Environmental Issues

Non-biodegradable pollutants are degraded either very slowly or not degraded at all. These are mainly created by various human activities like excessive use of plastics, industrialization, building of houses, use of leaded petrol in vehicles, etc.

The nature creates biodegradable waste like dry leaves, dead plants and animals, dung, etc.

The excessive use of resources is also done by humans like using excessive amount of petrol but the pollutants like carbon, released by excessive use of resources are biodegradable.

The natural disaster causes destruction of resources, not creation of non-biodegradable pollutants.

The pollutants with diameter 2.5 micrometer or lesser are responsible for causing great harm to human health because these can be inhaled by human respiratory and reach the lungs. This causes respiratory issues and in severe cases, leads to death. The pollutants with diameter greater than that can’t go deep inside the respiratory tract.

Styrofoam is generally used to sound proof rooms like a recording studio and auditorium. It is a special kind of polystyrene which reduces the noises from outside any immediate room or environment. Sounds are simply vibrations which are absorbed by the styrofoam and prevented from entering the recording studio making the studio soundproof.

Full form of CNG is Compressed Natural Gas and natural gas is mainly composed of methane. Methane stored at a high pressure makes CNG which is used as a fuel in vehicles and stoves.

Eichhornia(water hyacinth), also known as the Terror of Bengal, is the most problematic aquatic weed. These grow abundantly in eutrophic water bodies (eutrophic water bodies = water bodies overly enriched with nutrients and minerals). This leads to imbalance in the ecosystem dynamics of the water body.

Biomagnification refers to the accumulation of non-biodegradable toxic materials like mercury and DDT, in different trophic levels. The amount of non-biodegradable toxic materials increases at each successive trophic level of the food chain.

The expanded form of DDT is dichloro diphenyl trichloroethane.

DDT is an insecticide which was extensively used earlier but now is banned due to its harmful effects on the environment because DDT degrades either very slowly or doesn’t degrade at all.

Among cotton, paper, bone and jute, bone takes the longest time for biodegradation because bones are made up of proteins and minerals like phosphorus and calcium, which makes it a hard job for the microorganisms to degrade the bones faster.

Dobson units (DU) are used to measure thickness of ozone. Ozone gas forms a protection layer in our atmosphere, against the harmful UV rays from the sun. Ozone is formed by the following way-

O₂ + O ↔ O₃

When coal is burnt, it releases carbon which when combines with oxygen in the atmosphere, forms carbon dioxide or sometimes carbon monoxide which is a threat to human health. The rest of the things also cause indoor chemical pollution but burning coal has immediate threats.

The green scum seen in the fresh water bodies is blue green algae and green algae. The red algae is found in marine water bodies.

The standard unit to measure noise is decibels (dB).Noise below 80 dB is bearable but prolonged exposure to noise above 80dB turns into noise pollution which is painful and hazardous as it gradually leads to permanent loss of hearing power.

With increasing number of vehicles, the noise created by honking horns of vehicles is also increasing. The rest of the machines are also sources of noise pollutions but the major source of noise pollution in every part of the world is transport system.

A. Environment Protection Act – (iii) 1986

The Environment Protection Act came in force in the year 1986.

B. Air Prevention & Control of Pollution Act – (iv) 1981

Air prevention and control of pollution Act was implemented in 1981.

C. Water Act – (i) 1974

Water Act came into existence in 1974.

D. Amendment of Air Act to include noise as an Air Pollutant - (ii) 1987

Amendment of Air Act to include noise as an air pollutant came into force in 1987.

Catalytic converters are fitted into automobiles to reduce the emissions of harmful and poisonous gases. It has platinum-palladium (Pt-Pd) and rhodium (Rh) as catalysts.

When the exhaust gases passes through the catalytic converters, the unburnt hydrocarbons are oxidised into Carbon dioxide and water, carbon monoxide into carbon dioxide and nitric oxide into Nitrogen gas.

To reduce the emission of sulphur dioxide in exhaust fumes, it is necessary to remove sulphur from petroleum products. Sulphur dioxide is extremely dangerous for our lungs and also it can cause irritation in eyes.

The types of impurities found in waste water are :-

• Suspended impurities

• Colloidal impurities

• Dissolved impurities

• Microorganisms

Out of these only suspended impurities can be removed most easily as they are solid and solids can be extracted from liquid more easily then colloidal and dissolved impurities.

Hepatitis – B is not caused by contaminated water. The rest of the diseases i.e. Jaundice, Cholera and Typhoid mentioned are caused by contaminated water. Causative agents of these diseases are :

a. Hepatitis-B – Hepatitis-B virus

b. Jaundice – Seriola quinqueradiata

c. Cholera – Vibro cholerae

d. Typhoid – Salmonella Typhi

Sewage and untreated water from homes and industries contain these pathogens and when thrown into water bodies, harmful diseases breakout.

Nuisance growth of aquatic plants and bloom-forming algae in natural waters is generally due to high concentrations of phosphorus. Phosphorus increases the fertility of water body which encourages the nuisance growth of aquatic plants and bloom-forming algae. This is called Eutrophication i.e. natural aging of water body by nutrient enrichment of its water.

Different pigments are responsible for different colours in algal blooms. Brown algae gets its colour from the xanthophylls pigment fucoxanthin, red algae get their colour from phycoerythrin, green is from chlorophyll.

A. UV – (iii) Snow blindness

Over exposure to UV rays causes Snow blindness (painful and temporary loss of vision)

B. Biological Organic Matter – (iv) BOD

When Biological organic matter such as dead plants, leaves and other biodegradable waste, is acted upon by microorganisms to decompose then these microorganisms consume oxygen to support the process of decomposition which leads to increased Biological Oxygen Demand (BOD).

C. DDT – (i) Biomagnification

The concentration of DDT increases at successive trophic levels because a toxin like DDT can’t be metabolised by the organisms. This process is called Biomagnification.

D. Phosphates – (ii) Eutrophication

Increased amount of phosphates in a water body increase its fertility which causes excessive growth of aquatic plants and algae in the water body. This process is called Eutrophication.

The Bhopal gas tragedy was associated with Methyl Isocyanate (MIC). MIC is a colourless, odourless and poisonous gas. The gas was leaked from the insecticide unit of the Union Carbide at Bhopal which caused the death of two-three thousand people overnight in Bhopal.

Vehicles are fitted with catalytic converters which use expensive heavy metals, like platinum-palladium and rhodium, as catalysts. These catalytic converters help in reduction of emission of poisonous gases and conversion of unburnt hydrocarbons into carbon dioxide and water.

If leaded petrol is used in such vehicles then the lead in the petrol inactivates the catalysts and causes the emission of unburnt hydrocarbons into the atmosphere which will result into air pollution.

In India, the Air (Prevention and Control of Pollution) Act came into force in 1981.But in year 1987, it was amended to include Noise as an air pollutant.

Noise is undesired high level of sound. Exposure to noise for long time causes sleeplessness, increased heart beat, altered breathing pattern, thus considerably stressing humans.

In Delhi, the entire public transport runs on CNG. By the end of year 2002, all the buses in Delhi were converted to run on CNG. This was done because CNG is better than diesel and petrol as it burns most efficiently and in the automobiles, very little of CNG is left unburnt. Also, CNG is cheaper than petrol and diesel, can’t be siphoned off (drawn out) by the thieves and can’t be adulterated.

The water supply drawn to the overhead water tanks is mainly drawn from the sources like river, deep borewell, etc. The water from these sources carries sand particles along. These sand particles are the source of the silt that gets deposited in the water tanks.

Eutrophication is the natural aging of a lake by nutrient enrichment of its water. As lake’s fertility increases, plant and animal life increases, and organic remains begin to deposit at the bottom of the lake. Depending upon the climate, size of the lake and other factors, the natural aging of a lake may span thousands of years. But, pollutants from human’s activities like effluents from the industries and homes can radically accelerate the aging process. This process is known as Cultural Eutrophication or Accelerated Eutrophication.

Particulate matter means the solid and liquid particles suspended in air. There are many adverse effects of particulate matter on human health such as:

i) Breathing and respiratory issues

ii) Irritation

iii) Inflammation

iv) Damage to lungs

v) Premature death

The raw material for polyblend is Polythene. Polyblends are the natural man-made fibres which are made by the mixture of two or more polymers.

Blends of polyblend and bitumen, when used, help to increase road life by a factor of three because:

i) In India, the weather is mainly hot and extremely humid and plastic increases the melting point of bitumen and prevent it from melting.

ii) Rainwater is prevented from seeping in through the roads due the presence of plastic.

Wind breakers are used to prevent soil erosion by wind. They do it by reducing the speed of wind. They are also called shelter belts. Examples of such plants are Jamun, Imli, Neem, Babul, etc.

The fertilizer industry can cause both air and thermal pollution and as well as eutrophication because:

i) The exhaust from the fertilizer industry consists of gases such as Carbon monoxide, carbon dioxide, sulphur oxides and particulate matter. This causes air pollution.

ii) The effluents released into water bodies from the fertilizer industries causes the degradation of water quality by changing the temperature of water. This causes thermal pollution.

iii) These effluents contain nutrients like Nitrogen, Potassium, phosphorus, etc. enhances nutrient richness of the water body which causes excessive growth of algae. This causes Eutrophication.

The excessive growth of free-floating algae caused by nutrient enrichment of water bodies through various means is called algal bloom. The nutrients act as food for algae hence support the growth of algae. Due to the algal bloom, the water body is green in colour.

The increase of concentration of toxic substances at successive trophic levels in the food chain is known as Biomagnification. The toxic substances can’t be metabolized in an organism. When this organism is eaten by the organism in the higher trophic level, the toxins too are passed on.

The domestic waste water contains 3 major kinds of impurities-

(i) Dissolved material, like nutrients (nitrates, phosphates, sodium, calcium)

(ii) Colloidal material, like faeces, bacteria, cloth,etc.

(iii) Suspended material, like sand, silt, etc.

Reforestation is the restoration of a forest that once existed but was removed at some point in past. Due to increasing pollution and global warming, these forests need to be restored at the faster rate than their natural rate of restoration.

The best solution for the treatment of electronic waste is recycling. With modern recycling technologies, they can be recycled 95-98% by weight.

Benefit of recycling e-waste is that it prevents the toxic components of computers from entering the delicate environment and ground water via landfill.

Yes, it is true that carpets and curtains/drapes placed on the floor or wall surfaces can reduce noise level because these items absorb sound waves. For example, the slightest whisper can be heard clearly in a room without any furniture but not in a well-furnished room. This is because the furniture acts as sound absorbers.

The word hybrid itself suggests the combination of two.Hybrid Vehicle technology is the technology which allows the vehicle to run on dual mode like petrol and CNG.

Advantages of hybrid vehicle technology:

• As CNG is a green fuel, the fossil fuels are conserved.

• Reduction in environmental pollution.

• CNG is cheaper than petrol and diesel.

• CNG can’t be adulterated like petrol or diesel.

When the dissolved oxygen level drops to zero, many aquatic animals die because they don’t get any dissolved oxygen to breathe. This results in water becoming septic.

Organic pollution (increased growth of nitrogen and phosphates leads to increased growth of algae and plants and when these plants and algae die, they become organic matter) is an example which causes lowered dissolved oxygen content of an aquatic body.

Carbon dioxide is one of the most common greenhouse gases.

Possible sources of production on a large scale:

• Deforestation

• Smoke emitted from vehicles and factories.

• Excessive burning of wood, coal etc.

• Increased industrialization.

Harmful effects of increase of greenhouse gases are increased temperature of earth, melting of glaciers, breathing issues in human beings, etc.

The trees and shrubs near the boundary walls of buildings are not only meant for the decoration purpose but also as barriers against noise pollution, air purifiers and dust catchers which provides a healthy life to the people living in that building. The aesthetic beauty lifts up the mood and helps in relaxing, the oxygen rich and dust-free air gives healthy respiratory system. This improves the overall health of the people.

In order to prevent soil erosion, to facilitate percolation and recharging of ground water, to maintain flora and fauna and to avoid landslides and other natural calamities, the National Forest Commission of India(1988) recommended a relatively larger forest cover for hills(67%) than for plains(33%).

Forests are very important for the survival of the mankind. It’s not only our moral duty but also the need of the hour to restore as much forests as we can, in order to survive and live a better life.

Slash and burn agriculture, also called Jhum cultivation, has also contributed to the deforestation.

In this type of cultivation, the farmers cut down the trees of the forest and then burn the plants remains. The ash so obtained serves as a fertilizer. This land is then used for farming. After cultivation, the land is left for several years to recover its nutrients. Meanwhile, the farmers move on and do the same process on some other land. With increasing population, this practice is causing deforestation to a large extent.

The slash and burn agriculture can become environment friendly if-

i) The practice is carried out on small widely scattered plots in order to protect the forests.

ii) The land on which once it is practiced is left for longer period of time for nutrient recovery.

The Joint Forest Management Concept introduced by the Government of India mainly focuses on the idea that the local communities should be motivated to identify themselves with the development and protection of the forests from which they derive benefits (eg. Fruits, gum, wood, medicine, etc). It not only protects forests and environment but also generates employment to the local communities. So, it is one of the cheapest ways to restore forests.

Due to excessive absorption of UV rays, the cornea inflames which causes Snow Blindness. It is a painful, temporary loss of vision. It causes pain in eyes, headaches, blurred vision and loss of vision temporarily. But it can be cured by giving eyes rest and keeping them away from UV rays.

The process of increasing concentration of DDT and other heavy metals in the bodies of the organisms at relatively higher trophic level in the food chain is called Biomagnification.

The calcium metabolism of birds is disturbed due to the presence of high concentrations of DDT in their bodies which causes thinning of egg shells and their premature breaking. Due to this, the bird population declines.

The picture A shows solar panels which generate while picture B shows wind mill. The Solar panel uses solar energy to generate power while Wind mill uses wind energy to generate power.

i) It is true that both of the methods are non-polluting & environment friendly as they don’t release any toxins in the environment. Also, there’s plenty of sunlight and wind so there’s no risk of exhaustion of the major source of energy.

ii) The applications of Solar Energy are-

• Solar electric power generation – The solar energy is converted into electrical energy with the help of solar cells.

• Solar Water Heater – The solar energy converted into heat for heating water.

iii) A photovoltaic cell is a device which converts solar energy directly into electrical energy by photovoltaic effect (generation of electric current when exposed to sunlight).

i. Electronic waste means unusable electronic gadgets like computers, televisions, mobile phones, etc.

ii. E-wastes are buried in landfills or incinerated.

iii. Over half of the e-wastes generated in the developed countries like USA, UK, etc. are exported to the developing countries like India, Pakistan and China.

iv. The developed countries have proper and specifically built facilities for recycling of e-waste.

v. In developing countries, metals like copper, iron, silicon, nickel and gold are recovered manually during recycling process.

vi. Apart from metals, the e-waste also contains harmful toxins to which the manual labour is exposed to and ends up having severe diseases.

a) Organic farming is the use of bio-fertilisers in agriculture.

b) Bio-fertilizers are the organisms which improve the fertility of soil by enriching it with nutrients.

c) Main sources of biofertilizers – bacteria, fungi, cyanobacteria.

d) Benefits of organic farming are-

i. Maintains long term soil fertility

ii. Eco-friendly

iii. Controls pests without harming the environment

iv. Since chemical fertilizers and pesticides are not used, the water bodies remain safe and pollution free.

v. The food produced is chemical-free and highly nutritious.

vi. Makes use of resources, already available to the farmer. Hence, it is economic.

e) A developing country like India needs organic farming due to the above mentioned benefits.

Water logging and soil salinity are some of the problems that have come in the wake of the Green Revolution.

Causes of water logging and soil salinity –

i. Irrigation without proper drainage system.

ii. Continuous presence of water draws salt to the surface of the soil, which gets deposited as a thin crust on the land surface or start collecting at the roots of the plants.

Adverse effects-

i. Increased salt content causes reduction in the growth of crops which causes extreme damage to the agriculture.

ii. Root cells get shrinked due to saline water. They lose water by the process of osmosis (The flow of water from higher concentration to lower concentration).

iii. Crops get affected and cause extreme financial loss to the farmers.

As the name suggests, multipurpose trees are those tree which solve multiple purposes like providing fruits, shade, timber, medicine, etc.

For example

• Coconut tree (Cocos nucifera) has multiple uses. Its fruit is edible, its oil is used in cooking, the coconut husk is used as fibre to make many products ( like door mats, brushes , mattresses), coconut oil is also effective in reducing scars.

• Mango tree (Mangifera indica) also serves multiple purposes like providing mango fruit, provides shades, its wood is used in construction, the mango leaves are extensively used in ayurveda.

• There are many other examples of multipurpose trees like Neem (Azadirachta indica), Peepal (Ficus religiosa), Basil (Ocimum basilicum), etc. have medicinal as well as religious values.

Modern landfill site is a well-engineered and has managed facilities for the disposal of waste. They prevent the contamination of environment by the contaminants or toxins present in the waste.

The basic characteristics of a modern landfill site include-

(i) Methods to contain leachate such as lining clay or plastic liners.

(ii) Compaction 'and covering of the waste to prevent it from being blown by wind.

(iii) Installation of a landfill gas extraction system to extract the gas for use in generation of power.

The use of modern landfill site should be promoted for the following reasons-

i) The waste prevention by recycling and recovery of waste is stimulated.

ii) A uniform cost for waste disposal is created.

iii) It is environment – friendly and has no negative effect on human health.

i) Electrostatic precipitator is a device which is used to extract the suspended dust particles from the gas.
It uses high voltage charge to collect particles on the charged plates.

ii) It has electrode wires which are maintained at high voltages. This produces corona which releases electron.

iii) These electrons get attached to the dust particles, giving them a net negative charge.

iv) The collecting plates collect the negatively charged dust particles.

v) The velocity of air between plates is kept low to allow the dust particles to fall and settle down.

vi) Electrostatic precipitator can remove over 99% particulate matter present in the exhaust from a thermal power plant.

i) The ecological term used to describe DDT accumulation at different trophic levels is Biomagnification.

The increase of concentration of toxic substances at successive trophic levels in the food chain is known as Biomagnification.

ii) High concentration of DDT in birds disturbs their metabolism resulting into thinning of their egg shells and their premature breaking. This causes a decline in the population of birds.

iii) Yes, DDT accumulation leads to eutrophication. Eutrophication is the natural aging of a water body due to its increased nutrient enrichment which increases its fertility. This causes increased growth of algae.

iv) Since DDT accumulation leads to eutrophication (increased life in water body) which ultimately results in increased Biological Oxygen Demand. Biological Oxygen Demand is the amount of dissolved oxygen used by microorganisms in the biological process of metabolizing organic matter in water.

v) There are numerous diseases caused by accumulation of any heavy metal. For example-

• Minamata Disease due to Mercury

• Black foot due to Arsenic

• Itai-Itai due to Cadmium