Pollution Questions in English

(B) The $CPCB$ stands for Central Pollution Control Board.
It is a statutory organization under the Ministry of Environment,Forest and Climate Change,Government of India.
It was constituted in $1974$ under the Water (Prevention and Control of Pollution) Act,$1974$.

(B) Particulate matter in smoke chimneys is removed using an $Electrostatic \text{ } Precipitator$ $(ESP)$.
An $ESP$ works by charging the dust particles electrically and then collecting them on grounded collection plates.
It is highly efficient and can remove over $99\%$ of the particulate matter present in the exhaust from thermal power plants.

(C) The most widely used method for removing particulate matter from industrial exhaust is the Electrostatic Precipitator. It works by charging the dust particles electrically and then collecting them on grounded plates. This process can remove over $99\%$ of the particulate matter present in the exhaust from a thermal power plant.

(A) Catalytic converters are used in automobiles to reduce the emission of poisonous gases.
They contain expensive metals like platinum,palladium,and rhodium as catalysts.
When exhaust gases pass through the catalytic converter,unburnt hydrocarbons are converted into $CO_2$ and $H_2O$,while carbon monoxide $(CO)$ and nitric oxide $(NO)$ are changed to $CO_2$ and $N_2$ gas,respectively.

(B) Catalytic converters are used in automobiles to reduce the emission of poisonous gases. They contain expensive metals acting as catalysts,which include $Platinum$,$Palladium$,and $Rhodium$. These metals facilitate the conversion of unburnt hydrocarbons into $CO_2$ and $H_2O$,and carbon monoxide $(CO)$ and nitric oxide $(NO)$ into $CO_2$ and $N_2$ gas,respectively. $Copper$ is not used as a catalyst in these converters. Therefore,the correct option is $B$.

(D) Catalytic converters are fitted into automobiles for reducing emission of poisonous gases.
They have expensive metals like platinum-palladium and rhodium as catalysts.
As the exhaust passes through the catalytic converter,unburnt hydrocarbons are converted into $CO_2$ and $H_2O$,while carbon monoxide is converted into $CO_2$ and nitric oxide is changed to nitrogen gas $(N_2)$.

(B) Catalytic converters are fitted into automobiles for reducing emission of poisonous gases.
They contain expensive metals like platinum,palladium,and rhodium as catalysts.
As the exhaust passes through the catalytic converter,unburnt hydrocarbons are converted into $CO_2$ and $H_2O$,while carbon monoxide $(CO)$ and nitric oxide $(NO)$ are changed to carbon dioxide $(CO_2)$ and nitrogen gas $(N_2)$ respectively.
Therefore,the correct conversion is $CO$ and $NO$ $\rightarrow$ $CO_2$ and $N_2$.

(B) The term $dB$ is an abbreviation for $Decibel$.
It is a logarithmic unit used to express the ratio of two values of a physical quantity,often power or intensity.
In acoustics,it is used to measure the intensity or loudness of sound.

(C) The Air (Prevention and Control of Pollution) Act was enacted in $1981$.
In $1987$,this Act was amended to include noise as an air pollutant.
Therefore,$i = 1987$ and $ii = \text{noise}$.

(A) According to the $NCERT$ textbook,noise pollution is defined as undesired high levels of sound.
Sound levels above $150 \, dB$ or more generated by a jet plane take-off or rocket launch can damage eardrums or permanently impair human hearing ability.
Therefore,the correct option is $A$.

(D) Noise pollution is defined as undesired high levels of sound. It can cause various psychological and physiological problems in humans.
$1$. It leads to psychological stress,which can manifest as $Depression$ and $Insomnia$ (sleeplessness).
$2$. It causes physiological changes such as increased heart rate,altered breathing patterns,and considerable stress.
$3$. $Allergies$ are immune system responses to foreign substances (allergens) and are not caused by noise pollution.
Therefore,the correct option is $D$.

(B) Noise is defined as an undesirable high intensity sound. It is a form of environmental pollution that can cause physical and psychological stress to humans and other organisms. High intensity sounds,often measured in decibels $(dB)$,are considered noise pollution when they become annoying or harmful to health.

(D) The sound level produced by a jet plane during takeoff is approximately $150 \, dB$ or more.
This level of noise is extremely harmful to human hearing and can cause permanent damage to the eardrums.
In contrast,other vehicles like two-wheelers,three-wheelers,and buses produce significantly lower noise levels compared to a jet plane.

(C) $PPM$ stands for $\text{Parts Per Million}$. It is a unit of concentration used to express the amount of a substance in a mixture,specifically representing one part of a solute per one million parts of the total solution or mixture. In environmental science,it is commonly used to measure the concentration of pollutants in air or water.

(D) Adulteration is the act of adding inferior or cheaper substances to a product to increase its volume or profit.
$Pb$ (Lead) was historically added to petrol as an anti-knock agent.
Sulfur is a natural impurity in crude oil that is often not removed completely.
Ethanol is intentionally blended with petrol (gasohol) as a biofuel.
$LPG$ (Liquefied Petroleum Gas) is a gaseous fuel stored under high pressure and cannot be mixed into liquid petrol or diesel in a standard fuel tank,as it would immediately escape as a gas. Therefore,$LPG$ cannot be used as an adulterant for liquid fuels.

(C) According to the Euro-$III$ emission norms,the sulfur content in diesel was controlled to $350$ $ppm$.
These norms were implemented to reduce the emission of harmful pollutants from vehicles.
Further,Euro-$IV$ norms reduced this limit to $50$ $ppm$ for both petrol and diesel.

(C) The Bharat Stage emission standards were introduced by the Government of India to regulate the output of air pollutants from internal combustion engine equipment,including motor vehicles.
These standards are based on European regulations.
Specifically,the Bharat Stage $II$ $(BS-II)$ emission norms are equivalent to the Euro $II$ norms.
Therefore,the correct option is $C$.

(A) Domestic sewage primarily consists of organic waste,which is biodegradable.
These organic materials are broken down by microorganisms present in the water,which leads to the consumption of dissolved oxygen,causing a high Biological Oxygen Demand $(BOD)$.
Therefore,the correct answer is $A$ (Biodegradable).

(B) The presence of excessive nutrients (such as nitrogen and phosphorus) in water bodies leads to a phenomenon known as $Eutrophication$.
These nutrients stimulate the rapid and excessive growth of planktonic algae, which is commonly referred to as an $Algal \text{ } bloom$.
This excessive growth imparts a distinct color to the water bodies and causes deterioration of water quality and fish mortality.

(C) The Euro $III$ emission norms were implemented to reduce air pollution from vehicles.
According to these norms,the sulfur content in petrol was controlled to $350 \, ppm$ and in diesel to $350 \, ppm$.
Furthermore,the aromatic content in fuel was also restricted to $42\%$ of the concerned fuel.

(C) Eutrophication is the natural aging of a lake by nutrient enrichment of its water. In a eutrophic water body,the excessive growth of planktonic algae (algal bloom) occurs due to the presence of excess nutrients like nitrogen and phosphorus. This algal bloom imparts a distinct color to the water bodies. These blooms cause deterioration of water quality and fish mortality. Therefore,the excessive growth of $X$ (algal bloom) leads to the death of $Y$ (fishes).

(D) Biomagnification refers to the increase in concentration of non-biodegradable toxic substances at successive trophic levels in a food chain.
Mercury $(Hg)$ and $DDT$ are classic examples of substances that undergo biomagnification.
Biodegradable substances are broken down by microorganisms and do not accumulate.
Bacteria are decomposers,and ammonia is a metabolic waste product,neither of which typically causes biomagnification in this context.

(C) The phenomenon where the concentration of non-biodegradable toxic substances (such as $DDT$ or mercury) increases at each successive trophic level in a food chain is called $Biomagnification$ or $Biological \text{ magnification}$.
This occurs because the toxic substance accumulated by an organism cannot be metabolized or excreted, and thus passes on to the next higher trophic level in a higher concentration.

(D) The full form of $DDT$ is $Dichlorodiphenyltrichloroethane$.
$DDT$ is a well-known organochlorine insecticide that was widely used in the past.
It is chemically represented as $1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane$.

(B) Biomagnification refers to the increase in concentration of non-biodegradable pollutants (like $DDT$) at successive trophic levels in a food chain.
According to the $NCERT$ textbook data for aquatic food chains,the concentration of $DDT$ increases from $0.003\, ppm$ in water to $0.04\, ppm$ in zooplankton.
It further increases to $0.5\, ppm$ in small fish,$2\, ppm$ in large fish,and up to $25\, ppm$ in fish-eating birds.
Therefore,the concentration in small fish is $0.5\, ppm$.

(B) $DDT$ (Dichlorodiphenyltrichloroethane) is a persistent organic pollutant. In birds,$DDT$ interferes with the calcium metabolism by inhibiting the enzyme $Ca^{2+}-ATPase$ in the shell gland. This leads to the thinning of eggshells,which often break prematurely during incubation,resulting in a decline in bird populations.

(A) The aging of a lake is a natural process known as $Eutrophication$.
It occurs as a result of the accumulation of nutrients and sediments over time.
As nutrients like nitrogen and phosphorus enter the lake,they promote the growth of aquatic plants and algae.
These organisms eventually die and decompose,leading to the accumulation of organic matter at the bottom.
Over thousands of years,the lake becomes shallower and warmer,eventually transforming into a marsh and finally into land.

(B) The process described is known as $Eutrophication$. When nutrients like nitrogen and phosphorus enter a lake through streams or agricultural runoff, they act as fertilizers for aquatic plants and algae. This leads to an excessive growth of algae, known as an $Algal$ $Bloom$. This process significantly increases the nutrient content and biological productivity of the lake, which is referred to as an increase in the fertility of the lake. Over time, this leads to the accumulation of organic matter and the gradual filling up of the lake, making it shallower, not deeper.

(D) The natural aging of a lake by nutrient enrichment of its water is called eutrophication.
When this process is significantly speeded up by human activities,such as the discharge of effluents from industries and homes,it is known as accelerated eutrophication.
This leads to excessive growth of algae and depletion of dissolved oxygen,which can eventually kill aquatic life.

(D) Biomagnification refers to the increase in concentration of toxic substances at successive trophic levels.
In an aquatic food chain,the concentration of $DDT$ increases as it moves up the trophic levels.
Starting with water at $0.003 \, ppm$,the concentration in zooplankton becomes $0.04 \, ppm$.
It further increases to $0.5 \, ppm$ in small fish.
In large fish,it reaches $2.0 \, ppm$.
Finally,in fish-eating birds,it reaches $25 \, ppm$ due to high metabolic accumulation.
Therefore,the correct sequence is $0.04 \, ppm \rightarrow 0.5 \, ppm \rightarrow 2.0 \, ppm \rightarrow 25 \, ppm$.

(A) The addition of nitrates and phosphates to a lake leads to a phenomenon known as $Eutrophication$.
These nutrients act as fertilizers, which stimulate the excessive growth of algae, often referred to as an $Algal \text{ } bloom$.
This excessive growth covers the water surface, blocking sunlight and depleting dissolved oxygen, which eventually leads to the death of aquatic organisms like fish.

(C) The phenomenon of biomagnification of $DDT$ (Dichlorodiphenyltrichloroethane) leads to its accumulation in the food chain.
In birds,high concentrations of $DDT$ interfere with calcium metabolism.
This interference inhibits the enzyme calcium ATPase,which is essential for the deposition of calcium carbonate in the eggshell.
As a result,the eggshells become thin and break prematurely,leading to a decline in bird populations.

(A) The project at Arcata,California,involved the creation of an integrated wastewater treatment process.
Scientists from Humboldt State University created a series of six connected marshes over $60$ hectares of marshland.
These marshes were seeded with appropriate plants,algae,fungi,and bacteria,which neutralize,absorb,and assimilate the pollutants,including heavy metals.
Therefore,the correct answer is $60$ hectares.

(B) Soil salinity is primarily caused by waterlogging. When fields are over-irrigated without proper drainage,the water table rises. This water brings dissolved salts from the soil surface to the root zone. As the water evaporates,it leaves behind a crust of salt,which makes the soil saline and toxic for plant growth.

(C) An electrostatic precipitator $(ESP)$ is a device used to remove particulate matter (dust,soot,etc.) from the exhaust of industrial plants like thermal power plants.
It works by creating an electric field that charges the dust particles,which are then attracted to and collected by grounded collecting plates.
It is highly efficient and can remove up to $99 \%$ of particulate matter.
However,ESPs are designed to remove particulate matter,not gaseous pollutants like sulfur dioxide $(SO_2)$.
Therefore,the statement that ESPs can remove $SO_2$ completely is false.

(B) $1$. Noise is considered an air pollutant because it travels through the air and causes environmental degradation.
$2$. Exposure to high sound levels is extremely harmful. $A$ sound level of $150 \ dB$ or more (generated by a jet plane take-off or rocket launch) can permanently damage eardrums and cause severe hearing loss.
$3$. Therefore,the statement that $150 \ dB$ is not harmful is false.
$4$. Since statement $C$ is true and statement $B$ is false,the option 'Both $B$ and $C$' is incorrect as a choice for the false statement.

(C) The figure represents an Electrostatic Precipitator,which is used to remove particulate matter from industrial exhaust. In this device,'$X$' represents the discharge corona,which releases electrons. These electrons attach to dust particles,giving them a negative charge. These negatively charged dust particles are then attracted to the collecting plates (represented by '$Y$') which are grounded.

(B) The figure represents an Electrostatic Precipitator $(ESP)$,which is used to remove particulate matter from industrial exhaust.
In this diagram:
- '$X$' represents the corona discharge.
- '$Z$' represents the negatively charged wire,which emits electrons that charge the dust particles.
- '$Y$' represents the collection plate,which is grounded and attracts the charged dust particles.
Therefore,'$Z$' represents the negatively charged wire.

(A) The given figure represents an Electrostatic Precipitator $(ESP)$,which is used to remove particulate matter from industrial exhaust gases.
In this device:
- '$X$' represents the corona discharge.
- '$Z$' represents the discharge corona wires.
- '$Y$' represents the grounded collecting plates,which attract the charged dust particles.
Therefore,'$Y$' represents the grounded collecting plates.

(A) The given figure represents an Electrostatic Precipitator,which is used to remove particulate matter from industrial exhaust gases.
In an Electrostatic Precipitator,the '$X$' points to the collecting plates.
These plates are grounded and attract the charged dust particles,allowing clean air to pass through.

(C) According to the Central Pollution Control Board $(CPCB)$,particulate matter with a diameter of $2.5$ micrometers or less (known as $PM_{2.5}$) is responsible for causing the greatest harm to human health.
These fine particles can be inhaled deep into the lungs and can cause respiratory problems,inflammation,and damage to the lungs,and they can even enter the bloodstream.

(C) Biomagnification is a phenomenon through which certain pollutants get accumulated in tissues in increasing concentrations at successive trophic levels along the food chain.
Many pesticides,such as $DDT$,have a long life.
Thus,they get incorporated into the food chain and get magnified at higher trophic levels.

(B) Eutrophication is the process of nutrient enrichment in water bodies,primarily due to the influx of inorganic nutrients like phosphorus and nitrogen from fertilizers or sewage.
These nutrients promote the excessive growth of algae and aquatic plants,a phenomenon known as algal bloom.
As these algae die,their organic matter is decomposed by microorganisms,a process that consumes large amounts of dissolved oxygen.
This depletion of oxygen leads to the death of aquatic animals and fish.
Over time,the accumulation of organic matter and the reduction of water quality result in the aging of the lake or pond,which is termed as eutrophication.

(D) Lead $(Pb)$,Cobalt $(Co)$,and Uranium $(U)$ are heavy metals that are toxic to living organisms. Lead exposure can cause neurological damage,Cobalt can cause respiratory and cardiac issues,and Uranium is radioactive and chemically toxic. Therefore,all of these metals cause harmful effects.

(D) Bronchitis is a respiratory condition that is significantly aggravated by air pollution.
It involves the chronic swelling and inflammation of the bronchi,which are the airways leading to the lungs.
Symptoms include a persistent cough,the production of thick mucus,and the expulsion of pus cells.

(B) Arsenic compounds are known to cause the degradation of $RBCs$ (red blood cells) by inducing oxidative stress and damaging the cell membrane,which leads to hemolysis.
Sulphur oxides,while harmful to the respiratory system,are not the primary cause of $RBC$ degradation compared to arsenic compounds.

(D) Noise is defined as unwanted sound that is released into the atmosphere,causing disturbance to the ear.
Sound intensity of $100 \; dB$ is generally considered uncomfortable for the human ear.
Exposure to sound levels exceeding $120 \; dB$ can cause immediate and permanent damage to the hearing mechanism.

(C) Water hyacinth $(Eichhornia \text{ } crassipes)$ is one of the most invasive weeds,which spreads very rapidly in stagnant water bodies.
It consumes a large amount of oxygen from the water,which leads to a decrease in the level of dissolved oxygen $(DO)$ in the water.
As a result,it causes the death of fishes and other aquatic organisms.
Therefore,Assertion $A$ is correct,but Reason $R$ is incorrect.

(D) Biochemical Oxygen Demand $(BOD)$ refers to the amount of oxygen that would be consumed if all the organic matter in one liter of water were oxidized by bacteria.
It is a measure of the amount of biodegradable organic matter present in the water.
Therefore,$BOD$ is estimated by measuring the rate of oxygen consumption by microorganisms during the decomposition of organic matter.

(A) $DDT$ (Dichlorodiphenyltrichloroethane) is an organochlorine pesticide.
Nowadays,$DDT$ is banned in most countries because it is highly persistent in the environment and has a high affinity for the fatty tissues of animals.
This leads to biomagnification,where the concentration of the chemical increases at higher trophic levels.
Additionally,the repeated use of such pesticides leads to the development of resistant populations of pests through accelerated evolution.