Text 5: water pollution and the waste problem

BASIC INFORMATION

Water pollution, which has become a problem worldwide, is one of the vital issues of our times. The coastal waters have suffered the worst effects of pollution as they have become the dumping ground for industrial waste. Dumping sewage and toxic waste – untreated – in the sea or on unlicensed dumps is quite a common practice, sometimes even the rule.

One reason for the increase in water pollution is overpopulation. Other reasons are inadequate waste management and waste disposal.

Thus large quantities of effluents containing heavy metals like lead, cadmium, zinc etc. are discharged into rivers or the coastal waters and towns and large cities have more and more sewage to dispose of. Serious problems are posed not only by the huge quantity but also by the kind of waste involved. Although most sewage-treatment plants are equipped to extract solids and organic matter from sewage, they are normally incapable of removing harmful and toxic chemical substances. Therefore synthetic detergents, heavy metals and dissolved phosphates and nitrates eventually end up in the sea.

Drinking water for millions of people has been contaminated by dangerous pollutants.

The immune systems of animals have been impaired by water pollution. In 1988 thousands of seals died in the North Sea, so that the species was in danger of becoming extinct. Every year algae blooms (known as ‘red tides’) kill marine life in large areas. Survivors of decimated species are already afflicted with a number of symptoms: they have skin infections, their skeletons are deformed and they have developed tumors.

WAYS OF COPING WITH WATER POLLUTION AND WASTE

Text 6: destruction of the ozone layer and greenhouse effect

BASIC INFORMATION

The destruction or depletion of the world’s vital ozone layer may turn out to be the major environmental issue of the 21^st century.

Ozone in the stratosphere is vital to life because it screens us from most of the sun’s harmful radiation: it shields / protects the earth. It absorbs more than 99 per cent of the lethal ultraviolet rays reaching the earth’s atmosphere. The ozone layer is created by the interaction of ultraviolet radiation from the sun with oxygen in the atmosphere. But, as a result of the decline in the ozone layer, there is an increase in the amount of ultraviolet light that reaches the earth, so that life on earth is now exposed to increasingly dangerous levels of radiation.

There is no indirect link between the damage to the ozone layer and the greenhouse effect, the overheating of the earth or global warming. Carbon dioxide (CO2) and other greenhouse gases are accumulating in the atmosphere at an alarming pace. The increasing concentrations of greenhouse gases block the escape of infrared radiation from the earth into space; they prevent the earth from reflecting solar heat back into space and trap it in the lower air.

Scientists argue that the depletion of the ozone layer is caused mainly by man-made pollutants: CFCs, which propel aerosols, are also to be found in refrigerators (as refrigerants), insulation in houses, the foam in furniture and car seats, air-conditioners, solvents, some fast-food containers etc. At first harmless, they do not react until they have floated some 20 km up into the stratosphere. There they are broken down, giving off chlorine, and attack ozone molecules.

Man is also mainly to blame for the greenhouse effect, which can be traced back to the burning of fossil fuels in vehicles, power stations, factories and homes, as well as to the large-scale burning of tropical forests.

The dangerous greenhouse gases are:

POSSIBLE CONSEQUENCES

POSSIBLE SOLUTIONS TO THE PROBLEM