The water we drink
The water we drink usually comes from reservoirs, lakes, or rivers. A large number of cities uses river water and dumps it back
into the river. Sometimes another city downstream uses the same water. This water may be badly polluted with chemicals and
pathogenic bacteria. Many different chemical treatments are necessary to make it safe and palatable.
Many communities add some form of fluoride to their water. Fluoride in concentrations of 0.7 to 1.0 ppm (parts per million)
can significantly reduce tooth decay in children.
Smaller communities usually obtain water from wells. Even they have problems because sometimes the ground water is
contaminated by nitrates. These nitrates come from agricultural fertilizers and from the decomposition of organic wastes.
What can we do? We can fight for clear water and convince our neighbors to do the same. We can demand an end to water
pollution by industries and cities. And finally, we must know how to use the water of the earth because that is all the water we have.
Comprehension
Write T for True and F for False:
1. Nitrates pollute the water. ( )
2. People dump purified water into the river. ( )
3. We drink water from reservoirs. ( )
4. Fertilizers purify the water. ( )
5. Chemical reactions carry bacteria into a settling basing. ( )
6. Fluoride doesn't reduce tooth decay. ( )
7.The smaller communities obtain water from lakes.( )
8. Many cities use river water. ( )
9. Chemical treatments are necessary to make water palatable. ( )
10. The maximum safe level of nitrate in water is 1.0 ppm. ( )
Choose the correct alternative.
1. Aluminum sulfate reacts with:
a) a gelatinous mass.
b) bacteria.
c) slaked lime.[1]
d) nitrates.
2. A gelatinous mass:
a) reduces tooth decay.
b) purifies the settling basing.
c) contaminates ground water.
d) carries down dirt particles and bacteria.
3. We obtain safe and palatable water:
a) from wells.
b) after chemical treatments.
c) from lakes.
d) from agricultural fertilizers.
4. We can:
a) demand an end to water pollution.
b) stop the decomposition of organic wasters.
c) use river water.
d) convince our neighbors to use fluoride.
5. Some small communities:
a) obtain nitrates from wells.
b) have purified well water.
c) also have problems with their water.
d) obtain agricultural fertilizers from nitrates.
6. Answer the questions.
1. Where does the water we drink come from?
2. Where do many cities dump their water?
3. What do chemicals and pathogenic bacteria cause to water?
4. What is necessary to make water safe and palatable?
5. Why do chemical engineers use a settling basing?
6. What chemical elements do they use to purify the water?
7. What does the gelatinous mass do?
8. How do many communities reduce tooth decay in children?
9. What's the problem with well water?
10. What do nitrates cause?
11. Describe what you faouding most interesting in the “Parque Nacional de Brasília."
“Water is the driving force of all nature”
Leonardo da Vince
Soluções para a tarefa
1.a
2.d
3.b
4.a
5.c
6.
1)usually comes from river lakes or reservoirs
2)at the river
3)make the water safe and palatable
4)chemicals elements and pathogenic bacteria
5)...
6)fluoride and nitrates
7)purifies the settling basing
8)putting fluoride in their water
9)the problem is that sometimes the well’s water is contaminated by nitrates
10)As it comes from agricultural fertilizers and from the decomposition of organic wastes it pollute the water
11)resposta pessoal
Resposta:
1. Write “T” for true and “F” for false according to the text.
a) Nitrates pollute the water. (T)
b) People dump purified water into the river(F)
c) We drink water from reservoirs.(T)
d) Fertilizers purify the water.(F)
e) We can't drink safe water.(F)
f) Fluorine does not reduce tooth decay.(F)
g) The smaller communities obtain water from lakes.(F)
h) Many cities use river water.(T)
i) Chemical treatments are necessary to make water palatable.(T)
j) There is nothing we can do to help solve the problem of water pollution.(F)
2. Answer the question in English.
a) Where does the water we drink come from?
usually comes from river lakes or reservoirs
b) Where do many cities dump their water?
at the river
c) What do chemicals and pathogenic bacteria cause to water?
make the water safe and palatable
d) What is necessary to make water safe and palatable?
chemicals elements and pathogenic bacteria
e) How do many communities reduce tooth decay in children?
putting fluoride in their water
Explicação: CONFIA