environmental issues

Human population size has grown enormously over the
last hundred years. This means increase in demand for

1. food,
2. water,
3. home,
4. electricity,
5. roads,
6. automobiles and
numerous other commodities.

what is the need of the hour?

The need of the hour is to
check the
1. degradation and
2. depletion
of our precious natural resources and
3. pollution
4. without
halting the process of development

what is pollution

Pollution is any undesirable change in physical,
chemical or biological characteristics of air, land, water or
soil.

pollutants

Agents that bring about such an undesirable change
are called as pollutants

In order to control environmental
pollution, the Government of India has passed

the Environment (Protection) Act, 1986 to protect
and improve the quality of our environment (air, water
and soil).

Air pollutants cause injury to plants. how?

They reduce growth and yield of crops and cause premature
death of plants

Air pollutant harmful effects depends on?

1. concentration
2. duration of exposure

which large scale buildings need to purify air

industry
thermal power plant
smelter

what device is responsible for release for gas pollutants

smokestacks

why purify

release particulate and gaseous air pollutants together with harmless
gases, such as nitrogen, oxygen, etc. These pollutants must be separated/
filtered out before releasing the harmless gases into the atmosphere.

There are several ways of removing particulate matter; the most widely
used of which

electrostatic precipitator

which can remove over ___ per cent particulate matter present in the exhaust from a __________

99//
thermal power plant.

what does the esp have to generate charge?
what is their potential maintained at

electrode wires, which are maintained at several
thousand volts.

what does the potential result in formation of?

which produce a corona that releases electrons

what do electrons attach to

These
electrons attach to dust particles giving them a net negative charge

what is done to the collector plates so it can attract electrons

grounded so that it may attract electrons

what care must be taken

The velocity of air between the plates must be low enough to allow the
dust to fall.

A scrubber can remove gases like

SO2, NH3

In a scrubber, the exhaust is passed through a

spray of water or
lime

what danger have we recently realised?

Recently we have realised the dangers of particulate matter that are
very very small and are not removed by these precipitators

According to
_____________ particulate size ____ are responsible for causing the greatest harm
to human health.

(CPCB)//
2.5 micrometers
or less in diameter (PM 2.5)

CPCB

central pollution control board

These fine particulates can be inhaled deep into the
lungs and can cause

1. breathing and respiratory symptoms,
2. irritation,
3. inflammations
4. damage to the lungs
5. premature deaths.

_______ are a major cause for atmospheric pollution atleast in
the metro cities.

Automobiles

what can reduce pollutants of vehicles

1. Proper maintenance of
automobiles along with use of
2. lead-free petrol or diesel can reduce the
pollutants they emit

catalytic converters catalysts

platinum-palladium and rhodium

use of catalytic converters

are fitted into
automobiles for reducing emission of poisonous gases

As the exhaust
passes through the catalytic converter-
unburnt Hydrocarbons -->
CO and NO -->

CO2 and H2O//
CO2 and N2

what care must be taken while using catalytic converter equipped vehicles?
why?

Motor vehicles equipped with catalytic converter should use unleaded petrol
because lead in the petrol inactivates the catalyst

Air (Prevention and Control of Pollution) Act

1981

Air (Prevention and Control of Pollution) Act to include noise

1987

noise

undesired high level of sound

dB of sound by take off of a jet plane or rocket,

150 dB

2 ways in which permanent hearing damage may occur

1. brief exposure to very loud sounds (150 dB)
2. chronic exposure to relatively low noise level of cities may permanently damage hearing

what does noise cause

1. increase in stress
2. heart rate increases
3. sleeplessness
4. altered breathing pattern

Reduction of noise in our industries can be affected by use of

soundabsorbent materials or by muffling noise.

what needs to be enforced to protect ourselves from sound pollution

1. stringent following of laws laid down in relation to noise like delimitation of horn free zones around hospitals, schools
2. permissible level of crackers
3. loud speakers// timings after which loudspeakers cannot be played

green muffler

trees are planted around noisy places

_______ leads the country in its levels of air-pollution

Delhi

it has more cars than the states of
_____ put together

Gujarat and West Bengal

In the 1990s, Delhi ranked
______ among the __ most polluted cities of the world

4//
41

PIL

public interest litigation

Air pollution
problems in Delhi became so serious that

a public interest litigation
(PIL) was filed in the Supreme Court of India

After being censured very
strongly by the Supreme Court, under its directives, the government
was asked to take, within a specified time period, appropriate measures, ___

switching over the entire fleet of public transport, i.e.,
buses, from diesel to compressed natural gas (CNG).

All the buses of
Delhi were converted to run on ___ by the end of 2002

buses//
to CNG

why is CNG is better than diesel.

1. CNG burns most efficiently, unlike petrol or diesel, in the automobiles// very little of it is left unburnt.
2. Moreover, CNG is cheaper than petrol
or diesel,
3. cannot be siphoned off by thieves and adulterated like petrol
or diesel.

The main problem with switching over to CNG

1. the difficulty of laying down pipelines to deliver CNG through distribution points/ pumps and ensuring uninterrupted supply

steps taken in Delhi for reducing vehicular pollution

1. phasing out of old vehicles,
2. use of unleaded petrol,
3. use of low-sulphur petrol and diesel,
4. use of catalytic converters in vehicles,
5. application of stringent pollution-level norms for vehicles,

The Government of India through a ______ has laid
out a roadmap to cut down vehicular pollution in Indian cities

new auto fuel policy

More stringent norms for fuels means

steadily reducing the
1. sulphur and
2. aromatic content in petrol and diesel fuels

Euro III
goal
sulphur diesel

350 ppm
50 ppm

Euro III
goal
sulphur petrol

150 ppm
50 ppm

Euro III
goal
aromatic hydrocarbons

contained at 42%
35%

Corresponding to the fuel, ___ will also
need to be upgraded.

vehicle engines

Mass Emission Standards (______ which is equivalent to
____ norms)

Bharat Stage II
Euro-II

bharat stage IV applicable on which wheelers

4, 3, 2

since when is bharat stage IV implemented?

April 2017
3 wheelers -> 1st April 2017

According to an estimate, a substantial fall in ____ and _____
level has been found in Delhi between ___ and ____.

CO2 and SO2

1997 and 2005

\

. Realising the importance of maintaining the cleanliness of the water
bodies, the ___ safeguard our water resources.

Government of India has passed the Water (Prevention and
Control of Pollution) Act

Government of India has passed the Water (Prevention and
Control of Pollution) Act
when

1974

A ___
per cent impurities make
domestic sewage unfit for human
use

0.1

0.1 % impurities consist of

1. suspended solids- sand, silt and clay
2. colloidal material - fecal matter, bacteria, cloth, paper fibres
3. dissolved materials- nutrients- ammonia, nitrates, phosphate, sodium, calcium

BOD lhigh effect on water organisms

1. fish kill
2. disappearance of clean water organisms

BOD low effect on water organisms

1. reappearance of clean water organisms

what is most easy to remove from water

solids

what is most difficult to remove from water

1. dissolved salts such as nitrates, phosphates, and other nutrients, and
2. toxic metal ions and
3. organic compounds

how do bacteria and other microogranisms help in decomposition

Domestic sewage primarily
contains biodegradable organic matter, which readily decomposes –
thanks to bacteria and other micro-organisms, which can multiply using these organic substances as substrates and hence utilise some of the components of sewage

It is possible to estimate the amount of
biodegradable organic matter in sewage water by measuring

BOD-
biochemical oxygen demand
the oxygen required by 1l of water so that all organic matter may be decomposed

mortality of
fish and other aquatic creatures. why?

Micro-organisms involved in
biodegradation of organic matter in the receiving water body consume a lot of oxygen, and as a result there is a sharp decline in dissolved oxygen

sharp decline in dissolved oxygen is seen where?

dissolved oxygen
downstream from the point of sewage discharge

Presence of large amounts of nutrients in waters also causes excessive
growth of

planktonic algae -->phytoplankton

plankton

free floating

what does algal bloom do to a water body

algal bloom
1. which imparts a distinct colour to the water bodies.
2. Algal blooms cause deterioration of the water quality
3. fish mortality
4. block sunlight
5. bloom-forming algae are extremely toxic to human beings and animals.

Eichhornia crassipes colour

beautiful mauve

why was water hyacinth introduced in india?
what is the result?
what is an advantage

These plants
which were introduced into India for their lovely flowers have caused havoc
by their excessive growth by causing blocks in our waterways//
absorb heavy metals and can be used in compost

what is another name for water hyacinth

worlds most problematic weed
and terror of bengal

where do they grow abundantly?

They grow abundantly in
eutrophic water bodies, and lead to an imbalance in the
ecosystem dynamics of the water body.

Sewage from our homes as well as from hospitals are
likely to contain

1. pathogenic micro- organisms

what can disposal of those microorganisms in water cause

outbreak of serious diseases, such
as,
1. dysentery,
2. typhoid,
3. jaundice,
4. cholera

which industries contribute to waste water

1. petroleum
2. metal extraction
3. paper manufacture
4. chemical manufacture

what does this waste water contain

toxic substances, notably, heavy metals and a variety of organic
compounds

heavy metals-
1. definition
2. examples

1. density > 5g/cc
2. mercury, cadmium, copper, lead

A few toxic substances, often present in industrial
waste waters, can undergo ___ in the aquatic food chain.

biological magnification
(Biomagnification)

biomagnification

Biomagnification refers to increase in concentration of
the toxicant at successive trophic levels

why does biomagnification happen?

This happens
because a toxic substance accumulated by an organism
cannot be metabolised or excreted, and is thus passed on
to the next higher trophic level.

example

This phenomenon is wellknown for mercury and DDT

Biomagnification of
DDT in an aquatic
food chain

water (0.003 ppb)
v
zooplankton (0.04 ppm)
v
small fish (0.5 ppm)
v
large fish (2 ppm)
v
fish eating birds (25 ppm)

DDT in water

0.003 ppb

DDT in fish eating birds

25 ppm

High concentrations of DDT in birds complications

1. thinning of eggshell
2. premature breaking
3. eventual decline in bird population

is eutrophication natural?

yes

what is not natural?

Accelerated eutrophication is Not Natural

Eutrophication

Eutrophication is the natural aging of a lake by
nutrient enrichment of its water.

conditions in a young lake

1. water is cold
2. water is clear
3. supporting little life

what happens with time

With time, streams draining into the lake
introduce nutrients such as nitrogen and phosphorus, which encourage
the growth of aquatic organisms

what happens are the lake fertility increases??

As the lake’s fertility increases,
1. plant and animal life burgeons/ grow rapidly/flourish
2. and organic remains begin to be deposited on the lake bottom

Over the centuries, what happens to


1. fertility (__ and __ piles up)
2. lake (depth)
3. organisms

1. silt and debris pile up
2. lake becomes shallower and warmer
3. warm water organisms replace cold water ones

which plants come?
what do they do ?
where?

marsh plants //
"take root"//
in the shallows and fills the basin

bog

large masses of floating plants

Marsh plants take
root in the shallows and begin to fill in the original lake basin. Eventually,
the lake gives way to __ and finally__

large masses of floating plants (bog), finally converting
into land.