IX. Read the following selections using the dictionary.
"The most alarming of all man's assaults upon the environment is the
contamination of air, earth, rivers and sea with dangerous and even lethal
chemicals."—Rachel Carson, Silent Spring
Air pollution is the result of man's use of lethal chemicals, and is a
common hazard in both industrial and developing countries. One form of
air pollution is acid rain.
Acid rain results from the release into the atmosphere of sulfur oxide
and nitrogen oxide. Electrical generating plants, industrial boilers, large
smelters, and automobiles are among the chief source of these emissions.
The gases react with water droplets, forming a diluted mixture of sulfuric
acid and nitric acid, and it is this mixture that returns to earth in the form
of acid rain, mist, or snow. Pushed by wind currents, the acid rain often
falls to the ground far from its point of origin.
Acid rain is killing vast stretches of forest in Canada, the United
States, and central and northern Europe. In Europe nearly every species of
tree is affected. Symptoms include thinning of leaves and needles,
deformed growth, and, in some cases, death. Acid rain has acidified lakes
and streams, rendering them unable to support fish, wildlife, plants, or
insects. In Sweden at least 40,000 of the 90,000 lakes have been affected,
and in the United States one in five lakes suffers from this type of
pollution.
********************************************************
Oceans cover more than 70% of the earth surface. Despite the vastness of
this area, we know little about it. The oceans are just as diverse as the land. They
are interwoven with history, although man has looked upon them as barriers and
alien spaces.
Life began in the ocean. More than 3
1
/
2
billion
years ago there evolved simple single-celled organisms.
Today the oceans support a wealth of simple and
complex sea life, from phytoplankton (drifting plants) to crustaceans (shrimp,
crabs) to marine mammals (whales, dolphins). But through ignorance and
misunderstanding we are placing these resources in jeopardy. There is
widespread pollution and disruption of our coastal waters, whales and dolphins
are hunted to near extinction, and many fishing areas are being depleted.
The oceans do not belong to a single nation, but are free, open territory to
be enjoyed and shared. However, too often nations are overly aggressive in
taking the resources the oceans have to offer. A tragic result has been the
systematic hunting of whales from one species to another for whalebone,
blubber, and oil. In 1985 whales were given a reprieve when the International
Whaling Commission imposed, a moratorium on killing whales.
Generated by Foxit PDF Creator © Foxit Software
http://www.foxitsoftware.com For evaluation only.