Viết PTHH xảy ra nếu có khi cho các chất sau: Mg, NaOH, Al 2 O 3 , Cu, C 12 H 22 O 11 ,
AgNO 3 , CuCO 3, K 2 S, Fe(OH) 3 tác dụng với:
a) H 2 SO 4 loãng b) H 2 SO 4 đặc

Water pollution is a major global problem which requires ongoing evaluation and
revision of water resource policy at all levels. It has been suggested that water
pollution is the leading worldwide cause of deaths and diseases, and that it accounts
for the deaths of more than 14,000 people daily. An estimated 580 people in India
die of water pollution related illness every day. About 90 percent of the water in the
cities of China is polluted. As of 2007, half a billion Chinese had no access to safe
drinking water. In addition to the acute problems of water pollution in developing
countries, developed countries also continue to struggle with pollution problems. For
example, in the most recent national report on water quality in the United States, 44
percent of assessed stream miles, 64 percent of assessed lake acres, and 30
percent of assessed bays and estuarine square miles were classified as polluted.
The head of China’s national development agency said in 2007 that one quarter the
length of China’s seven main rivers were so poisoned the water harmed the skin.
Water is typically referred to as polluted when it is impaired by anthropogenic
contaminants and either does not support a human use, such as drinking water, or
undergoes a marked shift in its ability to support its constituent biotic communities,
such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and

earthquakes also cause major changes in water quality and the ecological status of
water.
1. What is the leading worldwide cause of deaths and diseases?
2. How many people die every day by water pollution?
3. How many percent of the water in the cities of China is polluted?
5. What phenomena cause major changes in water quality and the ecological status
of water?

Read and put the headings into the correct paragraphs.
(There is one extra)
1. Effect on health of humans
2. Effect on growth of plants
3. Decreased soil fertility

4. Toxic dust
5. Changes in temperature
6. Changes in soil structure

Effects of Soil Pollution

1. : Considering how soil is the reason we are
able to sustain ourselves, the contamination of it has major consequences on our
health. Crops and plants grown on polluted soil absorb much of the pollution and
then pass these on to us. This could explain the sudden surge in small and terminal
illnesses.
2. : The ecological balance of any system gets
affected due to the widespread contamination of the soil. Most plants are unable to
adapt when the chemistry of the soil changes so radically in a short period of time.
Fungi and bacteria found in the soil that bind it together begin to decline, which
creates an additional problem of soil erosion.
3. : The toxic chemicals present in the soil can
decrease soil fertility and therefore decrease in the soil yield. The contaminated soil
is then used to produce fruits and vegetables which lacks quality nutrients and may
contain some poisonous substance to cause serious health problems in people
consuming them.
4. : The emission of toxic and foul gases from
landfills pollutes the environment and causes serious effects on health of some
people. The unpleasant smell causes inconvenience to other people.
5. : The death of many soil organisms (e.g.
earthworms) in the soil can lead to alteration in soil structure. Apart from that, it
could also force other predators to move to other places in search of food.