31 Years NEET Previous Year Questions: Environmental Issues - 3 (Old NCERT) - Bank Exams MCQ

E. coli lives in the human intestine. If they are present in water it indicates that the water is polluted. E.coli coliform count test is done.

The affinity of the carbon monoxide towards haemoglobin is more compared to the affinity towards oxygen. The increase in the concentration of carbon monoxide in the atmosphere which results in the binding of carbon monoxide with haemoglobin, forming carboxyhemoglobin. There are very less sites for oxygen binding and transport of the oxygen is reduced in the body which is known as carbon monoxide poisoning.

Faecal pollution is indicated by Escherichia coli. MPN is the most probable number of E. coli in a water sample. It is an indicator of water pollution.

Some of the impor tant g reen house gases are CO₂, CFCs, Nitrous oxide, Ozone, Methane etc. Nitrous oxide is produced by denitrifying bacteria acting on artificial fertilisers applied to poorly aerated soil. 

DDT causes egg shell thinning in birds because it inhibits Calcium ATPase.

Silicosis is caused by exposure to dust containing silica.

Biological magnification is the increase in concentration of persistent pollutant per unit weight of the organism with the rise in trophic level.

Lichens are sensitive to sulphur dioxide pollution, hence they serve as bioindicators of pollution.

Green house effect is the rise in atmospheric temperature due  to increase in concentration of green house gases.
The greenhouse effect, discovered by Joseph Fourier in 1824 and first investigated quantitatively by Svante Arrhenius in 1896, is the process in which the emission of infrared radiation by an atmosphere warms a planet’s surface. In the case of the Earth, without these greenhouse gases its surface would be up to 30°C cooler. The name comes from an incorrect analogy with the way in which greenhouses are heated by the sun in order to facilitate plant growth. In addition to the Earth, Mars and especially Venus have greenhouse effects. The maximum green house gases are emitted by USA.

Organisms found in the higher trophic level show greater accumulation of pesticides due to the phenomenon of biomagnification - which is defined as the gradual increase in concentration of harmful pesticides in the food chain, with increase in trophic level.

Primary pollutant is that which persists in the form in which it is released in the environment eg. CO. A secondary pollutant is one which is formed from another pollutant due to change or reaction eg. PAN (Peroxy acytyl nitrate).

DDT cannot be broken down or converted to harmless state by natural processes of oxidation or biological decomposition. Hence it is non biodegradable.

Stoneflies are exopterygote insects with aquatic nymphs; long antennae, biting mouthparts and a weak flight. Adults have the tendency to feed on lichens and unicellular algae. These are good pollution indicators. Stonefly (Plecoptera order) larva requires well-aerated, non-polluted water. It is absent in polluted water.

So, the correct answer is 'Larva of stonefly'.

E. coli grows in water polluted by sewage and domestic waste.

Methane forms a major part of gobar-gas. Ammonia is toxic. Ethane and butane are not  major components of gobar gas.

In Bhopal gas tragedy methyl isocyanate (MIC) reacted with water to produce a large amount of heat, as it was an exothermic reaction. Due to this increase in pressure the safety valve of the tank bursted and the gas came out.

Lead, the primary heavy metal pollutant emitted by vehicle exhaust, remains in the atmosphere and settles during rainfall. It enters the human body through ingestion via water or inhalation of suspended particles. When present at a concentration of 30μg/100ml in the bloodstream, it is deemed toxic, potentially leading to conditions such as aplastic anemia, tumors, and cancer. Therefore, the accurate statement is '30μg/100ml.'

Alcohol to the tune of 5% is allowed to be mix in petrol as per the Govt. of India decision.

Salinity causes the problem of prolonged liberal irrigation of agricultural fields. As the soil becomes water logged, vegetation and crops die due to the insufficient supply of oxygen.

Disinfectants are the antimicrobial agents which are mainly used to stop the growth of pathogens on the non-living organism. It may affect the substances on which it is applied. Phenyl is a disinfectant which cannot be used for purification of drinking water because it will kill the pathogens of the bacteria but the quality of the water will  degrade as it is poisonous for the living organisms. It has a pungent odour. All the other options are used as disinfectant because they do not have an adverse effect on the quality of water.

Biochemical Oxygen Demand (BOD) is the amount of oxygen required to destroy the organic waste by the bacteria. The more oxygen required for bacteria that means there is more organic waste. For pure drinking water it is decided less than 1 ppm and for industrial & municipal waste it is less than 10 ppm. In Yamuna water in Delhi it is about 1000 ppm.

Photochemical smog is made by the deposition of dust & carbon particles on the pollutant gases and water vapours. The gases found in photochemical smog are NO₂, PAN, O₃ etc.

Montreal protocol which calls for appropriate action (like less production of ozone depleting substances called ODS such as CFCs) to protect the ozone layer was passed by a forum of 27 industralized countries on 16 September 1987. Till now 175 countries have joined this.

More value of BOD means the water sample is polluted by organic matter. BOD of distillary effluent is 40000 mg/L and that of paper mill effluent and sewage is 190 mg/L and 30 mg/L respectively.

In recent years, the increases in toxic substances of NOx and/or SPM (Suspended Particulate Matter) from vehicles come to be serious problem. About the correlation between the traffic volume in our model and the real volume, we obtained the correlation coefficient of 0.74. Simultaneously, we got the result that the concentration of NOx was approximately 70 to 230 ppm. That of SPM was approximately 40 to 100 µg/m³.