CLASS X BIOLOGY POLLUTION Q1. Define pollution. The addition of constituents into air, water or land which deteriorates the natural quality of that environment and adversely affects the organisms living in it is called pollution. Q2. Define pollutant. A pollutant is that substance which when added to an environment causes pollution. Q3. Name the five major types of pollution. The five major types of pollution are:- 1. Air pollution 2. Water pollution 3. Soil pollution 4. Radiation 5. Noise AIR POLLUTION Q4. Define air pollution. The addition of harmful gases such as nitrogen di oxide, sulphur di oxide etc to the air, such that the quality of the atmospheric air deteriorates, which in turn affects the living organisms is called air pollution. Q5. Name and differentiate the two types of air pollution. The two types of air pollution are 1. Gaseous pollution 2. Particulate pollution Gaseous pollution: is that type of air pollution caused as a result of harmful gases such as sulphur di oxide, carbon monoxide being emitted into the atmospheric air from different sources. Particulate pollution: is air pollution caused due to the addition of minute particles into the atmospheric air as a result of vehicular combustion, mining, drilling etc. Q6. Name the different sources of air pollution. The different sources of air pollution are:- 1. Vehicles/automobiles: smoke emitted from vehicles produce particles of soot and hydrocarbons as well as harmful gases such as carbon monoxide, carbon di oxide, sulphur di oxide etc. Speeding vehicles also raise dust particles. Friction caused due to the rubber tyres against road surface releases fine rubber particles into the air. 1
2. Industries: emit large amounts of soot, hydrogen sulphide gas and oxides of nitrogen along with carbon monoxide and carbon di oxide. 3. Garbage: burning garbage emits hydrogen sulphide gas. 4. Mining and stone drilling: produce fine particulate matter which poses health hazards to labourers who are constantly exposed to it. 5. Brick kilns: produce large quantities of particulate matter such as fly ash and fine brick dust. Q7. State the effects of Air pollution. The effects of air pollution are:- Causes respiratory disorders like asthma, bronchitis and certain allergies. Particulate lead emitted from automobiles can cause brain damage and reduction in blood cells. Smog (smoke+ fog) formation during winters causes poor visibility which often leads to road accidents. Smog formation also prevents aircrafts from flying which cause endless problems to passengers. Presence of Hydrogen sulphide gas in the atmosphere causes headaches and nausea. Exhaust gases such as sulphur di oxide also cause respiratory disorders. Q8. Name four ways to control vehicular air pollution. Four ways of controlling vehicular air pollution is by using- Efficient engines for automobiles Good quality automobile fuels Lead free petrol Greater use of CNG (compressed natural gas) Q9. Name two small scale industries and two large scale industries that is a source of particulate air pollution. 2 small scale industries are: Pottery and carpet weaving 2 large scale industries are: Pharmaceutical industries and oil refineries. WATER POLLUTION Q10. Define water pollution. Changes caused in the quality of water due to the presence of harmful substances which make it unfit for use by humans and other living organisms. Q11. Name the major sources of water pollution. The major sources of water pollution are: Sewage and household/domestic wastes Industrial wastes Oil spills Thermal pollution 2
Q12. What is sewage? How does it cause water pollution? Sewage is the liquid wastes produced in households due to various activities. It consists of detergents used for cleaning dishes and clothes as well as waste water used in bathrooms and toilets. Very often sewage, if not treated properly in sewage treatment plants, fails to remove the toxic matter. This when released into nearby water bodies reduces the quality of the water there. Q13. What are oil spills? State their harmful effects. Oil spills are accidental discharge of petroleum in oceans and estuaries. These cause large scale damage to marine life as well as to birds which depend on the marine animals for their food. In fact, the entire eco system in the marine water body is destroyed. Q14. Name the sources of oil spills? Offshore oil drills Oil refineries Damaged oil tankers Q15. What do you understand by Thermal Pollution? Many industries such as thermal power plants and nuclear power plants require large amounts of water to cool their machinery. While cooling the machinery the temperature of the water is raised by 8-10 0 C. This hot, waste water is then released into nearby streams, rivers and sea. This results in the heating up the water body. This resultant increase in the temperature of the water body adversely affects the aquatic life both plants and animals living in it. Q16. State the effects of water pollution. Pollution of drinking water can cause diseases like typhoid, dysentery, cholera and jaundice. Oil spills in seas and oceans cause death of sea birds and all aquatic animals and plants. Hot water discharged into water bodies cause thermal pollution. This results in the destruction of aquatic eco systems. SOIL POLLUTION Q17. What is soil pollution? Addition of chemical substances to the soil which deteriorate its natural quality and destroy the plants growing in it as well as organisms living in it is called soil pollution. Q18. Name the major sources of soil pollution. Industrial wastes Urban commercial and domestic wastes Chemical fertilisers Bio medical wastes Pesticides Q19. Name some pollutants released by the industries that cause soil pollution. 3
Industries release solid wastes such as fly ash, metallic ash and various chemical residues. Q20. Name the different types of domestic and commercial wastes which cause soil pollution. Domestic wastes- a lot of waste is generated in our homes in the form of plastic bags, glass bottles, electric bulbs, kitchen wastes, peels of vegetables, waste food and now e-waste. Commercial wastes- lots of rotten fruits, vegetables and paper collect in markets left over and waste food from restaurants and banquet halls. Q21. What is a landfill? Sanitary landfills are places far away from the city where the domestic and commercial wastes are dumped in large depressions in the ground. Q22. Define noise. Any disturbing sound is defined as Noise. Q23. Name the major sources of noise pollution. The major sources of noise pollution are:- Machinery in industries and workshops Constant movement of trains Honking of horns of automobiles Jet aircrafts- esp. when landing and taking off Increased volume of music playing through loud speakers in the neighbourhood. TV s and music at high volume in homes. Q24. List out the harmful effects of noise pollution. It interrupts concentration of thought and disturbs one s peace of mind It disturbs sleep and leads to irritability. Can cause hypertension. Exposure to prolonged noise can cause deafness. The loud noise caused by landing or taking off of aircrafts around airports disturbs bird life in that area. Q25. What are the measures taken to minimise noise pollution? Restriction of music playing on loud speakers, esp. at night time. Unnecessary blowing of horns esp. near hospitals and educational institution. Planting trees by the roadside minimizes the sound produced by speeding vehicles. Reducing burning of noisy firecrackers during festivals. Q26. What is the tolerable level of sound? A noise above 80 decibel causes noise pollution. 4
RADIATION Q27. What does the term radiation mean? Radiation is a form of energy consisting of high energy particles. It is used extensively in the medical field and in generating electricity in nuclear power plants. Q28. Name the two sources of radiation. The two sources of radiation are: X - rays Leakage of radioactive particles from nuclear plants. Q29. How can X-rays cause harm? X-rays contain units of energy called photons. Too much exposure to X-rays may result in gene and chromosome mutations and certain forms of cancer. Q30. Name one chief radiation pollutant and state its effect. Iodine 131 is one chief radiation pollutant. This raises the risk of thyroid cancer. This is also responsible for Minamata disease reported in Japan. Q31. Powerful nuclear explosions occurred in 2 cities some time ago. Name them. CHERNOBYL in Ukraine. FUKUSHIMA DAIICHI in Japan. Q32. List out the harmful effects of exposure to radiation. Exposure to radiation can cause the following: Cancers Haemorrhaging Genetic mutations Destruction of ecosystems. Q33. Name a radioactive waste. Cobalt 60 is a radioactive waste. EFFECTS OF POLLUTION ON CLIMATE AND ENVIRONMENT Q34. State three ways by which pollution affects the climate and environment. The three ways are: Acid rain Greenhouse effect and global warming Ozone layer depletion Q35. How is acid rain formed? As a result of air pollution, there is an increased presence of carbon di oxide, sulphur di oxide and oxides of nitrogen in the atmosphere. These gases get dissolved in the rain drops, to form nitric acid and sulphuric acid. This increases the ph of the rain forming acid rain. 5
Q35. List out the harmful effects of acid rain. Increased ph level of the soil, destroys its natural quality and this prevents plant growth and destroys vegetation. It increases the acidity of water in the water bodies, thus harming aquatic life. The acid present in the rain water, reacts with calcium, an important constituent of monuments and statues and corrodes them. It causes fast decay of buildings due to the corrosion of paints and building materials. Q36. What does the term greenhouse effect mean? Burning of fossil fuels produces carbon di oxide gas which is used by plants for photosynthesis. Due to the pollution of the air, there is an accumulation of carbon di oxide near the earth s surface. This traps the heat radiated from the earth, similar to a greenhouse. This results in the warming up of the earth. Q37. State the causes of global warming? Increased industrialisation and burning of fossil fuels by vehicles releases more carbon di oxide into the atmosphere. Deforestation and decreased vegetation is leading to less carbon di oxide utilisation for photosynthesis. An overall rise in carbon di oxide and methane gas is leading to greater retention of the solar radiation in the atmosphere. Q38. What are the effects of global warming? The effects of global warming are: The temperature of the earth s atmosphere has increased by about 0.5 0 C. Causes the melting of ice at the poles and glaciers on the mountains Rising of sea levels would result in the sinking of islands and coastal cities. Overall change in the climatic conditions Decline in food production and marine resources. Q39. What is the ozone layer? How is it useful? A layer of ozone gas surrounds our atmosphere (stratosphere) acting like a sunscreen. This is referred to as the ozone layer. This prevents the harmful ultra violet rays of the sun (UV-B) from reaching the earth s surface. Q40. What is the main cause for the depletion of the ozone layer? Certain gaseous compounds like CFC s (chlorofluorocarbons) released from refrigerators, aerosol sprayers and packing material Styrofoam, rise into the atmosphere. There they break down into chlorine atoms, which in turn break down ozone into oxygen (O 2 ) and nascent oxygen (O). This results in the slow destruction of the ozone layer. Q41. State the effects of the depletion of the ozone layer. The holes in the ozone layer allow the entry of the harmful UV rays of the sun into the earth s atmosphere. The UV-B rays cause sunburn, skin cancer and genetic disorders. It also causes a reduction in the resources from forests and oceans. 6
Q42. Which day in the calendar is called as the International ozone day? September 6 th is called the International ozone day. Q43. Name the Vehicular standard adopted by the Government of India. The vehicular standard adopted by the Government of India is called the EuroIII/BharatIII norms. This is applicable to automobiles, on the levels of emissions given out by it. Q44. What is the advantage of the auto fuel policy which the government of India has adopted? This auto fuel policy ensures that the gaseous pollutants like sulphur and oxides of nitrogen are cut down in the automobile exhausts, thus bringing about a reduction in the air pollution. Q45. State some measures which are taken to reduce pollution. Recycling of plastic, metal and glass material. Burning of non-recyclable waste. Planting of trees along roadside, waste land and mountainous slopes to reduce soil erosion. More trees give more fresh air to breathe. Food wastes and all litter to be put in bins provided and not in open spaces and drains Installation of tall chimneys in factories and fitting them with filters and electrostatic precipitators. Treating industrial effluents before discharging them into water bodies. Greater use of compost instead of chemical fertilisers. Use of unleaded petrol and CNG (compresses natural gas) in automobiles. Q46. Define the following terms: a) Bio magnification b) Eutrophication a) Bio magnification: Are the high concentrations of toxic substances like DDT at various levels of the food chain. b) Eutrophication: is the loss of aquatic life due to the increased growth of algae brought about by the continuous discharge of sewage into static water bodies. The algae consume all the oxygen leaving very little for the aquatic plants and animals living in it. 7