SOURCES OF POLLUTIONS
Q1. Name any three air pollutants and the sources of each of them.
Three air pollutants are-
(a) Carbon Monoxide — It is produced by gasoline fuel, motor vehicles fuel, burning of wood and coal, solid waste disposal and industrial processes.
(b) Nitrogen Oxides — Its primary sources are motor vehicles and power generation stations, combustion of organic matters, furnace stacks and incinerators.
(c) Hydrocarbons — These are produced by motor vehicles, industrial processes, garbage and agricultural waste.
Q2. What are natural sources of air pollution? Name one industry which pollutes the atmosphere with gaseous as well as with particulate matter.
Natural sources of air pollution produce air pollutants as a result of natural phenomena. These include volcanic eruptions, deflation of sand and dust as well as forest, or wild fires of natural vegetation, etc.
Automobile industry pollutes the atmosphere with gaseous as well as with particulate matter (PM).
Q3. What is known as smog? What harm is done by SMOG especially in winter?
SMOG is a combination of smoke and fog.
During the winter months, due to severe cold, the use of coal and fossil fuels to heat homes and for other purposes increases. These lead to the formation of smog. Smog is harmful for health as it causes asthma, bronchitis, shortness of breath, eye and nose irritation, etc. It also reduces visibility and leads to problems in traffic movement.
Q4. Name three gases emitted during burning of garbage.
Answer: Three gases emitted during burning of garbage are: Carbon dioxide, Sulphur dioxide and Nitrogen oxides.
Q5. Mention any two sources of water pollution.
Two sources of water pollution are-
Domestic sources, like phosphates from detergents and fertilisers.
Industrial sources, like heavy metals and synthetic organic compounds (Lead and Manganese)
Q5. Why are radioactive pollutants very dangerous?
Answer: Radioactive pollutants are very dangerous because of the following reasons-
(i) Radioactive wastes from atomic reactors are hazardous to living organisms.
(ii) Even if radioactive wastes are buried underground, they may escape into the surroundings.
(iii) The radioactive wastes emitted during the testing of nuclear weapons makes the surrounding materials radioactive.
(iv) Radioactive materials are carried away to distant places by winds.
(v) They are brought down by rain. Raindrops containing these radioactive particles fall on earth, and affect the soil causing soil pollution.
The radioactive materials in the soil reach water sources, where the aquatic organisms absorb and accumulate them through the food chains and pass them on to human beings.
Q6. In what way does the industrial waste pollute water?
Industries dealing
with chemicals, pulp and paper, food processing, etc. produce waste material such as heavy metals or
synthetic organic compounds. These reach water bodies either through
direct discharge or by leaching from waste dumps. Among the heavy metals,
cadmium, lead, mercury, copper, chromium etc., get into water. The industrial waste mixed with water
makes it poisonous and unhygienic. It may also cause various diseases in
humans and animals, if consumed without treatment. May cause a disease like, Minamata (mercury), itai itai
(Cadmium) and Flurosis (Fluoride).
Q7. What are the domestic sources of water pollution?
Man uses water for drinking, preparation of food, bathing, for cleaning the house, etc. Most of the used water is drained out through municipal drains and poured into a river or lake. Domestic waste water that is mixed with other wastes such as plastic, detergents, animal dung and human faecal material is known as municipal waste.
Many detergents and fertilisers contain phosphates. When phosphates are discharged into waterways, their remnants promote rapid growth of algae. Such enrichment process is known as Eutrophication. Aquatic weeds multiply rapidly in many water bodies. They interfere with fishing, navigation and irrigation.
Q8. What are the sources of radioactive pollution? Describe each of them.
The two main sources of radioactive pollution are-
(1) Natural sources — These sources are cosmic rays with energetic radiations reaching the earth from outer space. Though they are a major hazard in space, they are not dangerous for organisms on earth.
(2) Man made sources — The following sources cause radioactive pollution-
(i) X-rays waste: The use of X-rays is common for detecting skeletal disorders. The X-rays pass through genetic cells and affect the chromosomes, resulting in mutations.
(ii) Radioactive fallout from nuclear plants: In a nuclear power establishment, both fuel elements and coolants are sources of radiation pollution. Radioactive wastes from atomic reactors are hazardous to living organisms. Even if radioactive wastes are buried underground, they may escape into the surroundings.
(iii) Nuclear weapons —Nuclear weapons testing involves the use of radioactive materials like Uranium-235 and Plutonium-239, leading to the emission of radioactive waste. This waste contaminates nearby materials, and wind carries radioactive particles to distant locations. Upon precipitation, raindrops with these particles reach the Earth, causing soil pollution. From the soil, radioactive materials reach water sources, where aquatic organisms absorb and pass them on to humans through the food chain.
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