mud -грязь, ил.
swamp -болото, топь.
2) а) Now you will read a text.
How Does a Lake Die?
LAKE ERIE IS DYING.
DEATH OF GREAT LAKE.
LAKE ERIE: A DEAD SEA.
People in the USA and Canada may read headlines like these in newspapers or see
reports on television about Lake Erie. This big lake is not dead yet, but it is in
danger of dying.
Like many lakes in North America, Lake Erie was born more than 10,000 years
ago. Its area is 25,745 square kilometres. Lake Erie is the oldest and shallowest of
the Great Lakes, so it is natural that it is dying faster than the others.
But it is dying not only because a lot of soil, dead plants, and animal
materials are carried into it. Pollution is the greatest danger. Waste products of
many kinds are brought into the lake by rivers from cities and industries. Some of
the wastes kill fish and some kill the life on the bottom of the lake. When plants
growing in the lake die, they go down to the bottom. The same thing happens to
plant life that falls into the water. There they decay. But the process of decay is
impossible without oxygen, and in Lake Erie there is so much wastes that most of
all the oxygen is taken from the water. Most of decay stops, and the wastes
accumulate on the bottom. It was found that over 2500 square kilometers of the
lakes bottom waters have no oxygen at all.
As decay takes oxygen from the water, the animal life becomes very difficult in
Lake Erie. The fish that are best for food are disappearing. The need very much
The pollution of Lake Erie is a great danger not only for fish, but for people
too, especially for children. In many places swimming in its waters is impossible
now because of the danger to health.
Biologists think that Lake Erie will take not less than twenty years to clean
itself of undecayed wastes if all pollution is stopped now.
City and state governments in both Canada and the United States are trying to
clean up Lake Erie and put a stop to the thousands of tons of industrial and city
wastes that flow into the lake. But progress is slow, and much money is needed,
both by city and state organizations and by factories to the work well.
There is also another thing which specialists worry about navigation on the
Great Lakes. There are many important ports both on the US side and on the