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Chapter 18

Effects of Pollution

Class 9 - Total Geography Morning Star


Short Answer Questions

Question 1

How does noise pollution affect animals?

Answer

Noise from industries, railways, crackers, explosions and commotion in the cities and aircraft, affect animals, birds, mice, fishes and domestic animals in the following ways-

  1. Birds avoid migrating to places where noise level is above 100 dB.
  2. The noise emissions caused by supersonic aircraft and railways may cause miscarriage in mammals and fishes as well.
  3. Some of the birds have been found to have stopped laying eggs due to noise pollution.

Question 2

What major harm is done to human beings by air pollution?

Answer

Major harm done to human beings by air pollution are-

  1. Chronic respiratory diseases
  2. Lung cancer
  3. Cardiovascular diseases and coma
  4. Damage to the nerves, brain, liver, kidney etc.

Question 3

How are animals affected by air pollution?

Answer

Animals that feed on grass and plants, coated with polluted particulate matter, are affected with arsenic poisoning. Lead poisoning results in bronchitis and lack of appetite in pet animals.

Question 4

What is the effect of oil spills on marine life?

Answer

Sea water polluted with crude oil leakage causes oil spills which contaminate sea water and lead to the death of marine organisms.

Oil spills kill marine mammals such as whales, dolphins, seals, and sea otters. Oil can clog blow holes of whales and dolphins, making it impossible for them to breathe properly and disrupting their ability to communicate. Oil coats the fur of otters and seals, leaving them vulnerable to hypothermia.

Question 5

What causes waterborne diseases? Name two waterborne diseases.

Answer

Most of the waste waters especially sewage contain pathogens like bacteria, viruses and protozoa. These pathogens enter the human body from contaminated drinking water and are responsible for several waterborne diseases like cholera, typhoid etc.

Question 6

In what way does soil pollution affect human beings?

Answer

Soil pollution affects human beings in the following ways-

  1. Soil contains many pathogenic bacteria, viruses and intestinal worms which are transmitted to man by the consumption of fruits and vegetables. These pathogens cause various types of diseases.
  2. Radioactive fallout on vegetation is the source of radioisotopes which enter the food chain through the grazing animals. Some of these radioisotopes cause abnormalities.
  3. Use of animals and human excreta as manure pollutes the soil. Excreta contains pathogens that contaminate the soil and vegetable crops and affect the health of human beings.

Question 7

Give the impact of radiations on human body.

Answer

Radiations affect living organisms. They cause harmful changes in the body cells and at genetic level. Some impacts of radiations on human body are-

  1. Genetic variations — The damage caused by radiations is often seen in the offsprings and may be transmitted to many generations.
  2. Somatic variations — Short term exposures to radiation can cause damage to organs of the body. The harm done by them includes breast cancer, thyroid cancer, lung cancer and brain cancer, sterility and defective eyesight.

Question 8

Why are nuclear radiations more dangerous than other forms of pollution?

Answer

Nuclear radiations are more dangerous than other forms of pollution because the high level products of nuclear wastes remain in the environment for several hundred years.

Structured Questions

Question 1(a)

State briefly how is noise pollution detrimental to human health.

Answer

Noise pollution is detrimental to human health because of the following effects-

  1. Effect on hearing or deafness — Continuous exposure to noise levels above 100 dB has an adverse effect on hearing ability within a fairly short time.
  2. Effect on Communication — External sounds can interfere with conversation and use of the telephone, as well as the enjoyment of radio and television programmes. It can affect the efficiency of offices, schools and other places where communication is of vital importance.
  3. Interference with sleep — Noisy conditions near residential areas at night cause difficulties in sleeping.
  4. Mental or Physiological effects — Doctors and scientists have medically confirmed that noise disturbs the biological organisms and their respective functions. Recent researches have concluded that short exposures to noise can lead to adverse effects on the foetus and cause headache, dizziness and stomach problems.
  5. Effects on physical health and psychological problems — Damage to the inner ear may result if continuous noise levels exceed about 100 dB and can lead to physical illness. Noise can also cause tension resulting in problems like speech interference, annoyance, fatigue,sleep interference and emotional distress.

Question 1(b)

How does air pollution affect human beings?

Answer

The short term effects are-

  1. irritation in the eyes, nose and throat
  2. respiratory infections like bronchitis, pneumonia
  3. headaches, nausea, vomiting, dizziness, convulsions and allergic reactions

The long term effects are-

  1. Chronic respiratory diseases
  2. Lung cancer
  3. Cardiovascular diseases and coma
  4. Damage to the nerves, brain, liver, kidney etc.

Question 1(c)

Explain how the accumulation of nutrients and chemicals in the water prove fatal for the marine organisms.

Answer

The accumulation of nutrients and chemicals in the water proves fatal for the marine organisms as the nutrient accumulation results in phenomenal growth of phytoplankton and algae, thereby reducing the penetration of oxygen, light and heat into the water body. As a result, most of the organisms die, draining water of all its oxygen.

Question 1(d)

With the help of a well labelled diagram explain how the accumulation of toxic substances increases as we move up the food chain.

Answer

Below diagram shows the increase in accumulation of toxic substances as we move up the food chain:

With the help of a well labelled diagram explain how the accumulation of toxic substances increases as we move up the food chain. Effects of Pollution, Total Geography Solutions ICSE Class 9.

Biomagnification means increasing the concentration of various toxic substances along the food chain. Toxic substances at the level of primary producers get concentrated at each trophic level as they move up the food chain. The phenomenon of concentrated toxic deposition at the higher trophic level is known as bioaccumulation.

For example, if there are traces of toxic chemicals in water, then their concentration in algae will be much higher. When fish eat the algae, the concentration of toxins will increase further. Therefore, accumulation of a small amount of toxic chemicals in water can have a serious impact on the fish that live in it.

Question 2(a)

State any two effects each of soil pollution on human beings and environment.

Answer

Effects of soil pollution on human beings are -

  1. Soil contains many pathogenic bacteria, viruses and intestinal worms which are transmitted to man by the consumption of fruits and vegetables. These pathogens cause various types of diseases.
  2. Radioactive fallout on vegetation is the source of radioisotopes which enter the food chain through the grazing animals. Some of these radioisotopes cause abnormalities.

Effects of soil pollution on environment are-

  1. Nitrogenous fertilisers produce toxic concentration of nitrate and nitrite in the leaves.
  2. Land and soil pollution is responsible for loss of fertility and productivity of soil.

Question 2(b)

Name three common air pollutants and their effects on human health.

Answer

Air PollutantsTheir effects on human health
Carbon monoxideIt damages lungs, weakens bones, reduces the oxygen carrying capacity of blood and damages heart.
Sulphur dioxideIt obstructs breathing, causes irritation of eyes and throat.
Suspended particulate matterIt causes asthma, irritation of eyes and cancer.

Question 2(c)

What are pathogens? How do they enter human body? Name any three diseases caused by these pathogens.

Answer

Pathogens are disease causing organisms like bacteria, viruses and protozoa.

Most of the waste waters especially sewage contain pathogens like bacteria, viruses and protozoa. These pathogens enter the human body from contaminated drinking water and are responsible for several waterborne diseases like cholera, typhoid, diarrhoea, dysentery etc.

Question 2(d)

State with examples the effects of radiations on the human beings and environment.

Answer

Example of radioactive accident

There was a radioactive accident in 1986 in Chernobyl in the Ukraine. On 26th April, 1986, a reactor at the nuclear power complex at Chernobyl exploded.

There was a massive steam explosion. The core of the reactor combined with water to produce hydrogen which exploded blowing toxic radioactive gases into the air. There were numerous fires. The Chernobyl accident is considered as the most disastrous nuclear power plant accident, both in terms of cost and casualties.

Due to the accident, 237 people suffered from acute radiation sickness, of whom 31 died within the first three months. After the disaster, four square kilometers of pine forest near the reactor turned reddish brown and died, earning the name of the 'Red Forest'. Some animals in the worst hit areas died or stopped reproducing.

Effects of radiations on human health

Radiations affect living organisms. They cause harmful changes in the body cells and at genetic level. Some impacts of radiations on human body are-

  1. Genetic variations — The damage caused by radiations is often seen in the offsprings and may be transmitted to many generations.
  2. Somatic variations — Short term exposures to radiation can cause damage to organs of the body. The harm done by them includes breast cancer, thyroid cancer, lung cancer and brain cancer, sterility and defective eyesight.

Effects of radiations on the environment

Radiations emitting from radioactive materials and the disposal of radioactive wastes cause pollution and damage the environment.

The high level products of nuclear wastes remain in the environment for several hundred years. Other radioactive threats to the environment are the accidents connected with the activities of nuclear reactors, nuclear powered vessels and satellites etc.

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