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WATER CYCLES: facts and pollution:
Introduction:
The Earth’s surface contains 70% water and 97% of this water is not available for
drinking. Americans consume about 100 gallons (378 L) of water per day.
How many gallons that makes in one week?
__________________ gallons
How many gallons in one month?
__________________________ gallons
Water is not free; it is purified and brought to your home, and you must pay each month for the
service. Water meter for home usage is measured in cubic feet.
1 cubic foot = 7 ½ gallons (284 L).
So, how many cubic feet does an average American family use each month?
________________________________________________________
How much do you pay for each cubic of water?
_________________________________
Thus, how much do an average American family pays each month for its water needs?
_____________________________________
Nowadays, we need more freshwater because we are more numerous on earth and our
seas are polluted. We are more numerous because less people die and we are fed better and we
are well protected against many natural hazards. So, we need water for our family, not only for
drinking, but also for eating, agriculture, bakeries, restaurants, schools that need more water as
they have to satisfy more customers.
Of the water consumed each year, 73% is used for agriculture, 21 % for industry, and only 6% for
domestic uses.
What is the % of water used to grow crops and in industry?
______________ %
What do you use water for in your house?
___________________________________________________________________________
Can you sometimes reduce the amount of water you are using daily? How?
___________________________________________________________________________
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If a lot of water is used to grow plants, and if we know that many pesticides (a dangerous
pollutant when it accumulates) are used in the fields, what can we conclude as far as pollution is
concerned?
_____________________________________________________________________________
Why do industries need water?
______________________________________
Where does the industries’soiled waters go when released?
______________________________________
When you wash the dishes or go to the bathroom, where is the water you used released?
______________________________________________________________________________
What does the word “sewage” mean?
_____________________________________________________________________________
Sewage, industrial wastes, and agricultural chemicals such as fertilizers and pesticides are
the main cause of water pollution.
In 1995, about 37% of the US's lakes and estuaries, and 36% of its rivers, were too polluted for
people to fish or swim in them!
How many (in %) natural water locations are polluted each year?
____________________________________________________________________________
That makes how many (in %) water locations not polluted, in 1995?
____________________________________________________________________________
How long ago was that?
____________________________________________________________________________
Do you think it is better or worse in year 2,000? Explain:
Better:
___________________________________________________________________________
Worse:
____________________________________________________________________________
If you know that over 95 % of urban sewage is discharged untreated into rivers and bays,
what can you conclude?
Imagine you were bathed in sewage, what would probably happen to you?
____________________________________________________________________________
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