. List two major harmful effects of each of the following


(i)   Rivers contaminated with sewage.
 
(ii)  Too much gaseous exhausts containing CO2 and SO2.
 
(iii) Pesticides such as DDT used in agriculture.
 
(iv) Prolonged noise such as the one produced by crackers
 

Best Answer

(i) Rivers contaminated with sewage:
 
(a) A number of waterborne diseases are produced by the pathogens present in polluted water, affecting humans as well as animals.
 
(b) The flora and fauna of rivers, sea and oceans is adversely affected.
 
(ii) Too much gaseous exhausts containing CO2 and SO2:
 
(a) The high concentration of CO2 in atmosphere has been the main component of the green house effect that has caused global warming i.e. the rise of atmospheric temperature in recent years. Global warming causes melting of snow caps rise in sea levels.
 
(b) SO2 is poisonous and irritates the respiratory system of animals and humans. A continuous exposure to SO2 has been reported to damage the lungs and increase the rate of mortality.
 
(c) SO2 is also responsible for acid rain
 
(iii) Pesticides such as DDT used in agriculture:
 
(a) Pesticides kill soil microbes which are responsible to recycle the nutrients in the soil.
 
(b) Pesticides can enter the food chain and affect the health of humans as well as animals. It can cause damage to the lungs and central nervous system, failures of reproductive organs and dysfunctions of the immune system, endocrine system, and exocrine system, as well as potential cancer risks and birth defects.
 
(iv) Prolonged noise such as the one produced by crackers :
 
(a) Prolonged exposure to the high decibel noise damages ear drums and can bring permanent hearing impairment.
 
(b) Noise pollution can lead to high blood pressure (hypertension), constant headache, lack of concentration.
 

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