WBBSE Class 7 Geography Solutions Chapter 7 Water Pollution

Detailed explanations in West Bengal Board Class 7 Geography Book Solutions Chapter 7 Water Pollution offer valuable context and analysis.

WBBSE Class 7 Geography Chapter 7 Question Answer – Water Pollution

Multiple Choice Questions & Answers : (1 mark for each question)

Question 1.
A water bourn disease-
i) cholera
ii) jaundice
iii) Typhid
iv) all the disease
Answer:
iv) all the disease

Question 2.
The percentage of the water in world is saline sea water-
i) 97 %
ii) 99 %
iii) 3 %
iv) 66 %
Answer:
i) 97 %

Question 3.
Cause for black foot disease-
i) arsenic pollution
ii) fluoride pollution
iii) cadmium pollution
iv) mercury pollution
Answer:
i) arsenic pollution

Question 4.
Itai-Itai disease is due to-
i) arsenic pollution
ii) fluoride pollution
iii) cadmium pollution
iv) mercury pollution
Answer:
iii) cadmium pollution

Question 5.
Problems of teeth and bone is due to-
i) arsenic pollution
ii) fluoride pollution
iii) cadmium pollution
iv) mercury pollution
Answer:
ii) fluoride pollution

Question 6.
Minamata disease is due to-
i) arsenic pollution
ii) fluoride pollution
iii) cadmium pollution
iv) mercury pollution
Answer:
iv) mercury pollution

Question 7.
Liquid mercury waste was released into the sea in Japan in-
i) 1942
ii) 1932
iii) 1935
iv) 1937
Answer:
ii) 1932

Question 8.
Exhaust fumes from factory-chimneys and vehicles emiting-
i) Sulphur dioxide
ii) Nitrogen oxide
iii) Carbon dioxide
iv) all are true
Answer:
iv) all are true

Fill in the blanks : (1 mark for each question)

1. Haldia Petrochemical industry is situated at the mouth of _______ river.
Answer:
Haldi

2. Chilka Lake is situated at the state of ________.
Answer:
Odisha.

3. During the gulf war many oil wells were ignited in _______ .
Answer:
Kuwait

4. Nitrates in fertilizers can cause ________.
Answer:
cancer

5. Medical wastes from hospitals can pollute _________.
Answer:
water

6. Chlorine and Fluoride also polutes _________.
Answer:
water

7. ___________ of the earth’s surface is covered with water bodies.
Answer:
three fourths

8. A large quantity of fish has died at Kuttuner of _________.
Answer:
Kerala

9. Soaps and detergents are also sources of water _________.
Answer:
pollution

10. Warm effluents of from thermal and nuclear power plants can reduce the ___________ in an aquatic environment.
Answer:
oxygen

State whether True or False : (1 mark for each question)

1) Presence of excessive fluorine and chlorine in water is harmful for heaith.
Answer:
true

2) 90 percent of the water on earth is saline sea water.
Answer:
false

3) Major rivers of the world are mush poluted.
Answer:
true

4) Demand for fresh water remains the main problem for the people all over the world.
Answer:
true

5) Drinking water from Ganga is safe.
Answer:
false

6) Rajasthan is suffering from acute water crisis.
Answer:
true

7) The cultivation of fish at the disheries of the wetlands of East Kolkata has increased.
Answer:
false

8) Dark lesions formed on the palms or sole of the feet are called Blackfoot disease.
Answer: true

9) As a result of eutrofication the percentage of oxygen in the water decreases.
Answer:
true

10) Minamata disease san occur due to cadmium pollution.
Answer:
false

Match the following : (1 mark for each question)

Match the column A with column B.

A	B
a) Black foot disease–	i) mercury pollution
b) Itai-Itai disease–	ii) causing death of marine creature
c) Flurosis disease–	iii) cadmium pollution
d) Minamata disease–	iv) death of people and animals
e) Mineral oil pollution in Persian Gulf	v) covered with water bodies
f) Mercury pollution at Minamata bay–	vi) arsenic pollution
g) Three-fourths of the earth’s body	vii) as our mother
h) We worship Ganga	viii) fluoride pollution

Answer:
a) Black foot disease–arsenic pollution
b) Itai-Itai disease–cadmium pollution
c) Flurosis disease–fluoride pollution
d) Minamata disease–mercury pollution
e) Mineral oil pollution in Persian Gulf causing death of marine creature
f) Mercury pollution at Minamata bay–death of people and animals
g) Three-fourths of the earth’s body covered with water bodies
h) We worship Ganga as our mother

Very Short Questions & Answers : (1 mark for each question)

Question 1.
What is water pollution
Answer:
When the unwanted substances and germs mix with water and make it unfit for use, it is called water, pollution.

Question 2.
How much part of the world is covered with water and how much part with land?
Answer:
The three-fourth part of the world is covered with water and one fourth is land.

Question 3.
How many part of the earth is covered with sweet water?
Answer:
One part of the world is covered with sweet water.

Question 4.
Which pollution was occured at Minamata in Japan?
Answer:
Mercury poliution was occured at Minamata in Japan.

Question 5.
What cultivation is done in the wetlands of East Kolkata?
Answer:
In the wetlands of East Kolkata the cultivation of fish is done.

Question 6.
What diseases is caused due to cadmium pollution?
Answer:
Due to the cadmium pollution Itai-Itai diseases is occured.

Question 7.
What diseases is caused due to arsenic pollution?
Answer:
Due to the arsenic pollution black foot diseases is occured.

Question 8.
What diseases is caused due to fluoride pollution?
Answer:
Due to the fluroride pollution flurosis diseases is occured.

Question 9.
What happened during the Gulf war?
Answer:
A large quantity of mineral oil polluted the Persian Gulf.

Question 10.
What happened after the formation of petro chemical industry at Haldia?
Answer:
Frequent visit of Hilsa fish at the mouth of the Haldi river has decreased.

Question 11.
Which chemical is added to for purifying water?
Answer:
Chlorine is added to for purifying water.

Question 12.
What happens if phenyl is added with the water of aquirium?
Answer:
The fishes will die if phenyl is added with the water of aquirium.

Short Questions & Answers : (2 marks for each question)

Question 1.
How did water get polluted at time of gulf war?
Answer:
At the time of gulf of war many oil wells in quait were ignited. For this a large quantity of mineral oil mixed with the water of Persian gulf. That caused the death of many sea animals.

Question 2.
What is the cause of reducing the visit of Hilsha fish at the mouth of Haldi river?
Ans. Haldia Petro Chemical industry has been set up. Thus the chemical waste of this factory mixes with the water of Haldi river that causes the pollution of water. It has reduced the visit of Hilsha fish at the mouth of Haldi river.

Question 3.
What is the cause of redusing fish cultivation at the fisheries of the wetlands of East Kolkata.
Ans.
The cause of reducing of fish cultivation at the fisheries of the wetlands of East Kolkata is water pollution. This is for using pesticides in the farmland.

Question 4.
What is Eutrophication?
Ans.
A heavy amount of weeds hyacinth grows for mixing of soap, phosphates of detergent in water of confined pond and wetland which is called Eutrophication.

Long Questions & Answers : (3 marks for each question)

Question 1.
What are the possible causes of water pollution?
Answer:
The causes of waster pollution-
i) Pollution from industry : The polythene plastic, mineral oil, amonia, cholrin, phenol copper, zinc, murcury wastes from various industries drain into water bodies and make the water polluted.
ii) Pollution from house hold: The grabage of daily household like peels of vagitables. fruits, stool-Urine, soap, ditergent, phenyle etc mix with local water bodies through ditches resulting water pollution.

iii) Water pollution from farmland : The insecticides, pesticides, fertiliser used in farmland, get mixed with pond water, river water through the rain water or canals and pollute the water.
iv) Pollution from fisheries: In the fisheries chemicals are used for the growth of fish and that pollute the water.
v) Radioactive substances: The radio active substances used in atomic reactor plants thrown intoi sea or river water and pollute water.
vi) Pollution from oil carrier ship : After accident of oil carrier ship or the time of oil mixing oil spilt in the sea water and makes it polluted.
vii) Water pollution from air pollution: The sulpher dioxide, nitrogen oxide, carbon dioxide accumulate in the air from the air emitted by the factory and vehicles. These pollutants mix with rain water and make the ground water polluted.
viii) Dead animals : The dead bodies of the the animals are thrown in the river water. That makes the water polluted.

Question 2.
What measure can be taken to prevent water pollution?
Answer:
The measure for preventing water pallution are :

1. The garbage should not throw out directly in the rivers, ponds or seas.
2. The sewage from factories should be thrown in the water after treatment.
3. Plastic, dead bodies, solid waste should not be thrown in the water bodies.
4. The excess use of fertiliser, pesticides insecticides in the farmland should be stopped. Instead of organic manure should be used.
5. The sewage of town of cities should be treated before throwing in the water.
6. The misuse of waste water should prevented.
7. We should not wash clothes or allow the cattles to get into the river and pond water.
8. The hot water of tharmal power station should be thrown in the river water after cooling.
9. Through the different bacteria and algae the pollution of floating mineral oil should be removed from the sea water.
10. We should be careful that the oil from ship could not spilt into the sea.
11. The stool-Urin medecinal waste of hospital should not be thrown in the water.

Question 3.
What can we do to prevent water pollution?
Answer:

1. We can prevent wasting water by stopping water tap when it is not needed.
2. We have to use such soap or shampoo which are not harmful for environment.
3. We have to throw the house hold garbage at such a place where the source of pure water is not present.
4. The vegetables, fruit, flower plants should be planted around the pond, well or beside the drainage of tube well.

Question 4.
What are the effects of water pollution in West Bengal.
Answer:
Arcenic has been found more or less many districts of West Bengal like Malda. Nadia, Hooghly, Howrah, Burdwan, North and South 24 parganas in the ground water. So the arsenie pollution is occuring. For that black wound is found in the palm and toe which is called black foot diseases. Besides anemea skin diseases lung and skin cancer have occured.

For fluride pollution the problem of teeth and bone is caused that leads to flurosis disseases. Besides for mercury pollution minamata diseases and for cadmium pollution itai-itai have occured.

As the set up of Haldia Petro chemical has caused the water pollution at the mouth of Haldi river. This leads to reducing the frequent visit of Hilsa fish at the mouth of Haldi river. The Cullivation of fish at wetlands of East Kolkata also has been reduced for the applying of insecticides. The store of ground water also decreased. As the result of drinking polluted water dyhrea. cholera, Typhoid are spreading rapidly.

Question 5.
What are the measures of purifying water?
Answer:

1. The bacterias of the water could be destroyed by boiling water at 100°C for 10 minutes.
2. Germfree water can be obtained by adding certain amount of chlorine with water.
3. Water should be covered and left for some hours. After that it will be found that the mud and sand have been sedimented at the bottom of water.
4. Water can be purified with the help of charcol, fine sand, pebbles and stones.
5. The masoor plants help to be sedimented of the dirt of water
6. Sametimes keeping in sunlight for long makes the water purified.

Question 6.
How water gets polluted from industriel source?
Answer:
Petro chemical industry, polythene and plastic industry, oil refineries, automobile industry, small and medium electrical and engineering industries, etc. generate huge quantities of wastes and effluents like ammonia, chlorine, phenol, cyanide as well as metals like zinc, mercury, lead and cadmium drain in to water bodies and pollute them.

Question 7.
How water gets polluted from industriel source?
Answer:
Households in villages and cities generate wastes like the peels and pieces of fruits and vegetables, kitchen wastes and excreta. Phenyl, soaps and detergents are also sources of water pollution. Medical wastes from hospitals and clinics, daily wastes generated from market places and wastes from cowsheds, stables and other domestic animal shelters also pollute water.

Question 8.
How water gets polluted due to air pollution?
Answer:
Exhaust fumes from factory-chimneys and vehicles emitting sulphur dioxide, oxides of Nitrogen, carbon dioxide etc. are absorbed in the air. Sulphur dioxide and Nitrogen dioxide react with rainwater to make the different waterbodies acidic.

Question 9.
How water gets polluted by Arsenic contamination?
Answer:
Excessive extraction of underground aquifer creates void that is filled by air. This air reacts with arsenic to form toxic metallic compounds that contaminate water which can seriously affect one’s health when used as drinking water. The presence of excessive Fluorine and Chlorine in water is also harmful for health and pollutes water.