Test: Environmental Issues - 2 (Old NCERT) - JAMB MCQ

Correct Answer :- a

Explanation : Classical smog does not contain any secondary pollutants. It is a mixture of fog, sulfur dioxide and coal smoke particulates

Photochemical smog is composed of primary and secondary pollutants.Primary pollutants, which include nitrogen oxides and volatile organic compounds, are introduced into the atmosphere via vehicular emissions and industrial processes.Secondary pollutants, like ozone, result from the reaction of primary pollutants with ultraviolet light. It is most common in sunny and dry cities, like Los Angeles.

Carbon dioxide is a quantitative pollutant. This gas is already present in environment in small quantity. When its concentration increases in the environmentit is termed as pollutant. It may cause greenhouse effect also.

Electrostatic precipitator is used to remove particulate matters from chimneys of factories. The dust collection efficiency of electrostatic precipitator is affected by the particle siz of the aerosol to be collected so, the collection efficiency is high for large particles and low for the small particles.

Planting trees on both the side of roads and highways is called providing green muffler. It is done to reduce noise pollution to nearby residential areas.

Irreparable computers and other electronic goods are known as e-wastes or electronic wastes. E-wastes are buried in landfills or incinerated.

For removing particulate pollutants from air various methods are applied such as use of activated charcoal and calcium hydroxide that absorbs the particulate matters form polluted air.

Deoxygenation of water bodies means reducing the oxygen from the water. Deoxygenation do not convert eutrophic water body back into oligotrophic. In such waters growth of anaerobic microbes producing secondary pollutants like H₂S.so, the statement i is wrong and ii is correct.

Huge quantity of sewage is dumped in a river, the BOD will increase as sewage contain large amount of organic matter that support large number of aquatic microbes that consume oxygen present in water.

Acid rain is due to air pollution. Burning of fossils fuels release sulphur dioxide and nitrogen oxides that combine with water to form sulphuric acid and nitric acid during rain.

Eutrophication of water body occurs due to addition of detergents, fertilizers and untreated sewage.

Terrestrial life would become impossible with change in atmosphere permitting all solar radiations to reach lithosphere. Solar radiations are essential for food preparation that supports the aquatic life.

Aerosols decrease primary productivity by reducing rate of photosynthesis of autotrophic organisms, which are primary producer of ecosystem of any kind of habitat.

Dichlorodiphenyltrichloroethane (DDT) is chemically an organochlorine that was used an insecticide. It is a stable compound that shows high solubility in the fatty tissues. When it is released in the water via the agricultural field surface run-off, it is ingested by the aquatic organisms like phytoplankton that are main producers in an aquatic food chain. From these, DDT continues rising up the food chain. Because successive consumers at the successive trophic level consume more food, it accumulates at the higher trophic level in greater amounts. This is called biomagnification. Sea/gulls and birds are the top consumers in an aquatic food chain, they will show the highest accumulation.

Hence, the correct answer is 'Sea Gull/Birds'.

Fertilizers added to fresh water increase the nutrients that cause growth of large number of microbes in water that leads to eutrophication.

The concentration of DDT increase with increase in trophic levels. Phytoplankton being producer have minimum concentration of DDT. Human being consume large number of fish so, concentration will be maximum due to biomagnifications.

DDT or dichloro-diphenyl trichloroethane was the first important synthetic pesticide (organo chlorine) discovered in 1939 by a Swiss chemist Paul Muller. It was toxic to wide range of insect pests ("broad spectrum") yet appeared to have low toxicity to mammals. It was persistent and didn’t break down rapidly in the environment, so that it didn’t have to be reapplied often. DDT was so effective at killing pests and thus boosting crop yields and was so inexpensive to make that its use quickly spread over the globe. Farmers used more and more DDT throughout the 1950s and 1960s to get an increased yield of crop,

Bioremediation is a waste management technique that involves the use of organisms to remove or neutralize pollutants. Bioremediation of phenol is carried out using earthworms and bacteria.

Mercury is inert and when swallowed remain non-toxic but becomes severely toxic when inhaled in volatile form. It enters the respiratory system and riches to lungs to cause lung cancer.

Bioremediation method is used to remove oil spill containments in water bodies. In this method large number of bacteria outcompete other organisms for oxygen creating a dead zone.

Global warming due to green house effect melts the glaciers and ice caps that increase the water level of oceans. The countries like Maldives and Bangladesh are in danger of submersion due to increasing ocean water level.

Global warming is caused by green house effect in which temperature of inner atmosphere increases that result into melting of ice caps and glaciers. The melting results into rise in levels of oceans.

Ozone layer in upper atmosphere is being destroyed by chlorofluorocarbon. CFC’s breaks the molecular O₃ into O₂ and O. thus layer of ozone get thinner and not able to prevent UV radiations.

The two main reasons for increase in CO₂ gas are destruction of forest and excessive combustion of fossil fuels. Forests help in decreasing CO₂ gas by photosynthesis process.

Concentration of green house is increasing due to deforestation, increased use of refrigerators and increased combustions of coal and petroleum. Deforestation causes increased level of CO₂ gas, refrigerators releases CFC’s gas and burning of fossil fuels also increases carbon dioxide level in atmosphere.

Deforestation generally decreases rainfall. Plants release water vapour in form of water vapour in the process of transpiration. The water vapour contribute in cloud formation to bring rains.