2. Look at the title of this report and answer the following questions.

1. What do you know about canaries?

2. Do you know how they can be useful to man?

3. What sea creature might be like a canary in some way?

Watch the video and do the following exercises.

1. Answer the following questions.

1. What lives in the waters of St. Lawrence Seaway?

2. What lines the banks of the St. Lawrence River? Why?

3. What flows downstream from hundreds of miles away?

4. What is killing the "canaries of the sea"?

2. The following sentences can be made more factually correct. Watch the report again and find out how to correct them.

1. These Beluga whales are unique.

2. Dead whales are found to have unusual cancers, ulcers and lesions.

3. The toxic compounds in water exceed international safety limits.

4. Toxic substances have been released into the water by Canadian firms.

5. Toxic waste is being dumped at river sites in America despite a ban.

6. The whales were called canaries because they warn man about the presence of toxic substances in the area.

3. Give your reasons why these proposed solutions are not entirely satisfactory.

• in America, clean-up schemes along the river;

• in Canada, a protected marine area for whales.

4. Enrich your vocabulary by learning words and phrases used in the report to refer to the following.

• dead whales;

• toxic substances.

5. Discuss in groups what warning these "canaries of the sea" have for us all and what we have to do if we don't want them to become extinct. Reading three

Read through the following text and analyse the dramatic consequences acid rain causes.

Acid Rain

The most serious environmental threat facing the countries of the northern hemisphere, acid rain, has been dubbed "The Silent Crisis". The term acid rain first coined in 1852, is now accepted as an umbrella description for the cocktail of atmospheric pollutants whose main effect is to cause acidification of soil and water, and hence the degradation of all that depends on these elements for survival.

Unlike the smogs that used to afflict European cities during the 1950's, and that were caused largely by soot particles in the air, acid rain is invisible, is spread far and wide, and is more insidious in its effect. Its main components are sulphur dioxide (SO₂) and the oxides of nitrogen (NO_x), which cause

acidification either through being deposited in the environment in a gaseous or particulate form or in the form of rain or mist. These primary pollutants and hydrocarbons (HC) are converted to secondary pollutants and transported long distances in the air. Amongst the most important of the secondary products are sulphuric acid, nitric acid, ammonium sulphate, and ozone.

Acid rain is having damaging effects at almost every level in the natural and built environments. Lakes and rivers throughout Europe and North America are dying, having been practically devoid of fish. Fish eating and insectivorous species of wildlife like otters have declining populations as a result of reduced food availability and the toxic effects of acidification. Food production is threatened, too, as cereal yields are reduced due to acidification, and human health is also under threat because heavy metals are mobilised by acid rain, and leach out into drinking water supplies. An increasing body of evidence is pointing to a role for acid rain in the incidence of Alzheimer's Disease, chest problems and kidney disease. Even buildings do not escape the ravages of acid rain; much of the world's most important architectural heritage is being eaten away by acidification. St. Paul's, the Taj Mahal, Cologne Cathedral and Notre Dame have all experienced more damage to their stonework in the last 40 years than in the years since they were built.

On a European scale the most widely documented effects of acid rain are those to rivers lakes and forests. Thousands of once productive Norwegian and Swedish lakes can now support no fish at all. This has been extremely damaging to the tourist industry, which has in the past been partly dependent on the trout and salmon fishery. Forests throughout Europe have been affected and in West Germany the percentage of trees damaged by acid rain rose from 34 per cent to 50 per cent between1984 and 1985. This is disastrous proposition as 22 per cent of the forest is "Conservation Forest" essential for the maintenance of the country's water table.

Drinking water is also being affected, because of the way acid rain mobilises toxic metals, and leaches them out of the soil into portable water supplies. Increased levels of lead, aluminium and cadmium in the water are bound to cause severe problems for our health.

The mechanisms by which acid rain is formed and causes damage are complex. 90 per cent of acidity in the rain in the northern hemisphere is "man-made". Pollution comes predominantly from the burning of fossil fuels, mainly in power stations and from exhaust fumes of vehicles. Vehicles produce other atmospheric pollutants such as hydrocarbons (HC) and carbon monoxide (CO). Nitrogen oxides and hydrocarbons react in the presence of sunlight to form another toxic gas, ozone (O₃), which has been found to be a significant contributory factor in forest decline.

Emissions from power stations are partly deposited close to source depending on weather and wind conditions, and the height of smoke stacks but a very large proportion of pollutants stay mobile in the atmosphere for some time.

For example, sulphur dioxide (SO₂) can travel for hundreds or even thousands of kilometres before being deposited as acid rain. In this way, pollution exports cross national boundaries.

Countries such as Great Britain, Italy and Poland export far more SO₂ than they receive. Great Britain is known as the "Dirty Man of Europe" as its power stations are responsible for the largest emissions in the EC – some 3 700 000 tons annually, which is more than France, Sweden, Norway and the Netherlands together.

The only solution to the problems of acid rain is to reduce emissions from power stations and car exhausts. The first step was the formation of the "30 percent Club", a group of countries who had reduced, or were willing to commit themselves to reducing SO₂ emissions by 30 per cent on 1980 levels by 1993. Likewise, with vehicle emissions the technology is currently available to make reductions immediately. There are several alternatives offering reductions, and three-way catalytic converters for exhausts seem to be the best option.

Both immediate reductions and long-term solutions are necessary. Policies such as increased liming of lakes to neutralize acid waters are only superficial remedies. Acidification is an accumulative problem in the environment, so the first step should be a reduction of all types of contributory emissions. The alternative is an increasingly sterile environment, with the stark prospect of lifeless soils and waters, and millions of hectares of dead trees, growing more certain every day.

Acid Rain. Centre to environmental information. Surrey; World Book