater pollution.
Unit 4.
Acidification and Eutrophication
Module 1.
Task 1. Read and translate the definitions of the terms. Do you know any examples illustrating these phenomena?
Acidification to make or become acid; convert into acid.
Ocean acidification a reduction in the PH of the ocean over an extended period of time caused primarily by uptake of carbon dioxide (CO2) from the atmosphere.
Eutrophication a process where water bodies receive excess nutrients that stimulate excessive plant growth.
Alkaline a substance that has the opposite effect or chemical behavior to an acid. (alkalinity (n)).
Task 2. Read the text and find the answers to the questions.
1. Where and when was the problem of acidification first identified?
2. Is acidification a purely man-made phenomenon?
3. How does the composition of soil influence the degree of acidification?
4. What are other causes of acidification?
5. What is acid pulse?
Freshwater acidification 4.1.1.
Acidification of freshwaters was a problem that was first identified in Scandinavia during the early 1970s, at which time many scientific studies were initiated. Since then the concerns that were voiced have been justified, and now thousands of lakes and rivers are known to be acified.
Evidence suggests that rapid acidification has been taking place at some sites for at least 100 years and is still occurring today.
Process
Acid rain can enter the water course either directly or more usually through the catchment. If the catchment has a thin, base-poor soil then acid water passes to the lake. If the catchment has alkaline-rich soil then the acid rain is neutralised and so water entering the lake is of low acidity. Acidification can also occur in surges after snowmelt or drought; the first 30% of snow melt can contain 50-80% of the total acids in the snow. During drought conditions sulphur dioxide (SO2) deposition onto the soil is reduced to sulphur and hydrogen; this is then reoxidised in combination with rainwater to form acids. This is termed an acid pulse.
Task 2. Translate the following words and word combinations into English.
, , , , , , , , , , , .
Task 3. Translate the text from Russian into English.
, (weathering). , . , , , .
|
|
|
Module 2
Task 1. Read the words and their definitions and guess their meaning.
1. Geology the study of the rocks, soil etc. that make up the Earth,
and of the way they have changed since the Earth was
formed.
2. Uplands the parts of a country that are away from the sea and are
higher than other areas.
3. Subject (v) to force someone or something to experience
something very unpleasant.
4. Affect (v) to do something that produces an effect or change in
Something or in someones situation.
5. Livestock animals such as cows or sheep that are kept on a farm.
6. Emission a gas or other substances that is sent into the air.
7. Reverse (v) to change a situation or change the order of things
so that it becomes the opposite.
8. Lime a white substance that is used especially to spread on the
land to improve the quality of earth so that crops grow
better.
9. Turnaround a complete change from a bad situation to a good one.
Task 2.
Causes of acidification and restoration of acid waters
Part 1.
Acidification takes place in areas where natural geology is slightly acidic. Upland regions that have been subject to land-use changes over the last few decades are showing the signs of acidification.
Several factors affect acidity:
Natural:
1. Action of atmospheric carbon acids.
2. Formation of organic acids by humus podsolization
3. Podzolization.
Land-use changes:
4. Livestock introduction into the catchment.
5. Use of nitrogen fertilizer.
6. Increased efficiency of drainage.
7. Dry deposition of air pollutants.
8. Wet deposition of sulphuric and nitric acids.
It will be a combination of the above factors that will lead to freshwater acidification.
Part 2.
The only sure way to prevent further acidification of other susceptible water bodies is to reduce the emissions of acid pollutants. There is a relationship between sulphur emissions, deposition, sulphur in run-off and loss of alkalinity. If acidification of soils and freshwater to be prevented then sulphur deposition rates need to be reduced further. At present the main way of reversing acidification in freshwaters is liming the water body or its surrounding catchment. The main liming method is to add the lime directly to the water body. However, in the cases of certain lakes where the turnaround is very quick, the lime is added to the catchment. This has disadvantages though, the main one being that the lime can have an adverse effect on wetland species of plants. The advantages, however, are that the effects are longer lasting and metals are prevented from leaching into the lake water from the soil. The effects of liming are almost entirely favourable within the lake. The alkalinity of the limed lake is increased, the pH increased and heavy metal concentrations decrease back to within the safe limits for fish life. The number of species of fish, benthic animals and plankton increases as does biomass production.
Podsolization . , , , .
Liming , , .
|
|
|
Task 2. Decide whether these statements are True (T) or False (F).
1. Acidification can occur on all types of soil.
2. Coastal regions are prone to acidification.
3. There are natural and man-made factors that affect acidity.
4. It is necessary to increase sulphur deposition in soil in order to prevent acidification.
5. Liming has both advantages and disadvantages.
6. The alkalinity of the limed lake decreases.
Task 3. Fill in the missing words into the gaps.
What is acid rain?
Acid rain is a_______ which describes the _________ of wet and dry deposition. This includes acidity falling as rain, ________, sleet, hail, mist or fog (wet __________) and the dry deposition of gases and particles.
Acid rain has been called the ____________ issue of the 1980s and it continues to be a problem today. However, _________ rain is not a new problem at all. It dates from the middle of the 19th century when a __________ chemist, Robert Angus Smith, began to study the __________ of air pollution in Manchester and used the term acid rain to describe his ____________.
Deposition, Scottish, acidity, effect, term, snow, acid, environmental, findings.
Task 4. Translate the following passage from Russian into English.
Module 3
Eutrophication
Task 1. Read the following definitions of eutrophication and decide which one best describes the process.
Definitions
Eutrophication (Greek: eutrophia healthy, adequate nutrition, development) or more precisely Hypertrophication, is the ecosystems response to the addition of artificial or natural substances, mainly phosphates, through detergents, fertilizers, or sewage, to an aquatic system. - Shindler, David and Vallentyne, John R. 2004
Eutrophication is defined as an increase in the rate of supply of organic matter in an ecosystem. Nixon, 1995
Eutrophication is the process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates. These typically promotes excessive growth of algae. As the algae die and decompose, high levels of organic matter and the decomposing organisms deplete the water of available oxygen, causing the death of other organisms, such as fish. Eutrophication is a natural, slow-aging process for a water body, but human activity greatly speeds up the process. Art, 1993
Task 2. Read the definition of words and word combinations and guess their meaning. Translate them into Russian
Task 3. Read the text with the dictionary
Mechanism of eutrophication
As can be seen from the definitions, eutrophication arises from the oversupply of nutrients, which induces explosive growth of plants and algae which, when such organisms die, consume the oxygen in the body of water, thereby creating the state of hypoxia.
Unit 4 Hydro construction
Module 1
