Unit 4. Water Pollution

Exercises (A)

1. Learn new words:

water pollution – загрязнение воды domestic sewage – местные

serious –серьезный сточные воды

urbanization – урбанизация way – путь, способ

bacteria – бактерия, микроб oxidation – окисление

desease – смерть dangerous – опасный

decomposable – разлагаемый purification – очистка

organic matter – органическое вещество growth – рост, развитие

oxygen – кислород

inorganic salt – неорганическая соль

irrigation – орошение

oily materials – маслянистые материалы

toxic agents – токсичные вещества

chemicals – химические препараты

A. 1. Translate the following word combinations:

almost all countries; water-pollution problem; became very serious; as а result of urbanization and industrialization; many types of water pollution; pollution by bacteria, viruses and other organisms; рollution by decomposable organic matter; to be removed by any simple treatment process; to make water quite unsuitable for drinking; for irrigation and for many industries; pollution by plant nutrients; pollution by oily materials; may screen the river surface from the air; to reduce reoxygenation; pollution by specific toxic agents; ranging from metal salts to complex synthetic chemicals; pollution control; а sanitary engineering problem; to be solved by strict laws; for sewage and industrial-waste treatment; the disposal of а certain amount of sewage by dilution; through bacterial action and aeration; to include an investigation of stream flows; by means of reservoirs; in additional sewage treatment plants; with responsibility for the conservation and utilization of water.

Text (A)

Read the text «Water Pollution Control»:

Almost all countries of the world have а water-pollution problem, which became very serious as а result of urbanization and industrialization.

There are many types of water pollution. It is convenient to divide them into classes, as follows: а) pollution by bacteria, viruses and other organisms that can cause diseasе; b) рollution by decomposable organic matter, which by absorbing the oxygen in the water kills fish; с) pollution by inorganic salts. They cannot be removed by any simple treatment process and may make water quite unsuitable for drinking, for irrigation and for many industries; d) pollution by plant nutrients; е) Pollution by oily materials which may screen the river surface from the air thus reducing reoxygenation; f) pollution by specific toxic agents ranging from metal salts to complex synthetic chemicals.

Pollution control is largely а sanitary engineering problem, to be solved by strict laws and enforcement and involving vast expenditures of public funds for sewage and industrial-waste treatment. However, the disposal of а certain amount of sewage by dilution is usually considered permissible, particularly in functioning through bacterial action and aeration. А complete stream pollution control study must include an investigation of stream flows. 1п some instances the augmentation of low flows, by means of reservoirs, has proved to be at least as important to the control of stream pollution as have investments in additional sewage treatment plants.

The Water Resources Act of 1963 set up а Water Resources Board acting through 29 river authorities, charged with responsibility for the conservation and utilization of water. Standards are laid down, enforceable by law, governing the permitted levels of pollutants which may be discharged into rivers. Similar regulations are applied in other countries — although accidents can occasionally happen, as was the сазе in 1969 when the illegal dumping ol chemicals caused the destruction ol millions о1 f!sh along the entire length of the River Rhine.

Exercises (B)

1. Establish compliance between parts of sentences:

1. almost all countries of the world have 1. an investigation of

а water-pollution problem, which became stream flows

very serious

2. there are many types of water pollution: 2. as а result of urbanization

pollution by bacteria, viruses and industrialization

3. Pollution control is largely а sanitary 3. рollution by decomposable

engineering problem organic matter, pollution by

4. a complete stream pollution control inorganic salts

study must include 4. to be solved by strict laws

and enforcement

Text (B)

Read the text «Water pollutants», using a dictionary:

Most water pollutants are eventually carried by rivers into the oceans. In some areas of the world the influence can be traced one hundred miles from the mouth by studies using hydrology transport models. Advanced computer models such as SWMM or the DSSAM Model have been used in many locations worldwide to examine the fate of pollutants in aquatic systems. Indicator filter feeding species such as copepods have also been used to study pollutant fates in the New York Bight, for example. The highest toxin loads are not directly at the mouth of the Hudson River, but 100 km (62 mi) south, since several days are required for incorporation into planktonic tissue. The Hudson discharge flows south along the coast due to the coriolis force. Further south are areas of oxygen depletion caused by chemicals using up oxygen and by algae blooms, caused by excess nutrients from algal cell death and decomposition. Fish and shellfish kills have been reported, because toxins climb the food chain after small fish consume copepods, then large fish eat smaller fish, etc. Each successive step up the food chain causes a cumulative concentration of pollutants such as heavy metals (e.g. mercury) and persistent organic pollutants such as DDT. This is known as bio-magnification, which is occasionally used interchangeably with bio-accumulation.

Groundwater pollution is much more difficult to abate than surface pollution because groundwater can move great distances through unseen aquifers. Non-porous aquifers such as clays partially purify water of bacteria by simple filtration (adsorption and absorption), dilution, and, in some cases, chemical reactions and biological activity; however, in some cases, the pollutants merely transform tosoil contaminants. Groundwater that moves through open fractures and caverns is not filtered and can be transported as easily as surface water. In fact, this can be aggravated by the human tendency to use natural sinkholes as dumps in areas of karst topography.

There are a variety of secondary effects stemming not from the original pollutant, but a derivative condition. An example is silt-bearing surface runoff, which can inhibit the penetration of sunlight through the water column, hampering photosynthesis in aquatic plants.

Groundwater pollution is much more difficult to abate than surface pollution because groundwater can move great distances through unseen aquifers. Non-porous aquifers such as clays partially purify water of bacteria by simple filtration (adsorption and absorption), dilution, and, in some cases, chemical reactions and biological activity; however, in some cases, the pollutants merely transform tosoil contaminants. Groundwater that moves through open fractures and caverns is not filtered and can be transported as easily as surface water. In fact, this can be aggravated by the human tendency to use natural sinkholes as dumps in areas of karst topography.