Sample Study M aterial P aper 2 Unit-I Fundamentals of … · 2019. 7. 12. · ¾ Tropopause - located at the top of the troposhere. The temperature remains fairly constant here

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Unit-I – Fundamentals of Environmnetal Sciences

Definitions, Principles and Scope of Environmental Science

The word ‘Environment’ is derived from the French word ‘Environner’ which means to encircle, around or

surround. The biologist Jacob Van Uerkal (1864-1944) introduced the term ‘environment’ in Ecology.

Ecology is the study of the interactions between an organism of some kind and its environment.

Environmental Science is the multidisciplinary field and requires the study of the interactions among the

physical, chemical and biological components of the Environment with a focus on environmental pollution

and degradation.

Environmental Science deals with the study of processes in soil, water, air and organisms which lead to

pollution or environmental damages and the scientific basis for the establishment of a standard which can

be considered acceptably clean, safe and healthy for human beings and natural ecosystems.

The environment consists of four segments of the earth namely atmosphere, hydrosphere, lithosphere and

biosphere:

1. Atmosphere: The Atmosphere forms a distinctive protective layer about 100 km thick around the earth. A

blanket of gases called the atmosphere surrounds the earth and protects the surface of earth from the Sun’s harmful,

ultraviolet rays. It sustains life on the earth. It also regulates temperature, preventing the earth from becoming too

hot or too cold. It saves it from the hostile environment of outer space. The atmosphere is composed of nitrogen

and oxygen besides, argon, carbon dioxide and trace gases. The atmosphere has a marked effect on the energy

balance at the surface of the Earth. It absorbs most of the cosmic rays from outer space and a major portion of the

electromagnetic radiation from the sun. It transmits only ultraviolet, visible, near infrared radiation (300 to 2500

nm) and radio waves. (0.14 to 40 m) while filtering out tissue-damaging ultra-violate waves below about 300 nm.

2. Hydrosphere: The Hydrosphere comprises all types of water resources oceans, seas, lakes, rivers, streams,

reservoirs, polar icecaps, glaciers, and ground water. Oceans represent 97% of the earth’s water and about 2% of

the water resources is locked in the polar icecaps and glaciers. Only about 1% is available as fresh water as surface

water in rivers, lakes, streams, and as ground water for human use.




3. Lithosphere: Lithosphere is the outer mantle of the solid earth. It consists of minerals occurring in the earth’s

crusts and the soil e.g. minerals, organic matter, air and water.

4. Biosphere: Biosphere indicates the realm of living organisms and their interactions with environment, viz

atmosphere, hydrosphere and lithosphere.

BIOGEOGRAPHICAL CLASSIFICATION OF INDIA

India is a mega diverse country. With only 2.4 per cent of the total land area of the world, the known

biological diversity of India contributes 8 per cent to the known global biological diversity.

The mega diverse countries are a group of countries that harbor the majority of Earth's species and high

numbers of endemic species .This status is based on the species richness and levels of endemism recorded

in a wide range of taxa of both plants and animals.

India is one of the 17 megadiversity countries of the world are Australia, Brazil, China, Colombia,

Democratic Republic of the Congo, Ecuador, India, Indonesia, Madagascar, Malaysia,Mexico, Papua New

Guinea, Peru, Philippines, South Africa, United States, Venezuela

In terms of Biogeography, India has been divided into 10 biogeographic zones as shown in the below table.




Sustainable development

The modern concept of sustainable development is derived most strongly from the 1987 Brundtland Report

“ Sustainable development is development that meets the needs of the present without

compromising the ability of future generations to meet their own needs.

It contains within it two key concepts:

1. The concept of 'needs', in particular, the essential needs of the world's poor, to which

overriding priority should be given; and

2. The idea of limitations imposed by the state of technology and social organization on

the environment's ability to meet present and future needs.

World Commission on Environment and Development, Our Common Future (1987)”

Millennium Summit




The Millennium Summit was a meeting among many world leaders lasting three days from 6

September to 8 September 2000 at the United Nations headquarters in New York City. Its purpose was to

discuss the role of the United Nations at the turn of the 21st century. At this meeting, world leaders ratified

the United Nations Millennium Declaration. This meeting was the largest gathering of world leaders in

history as of the year 2000.

Millennium Development Goals

The Millennium Development Goals (MDGs) were the eight international development goals for the

year 2015 that had been established following the Millennium Summit of the United Nations in 2000,

following the adoption of the United Nations Millennium Declaration. All 189 United Nations member

states at that time, and at least 22 international organizations, committed to help achieve the following

Millennium Development Goals by 2015:

1. To eradicate extreme poverty and hunger

2. To achieve universal primary education

3. To promote gender equality and empower women

4. To reduce child mortality

5. To improve maternal health

6. To combat HIV/AIDS, malaria, and other diseases

7. To ensure environmental sustainability

8. To develop a global partnership for development

Sustainable Development Goals

The Sustainable Development Goals (SDGs), officially known as Transforming our world: the 2030 Agenda

for Sustainable Development is a set of seventeen aspirational "Global Goals" with 169 targets between them.

Note- The Sustainable Development Goals (SDGs) replaced the MDGs in 2016




These included ending poverty and hunger, improving health and education, making cities more sustainable,

combating climate change, and protecting oceans and forests.

17 Sustainable Development Goals

Structure and Composition of Atmosphere

The Atmosphere is divided into layers according to major changes in temperature. Gravity pushes the layers of air

down on the earth's surface. This push is called air pressure. 99% of the total mass of the atmosphere is below 32

kilometre.




Troposphere - 0 to 12 km

Troposphere contains about 80% of total mass of the atmosphere, nearly all water vapour and dust particles

can be found here. Almost all weather phenomena and cloud formation take place in this layer.

The troposphere is heated from below by the Earth’s surface. Incoming solar radiation first warms the

surface, which radiates heat into the atmosphere. The warmer air in the near surface layer generates

turbulent vertical motions, which transfer water vapour and other tracers to higher altitudes.

Temperature decreases with increasing height in the troposphere to away from the warming surface. The

changing rate of temperature with height is called “lapse rate” Tropospheric air temperature is generally

proportional with distance from surface and lapse rate is fairly uniform, it is about 6,5 °C / 1000 m, but this

rate is affected by water vapour content. Temperature is generally lower than –50 °C to –60 °C at the top of

the troposphere

However, in the lower troposphere, the atmospheric stratification can differ from normal, and temperature

can increase with height in the function of time of day and weather condition. This situation is called

inversion, which generally occurs at night. When temperature remains the same with height, the

stratification is isothermal. The atmospheric stratification and thereby the stability conditions play

important role in dispersion of pollutants

The troposphere can be divided into two main parts. The lower part is the planetary boundary layer (PBL)

or atmospheric boundary layer, extending upward from the surface to a height that ranges from about 100 to

3000 m in the function of season, weather condition and time of day. Above this layer, the free troposphere

can be found.

Tropopause - located at the top of the troposhere. The temperature remains fairly constant here. This layer

separates the troposphere from the stratosphere. We find the jet stream here. These are very strong winds

that blow eastward.




*Concentration of water vapour is not included in dry atmosphere due to the evaporation and transpiration.

Water vapour (H2O) is a significant component of the atmosphere. Its concentration varies over a wide

range both spatially and temporally.

Most of water vapour concentrated in the lower atmosphere (about 90% of total atmospheric water

vapour is found in the lower 5 km atmospheric layer, and more than 99% of it can be found in the

troposphere).

The capacity of air to hold water vapour (called saturation level) is a function only of the air

temperature. The higher the temperature the greater amount of water vapour can be held without

condensation.

The highest atmospheric moisture content is observable over equatorial ocean area and tropical rain

forests, while the lowest water vapors concentrations can be measured over cold, polar regions, and

subtropical deserts.

Atmospheric water vapour has several significant direct and indirect effects on both weather and

climate. It plays important roles in the radiation and the energy budgets of the atmosphere, and also

in the formations of clouds and precipitations.

About 70% of total absorption of the incoming shortwave solar radiation, particularly in the infrared

region, and about 60% of total absorption of long-wave radiation by the Earth are realized by water

vapour thereby it is the most significant greenhouse gas.

Water vapour also influences heat energy transfer on the surface- atmosphere system through the

latent heat flux. The latent heat flux is a component of surface energy budget. It plays an important

role in the heat transfer from Earth’s surface into the atmosphere.

During this process heat from evaporation and transpiration of water at the surface is transferred to

the troposphere by water vapour and it is released there by condensation. Latent heat of evaporation

of water at the surface is released to the atmosphere when condensation occurs. Due to the

condensation, cloud, fog and precipitation can be produced.




Structures of Ocean Floor

1. Continental Shelf-

The shallow submerged extension of continent in ocean is called continental shelf which is granite

continental crust

They are much more like the continent than like the deep ocean floor and they may have hill, depressions,

sedimentary rocks, minerals and oil deposits.

About 7.5 % of the total area of the ocean is covered by the continental shelfs

Mean slope is less than 1 0, depth from 0 to 200 metre and width upto 300km.

The continental shelf are of great use-

1. Marine food comes almost from them.

2. They provide the richest fishing ground

3. They are about potential sites for minerals and about 30 % of world production of petroleum and

gas comes from here

4. Sand and Gravel

Various features are present in deep floor describe below.

1. Seamount - A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface

(sea level), and thus is not an island. Seamounts are typically formed from extinct volcanoes that rise abruptly and

are usually found rising from the seafloor to 1,000–4,000 metres (3,300–13,100 ft) in height.

2. Guyot- A guyot also known as a tablemount, is an isolated underwater volcanic mountain with a flat top below

the surface of the sea. Flat top suggests that they were near sea level were eroded by wave action.




The Stratification Process

In Winters, chilly air temperatures cool the lake's surface. As the surface water cools, it becomes more

dense and sinks to the bottom. Eventually the entire lake reaches about 40C. As the surface water cools even

more, it becomes less dense and "floats" on top of the denser 40C water, forming ice at 0

0C). The lake water

below the ice remains near 40C. This situation is referred to as winter stratification. Winter stratification

remains stable because the ice cover prevents wind from mixing the water.

Water salinity

Fresh water Brackish water Saline water Brine

< 0.05% 0.05 – 3% 3 – 5% > 5%

< 0.5 ‰ 0.5 – 30 ‰ 30 – 50 ‰ > 50 ‰

Concentration in Sea water

Cl- > Na

+ > SO4

2- > Mg> Ca

+ > K

+> HCO3

Concentration in River water

HCO3 > Ca+

> SO42-

> Cl- > Na

+ >

Mg> K

+>NO

3-

Residence Time

Cl- > Na

+ > Mg > SO4

2- > Ca

+ > K

+> Mn > Al> S




Relative humidity

a measure of degree of saturation with water vapour

a ratio that compares the amount of water vapour in the air with the amount of water vapour that would be

present in the air at saturation at a particular temperature

most commonly used measure of humidity, for example in weather forecasts.

Q- The most common units for vapor density are

gm/m3. For example, if the actual vapor density is 10 g/m3 at 20°C compared to the saturation vapor density at

that temperature of 17.3 g/m3 , then the relative humidity is.




Unit II : Air Pollution

Air pollution may be described as contamination of the atmosphere by gaseous, liquid, or solid wastes or

by-products that can endanger human health and welfare of plants and animals, attack materials, reduce visibility

or produce undesirable odors.

There are two types of sources for air pollution

NITROGEN OXIDES (NOx)

Nitrogen oxide (NOx) may refer to a binary compound of oxygen and nitrogen.The oxides of nitrogen area as

follows.

Nitric oxide (NO)

Nitrogen dioxide (NO2)

Nitrate (NO3)

Nitrous oxide (N2O)

Dinitrogen trioxide (N2O3)

Dinitrogen tetroxide (N2O4)

Dinitrogen pentoxide (N2O5)

NOx is a generic term for the nitrogen oxides that are most relevant for air pollution and out of 7 oxides of

nitrogen, 2 (two) namely nitric oxide (NO) and nitrogen dioxide (NO2) are major air pollutant. These gases

contribute to the formation of smog and acid rain, as well as tropospheric ozone, although it may have a

significant impact on the ozone layer.

NOx gases are usually produced from the reaction among the nitrogen and oxygen during the

combustion of fuels, especially at high temperatures, such as occur in car engines. In areas of high motor

vehicle traffic, such as in large cities, the nitrogen oxides emitted can be a significant source of air

pollution.




Role of NOx in Ozone (O3)

NO emitted from fossil fuel combustion, biomass burning, soils, lightning in troposphere where react and forms

NO2. Rapid cycling between NO and NO2 continually occurs in troposphere.

NO2 to create Tropospheric Ozone:

N2 + O2 --------------> 2NO

2NO + O2 --------------> 2NO2

NO2 + hν (<390 nm) --------------> NO + O°

O° + O2 + M--------------> O3 +M

NO destroys Ozone:

NO + O3 --------------> NO2 + O2

So NO plays a important role in the destruction of Trophosperic ozone and NO2 in producing Trophosperic

ozone but this cycle get disturb due to the addition of VOCs/HCs (Hydrocarbons) in troposphere and

increases the amount of Trophosperic ozone. (Deatil in Smog).

Sulphur Dioxide (SO2)

Sulfur dioxide is a toxic gas with a pungent, irritating smell. Sulfur dioxide (SO2) is one of highly reactive

gases of sulfur oxides (SOX) group. Other gases of SOx (such as SO3) are found in the atmosphere at

concentrations much lower than SO2.

Hydroxyl radical (OH)

The most important oxidizing species is the hydroxyl radical (OH). It is extremely reactive and able to

oxidize most of the chemicals found in the troposphere. The hydroxyl radical is therefore known as the

'detergent of the atmosphere' or atmospheric scavengers.

Note-

Tropospheric Ozone forms by NO2 in

wavelength <390 nm

M (N2 or O2) is third body which

makes reaction stable. It absorbs

excess energy and formation of stable

Ozone (O3)




Carbon Monoxide (CO)

CO + OH -------- CO2 + H -----------------------------------1

H + O2 ---M

----- HO2 ----------------------------------------2

HO2 + NO -------- NO2 -------------------------------------3

Destruction of NO tends to increase in concentration of Tropospheric Ozone and formation of NO2

also causes the formation of Tropospheric Ozone.

Aerosols or Particulate Matter (PM2.5 or PM10)

Aerosol particles -Aerosol are tiny solid or liquid particles which are suspended by a mixture of gases or

air which covers a wide range of small particles, like sea salt particles, mineral dust, pollen, drops of

sulphuric acid and many others.

Ranges from 0.005 m to 100m

Radative Forcing

Radiative forcing or climate forcing is defined as the difference of insolation (sunlight) absorbed by the

Earth and energy radiated back to space. Typically, radiative forcing is quantified at the tropopause in units

of watts per square meter of the Earth's surface. Causes of radiative forcing include changes

in insolation and the concentrations of radiatively active gases, commonly known as greenhouse

gases and aerosols.




Stratospheric Ozone

Ozone (O3) can be found in the earth’s atmosphere from the ground up to 50 km, but most of the ozone

(about 90%) resides maximum between 15 to 35 km above the Earth's surface). This stratospheric ozone

is commonly known as the “ozone layer”.

Ozone layer measure in DOBSON (DU) unit

Smog

The word “smog” was originally generated by the combination of words “smoke” and “fog” to describe a

type of air pollution that refer a mixture of natural fog and several air pollutants. The two types of smog

observed. It is a common term applied to different air pollution events mainly formed in large cities.

Classical Smog (In year 1952) Photochemical Smog (In year 1943)

Or Or

London Smog Los Angles Smog

Or Or

Reductive Type Smog Oxidative Type Smog

Acid Rain

Rainfall declared “acid rain” when its pH less than 5.6 because natural and unpolluted rainwater actually

has a pH between 5.6-6.5 (acidic) due to the reaction of water with the presence of CO2.

National Ambient Air Quality Standards (NAAQS) by CPCB

1 DOBSON (DU) = 0.01 mm of O3




Pollutant Time

Weighted

Average

Concentration in Ambient Air

Industrial,

Residential,

Rural and

Other

Areas

Ecologically

Sensitive

Area

(notified by

Central

Government)

Methods Of Measurement

Sulphur Dioxide

(SO2),

µg/m3

Annual*

24

hours**

50

80

20

80

-Improved West and Gaeke Method

- Ultraviolet flurorescence

Nitrogen Dioxide

(NO2),

µg/m3

Annual*

24

hours**

40

80

30

80

Modified Jacob& Hochheiser

-Chemiluminescence

Particulate Matter

(size less than 10

µm) or PM10 µg/m3

Annual*

24

hours**

60

100

60

100

-Gravimetric,

- Btea Attenuation

Particulate Matter

(size less than 2.5

µm) or PM2.5µg/m3

Annual*

24

hours**

40

60

40

60

Gravimetric,

- Btea Attenuation

Ozone (O3) µg/m3 8 hours*

1 hour**

100

180

100

180

--UV Photometric

--Chemiluminescence

Lead (Pb)

µg/m3

Annual*

24

hours**

0.50

1.0

0.50

1.0

--AAS/ICP

--ED-XRF

Carbon Monoxide

(CO) mg/m3

8 hours*

1 hour**

02

04

02

04

-NDIR (Non-Dispersive Infra Red) SpectoSscopy

Ammonia (NH3)

µg/m3

Annual*

24

hours**

100

400

100

400

- Indophenol Blue method

- Chemiluminescence

Benzene (C6H6)

µg/m3

Annual* 5 5 -Gas Chromatography

Benzo(a)Pyrene Annual* 1 1 - Solvent Extraction followed by HPLC/GC analysis




(BaP)- particulate

phase only,

ng/m3

Arsenic

(As),

ng/m3

Annual* 6 60 - AAS/ICP method after sampling on EPM 2000 or

equivalent filter paper.

Nickel (Ni),

ng/m3

Annual* 20 20 - AAS/ICP method after sampling on EPM 2000 or

equivalent filter paper

* Annual arithmetic mean of minimum 104 measurements in a year at a particular site taken twice a week 24 hourly

at uniform intervals.

** 24 hourly or 8 hourly or 1 hourly monitored values, as applicable, shall be complied with 98% of the time, they may

exceed the limits but not on two consecutive days of monitoring.

Source: National Ambient Air Quality Standards, Central Pollution Control Board Notification in the Gazette of India,

Extraordinary, New Delhi, 18th November, 2009




Gaussian Plume Model

Gaussian models are most often used for predicting the dispersion of pollutants from plumes originating

from ground-level sources. Mainly for the point sources e.g chimney.

Equation of Guassian Plume




Note:

Ground level concentration (C) is directly proportional to emission rate or source

strength (Q).

Ground level concentration (C) is inversely proportional velocity of wind (u).

Ground level concentration (C) is inversely proportional Effective stack height (H).

Higher wind speed reduces the effective height of stack (H)




Unit-III Water Pollution

Natural stores of water in the global hydrological cycle

Stores Percentage (%)

Oceans 97.71

Ice caps 1.9

Ground water 0.5

Soil moisture 0.01

Lakes and rivers 0.009

Atmosphere 0.0001

Biological Oxygen Demand (BOD)

The demand for O2 is directly related to increasing input of organic wastes and is expressed as biological

oxygen demand (BOD) of water.

Water pollution by organic wastes is measured in terms of Biochemical Oxygen Demand (BOD).

Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological

organisms in a body of water to break down organic material or biodegradable material present in a

given water sample at certain temperature over a specific time period.

5. Subtract the Day 5 reading from the Day 1 reading to determine the BOD level. Record your final BOD result in

ppm.

DOi = Initial Value of O2 present

DOf = Final Value of O2 present

P= Dilution Factor

BOD5 = DOi – DOf

p




Ultimate BOD (BODu)

Ultimate BOD means total BOD of the sample which means carbonaceous BOD plus Nitrogenous BOD.

How to calculate Ultimate BOD

BODulitimate = BOD5 + Lt

BODu = BOD5 + BODu 10-kt

BODu - BODu 10-kt

= BOD5

BODu (1- 10-kt

) = BOD5

K25 = 0.22 x 1.047 (25-20)

= 0.277/day

BOD5 = BODulitimate (1- e-kt

)

BOD5 = 300 (1- e-0.277 x 5

) = 225mg/L

Note = BOD at 25oC is higher than the 20

oC of BOD in 5 days

Q. A stream flowing at 10m3/s has a tributary feeding it with a flow of 5m

3/s. The stream concentration of

chloride upstream at the junction is 20mg/l and the tributary chloride concentration is 40mg/l. Find the

downstream concentration.

Solution :

BOD < COD

BOD5 < BODulitimate (Initial BOD)

BODu = BOD5

(1-10-kt

)




Point Source or tributary ( BOD =40mg/l, flow = 5m3/s)

BOD here

Stream Flowing with BOD = 20mg/l, flow = 10m3/s

Solution

Downstream conc of Cl = (Stream Flow x Conc. of Cl in Stream) + (Tributary Flow x Conc. of Cl in Tributary )

Stream Flow + Tributary Flow

= (10 x 20) + (5 x 40) = 26.7 mg/L

10+ 15

Persistent organic pollutants (POPs)

Note – Same formula used for any type of pollutant in downstream

Persistent (Residence time)

Organochlorine (years) >Herbicides (months) > Organophosphates (weeks) > Carbamates (days)

Toxicity

Organophosphates > Carbamates >Herbicides> Organochlorine

Note: All these pesticides are highly soluble in fat tissues (lipophilic) so penetrate the hard fat material

of insects and kill them by disrupting transmission of nerve impulse.




Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental

degradation through chemical, biological, and photolytic processes. Because of their persistence,

POPs bioaccumulation with potential significant impacts on human health and the environment.

The effect of POPs on human and environmental health was discussed, with intention to eliminate or

severely restrict their production, by the international community at the Stockholm Convention on

Persistent Organic Pollutants in 2001.

Many POPs are currently or were in the past used as pesticides, solvents, pharmaceuticals, and industrial

chemicals.

How Pesticides Degrade by micro-organisms?

Ans. Because attacks on following Functional Groups

Halogens (-Cl, -Br)

Nitro (−NO2)

Sulphonate (R-SO3−)

Amino (-NH2)

Methoxy (O–CH3)

carboxylic acid (- COOH)

Hydroxyl (-OH)

Phenoxy groups (-O-C2H5)

Methods for the Degradation of Pesticides

Chemical Degradation- Adding by chemicals

Hydrolytic Reaction- Adding water to break down the pesticides in

small

Microbial Degradation

Photochemical Reaction




WASTE WATER TREATMENT

The primary purpose of the treatment of sewage is to prevent the pollution of the receiving waters. In

general, these processes are divided into three stages: preliminary (physical), primary (physical) treatment

and secondary (biological) treatment.

Minimally, wastewater should receive primary (physical removal/settling) and secondary (biological)

treatment, which can be followed by disinfection before discharge. More advanced processes (advanced or

tertiary treatment) may be required for special wastes. When the effluent from secondary treatment is

unacceptable, a third level of treatment, tertiary treatment, can be employed.

1. Primary Treatment: This involves physical removal of particles through following process.

a.) Bar screens




Unit -IV Environmental Biology

‘Ecology may be defined as the scientific study of the relationship of living organisms with each other and

with their environment.’

Ernest Haeckel (1866), a German biologist, for the first time defined ecology as “the body of knowledge

The term Ecology’ was derived from two Greek words, OIKOS (means house) and LOGUS (means study

of) to denote the relationship between the organisms and their environment.

E.P. Odum (1969) defined ecology as “the study of structure and function of nature”.

Branches of Ecology

1. Autecology: It involves the study of an individual animal or plant (species) with its environment

2. Synecology: Study of relation of the group of different species with their environment.

Levels of ecological organization




Ecosystem

The term ‘ecosystem’was coined by A.G. Tansley in 1935.

An ecosystem is a functional unit of nature about complex interaction between its biotic (living) and abiotic

(non-living) components.

Components of an ecosystem: They are broadly grouped into:-

Ecological succession

Ecological succession is the series of changes in an ecosystem when one community is replaced by another

community as a result of changes in biotic and abiotic factors.

It can regenerate a damaged community

It can create a community in a previously unhabitated area

Succession occurs in all types of ecosystem(Forest, ponds, corals reefs, etc)

It may takes hundreds or thousands of years.




Types of ecological succession :

Ecological succession IS mainly of two types:

1. Primary succession:

The process of creating and developing an ecosystem in an area that was previously uninhabited

sides (volcanoes ,slides of glacier)

2. Secondary Succession:

Secondary succession is the process of repairing a damaged ecosystem. It occurs when community is

destroyed, altered but soil is still there (Such as: natural disasters, human activities, death of

organisms).




Population Interactions:

Organisms living together in a community influence each other directly or indirectly under natural conditions. All

the vital process of living such as growth, nutrition and reproduction requires such interactions between individuals

in the same species (intraspecific) or between species (interspecific)

The ecological of biological interactions are classified into two categories.




(I)Positive interactions:

In positive interactions, the interacting populations help one another. The benefit may be in respect of food,

shelter, substratum or transportation.

The positive association may be continuous, transitory, obligate or facultative.

(1). Mutualism: (+,+)

Mutualism, also called as symbiosis, is also a positive type of ecological interaction. Mutualism is a

symbiotic association between two organisms in which both the interacting partners are mutually

benefitted.

Mutualism is obligatory or no one of the partners of mutualism can survive individually.

Biodiversity

Biodiversity is the variety and variability of genus, species and ecosystem between and within

Or

“variability among living organisms”

The term Biodiversity is coined by Walter Rosen, 1985

Biodiversity also includes: Variability of genus, Variability of varieties, Variability of species,

Variability of populations in different ecosystems, Variability in relative abundance of species

Measuring biodiversity:

(1). Alpha diversity:

Alpha diversity refers to number of speciesin a single community at a particular time

Alpha diversity is better called as species richness




Alpha diversity is used to compare number of species in different communities

Unit- V – Soil and its characteristics

The word Soil is derived from Latin word “Solum” which means earthy materials in which plants grows.

The science which deals with the study of soil is called “Pedology” or “Edaphology”.

Soil Profile:

A soil consists of three horizontal layers. They are true soil at the top, sub soil and bedrock. Each horizon is

different from other by its own physical and chemical composition and organic contents produced during

the process of soil formation.




O -(humus or organic)- Mostly organic matter such as decomposing leaves. The O horizon is thin in some soils,

thick in others, and not present at all in others.

A1 -(topsoil)- Mostly minerals from parent material with organic matter incorporated. A good material for plants

and other organisms to live.

Soil components

The four major components of soil are shown: inorganic minerals, organic matter, water, and air.

inorganic mineral matter, about 40 to 45 percent of the soil volume

organic matter or Humus, about 5 percent of the soil volume

water, about 25 percent of the soil volume




air, about 25 percent of the soil volume

2. Organic Matter or Humus:

When the plants and animals die, their dead remains are acted upon by a number of micro organisms and

are finally degraded or decomposed into simple organic compounds. A product of this microbial

decomposition is humus which is a dark coloured, jelly-like amorphous substance composed of residual

organic matters not readily decomposed by soil microorganisms. The process of humus formation is called

humification.

Humic Substance

Dilute in alkali solution

Humin (precipitate) Solution

Humic Acid(precipitate) Fulvic Acid (Solution)

Soluble in base and insoluble in acid Soluble in both base and acid

Rate of degradation of plant materials

Hemicelluloses > Cellulose > Lignin > Citin

First degrade hemicelluloses. Chitin is very resistant to degradation called

Recaltriant.




3. Permanent wilting point

Little by little, the water stored in the soil is taken up by the plant roots or evaporated from the topsoil into

the atmosphere. If no additional water is supplied to the soil, it gradually dries out.

The dryer the soil becomes, the more tightly the remaining water is retained and the more difficult it is for

the plant roots to extract it. At a certain stage, the uptake of water is not sufficient to meet the plant's needs.

The plant looses freshness and wilts; the leaves change colour from green to yellow. Finally the plant dies.

The soil water content at the stage where the plant dies, is called permanent wilting point. The soil still

contains some water, but it is too difficult for the roots to suck it from the soil (see Fig.)

The water potential of such soil lies between -1.5 kPa or -1500 Mpa (Mega Pascal)

Note- Amount of water in soil is measurea by TENSIOMETER




Soil Colloid

The soil colloids are the most active portion of the soil and largely determine the physical and

chemical properties of a soil.

Soil colloidal are two kinds:

(1) Inorganic (minerals): Inorganic colloids (clay minerals, hydrous oxides) usually make up the bulk of soil

colloids. Colloids are particles less than 0.001 mm in size, and the clay fraction includes particles less than

0.002 mm in size. Therefore, all clay minerals are not strictly colloidal.

(2) Organic (humus): The organic colloids include highly decomposed organic matter generally called

humus. Organic colloids are more reactive chemically and generally have a greater influence on soil

properties per unit weight than the inorganic colloids.

Biofertlizers




(A)Nitrogen-Fixing Bacteria:

Nature of Saline and Alkaline Soil

The presence of an excess of sodium salts and the predominance of sodium in the exchangeable complex are

divided into the two main groups:

(1) Saline Soils: Saline soils contain an excess of sodium salts, but its colloidal material is not yet sodiumised.

(2) Alkali Soils: In the case of alkali soils, the exchange complex contains appreciable quantities of exchangeable

sodium. Such soils may or may not contain excess salts.

Alkali soils may be divided into following groups:

(a) Saline-alkali soils:

When they contain soluble salts in excess they are known as saline-alkali soils.

(b) Non-saline-alkali soils (Alkali soil):

When they do not contain soluble salts, they are called non-saline-alkali soils.

(c) Degraded alkali soils:

Under certain circumstances the clay complex of some alkali soils is broken down to give rise to degraded alkali

soils.




Unit-IV Renewable Energy

Energy is the capacity to do work. A plenty of energy is needed to sustain industrial growth and agricultural

production.

CLASSIFICATION OF ENERGY

It is broadly classified into

1. Conventional energy: is in practice for long duration of time and well established technology is available to tap and use

them. e.g. Coal, oil, natural gas, hydro power, nuclear power etc.

2.Non-conventional energy: source can be used with advantage for power generation as well as other applications in a

large number of locations and situations. These energy sources cannot be easily stored and used conveniently. e.g. Solar,

wind, tidal and geothermal etc.

Based upon nature, energy sources are classified as

1. Renewable energy sources are inexhaustible and are renewed by nature itself. Solar, wind, tidal, hydro and biomass

are few examples.

2. Non-renewable energy sources are exhaustible within a definite period of time depending upon its usage. Fossil fuels

(coal, oil, gas) and nuclear fuels are few examples.

WIND ENERGY

Wind results from air in motion. Wind energy is a form of solar energy. Wind turbines convert the kinetic energy in

the wind into mechanical power. A generator can convert mechanical power into electricity. Mechanical power can

also be utilized directly for specific tasks such as pumping water. The electrical energy can be generated by wind

energy by utilizing the kinetic energy of wind.

Indias wind speed values lies between 4-12m/sec and potential of India is 20,000 MW.




Wind speed increases with height. They have traditionally been measured at a standard height of 10 m where

they are found to be 20-25% higher then surface.

The three factor determine the output of a wind energy converter

The wind speed

The cross section of the wind swept by the rotor

Efficiency of rotor transmission system and generator.

Power in the wind

The wind mill works on the principle of converting kinetic energy of the wind to mechanical energy.

Power is equal to energy per unit time.

Power = Kinetic energy

P = ½ mv2 ----------------1

P = ½ ρ A v3 ----------2

P = 1/8 ρ π d2 v

3 -------------3

GEOTHERMAL ENERGY

Geothermal power plants derive energy from the heat of the earth’s interior. The average increase in

temperature with depth of the earth is 10C for every 30-40m. At a depth of 10-15km, the earth’s interior is

as hot as 1000-12000C.

Density (ρ) = Mass (m)/Volume (V)

Mass (m) = ρV (V= Area x velocity )

m = ρAv

A= π r2 = π/4

d2




2. Liquid Dominated Plant (Binary Cycle)

In order to isolate the turbine from corrosive or due to higher concentration of condensable gases the binary

cycle concept receiving attention. This is also called RANKINE CYCLE.

An organic fluid is used in this plant. A heat exchanger system is used to transfer a fraction of the brine heat

to vaporize the secondary working fluid. The vapors drive the generator.

Organic fluid with the low boiling point such as Isobutane (B.P-10oC) and Freon-12 (B.P-30

oC) are usually

recommended. Ammonia and Propane also used.

In the binary cycle there are no problems of corrosion in turbine. The heat exchanger is a tube type so that

no contact between brine and working fluid.




Ocean Energy

Ocean energy is an indirect form of solar energy. The seas and the oceans absorb solar radiations. This

results in temperature gradients in the water surface—downwards i.e. warm surface water and colder deep

waters.

A process called ocean thermal energy conversion (OTEC) uses the heat energy stored in the Earth's

oceans to generate electricity.

Tidal Energy

The periodic rise and fall of water level of sea which are carried by the action of the sun and moon on water

of the earth is called “tide”. The large scale up and down movement of sea water represents an unlimited

source of energy.

As the Earth, its Moon and the Sun rotate around each other in space, the gravitational movement of the

moon and the sun with respect to the earth, causes millions of gallons of water to flow around the Earth’s

oceans creating periodic shifts in these moving bodies of water.

These vertical shifts of water are called “tides”.




Tidal Power

The power is the rate of doing work.

The energy available is dependent on the volume of water. The potential energy contained in a volume of

water is:

E=½Apgh2

Magneto Hydrodynamic Power Generation

The MHD generation or, also known as magneto hydrodynamic power generation is a direct energy

conversion system which converts the heat energy directly into electrical energy, without any intermediate

mechanical energy conversion.




Unit –VII Statistics

Sampling Techniques

Sampling Methods can be classified into one of two categories:

1. Probability Sampling

In probability sampling it is possible to both determine which sampling units belong to which sample

and the probability that each sample will be selected. The following sampling methods are examples

of probability sampling:

a. Simple Random Sampling (SRS) : Sample are chosen at random and each member or sample unit of the

population has an equal chance of being selected in the sample, population is small and homogenous.

Central Tendency or Average

Mathematical Average Positional Average

Arithmetic Mean Geometric Mean Harmonic Mean Median Mode




1. Arithmetic Mean (A.M) : The arithmetic mean is equal to the sum of all the values in the data set divided by

the number of values in the data set. So, if we have n values in a data set and they have values x1, x2, ..., xn, the sample

mean, usually denoted by (pronounced x bar), is

This formula is usually written in a slightly different manner using the Greek capitol letter, , pronounced

"sigma", which means "sum of...":

Mean of two sample is called combined mean

Relationship between Mean, Median and Mode




1. Symmetric Distribution or Normal Distribution:

A distribution in which the values of mean, median and mode coincide (all fall at the same point) is

known as Symmetrical distribution.

Mean = Median = Mode

2.

2. Asymmetric Distribution or Skewed Distribution:

A distribution in which the values of mean, median and mode are not equal or coincide is known as

Asymmetrical or Skewed distribution.

More specifically, Mo < Md < X, when skewness is positive (Right skewed) and X < Md < Mo, when

skewness is negative (Left skewed), as shown in the following figure.

In asymmetrical distribution a very important relationship exists among Mean, Median and Mode. In such

distributions the distance between the mean and median is about one-third of the distance between the mean

and mode.




Karl Pearson expressed this relationship as:

Examples : Given median = 20.6, mode = 26. Find mean.

Solution:

4. Coefficient of Variation

5. Standard Error: The standard error(SE) is very similar to standard deviation. Both are measures of

spread. The higher the number, the more spread out your data is. To put it simply, the two terms are essentially

equal — but there is one important difference. While the standard error uses statistics (sample data) standard

deviations use parameters (population data).

6. Combined Standard Deviation

N1, N2, = Number of observations in group-1 and group-2

Mode = mean - 3 [mean - median]

Mode = 3 median - 2 mean




d = (Mean-M comb)’d’ is found by deducting M comb from the mean (M) of the concerned group. d is

deviation.

σ = Standard deviation of the group concerned σ1 are σ2 are the standard deviation of the group 1and

group-2. σ12 is combined standard deviation.

Example:

Solution:




Now put the values in formula.

7. Combined Variance: Formula and method is same as combined standard deviation remove square root only

Question – A class has equal no of boy and girls. The mean and standard deviation are 40 and 2 and for girls 50 and

2.Calculate combine variance.

Solution: Do it yourself

Student t- Test

The t test (also called Student’s T Test) is using for testing the significance of “difference between the

means of two different of small samples (n< 30).




Applications of t-distribution

The following are the important applications of the t-distribution:

1. Test of Hypothesis of the Population Mean: (Sample size ‘n’ is small): When the population is normally

distributed, and the standard deviation ‘σ’ is unknown, then “t” statistic is calculated as:

Examples: A random sample of size 16 has 56 mean. The sum of the squares of deviations takem from mean

is 135 and population having 53 as mean. Calculate t-statistic.

Solution : (Sample Mean) = 56

μ (Population Mean)= 53

n (Sample size) = 16

∑ ( - )2 = 135 (Sum of square of deviation)

Chi Square Test

A chi-squared test, also written as χ2 test, is a non parametric test. It is used when it is not possible to

assume that from which types of distribution of population samples are being drawn (No assumption about

the parameters of the population). That’s why it is called Non-parametric test.

Non parametric tests today are very popular in behavioral science.

F-test

F-tests was named in honor of Sir Ronald Fisher. The F-statistic is simply a ratio of two variances. Variances are a

measure of dispersion, or how far the data are scattered from the mean. Larger values represent greater dispersion.

Variance is the square of the standard deviation.

(X- ) = Deviation

∑ ( - ) Sum of deviation

√ ∑ (X- )2

= Square root of sum of square of

deviation




Correlation

The Correlation is a statistical tool used to measure the relationship between two or more variables, i.e. the degree

to which the variables are associated with each other, such that the change in one is accompanied by the change in

another. ex. Relation between height and weight.

Types of Correlation

1. Positive and Negative Correlation: Whether the correlation between the variables is positive or negative depends

on its direction of change. The correlation is positive when both the variables move in the same direction, i.e.

when one variable increases the other on an average also increases and if one variable decreases the other also

decreases. The correlation is said to be negative when both the variables move in the opposite direction, i.e. when

one variable increases the other decreases and vice versa.

2. Linear and Non-Linear (Curvilinear) Correlation: The correlation is said to be linear when the amount of

change in one variable to the amount of change in another variable For example, from the values of two variables

given below, it is clear that the ratio of change between the variables is the same:

X: 10 20 30 40 50

Y: 20 40 60 80 100

1. Perfect Positive Correlation (r=+1): The correlation is said to be perfectly positive when all the points lie on

the straight line rising from the lower left-hand corner to the upper

right-hand corner.




2. Perfect Negative Correlation (r=-1): When all the points lie on a straight line falling from the upper left-hand

corner to the lower right-hand corner, the variables are said to be negatively correlated.

Unit- VII Environmental Impact Assessment (EIA) and Environmental Management Plan

Environmental Impact Assessment (EIA) defined as the documentation of an environmental analysis which

includes identification, prediction, and mitigation of impacts caused by a proposed action or projects.

On 27th January 1994, the EIA Regulations came into force for the first time.

They made it mandatory for specified projects to conduct an EIA. Such projects need prior environmental

clearance. Before initiation, they must submit their report to the Impact Assessment Agency.

The Environment Protection Act (EPA), 1986 provided for these regulations. It means EIA notification is

under EPA, 1986 (Environment Protection Act (EPA), 1986 also called UMBRELLA ACT).

The primary aim of EIA is to assess the potential impact of a project on the environment. This provides

time for taking measures to curb these environmental impacts.

First of all, the project unit must make a self-assessment report. A review by the regulatory agency is the

next step. The final stage is approval by the agency.

EIA Process

Compressive EIA: The EIA report must be done or prepared by incorporation of data during all

the four seasons of the year.




Rapid EIA: Provision for a single season (3 months) collection of data, but this should not be

done during monsoon season.

The steps of the EIA process (1994) are presented in brief below:

Screening: First stage of EIA, which determines whether the proposed project, requires an EIA or not, and

if it does, then the level of assessment required. Project developer needed EIA team for preparation of EIA

report.

Scoping: This stage identifies the key issues and impacts that should be investigated for particular project.

MoEF has set guidelines and reviews checklist for relevant issues for different project types and provide

Public hearing process in India

The Indian system provides n opportunity to involve affected people and vulnerable peoples to develop

Terms of references (TORs) for EIA thus incorporating their concerns into decision making process.

It is a measure to disclose all the relevant information regarding a developmental project

to various sections of society

In India public hearing of development projects has been made mandatory for environmental clearance by

the Amendment to the EIA Notification of April 10, 1997

Environmental appraisal Committee (EAC) procedure or Review Decision Making

The MOEF is the nodal agency for environmental clearance. The project proponents of new projects must submit

an application to the secretary, ministry of Environment and Forests, New Delhi in the standard Performa specified

in the EIA notification. The application should be accompanied by a feasibility/ project report, including:

1 Environmental Appraisal questionnaire developed by MOEF.

2 Environment Impact Assessment Report.




3 Environment Management Plan and disaster Management plan

4 Details of public Hearing (where ever necessary)

5 Rehabilitation plans (where ever necessary)

6 Forest clearance certificate (where ever necessary)

7 NOC from the state pollution control board (SPCB)

The application is evaluated and assessed by the Impact Assessment Agency (IAA). The IAA may consult

a committee of experts constituted by it or other body authorized by it in this regard, if necessary.

The committee has full right of entry and inspection of the site or factory premises prior to, during or after

the commencement of the project .The IAA prepares a set of recommendations based on technical

assessment of documents and data , furnished by the project authorities or collected during visits to sites or

factories and details of public hearing.

The assessment shall be completed with in 90 days from receipt of documents and data from the project

authorities and completion of public hearing and decision conveyed within 30 days thereafter.




Validity of Environmental Clearance (EC):

The “Validity of Environmental Clearance” is meant the period from which a prior environmental

clearance is granted by the regulatory authority

1. Thirty years (30 years) for mining projects

2. Ten years (10 years) in the case of River Valley projects

3. Seven years (7 years) in the case of all other projects and activities. (Earlier it was 5 years but recently

amendment done in 2015)

4. However, in the case of Area Development projects and Townships the validity period shall be limited only

to such activities as may be the responsibility of the applicant as a developer

Environmental management Plan (EMP)

An environmental management plan is a set of policy measures, management actions, operating procedures,

documentation and record keeping with defined responsibilities and accountability pr personnel within an

organization to address environmental issues.

Environmental management Plan standard available.

ISO 14000 series of international standards on environmental management systems

ISO (International organization for standardization)

ISO 14000 is a family of standards related to environmental management that exists to help organizations

(a) minimize how their operations (processes, etc.) negatively affect the environment (i.e., cause adverse

changes to air, water, or land); (b) comply with applicable laws, regulations, and other environmentally

oriented requirements; and (c) continually improve in the above.

The series is divided into two separate areas-the organization evaluation standards and the product

evaluation standards. The first deals with Environmental Management System (EMS), Environmental




Auditing (EA), and Environmental Performance Evaluation (EPE), whereas later deals with

Environmental Impact Assessment (EIA) Methodologies

Any Environmental impact Analysis methodology should effectively deal with

a.impact identification, impact measurement, impact interpretation

b.impact communication to information users

Based upon the way impacts are identified, the six methods are named as

1. Ad Hoc method:

Broad areas of possible impacts like impacts upon flora and fauna, impacts on lakes and forests etc.; are

identified in this method.

This method does not define specific parameters to be investigated, and so may not provided sufficient

guidance for impact assessment.

A team of specialists will identify the nature of the impacts such as no effect, short or long term, reversible

or irreversible etc.

Ad hoc methods are for rough assessment of total impact giving the board areas of possible impacts and

general nature of these possible impacts.

Battelle Environment Evaluation System

The system is based on a classification consisting of four levels

Level I : Categories

Level II : Components

Level III : Parameters

Level IV : Measurements

Each category (level-1) is divided into several components, each component (level-II) into several

parameters and each parameter (level-III) into one or two measurements.




EIA Notification, 2006

The MOEF (now MOEFCC) , New Delhi has issued the Environmental Impact Assessment Notification on 14th

Sept 2006 which makes prior environmental clearance mandatory for developmental activities listed.

Step- 1 Application for prior environmental clearance (EC).

The following projects of activities require EC from the concerned regulatory authority before any construction

work starting or preparation of land by the project management.

(i) All new projects or activities listed in the Schedule of EIA notification 2006.

(ii) Expansion and modernization of existing projects or activities listed in the Schedule to

this notification with addition of capacity beyond the limits specified for the concerned sector, that is,

projects or activities which cross the threshold limits given in the Schedule, after expansion or

modernization;

(iii) Any change in product - mix in an existing manufacturing unit included in Schedule beyond the

specified range.

An application seeking prior environmental clearance in all cases shall be made in:

1. Fill Form 1 and Supplementary Form 1A

Form 1 mandatory for all projects

Form 1A only for Category 8 projects (construction)

2. Submit pre-feasibility report for all projects and conceptual plan for construction activities

Categorization of projects and activities:-

(i) All projects and activities are broadly categorized in to two categories - Category A and

Category B, based on the spatial extent of potential impacts and potential impacts on human health and natural and

manmade resources.

(ii) All projects or activities included as Category ‘A’ in the Schedule, shall require prior environmental clearance

from the Central Government in the Ministry of Environment and Forests (MoEF) on the recommendations of an

Expert Appraisal Committee (EAC) to be constituted by the Central Government for the purposes of this

notification;




(iii) All projects or activities included as Category ‘B’ in the Schedulewill require prior environmental clearance

from the State/Union territory Environment Impact Assessment Authority (SEIAA). The SEIAA shall base its

decision on the recommendations of a State or Union territory level Expert Appraisal Committee (SEAC) as to be

constituted for in this notification. In the absence of a duly constituted SEIAA or SEAC, a Category ‘B’ project

shall be treated as a Category ‘A’ project.

Unit-IX : Solid and Hazardous Waste Management

Introduction of Solid Waste:

According to the Environment Protection Act, 1990, waste is defined as: “any substance which constitutes a scrap

material, or an effluent or other unwanted surplus substance arising from application of any process”.

Classification of waste:

1. Biodegradable waste: These can be degraded through microbial activity. eg: food residue, human excreta,

etc.

2. Non-Biodegradable waste: Petroleum, plastic, glasses, etc.

3. Bio medical waste: Needle, syringe, body parts, etc.

4. E-waste: Computer parts, batteries, CFL bulbs, etc.

Sources of Waste:

1. Domestic waste: polythene, bottles, food, cotton, etc.

2. Industrial waste

a) Food processing: Organic wastes, pathogens, etc.

b) Paper: Chlorine, sulphur dioxide, methyl mercaptan, etc.

c) Textile: From boiling and processing of fibre

d) Petroleum: Inorganic sulphur, hydrocarbons, organic acids, etc.

e) Chemical: Phosphorus, fluorine, silica, etc.

f) Metal: Copper, lead, chromium, cadmium.

g) Cement: Particulate matter, dust.




h) Nuclear reactor: Radioactive waste.

i) Agricultural waste: Fertilizer, crop residue, pesticide (like DDT), fumigants.

3. Radioactive waste: X-Ray machines, nuclear plants, laboratories etc.

4. Municipal waste: Waste produced by public offices, parks, shops etc.

1. Types & Source of Solid Wastes:

Basically solid waste can be classified into different types depending on their source:

2. Effects of Solid Waste Pollution:

Municipal solid wastes heap up on the roads due to improper disposal system. People clean their own




houses and litter their immediate surroundings which affects the community including themselves.

This type of dumping allows biodegradable materials to decompose under uncontrolled and unhygienic

conditions. This produces foul smell and breeds various types of insects and infectious organisms besides

spoiling the aesthetics of the site. Industrial solid wastes are sources of toxic metals and hazardous wastes,

which may spread on land and can cause changes in physicochemical and biological characteristics thereby

affecting productivity of soils.

Toxic substances may leach or percolate to contaminate the ground water. In refuse mixing, the hazardous

wastes are mixed with garbage and other combustible wastes. This makes segregation and disposal all the

more difficult and risky.

Various types of wastes like cans, pesticides, cleaning solvents, batteries (zinc, lead or mercury),

radioactive materials, plastics and e-waste are mixed up with paper, scraps and other non-toxic materials

which could be recycled. Burning of some of these materials produces dioxins, furans and polychlorinated

biphenyls, which have the potential to cause various types of ailments including cancer.

3. Methods of Solid Wastes Disposal:

i. Sanitary Landfill

ii. Incineration

iii. Composting

iv. Pyrolysis

i. Sanitary Land Filling:

In a sanitary landfill, garbage is spread out in thin layers, compacted and covered with clay or plastic foam.

In the modern landfills the bottom is covered with an impermeable liner, usually several layers of clay,

thick plastic and sand. The liner protects the ground water from being contaminated due to percolation of




leachate.

Leachate from bottom is pumped and sent for treatment. When landfill is full it is covered with clay, sand,

gravel and top soil to prevent seepage of water. Several wells are drilled near the landfill site to monitor if

any leakage is contaminating ground water. Methane produced by anaerobic decomposition is collected

and burnt to produce electricity or heat.

ii. Incineration:

The term incinerates means to burn something until nothing is left but ashes. An incinerator is a unit or

facility used to burn trash and other types of waste until it is reduced to ash. An incinerator is constructed of

heavy, well-insulated materials, so that it does not give off extreme amounts of external heat.

The high levels of heat are kept inside the furnace or unit so that the waste is burned quickly and efficiently.

If the heat were allowed to escape, the waste would not burn as completely or as rapidly. Incineration is a

disposal method in which solid organic wastes are subjected to combustion so as to convert them into

residue and gaseous products. This method is useful for disposal of residue of both solid waste management

and solid residue from waste water management. This process reduces the volumes of solid waste to 20 to

30 per cent of the original volume.




Incineration and other high temperature waste treatment systems are sometimes described as “thermal

treatment”. Incinerators convert waste materials into heat, gas, steam and ash. Incineration is carried out

both on a small scale by individuals and on a large scale by industry. It is used to dispose of solid, liquid and

gaseous waste. It is recognized as a practical method of disposing of certain hazardous waste materials.

Incineration is a controversial method of waste disposal, due to issues such as emission of gaseous

pollutants.

iii. Composting:

Due to shortage of space for landfill in bigger cities, the biodegradable yard waste (kept separate from the

municipal waste) is allowed to degrade or decompose in a medium. A good quality nutrient rich and

environmental friendly manure is formed which improves the soil conditions and fertility.

Organic matter constitutes 35%-40% of the municipal solid waste generated in India. This waste can be

recycled by the method of composting, one of the oldest forms of disposal. It is the natural process of

decomposition of organic waste that yields manure or compost, which is very rich in nutrients.

Composting is a biological process in which micro-organisms, mainly fungi and bacteria, convert

degradable organic waste into humus like substance. This finished product, which looks like soil, is high in

carbon and nitrogen and is an excellent medium for growing plants.

The process of composting ensures the waste that is produced in the kitchens is not carelessly thrown and

left to rot. It recycles the nutrients and returns them to the soil as nutrients. Apart from being clean, cheap,

and safe, composting can significantly reduce the amount of disposable garbage.

The organic fertilizer can be used instead of chemical fertilizers and is better specially when used for

vegetables. It increases the soil’s ability to hold water and makes the soil easier to cultivate. It helped the

soil retain more of the plant nutrients.

Vermi-composting has become very popular in the last few years. In this method, worms are added to the

compost. These help to break the waste and the added excreta of the worms makes the compost very rich in




nutrients. In the activity section of this web site you can learn how to make a compost pit or a

vermi-compost pit in your school or in the garden at home.

To make a compost pit, you have to select a cool, shaded corner of the garden or the school compound and

dig a pit, which ideally should be 3 feet deep. This depth is convenient for aerobic composting as the

compost has to be turned at regular intervals in this process.

Preferably the pit should be lined with granite or brick to prevent nitrite pollution of the subsoil water,

which is known to be highly toxic. Each time organic matter is added to the pit it should be covered with a

layer of dried leaves or a thin layer of soil which allows air to enter the pit thereby preventing bad odour. At

the end of 45 days, the rich pure organic matter is ready to be used.

Composting: some benefits

i. Compost allows the soil to retain more plant nutrients over a longer period.

ii. It supplies part of the 16 essential elements needed by the plants.

iii. It helps reduce the adverse effects of excessive alkalinity, acidity, or the excessive use of chemical fertilizer.

iv. It makes soil easier to cultivate.

v. It helps keep the soil cool in summer and warm in winter.

vi. It aids in preventing soil erosion by keeping the soil covered.

vii. It helps in controlling the growth of weeds in the garden.

iv. Pyrolysis:

Pyrolysis is a form of incineration that chemically decomposes organic materials by heat in the absence of

oxygen. Pyrolysis typically occurs under pressure and at operating temperatures above 430 °C (800 °F).

In practice, it is not possible to achieve a completely oxygen-free atmosphere. Because some oxygen is

present in any pyrolysis system, a small amount of oxidation occurs. If volatile or semi-volatile materials




are present in the waste, thermal desorption will also occur.

Organic materials are transformed into gases, small quantities of liquid, and a solid residue containing

carbon and ash. The off-gases may also be treated in a secondary thermal oxidation unit. Particulate

removal equipment is also required. Several types of pyrolysis units are available, including the rotary kiln,

rotary hearth furnace, and fluidized bed furnace. These units are similar to incinerators except that they

operate at lower temperatures and with less air supply.

Limitations and Concerns:

i. The technology requires drying of soil prior to treatment.

ii. Limited performance data are available for systems treating hazardous wastes containing polychlorinated

biphenyls (PCBs), dioxins, and other organics. There is concern that systems that destroy chlorinated organic

molecules by heat have the potential to create products of incomplete combustion, including dioxins and furans.

These compounds are extremely toxic in the parts per trillion ranges. The MSO process reportedly does not

produce dioxins and furans.

iii. The molten salt is usually recycled in the reactor chamber. However, depending on the waste treated (especially

inorganics) and the amount of ash, spent molten salt may be hazardous and require special care in disposal.

iv. Pyrolysis is not effective in either destroying or physically separating in organics from the contaminated

medium. Volatile metals may be removed as a result of the higher temperatures associated with the process, but

they are not destroyed. By-products containing heavy metals may require stabilization before final disposal.

v. When the off-gases are cooled, liquids condense, producing an oil/tar residue and contaminated water. These

oils and tars may be hazardous wastes, requiring proper treatment, storage, and disposal

Basic Collection Scheme

1.) Based on the availability of service

1. Communal system

2. Block Collection




3. Kerbside/alley

4. Door to door collection

2) Based on mode of operation

1) Hauled Container System

2) Stationary Container System

1) Hauled Containers

An empty storage container (known as a drop-off box) is hauled to the storage site to replace the container that is

full of waste, which is then hauled to the processing point, transfer station or disposal site

•The time required per trip

Where,

T = time per trip for hauled-container system, h/trip hcs

PThcs= pick-up time per trip for hauled-container system, h/trip

q = at-site time per trip, h/trip

m = empirical haul constant, h/km

n = empirical haul constant, h/km

x = round-trip haul distance, km/trip

The pick-up time per trip PThcsis equal to:

Where,

Thcs= (PThcs+ q + m + nx)....... (1)

PThcs= pc + uc + dbc.......(2)




pc = pick-up time per trip, h/trip

uc= time required to unload empty container, h/trip

dbc= average time spent driving between container locations, h/trip (determined locally)

The number of trips that can be made per vehicle per day with a hauled-container system, including a factor to

account for off-route activities, is determined using equation 3:

Where,

M = number of trips per day, trip/d d

W = off-route factor, expressed as a fraction

L = length of working day, h/d

t1= time from garage to first container location, h

t2= time from last container location to garage, h

2. Stationary Containers

In this system, containers used for the storage of waste remain at the point of collection. The collection

vehicles generally stop alongside the storage containers, and collection crews load the waste from the

storage containers into the collection vehicles and then transport the waste to the processing, transfer or

Md= {(1-W)L (t1+t2)} /Thcs......(3)




disposal site.

For systems using mechanically self-loading compactors, the time per trip is:

Where,

Tscs= time per trip for stationary-container system, h/trip

PTscs= pick-up time per trip for stationary-container system, h/trip

q = at-site time per trip, h/trip

m = empirical haul constant, h/km

iil hl tt h/k

The pick-up time per trip PTscsis equal to:

Where,

Ct= number of containers emptied per trip, container/trip t

uc= average unloading time per container for stationary-container

systems, h/container

S = number of container pick-up locations per trip, locations/trip

dbc= average time spent driving between container

Where,

Vv= volume of collection vehicle, m3/trip

Vc= container volume, m3/container

z = compaction ratio

Tscs= (PTscs+ q + m + nx) .........(4)

PTscs= Ctuc +(S-1)(dbc)

........(5)




f = weighted container utilization factor.

Classification of dangerous goods chart




Characteristics of hazardous wastes

The regulations define characteristic hazardous wastes as wastes that exhibit measurable properties posing

sufficient threats to warrant regulation. For a waste to be deemed a characteristic hazardous waste, it must

cause, or significantly contribute to, an increased mortality or an increase in serious irreversible or




incapacitating reversible illness, or pose a substantial hazard or threat of a hazard to human health or the

environment, when it is improperly treated, stored, transported, disposed of, or otherwise mismanaged.

In other words, if the wastes generated at a facility are not listed in the F, K, P, or U lists, the final step to

determine whether a waste is hazardous is to evaluate it against the following 4 hazardous characteristics:

(i) Ignitability (EPA Waste Identification Number D001): A waste is an ignitable hazardous waste, if it has a

flash point of less than 600C; readily catches fire and burns so vigorously as to create a hazard; or is an ignitable

compressed gas or an oxidiser. A simple method of determining the flash point of a waste is to review the material

safety data sheet, which can be obtained from the manufacturer or distributor of the material. Naphtha, lacquer

thinner, epoxy resins, adhesives and oil based paints are all examples of ignitable hazardous wastes.

(ii) Corrosivity (EPA Waste Identification Number D002): A liquid waste which has a pH of less than or equal

to 2 or greater than or equal to 12.5 is considered to be a corrosive hazardous waste. Sodium hydroxide, a caustic

solution with a high pH, is often used by many industries to clean or degrease metal parts. Hydrochloric acid, a

solution with a low pH, is used by many industries to clean metal parts prior to painting. When these caustic or acid

solutions are disposed of, the waste is a corrosive hazardous waste.

(iii) Reactivity (EPA Waste Identification Number D003): A material is considered a reactive hazardous waste,

if it is unstable, reacts violently with water, generates toxic gases when exposed to water or corrosive materials, or

if it is capable of detonation or explosion when exposed to heat or a flame. Examples of reactive wastes would be

waste gunpowder, sodium metal or wastes containing cyanides or sulphides.

(iv) Toxicity (EPA Waste Identification Number D004): To determine if a waste is a toxic hazardous waste, a

representative sample of the material must be subjected to a test conducted in a certified laboratory. The toxic

characteristic identifies wastes that are likely to leach dangerous concentrations of toxic chemicals into ground

water.

HAZARDOUS WASTE TREATMENT




Hazardous wastes need Appropriate treatment, depending on the type of waste. The various options for

hazardous waste treatment can be categorised under physical, chemical, thermal and biological treatments.

We will discuss these options,

(A) Physical and chemical treatment

Physical and chemical treatments are an essential part of most hazardous waste treatment operations, and the

treatments include the following (Freeman, 1988):

(i) Filtration and separation: Filtration is a method for separating solid particles from a liquid using a porous

medium. The driving force in filtration is a pressure gradient, caused by gravity, centrifugal force, vacuum, or

pressure greater than atmospheric pressure. The application of filtration for treatment of hazardous waste fall into

the following categories:

Clarification, in which suspended solid particles less than 100 ppm (parts per million) concentration are

removed from an aqueous stream. This is usually accomplished by depth filtration and cross-flow filtration

and the primary aim is to produce a clear aqueous effluent, which can either be discharged directly, or

further processed. The suspended solids are concentrated in a reject stream.

Dewatering of slurries of typically 1% to 30 % solids by weight. Here, the aim is to concentrate the solids

into a phase or solid form for disposal or further treatment. This is usually accomplished by cake filtration.




The filtration treatment, for example, can be used for neutralisation of strong acid with lime or limestone, or

precipitation of dissolved heavy metals as carbonates or sulphides followed by settling and thickening of

the resulting precipitated solids as slurry. The slurry can be dewatered by cake filtration and the effluent

from the settling step can be filtered by depth filtration prior to discharge.

(ii) Chemical precipitation:

This is a process by which the soluble substance is converted to an insoluble form either by a chemical

reaction or by change in the composition of the solvent to diminish the solubility of the substance in it.

Settling and/or filtration can then remove the precipitated solids. In the treatment of hazardous waste, the

process has a wide applicability in the removal of toxic metal from aqueous wastes by converting them to

an insoluble form. This includes wastes containing arsenic, barium, cadmium, chromium, copper, lead,

mercury, nickel, selenium, silver, thallium and zinc. The sources of wastes containing metals are metal

plating and polishing, inorganic pigment, mining and the electronic industries. Hazardous wastes

containing metals are also generated from cleanup of uncontrolled hazardous waste sites, e.g., leachate or

contaminated ground water.

Fly Ash

The combustion of pulverized coal at high temperatures and pressures in power stations produces different

types of Fly ash. These micron-sized earth elements consist primarily of silica, alumina and iron. It is

captured from the power plant's exhaust gases and collected for different use.

The 'fine' ash fraction is carried upwards with the flue gases and captured before reaching the atmosphere

by highly efficient electro static precipitators. This material is known as Pulverized Fuel Ash (PFA) or 'fly

ash'. It is composed mainly of extremely fine, glassy spheres and looks similar to cement.

The 'coarse' ash fraction falls into the grates below the boilers, where it is mixed with water and pumped to

lagoons. This material, known as Furnace Bottom Ash (FBA) has a gritty, sand-like texture.

Fly ash particles are generally spherical in shape and range in size from 0.5 µm to 100 µm. They consist

mostly of silicon dioxide (SiO2), which is present in two forms: amorphous, which is rounded and smooth,

and crystalline, which is sharp, pointed and hazardous; aluminum oxide (Al2O3) and iron oxide (Fe2O3).




As per BIS Codification as notified in Rule 8 (b) of the Plastic Waste (Management and Handling)

(Amendment) Rules, 2011, there are seven categories of plastics:

Recycling of plastic waste shall conform to the Indian Standard: IS 14534:1998 titled as Guidelines for

Recycling of Plastics.

Each recycled carry bag shall bear a label or a mark “recycled” as shown above and shall conform to the

Indian Standard: IS 14534: 1998 titled as “Guidelines for Recycling of Plastics”, as amended from time

to time

The provision of thickness shall not be applicable to carry bags made up of compostable plastic. Carry

bags made from compostable plastics shall conform to the Indian Standard: IS 17088:2008 titled as

Specifications for Compostable Plastics, as amended from time to time. The manufacturers or seller of

compostable plastic carry bags shall obtain a certificate from the Central Pollution Control Board before

marketing or selling; and

“compostable plastics” mean plastic that undergoes degradation by biological processes during

composting to yield CO2, water, inorganic compounds and biomass at a rate consistent with other known




compostable materials, excluding conventional petro-based plastics, and does not leave visible,

distinguishable or toxic residu

Unit- X Contemporary Environmental Issues

National action plan on climate change

There are Eight National Missions which form the core of the National Action Plan, representing

multipronged, long-term and integrated strategies for achieving key goals in the context of climate change.

The focus will be on promoting understanding of climate change, adaptation and mitigation, energy

efficiency and natural resource conservation.




1) National Solar Mission

The National Solar Mission is a major initiative of the Government of India and State Governments to

promote ecologically sustainable growth while addressing India's energy security challenge. The program was

inaugurated by former Prime Minister Manmohan Singh on 11 January 2010 with a target of 20GW by 2022

which was later increased to 100 GW by the NDA government in the 2015 Union budget of India. The objective

of the National Solar Mission is to establish India as a global leader in solar energy, by creating the policy

conditions for its diffusion across the country as quickly as possible.

Mission targets are:

1. The centre has revised cumulative targets under National Solar Mission from 20,000MW by 2021-22 to

1,00,000 MW a quantum jump.

2. The targets will principally comprise of 40 GW rooftop and 60 GW through Large and Medium Scale Grid

Connected Solar Power Project.

2) The National Mission for Enhanced Energy Efficiency (NMEEE)

Promoting innovative policy and regulatory regimes, financing mechanisms, and business models which

not only create, but also sustain markets for energy efficiency in a transparent manner with clear

deliverables to be achieved in a time bound manner.

Sustainable Habitat

Green Building

Buildings are one of the major pollutants that affect urban air quality and contribute to climate change.

Human Habitats (Buildings) interact with the environment in various ways. Throughout their life cycles,

from construction to operation and then demolition, they consume resources in the form of energy, water,

materials, etc. and emit wastes either directly in the form of municipal wastes or indirectly as emissions

from electricity generation.




Green building is the core of which would be to address all the pollution related issues of a building in an

integrated and scientific manner.

The aim of a green building design is to:

Minimize the demand on non-renewable resources and maximize the utilization efficiency of these

resources when in use, and

Maximize reuse and recycling of available resources

Utilization of renewable resources.

It costs a little more to design and construct a green building.

It maximizes the use of efficient building materials and construction practices; optimizes the use of on-site

sources and sinks by bioclimatic architectural practices; uses minimum energy to power itself; uses

efficient equipment to meet its lighting, air-conditioning, and other needs; maximizes the use of renewable

sources of energy; uses efficient waste and water management practices; and provides comfortable and

hygienic indoor working conditions.

It is evolved through a design process that requires all concerned (the architect and landscape designer and

the air conditioning, electrical, plumbing, and energy consultants) to work as a team to address all aspects

of building and system planning, design, construction, and operation.

Selection of ecologically sustainable materials (with high recycled content, rapidly renewable resources

with low emission potential, etc.) for Water and waste management. >Indoor environmental quality

(maintains indoor thermal and visual comfort and air quality)

Green Rating for Integrated Habitat Assessment (GRIHA)

GRIHA is a Sanskrit word meaning - 'Abode or home '.

GRIHA has been conceived by TERI and developed jointly with the Ministry of New and Renewable

Energy, Government of India.




The green building rating system devised by TERI and the MNRE is a voluntary scheme.

Objective: The primary objective of the rating system is to help design green buildings and, in turn, help evaluate

the 'greenness' of the buildings.

Aim: The rating system aims to achieve efficient resource utilization, enhanced resource efficiency, and better

quality of life in the buildings.

Rating system

GRlHA rating system consists of 34 criteria categorized under 4 categories. They are

1. Site Selection and Site Planning,

2. Conservation and efficient utilization of resources,

3. Building operation and maintenance, and

4. Innovation points.

Eight of these 34 criteria are mandatory, four are partly mandatory, while the rest are optional. Each

criterion has a number of points assigned to it.

It means that a project intending to meet the Criterion would qualify for the points. Different levels of

certification (one star to five stars) are awarded based on the number of points earned. The minimum points

required for certification is 50.

The benefits

Some of the benefits of a green design to a building owner, user, and the society as a whole are as follows:

• Reduced energy consumption without sacrificing the comfort levels

• Reduced destruction of natural areas, habitats, and biodiversity, and reduced soil · loss from erosion

etc.

• Reduced air and water pollution (with direct health benefits)

• Reduced water consumption

• Limited waste generation due to recycling and reuse




• Reduced pollution loads

• Increased user productivity

Carbon Sequestration

Carbon Sequestration is capturing and securely storing carbon dioxide emitted from the global energy

system.

Types of Sequestration:

There are number of technologies under investigation for sequestering carbon from the atmosphere. These

can be discussed under three main categories:

Ocean Sequestration: Carbon stored in oceans through direct injection or fertilization.

Geologic Sequestration: Natural pore spaces in geologic formations serve as reservoirs for long-term

carbon dioxide storage.

Terrestrial Sequestration: A large amount of carbon is stored in soils and vegetation, which are our

natural carbon sinks. Increasing carbon fixation through photosynthesis, slowing down or reducing

decomposition of organic matter, and changing land use practices can enhance carbon uptake in these

natural sinks.

Geologic Sequestration Trapping Mechanisms

Hydrodynamic Trapping: Carbon dioxide can be trapped as a gas under low-permeability cap rock

(much like natural gas is stored in gas reservoirs).

Solubility Trapping: Carbon dioxide can be dissolved into a liquid, such as water or oil.




Mineral Carbonation: Carbon dioxide can react with the minerals, fluids, and organic matter in a

geologic formation to form stable compounds/minerals; largely calcium, iron, and magnesium carbonates.

Carbon credits

A carbon credit is a tradeable certificate or permit representing the right to emit one tonne of carbon or

carbon dioxide equivalent (tC02e).

One carbon credit is equal to one ton of carbon dioxide, or in some markets, carbon dioxide equivalent

gases.

How does one earn a carbon credit?




An organisation which produces one tonne less of carbon or carbon dioxide equivalent than the standard

level of carbon emission allowed for its outfit or activity, earns a carbon credit.

Countries which are signatories to the Kyoto Protocol under the UNFCCC have laid down gas emission

norms for their companies to be met by 2012. In such cases, a company has two ways to reduce emissions.

(i) It can reduce the GHG (greenhouse gases) by adopting new technology or improving upon the existing

technology to attain the new norms for emission of gases.

(ii) It can tie up with developing nations and help them set up new technology that is eco-friendly, thereby helping

developing country or its companies 'earn' credits. This credit becomes a permit for the company to emit GHGs in

its own country. However, only a portion of carbon credits of the company in developing country can be

transferred to the company in developed country.

Developing countries

Developing countries like India and China are likely to emerge as the biggest sellers and Europe is going to

be the biggest buyers of carbon credits.

Last year global carbon credit trading was estimated at $5 billion, with India's contribution at around, $1

billion.

China is currently the largest seller of carbon credits controlling about 70% of the market share.

Carbon, like any other commodity, has begun to be traded on India's Multi Commodity Exchange.

MCX has become first exchange in Asia to trade carbon credits.




Wild Life Conservation Project

1) Project Tiger

A potential example of conservation of a highly endangered species is the Indian Tiger (Panthera tigris);

The fall and rise in the number of Tiger population in India is an index of the extent and nature of

conservation efforts.It is estimated that India had about 40, 000 tigers in 1900, and the number declined to

a mere about 1800 in 1972.

Hence, Project Tiger centrally sponsored scheme was launched in 1973 with the following objectives:

To ensure maintenance of available population of Tigers in India for scientific, economic, aesthetic,

cultural and ecological value

To preserve, for all times, the areas of such biological importance as a national heritage for the benefit,

education and enjoyment of the people

Aim

(i) Conservation of the endangered species and

(ii) Harmonizing the rights of tribal people living in and around tiger reserves

Tiger Reserve

Tiger reserves are areas that are notified for the protection of the tiger and its prey, and are governed by

Project Tiger which was launched in the country in 1973.

Initially 9 tiger reserves were covered under the project, and has currently increased to 42, falling in 17

States (tiger reserve States).

The State Government shall, on recommendation of the National Tiger Conservation Authority, notify an

area as a tiger-reserve.




EUTROPHICATION ·

Greek word - Eutrophia means adequate & healthy nutrition.

Eutrophication is a syndrome of ecosystem, response to the addition of artificial or natural substances such

as nitrates and phosphates through fertilizer, sewage, etc that fertilize the aquatic ecosystem.

The growth of green algae which we see in the lake surface layer is the physical identification of an

Eutrophication.

Eutrophication is the enrichment of an aquatic system by the addition of nutrients.

It is primarily caused by the leaching of phosphate and - or nitrate containing fertilisers from agricultural

lands into lakes or river.

Some algae and blue-green bacteria thrive on the excess ions and a population explosion covers almost

entire surface layer is known as algal bloom. This growth is unsustainable, however.

As Algal Bloom covers the surface layer, it restricts the penetration of sunlight. Perhaps because another

nutrient becomes limiting, death of aquatic organisms takes place.

Oxygen is required by all respiring animals in the water and it is replenished by photosynthesis of green

plants.

The oxygen level is already low because of the population explosion and further oxygen is taken up by

microorganisms which feed off the dead algae during decomposition process.

Due to reduced oxygen level, fishes and other aquatic organism suffocate and they die.

The new anaerobic .conditions can promote growth of bacteria such as Clostridium botulinum which

produces toxins deadly to aquatic organisms, birds and mammals.

All this eventually leads to degradation of aquatic ecosystem and death of its organisms.

It often leads to change in animal and plant population & degradation of water & habitat quality.




Process of Eutrophication

Sources




Soil Erosion

Soil erosion is defined as the wearing-away of topsoil. Topsoil is the most fertile part of the soil because it contains

the most organic, nutrient-rich materials. Therefore, this is the layer that farmers want to protect for growing their

crops and ranchers want to protect for growing grasses for their cattle to graze on. There are various ways by which

this fertile topsoil is lost and wasted.

Types of soil erosion:

1. Water Erosion: It is caused by the action of water, which removes the soil by falling on as rain drops as well as

by its surface flow action. Depending upon the form of the lost soil it may be:

(a)Splash erosion is the first stage of the erosion process. It occurs when raindrops hit bare soil.

The explosive impact breaks up soil aggregates so that individual soil particles are 'splashed' onto the soil surface.

(b) Sheet erosion: The removed soil is like a thin covering from large area. This sheet is lost more or less

uniformly.

(c) Rill erosion: If sheet erosion occurs with full force, the runoff water moves rapidly over the soil surface

cutting well defined finger-shaped groove like structures, appearing as thin channels or streams.

(d) Gully erosion: This results due to the convergence of several rills (thin channels formed during rill erosion)

towards the steep slope, which form together wider channels (grooves) of water, known as gullies.




(e) Ravine: When a gully bed is eroded further, the bed gradually deepens and flattens out and a ravine is formed.

The depth of a ravine may extend to 30 metres or more.

(f) Stream bank erosion: The erosion of soil from the banks (shores) of the streams or rivers due to the flowing

water is called bank erosion.

2. Wind erosion: Wind erosion or Aeolian erosion is quite significant in arid and semi-arid regions where soil is

chiefly sandy and the vegetation is very poor or even absent. Once the top soil is laid bare to the fury of strong

winds, it gets blown off in the form of dust storm and sand storm. Wind erosion may be of the following three

types:

(a) Saltation: The major fraction of soil moved by the wind is through the process of saltation. In saltation, fine

soil particles are lifted into the air by the wind and drift horizontally across the surface increasing in velocity as

they go. Soil particles moved in this process of saltation can cause severe damage to the soil surface and vegetation.

They travel approximately four times longer in distance than in height. When they strike the surface again they

either rebound back into the air or knock other particles into the air.

(b) Suspension: The wind throws away smallest soil particles into air, which moves as fine crust with the wind. By

this way soils are transported to fairly long distances.

(c) Surface creep: the heavier particles of soil that are not easily thrown up by wind, are simply pushed or spread

along the surface by wind.




3.

Landslides or slip erosion: The hydraulic pressure caused by heavy rains increases the weight of rocks at cliffs

which come under the gravitational force and finally slip or fall off.

4. Deforestation and over-grazing: Deforestation makes soil cover vulnerable for wind and water erosion. Over

grazing is a major hazard affecting pastures, forests, and mountains. Grazing destroys the little cover and enhances

wind and water erosion.

Methods of controlling Soil Erosion

1. Biological methods: It includes the use of plant of vegetation cover.

(i) Agronomic practices: It includes natural protection by growing vegetation in a manner that reduces soil loss.

These are:

(a) Contour farming: In which preparation of fields with alternate furrows and ridges to reduce water flow.

Ridges at the same level are known as contour. On slopes, however, this type of farming is coupled with terracing.




Contour Farming Terrace Farming

(b) Mulching: It is effective against wind as well as waster erosion. Some such plants as maize stalks, cotton stalks

etc.., are used as a 'mulch' (a protective layer formed by the stubble). Mulches reduce soil moisture evaporation and

increase amount of soil moisture by addition of organic matter to soil.

(c) Crop rotation: It decreases soil loss and preserves the productivity of land.

(d) Strip cropping: It involves the planting of crop in rows or strips to check flow of water

(ii) Agrostological methods: Grasses such as Cynodon dactylon are utilized as erosion-resisting stabilizer plants.

They are grown in strips between the crops. Such methods include:

(a) Hay farming: This aims to grow grasses in rotation with the fields’ crops, which helps in building up the

structure of soil, preventing soil erosion and improving its fertility

(b) Retiring lands to grass: It involves to grow grasses on such lands where major proportion of the top soil has

been eroded. Generally grasses are allowed to grazing under suitable climate conditions.

2. Mechanical methods: These methods are used as supplements to biological methods. These are:

(i) Basin listing: i.e. to construct small basin along the slope to intercept and divert the runoff water.




(ii) Contour terracing: To construct a channel along the slope to intercept and divert the runoff water. This may

be:

(a) Channel terrace: To dig channels at suitable intervals and the excavated soil deposited as a wide, low, ridge

along, the lower edge of the channel.

(b) Broad based ridge terrace: i.e. to construct ridge along both the sides of the channel:

(c) Bench terrace: To construct a number of platforms along contours or suitable graded lines across the slope.

3. Other methods: These include:

(i) Stream bank protection: To grow vegetation alongside the river bank, to construct drains, concrete or stone

Pitching etc. for checking & cutting and carving 'of riverbanks.

(ii) Afforestation: Trees as windbreaks are planted at 90° to the prevailing wind in deserts which check the

velocity of wind. They check the spread of sand dunes or desert conditions or blowing away of the fertile top soil.

Windbreaks may be planted in several rows.

Desertification: Causes, Effects and Control

Desertification is taking place much faster worldwide than historically and usually arises from the demands

of increased populations that settle on the land in order to grow crops and graze animals.

It is land degradation occurring in arid, semiarid and dry sub-humid areas of the world. It is a process where

in fertile lands become arid through land mismanagement or climate changes. Many deserts in the world

are man-made.

Causes of Desertification:

1. Overgrazing: By pounding the soil with their hooves, livestock compact the substrate, increase the proportion

of fine material, and reduce the percolation rate of the soil, thus encouraging erosion by wind and water. Grazing

and the collection of firewood reduce or eliminate plants that help to bind the soil.




2. Increased population: Livestock pressure on marginal lands accelerates desertification.

3. Deforestation practices: Loss of vegetation results in surface runoff as there are no plants to bind the soil and

resulting in soil erosion and depletion of nutrients.

4. Increased food production from marginal lands in arid or semiarid areas.

5. Irrigation projects in areas with no drainage facility.

6. Shifting of sand dunes by wind storms.

Effects:

Major impact of desertification is biodiversity loss, and loss of productive capacity, such as the transition

from grassland dominated by perennial grasses to one dominated by perennial shrubs. In extreme cases, it

leads to the destruction of land’s ability to support life.

Control of Desertification:

1. Afforestation and planting of soil binding grasses can check soil erosion, floods and water logging.

2. Crop rotation and mixed cropping improve the fertility of the soil. It would increase production which can

sustain large population.

3. Desertification can be checked by artificial bunds or covering the area with proper type of vegetation.

4. shifting of sand can be controlled by mulching (use of artificial protective covering.)

5. Salinity of the soil can be checked by improved drainage. Saline soil can be recovered by leaching with more

water, particularly where water table of the ground is not very high.




Miscellaneous Topics

Analytical Techniques

Spectrophotometry

Spectrophotometry is a method to measure how much a chemical substance absorbs, transmits, or

reflects light by measuring the intensity of light as a beam of light passes through sample solution.

Every chemical compound absorbs, transmits, or reflects light (electromagnetic radiation) over a certain

range of wavelength which is used to measure the amount of a known chemical substance.

1. Flame Photometry

Flame photometry is a process where in emission of radiation by neutral atoms is measured.

The neutral atoms are obtained by introduction of sample into flame. Hence the name flame photometry.

Since radiation is emitted it is also called as flame emission spectroscopy.

Flame photometer working principle:

When a solution of metallic salt is sprayed as fine droplets into a flame. Due to heat of the flame, the

droplets dry leaving a fine residue of salt. This fine residue converts into neutral atoms.

Due to the thermal energy of the flame, the atoms get excited and there after return to ground state. In this

process of return to ground state, exited atoms emit radiation of specific wavelength. This wavelength of

radiation emitted is specific for every element.




This specificity of wavelength of light emitted makes it a qualitative aspect. While the intensity of

radiation, depends on the concentration of element. This makes it a quantitative aspect.

Note : The process seems to be simple and applicable to all elements. But in practice only a few elements of

Group IA and group IIA (like Li, Na, k & Ca, Mg) are only analyzed.

The radiation emitted in the process is of specific wavelength. Like for Sodium (Na) 589nm yellow

radiation, Potassium 767nm range radiation.

FLAME PHOTOMETER INSTRUMENTATION:

1. Burner

2. Monochromators

3. Detectors

4. Recorder and display.

Burner: This is a part which produces excited atoms. Here the sample solution is sprayed into fuel and oxidant

combination. A homogenous flame of stable intensity is produced.

Fuel and oxidants:

Fuel and oxidant are required to produce flame such that the sample converts to neutral atoms and get

excited by heat energy.The temperature of flame should be stable and also ideal. If the temperature is high,

the elements in sample convert into ions instead of neutral atoms. If it is too low, atoms may not go to exited

state. So a combination of fuel and oxidants is used such that there is desired temperature.

The following combination of fuel and oxidants are commonly used.

Fuel Oxidant Temperature of Flame

Propane + Air 2100 Degree C

Propane + Oxygen 2800 Degree C




Hydrogen + Air 1900 Degree C

Hydrogen + Oxygen 2800 Degree C

Acetylene + Air 2200 Degree C

Acetylene + Oxygen 3000 Degree C

Monochromators:

Filters and monochromators are needed to isolate the light of specific wavelength from remaining light of

the flame. For this simple filters are sufficient as we study only few elements like Ca, Na, K and Li. So a

filter wheel with filter for each element is taken. When a particular element is analyzed, the particular filter

is used so that it filters all other wavelengths.

Detector: Flame photometric detector is similar to that used in spectrophotometry. The emitted radiation is in

the visible region i.e. 400nm to 700nm. Further the radiation is specific for each element so simple detectors are

sufficient for the purpose like photo voltaic cells, photo tubes etc.

Recorders and display: These are devices to read out the recording from detectors.




Flame photometer Applications

1. For qualitative analysis of samples by comparison of spectrum emission wavelengths with that of standards.

2. For quantitative analysis to determine the concentration of group IA and IIA elements. For example

a) Concentration of calcium in hard water.

b) Concentration of Sodium, potassium in Urine

c) Concentration of calcium and other elements in bio-glass and ceramic materials.

Flame photometry limitations:

1. Limited number of elements that can be analyzed.

2. The sample requires to be introduced as solution into fine droplets. Many metallic salts, soil, plant and other

compounds are insoluble in common solvents. Hence, they can’t be analyzed by this method.

3. Since sample is volatilized, if small amount of sample is present, it is tough to analyze by this method. As some of

it gets wasted by vaporization.

Spectrophotometer

A spectrophotometer is an instrument that measures the amount of photons (the intensity of light) absorbed

after it passes through sample solution. With the spectrophotometer, the amount of a known chemical




substance (concentrations) can also be determined by measuring the intensity of light detected. Depending

on the range of wavelength of light source, it can be classified into two different types:

UV-visible spectrophotometer: uses light over the ultraviolet range (185 - 400 nm) and visible range (400

- 700 nm) of electromagnetic radiation spectrum.

IR spectrophotometer: uses light over the infrared range (700 - 15000 nm) of electromagnetic radiation

spectrum.

Devices and mechanic

Figure 1 illustrates the basic structure of spectrophotometers. It consists of a light source, a collimator, a

monochromator, a wavelength selector, a cuvette for sample solution, a photoelectric detector, and a digital

display or a meter. Detailed mechanism is described below

Basic structure of spectrophotometers

A

spectrophotometer, in general, consists of two devices; a spectrometer and a photometer. A spectrometer

is a device that produces, typically disperses and measures light. A photometer indicates the photoelectric

detector that measures the intensity of light.

Spectrometer: It produces a desired range of wavelength of light. First a collimator (lens) transmits a

straight beam of light (photons) that passes through a monochromator (prism) to split it into several

component wavelengths (spectrum). Then a wavelength selector (slit) transmits only the desired

wavelengths, as shown in Figure 1.




Photometer: After the desired range of wavelength of light passes through the solution of a sample in

cuvette, the photometer detects the amount of photons that is absorbed and then sends a signal to a

galvanometer or a digital display, as illustrated in Figure 1.

Principle

It is based on the Beer-Lambert Law. The amount of photons that goes through the cuvette and into the detector is

dependent on the length of the cuvette and the concentration of the sample.

Absorbance:

The absorbance of a transition depends on two external assumptions.

1. The absorbance is directly proportional to the concentration (c) of the solution of the the sample used in the

experiment.

2. The absorbance is directly proportional to the length of the light path (l), which is equal to the width of the

cuvette.

Assumption one relates the absorbance to concentration and can be expressed as

A∝ c---------------------------1

Assumption two can be expressed as

A ∝ l--------------------------2

Combining Equations 1 & 2

: A∝ c . l-----------------------3




This proportionality can be converted into equality by including a proportionality constant (ϵ).

A= ϵ.c.l----------------------4

The absorbance (A) is defined via the incident intensity Io and transmitted intensity I by

-------------5

Combine equation 4 and 5

The constant ϵ is called molar absorptivity or molar extinction coefficient

Transmittance =

---------------6

Once you know the intensity of light after it passes through the cuvette, you can relate it to transmittance

(T). Transmittance is the fraction of light that passes through the sample (after some amount of absorption).

This can be calculated using the equation no -6

Percentage of Transmittence

% Transmittance =

x 100




Take log both side

Absorbance = Log I0/I put in above equation

------------7

Atomic absorption spectrophotometer (AAS)

Atomic absorption spectrophotometer (AAS) is an instrument that measures the concentrations of

heavy metals in ppm and ppb range in liquid medium.

The sample is taken inside the instrument through nebuliser which converts the liquid sample

into aerosol.

This aerosol sample is sprayed into the flame in which metal ion is reduces to its elemental state

(no charge).

Flame (2300ºC to 2700ºC) converts the elements in ionic state to atomic state by detecting the

values of transmittance.

Atoms of different elements absorb characteristic wavelengths of light.

A cathode lamp containing different elements (single element in 1 lamp) emits light from excited

atoms that produce the right mix of wavelengths to be absorbed by the same elements from the

sample.

The absorbed wavelength is recorded by the detector and is computed.

The greater the number of atoms there is in the vapour, the more radiation is absorbed.

The amount of light absorbed is proportional to the number atoms of the element under study.




Chromatography

Chromatography is a technique to separate mixtures of substances into their components on the basis of

their molecular structure and molecular composition. This involves a stationary phase (a solid, or a liquid

supported on a solid) and a mobile phase (a liquid or a gas).

The mobile phase flows through the stationary phase and carries the components of the mixture with it.

Sample components that display stronger interactions with the stationary phase will move more slowly

Hollow Cathode Lamp A+ + e- = A0 Detector

Nebuliser (Converts sample to aerosol)




through the column than components with weaker interactions. These differences in rates cause the

separation of various components.

Chromatographic separations can be carried out using a variety of stationary phases, including immobilized

silica on glass plates (thin-layer chromatography), volatile gases (gas chromatography), paper (paper

chromatography) and liquids (liquid chromatography)

Gas Chromatography

Principle

The principle in gas chromatography principle involves separation of components of the sample under test

due to partition in between gaseous mobile phase and stationary liquid phase. The

elements partitioned into gas come out first while other comes later.

Gas chromatography runs on the principle of partition chromatography for separation of components.

Based on the stationary and mobile phases it is categorized under the gas-liquid type of chromatography,

i.e., the stationary phase is a liquid layer supported over a stationary phase while the mobile phase is an

inert and stable gas.

Working

First, a small amount of sample of the mixture of substances is placed in a syringe and injected into the machine.

The components of the mixture are heated and instantly vaporize. Next, we add a carrier (the eluant), which is

simply a neutral gas such as hydrogen or helium, designed to help the gases in our sample move through the

column. In this case, the column is a thin glass or metal tube usually filled with a liquid that has a high boiling point

(or sometimes a gel or an adsorbent solid). As the mixture travels through the column, it's adsorbed and separates

out into its components. Each component emerges in turn from the end of the column and moves past an electronic

detector (sometimes a mass spectrometer), which identifies it and prints a peak on a chart. The final chart has a

series of peaks that correspond to all the substances in the mixture.




Gas

chromatography instrumentation

The gas chromatography apparatus can be listed as

1. The mobile phase gas in a cylinder: The mobile phase is an inert gas (monoatomic element gases or

non-reactive gases like nitrogen, helium & hydrogen. The carrier gas is kept in a metallic cylinder and outflow

is controlled by a regulator. From gas carrier cylinder, the gas is passed under fixed rate through a pressure gauge

which indicates the speed of flow of gas into the column. Most commonly used gas is helium.

2. The injection system: This is present before column yet inside the thermal chamber to load sample under

analysis into the system.

3. The column for gas chromatography: The gas chromatography column is a usually long (few meters like 3

to 6 meters) and coiled for accommodation into a small thermal chamber. The column is mostly made of steel or

glass.

The GC columns are of three types viz.

♠ Packed column. This is a column into which solid beads are packed. This column has advantages like efficient

separation and precise readings.

♠ Tubular column. Here into a stainless steel hollow tube a thin layer of liquid is coated to act as a stationary phase.

This column offers least resistance to flow of gas.




♠ Support coated tubular column. Here into stainless steel column a thin solid layer is coated on to which a thin

layer of liquid stationary phase is present.

4. The Detector: is another vital component of the gas chromatography apparatus. GC detectors detect the

isolated components and helps in identification and quantification of the sample.




Type of Detector Applicable Samples Detection Limit

Mass Spectrometer (MS) Tunable for any sample .25 to 100 pg

Flame Ionization (FID) Hydrocarbons 1 pg/s

Thermal Conductivity (TCD) Universal 500 pg/ml

Electron-Capture (ECD) Halogenated hydrocarbons 5 fg/s

Atomic Emission (AED) Element-selective 1 pg

Chemiluminescence (CS) Oxidizing reagent Dark current of PMT

Photoionization (PID) Vapor and gaseous Compounds .002 to .02 µg/L

Typical gas chromatography detectors and their detection limits.

5. The computer to record the analysed readings. This is connected with the detector and hence records the

detector changes in reference to the flow of separated components from the exit of the column. The record is

called gas chromatograph.

5. The thermal chamber to fix or maintain fixed temperature.

Application

1. Separation of PAH (Polyaromatic Hydrocarbins), PCB (Poly chlorinated biphenyl), pesticides and

phthalates

2. Analysis of volatile halogenated hydrocarbons

3. Analysis of volatile hydrocarbons

4. Analysis of chlorinated hydrocarbons

5. Analysis of volatile organic compounds

The Distribution Coefficient (Partition Coefficient) (Kc)

The ‘distribution coefficient’ measures the tendency of an analyte to be attracted to the stationary




Phase (Equation 1). Large Kc values lead to longer retention analyte times. The value of Kc can be controlled by

the chemical nature of the stationary phase and the column temperature

Where:

CS= concentration of analyte in the stationary phase

CM= concentration of analyte in the mobile phase

Retention Time

Retention time (RT) is a measure of the time taken for a solute to pass through a chromatography column. It is

calculated as the time from injection to detection.

The RT for a compound is not fixed as many factors can influence it even if the same GC and column are used.

These include:

The gas flow rate

Temperature differences in the oven and column

Column degradation

Column length

The Rf value is defined as the ratio of the distance moved by the solute (i.e. the dye or pigment under test)

and the distance moved by the the solvent (known as the Solvent front)

Rf Value = Distance from Baseline travelled by Solute

Distance from Baseline travelled by Solvent (Solvent Front)

High performance Liquid Chromatography

High performance liquid chromatography (HPLC) is basically a highly improved form of column liquid

chromatography. Instead of a solvent being allowed to drip through a column under gravity, it is forced through

under high pressures of up to 400 atmospheres. That makes it much faster. All chromatographic separations,

including HPLC operate under the same basic principle; separation of a sample into its constituent parts because of




the difference in the relative affinities of different molecules for the mobile phase and the stationary phase used in

the separation.

Types of HPLC

There are following variants of HPLC, depending upon the phase system (stationary) in the process :

1. Normal Phase HPLC:

This method separates analytes on the basis of polarity. NP-HPLC uses polar stationary phase and

non-polar mobile phase. Therefore, the stationary phase is usually silica and typical mobile phases are

hexane, methylene chloride, chloroform, diethyl ether, and mixtures of these. Polar samples are thus

retained on the polar surface of the column packing longer than less polar materials.

2. Reverse Phase HPLC:

The stationary phase is nonpolar (hydrophobic) in nature, while the mobile phase is a polar liquid, such as

mixtures of water and methanol or acetonitrile. It works on the principle of hydrophobic interactions hence

the more nonpolar the material is, the longer it will be retained.

3. Size-exclusion HPLC:

The column is filled with material having precisely controlled pore sizes, and the particles are separated

according to its their molecular size. Larger molecules are rapidly washed through the column; smaller

molecules penetrate inside the porous of the packing particles and elute later.

4. Ion-Exchange HPLC:

The stationary phase has an ionically charged surface of opposite charge to the sample ions. This technique

is used almost exclusively with ionic or ionizable samples. The stronger the charge on the sample, the

stronger it will be attracted to the ionic surface and thus, the longer it will take to elute. The mobile phase is

an aqueous buffer, where both pH and ionic strength are used to control elution time.




Instrumentation of HPLC

As shown in the schematic diagram in Figure above, HPLC instrumentation includes a pump, injector, column,

detector and integrator or acquisition and display system. The heart of the system is the column where separation

occurs.

1. Solvent Resorvoir : Mobile phase contents are contained in a glass resorvoir. The mobile phase, or solvent,

in HPLC is usually a mixture of polar and non-polar liquid components whose respective concentrations

are varied depending on the composition of the sample.

2. Pump : A pump aspirates the mobile phase from the solvent resorvoir and forces it through the system’s

column and detecter. Depending on a number of factors including column dimensions, particle size of the

stationary phase, the flow rate and composition of the mobile phase, operating pressures of up to 42000 kPa

(about 6000 psi) can be generated.

3. Sample Injector : The injector can be a single injection or an automated injection system. An injector for

an HPLC system should provide injection of the liquid sample within the range of 0.1-100 mL of volume

with high reproducibility and under high pressure (up to 4000 psi).

4. Columns : Columns are usually made of polished stainless steel, are between 50 and 300 mm long and

have an internal diameter of between 2 and 5 mm. They are commonly filled with a stationary phase with a

particle size of 3–10 µm. Columns with internal diameters of less than 2 mm are often referred to as

microbore columns. Ideally the temperature of the mobile phase and the column should be kept constant

during an analysis.




5. Detector : The HPLC detector, located at the end of the column detect the analytes as they elute from the

chromatographic column. Commonly used detectors are UV-spectroscopy, fluorescence,

mass-spectrometric and electrochemical detectors.

6. Data Collection Devices : Signals from the detector may be collected on chart recorders or electronic

integrators that vary in complexity and in their ability to process, store and reprocess chromatographic data.

The computer integrates the response of the detector to each component and places it into a chromatograph

that is easy to read and interpret.

Applications of HPLC

The information that can be obtained by HPLC includes resolution, identification and quantification of a

compound. It also aids in chemical separation and purification. The other applications of HPLC include :

Pharmaceutical Applications

1. To control drug stability.

2. Tablet dissolution study of pharmaceutical dosages form.

3. Pharmaceutical quality control.

Environmental Applications

1. Detection of phenolic compounds in drinking water.

2. Bio-monitoring of pollutants.

Applications in Forensics

1. Quantification of drugs in biological samples.

2. Identification of steroids in blood, urine etc.

3. Forensic analysis of textile dyes.

4. Determination of cocaine and other drugs of abuse in blood, urine etc.

Food and Flavour

1. Measurement of Quality of soft drinks and water.

2. Sugar analysis in fruit juices.

3. Analysis of polycyclic compounds in vegetables.

4. Preservative analysis.




Applications in Clinical Tests

1. Urine analysis, antibiotics analysis in blood.

X-ray fluorescence (XRF)

An X-ray fluorescence (XRF) spectrometer is an x-ray instrument used for chemical analyses of rocks,

minerals, sediments and fluids.

The analysis of elements in geological materials by XRF is made possible by the behaviour of atoms when

they interact with radiation. The following steps occur during the XRF analysis:

When the materials are bombarded with X-rays, they become ionized.

The energy of the radiation displaces a tightly-held inner electron, the atom becomes unstable and an outer

electron replaces the missing inner electron.

During this the energy is released due to the decreased binding energy of the inner electron orbital

compared with an outer one.

The emitted radiation is termed as fluorescent radiation and is of lower energy than the primary incident

X-rays.

The resulting fluorescent X-rays can be used to detect the abundances of elements that are present in the

sample.

Applications

X-Ray fluorescence is used in a wide range of applications, including

research in sedimentary, igneous and metamorphic petrology

soil surveys

mining

cement production




ceramic and glass manufacturing

metallurgy

environmental studies (e.g., analyses of particulate matter on air filters)

petroleum industry (e.g., sulfur content of crude oils and petroleum products)

field analysis in geological and environmental studies (using portable, hand-held XRF spectrometers)

X-ray fluorescence is limited in

accurately measuring the abundances of elements with atomic no <11.

XRF analyses cannot distinguish variations among isotopes of an element

XRF analyses cannot distinguish ions of the same element in different valence states

XRD (X-ray diffraction)

X-ray diffraction is based on Bragg’s Law and it consist of three basic elements:

1. an X-ray tube

2. a sample holder

3. an X-ray detector.

When a beam of X-rays of wavelength λ enters a crystal, the maximum intensity of the reflected ray occurs when

sin θ = n λ/2 d, where θ is the complement of the angle of incidence, n is a whole number, and d is the distance

between layers of atoms.

nʎ = 2d sinӨ




ʎ= wavelength of incident X-Ray

d= lattice spacing

Ө= angle of incidence/scattering

n= an integer

X-Rays are generated in a cathode ray tube by heating a filament to produce electrons, accelerating the

electrons toward a target by applying a voltage, and bombarding the target material with electrons. When

electrons have sufficient energy to dislodge inner shell electrons of the target material, characteristic X-ray

spectra are produced. The specific wavelengths are characteristic of the target material.

These X-rays are collimated and directed onto the sample. As the sample and detector are rotated, the

intensity of the reflected X-rays is recorded. When the geometry of the incident X-rays impinging the

sample satisfies the Bragg Equation, constructive interference occurs and peak intensity occurs. A detector

records and processes this X-ray signal and converts the signal to a count rate which is then output to a

device such as a printer or computer monitor.




Applications:

X-ray Diffraction is most widely used for:

identification of unknown crystalline materials (e.g. minerals, inorganic compounds)

Determination of unknown solids is critical to studies in geology, environmental science, material science,

engineering and biology.

Other applications include:

characterization of crystalline materials

identification of fine-grained minerals such as clays and mixed layer clays that are difficult to determine

optically

determination of unit cell dimensions

measurement of sample purity




Scanning Electron Microscope (SEM)

The scanning electron microscope (SEM) uses a focused beam of high-energy electrons to generate a variety of

signals at the surface of solid specimens. The signals reveal information about the sample including external

morphology (texture), chemical composition, and crystalline structure and orientation of materials making up the

sample. In most applications, data are collected over a selected area of the surface of the sample, and a

2-dimensional image is generated that displays spatial variations in these properties. Areas ranging from

approximately 1 cm to 5 microns in width can be imaged in a scanning mode using conventional SEM techniques

(magnification ranging from 20X to approximately 50,000X, spatial resolution of 10 to 100 nm). SEM analysis is

considered to be "non-destructive"; that is, x-rays generated by electron interactions do not lead to volume loss of

the sample, so it is possible to analyse the same materials repeatedly.




Principle:

Accelerated electrons (in vacuum) in an SEM carry significant amounts of kinetic energy,

and this energy is dissipated as a variety of signals produced by electron-sample interactions when the incident

electrons are decelerated in the solid sample. These signals include secondary electrons (that produce SEM

images), backscattered electrons (BSE), diffracted backscattered electrons (EBSD). Secondary electrons and

backscattered electrons are commonly used for imaging samples: secondary electrons are most valuable for

showing morphology and topography on samples and backscattered electrons are most valuable for illustrating

contrasts in composition in multiphase samples. The SEM is also capable of performing analyses of selected point

locations on the sample; this approach is especially useful in qualitatively or semi-quantitatively determining

chemical compositions (using EDS), crystalline structure, and crystal orientations (using EBSD).




Figure: SEM images of PM 2.5 in Delhi in summer and winter.

Applications:

Biology: about microscopic organisms, like bacteria and viruses, field of genetics etc.

Geology: to learn more about crystalline structures, soil and rock sampling etc.

Industries: microelectronics, semiconductors, medical devices, general manufacturing, insurance and

litigation support and food processing.

Forensics: Analysis of gunshot residue, jewellery examination, bullet marking, comparison handwriting

and print analysis, examination of banknote authenticity etc.

To identify cracks, imperfections, or contaminants on the surfaces of coated products.

Identify the problems with particle size or shape.

Transmission Electron Microscope (TEM)

The transmission electron microscope (TEM) is a very powerful tool for material science. A TEM utilizes

energetic electrons to provide morphologic, compositional and crystallographic information on samples. A high

energy beam of electrons is shone through a very thin sample, and the interactions between the electrons and the

atoms can be used to observe features such as the crystal structure and features in the structure like dislocations and

and grain boundaries. Chemical analysis can also be performed. At a maximum potential magnification of 1

nanometer, TEMs are the most powerful microscopes. TEMs produce high-resolution, two-dimensional images,




allowing for a wide range of educational, science and industry applications. TEM analysis is a "destructive"

technique and the sample preparation is very expensive and time consuming.

Principle:

The beam of electrons from the electron gun is focused into a small, thin, coherent beam by the use of the

condenser lens. This beam is restricted by the condenser aperture, which excludes high angle electrons. The beam

then strikes the specimen and parts of it are transmitted depending upon the thickness and electron transparency of

the specimen. This transmitted portion is focused by the objective lens into an image on phosphor screen or charge

coupled device (CCD) camera. Optional objective apertures can be used to enhance the contrast by blocking out

high-angle diffracted electrons. The image then passed down the column through the intermediate and projector

lenses, is enlarged all the way. The image strikes the phosphor screen and light is generated, allowing the user to

see the image. The darker areas of the image represent those areas of the sample that fewer electrons are

transmitted through while the lighter areas of the image represent those areas of the sample that more electrons

were transmitted through.




Figure: TEM images of Schwann cell and nano-crystalline palladium.

Applications:

TEM is ideal for a number of different fields such as life sciences, nanotechnology, medical, biological and

material research, forensic analysis and metallurgy as well as industry and education.

TEMs provide topographical, morphological, compositional and crystalline information.

The images allow researchers to view samples on a molecular level, making it possible to analyze structure

and texture in biological samples.

This information is useful in the study of crystals and metals, but also has industrial applications.

TEMs can be used in semiconductor analysis and production and the manufacturing of computer and

silicon chips.

Technology companies use TEMs to identify flaws, fractures and damages to micro-sized objects; this data

can help fix problems and/or help to make a more durable, efficient product.

SEM vs TEM:

There are some of the differences between SEM and TEM:

SEM is based on scattered electrons while TEM is based on transmitted electrons.

SEM focuses on the sample’s surface and its composition whereas TEM provides the details about internal

composition. Therefore, TEM can show many characteristics of the sample, such as morphology,

crystallization, stress or even magnetic domains. On the other hand, SEM shows only the morphology of

samples.




The sample in TEM has to be cut thinner whereas there is no such need with SEM sample.

TEM has much higher resolution than SEM.

SEM allows for large amount of sample to be analysed at a time whereas with TEM only small amount of

sample can be analysed at a time.

SEM is used for surfaces, powders, polished & etched microstructures, IC chips, chemical segregation

whereas TEM is used for imaging of dislocations, tiny precipitates, grain boundaries and other defect

structures in solids

In TEM, pictures are shown on fluorescent screen whereas in SEM, picture is shown on monitor.

SEM also provides a 3D image while TEM provides a 2D picture.

Fourier Transform Infrared Spectroscopy (FTIR)

FTIR stands for Fourier transform infrared, the preferred method of infrared spectroscopy. When IR radiation is

passed through a sample, some radiation is absorbed by the sample and some passes through (is transmitted). The

resulting signal at the detector is a spectrum representing a molecular ‘fingerprint’ of the sample. The usefulness of

infrared spectroscopy arises because different chemical structures (molecules) produce different spectral

fingerprints. FTIR spectrometers are widely used in organic synthesis, polymer science, petrochemical

engineering, pharmaceutical industry and food analysis. In addition, since FTIR spectrometers can be hyphenated

to chromatography, the mechanism of chemical reactions and the detection of unstable substances can be

investigated with such instruments.




Principle:

An FTIR is typically based on The Michelson Interferometer Experimental Setup; an example is shown in the

Figure. The interferometer consists of a beam splitter, a fixed mirror, and a mirror that translates back and forth,

very precisely. The beam splitter is made of a special material that transmits half of the radiation striking it and

reflects the other half. Radiation from the source strikes the beam splitter and separates into two beams. One beam

is transmitted through the beam splitter to the fixed mirror and the second is reflected off the beam splitter to the

moving mirror. The fixed and moving mirrors reflect the radiation back to the beam splitter. Again, half of this

reflected radiation is transmitted and half is reflected at the beam splitter, resulting in one beam passing to the

detector and the second back to the source. Light absorption is measured and a computer infers the absorption rate

of each wavelength within the beam. Once the data has been obtained, it is converted into digital information using

using a mathematical algorithm known as the “Fourier transform.” When a molecule absorbs infrared radiation, its

its chemical bonds vibrate. The bonds can stretch, contract, and bend. This is why infrared spectroscopy is a type of

of vibrational spectroscopy. Molecules vibrate at specific frequencies so different molecules vibrate at different

frequencies because their structures are different. This is why molecules can be distinguished using infrared

spectroscopy.




Figure: FTIR spectrum of a polymer.

Applications:

FTIR spectroscopy can be used to separate individual molecules in gases in order to detect isomers and

other compounds, as well as analyze the properties of the gas.

It can also be used to detect emissions from a sample, such as in the case of luminescence, radioactivity,

and thermal applications.

Identification of foreign materials such as Particulates, Fibers, Residues etc.

Investigate proteins in hydrophobic membrane environments

Quality verification of incoming/outgoing materials

De-formulation of polymers, rubbers, and other materials through thermogravimetric infra-red (TGA-IR)

or gas chromatography infra-red (GC-IR) analysis

Microanalysis of small sections of materials to identify contaminants

Analysis of thin films and coatings

Monitoring of automotive or smokestack emissions and Failure analysis

Nuclear magnetic resonance spectroscopy (NMR)

Nuclear Magnetic Resonance (NMR) spectroscopy is an analytical chemistry technique used in quality control and

control and research for determining the content and purity of a sample as well as its molecular structure. For

example, NMR can quantitatively analyse mixtures containing known compounds. For unknown compounds,

NMR can either be used to match against spectral libraries or to infer the basic structure directly. Once the basic

structure is known, NMR can be used to determine molecular conformation in solution as well as studying physical

physical

properties at the

molecular level

such as conformational




exchange, phase changes, solubility, and diffusion.

Principle:

Nucleuses have two different orientations of spinning having -1/2 and +1/2 spin quantum number. In absence of

magnetic field these have equal energy levels. A static magnetic field is applied to the probe, hence the magnetic

levels are split. Then a variable magnetic field is applied by scanning its frequency. When the frequency of the

variable magnetic field reaches the value according the Einstein formula: ΔE = hʋ. Where ΔE is the difference

between the splitted by the static field energy levels and w is the frequency of the scanning variable field. When the

condition from the expression is accomplished then a resonance appear and an electrical current in the NMR

instrument results. Because different shielding from the electron density of different groups in the molecule, the

resonance appeared in different frequencies, hence a spectrum is recorded.




Figure: NMR spectrum of ethanol.

Applications:

NMR techniques are used successfully in various food systems for quality control.

To determine structure of proteins, amino acid profile, carotenoids, organic acids, lipid fractions, the

mobility of the water in foods.

To identify and quantify the metabolites in foods, vegetable oils, fish oils, fish and meat, milk, cheese,

wheat, fruit juices, coffee, green tea, foods such as wine and beer.

NMR is also routinely used in advanced medical imaging techniques, such as in magnetic resonance

imaging (MRI).

It is also be used in forensic, agriculture and medicines fields.

Coral Reef

A coral reef is an underwater ecosystem.

Coral reefs are built by and made up of thousands of tiny animals—coral “polyps”

Polyps are shallow water organisms which have a soft body covered by a calcareous skeleton. The polyps

extract calcium salts from sea water to form these hard skeletons. This calcareous skeleton protects the soft,

delicate body of the polyp.

The polyps live in colonies fastened to the rocky sea floor.

When the coral polyps die,] on which new polyps grow.




The cycle is repeated for over millions of years leading to accumulation of layers of corals [shallow rock

created by these depositions is called reef].

These layers at different stages give rise to various marine landforms. One such important landform is

called coral reef.

Coral reefs over a period of time transform or evolve into coral islands (Lakshadweep).

The corals occur in different forms and colours, depending upon constituents they are made of.

Small marine plants (algae) also deposit calcium carbonate contributing to coral growth.

Coral Reef Features

Fringing Reefs (Shore Reefs)

Fringing reefs are reefs that grow directly from a shore. They are located very close to land

A fringing reef runs as a narrow belt [1-2 km wide]. This type of reef grows from the deep sea bottom with

the seaward side sloping steeply into the deep sea

The fringing reef is by far the most common of the three major types of coral reefs, with numerous

examples in all major regions of coral reef development.




Mangroves

Mangroves represent a characteristic littoral (near the seashore) forest ecosystem.

These are mostly evergreen forests that grow in sheltered low lying coasts, estuaries, mudflats, marshes

and lagoons of tropical and subtropical regions.

Mangroves grow below the high water level of spring tides.

The best locations are where abundant silt is brought down by

Mangroves are highly productive ecosystems, and the trees may vary in height from 8 to 20 m. They

protect the shoreline from the effect of cyclones and tsunamis.

They are breeding and spawning ground for many commercially important fishes.

Since mangroves are located between the land and sea, they represent the best example of ecotone

Types of Mangroves

1. Red Mangroves

Growing along the edge of the shoreline where conditions are harshest, the red mangrove (Rhizophora mangle) is

easily distinguished from other species by tangled, reddish prop roots. These prop roots originate from the trunk

with roots growing downward from the branches. Extending three feet (1 m) or more above the surface of the soil,

prop roots increase stability of the tree as well as oxygen supply to underground roots.

2. Black Mangroves

Avicennia germinans, the black mangrove, is characterized by long horizontal roots and root-like projections

known as pneumatophores. It grows at elevations slightly higher than the red mangrove where tidal change

exposes the roots to air. The pencil-shaped pneumatophores originate from underground horizontal roots

projecting from the soil around the tree’s trunk, providing oxygen to the underground and underwater root systems.

3. White Mangroves




Occupying higher land than the red and black mangroves, the white mangrove (Laguncularia racemosa) has no

visible aerial roots, unlike the black mangrove which has pneumatophores and the red mangrove with prop roots.

However, when it is found in oxygen-depleted sediments or flooded for extended periods of time, it often develops

peg roots.

1. SWAMP, MARSH, BOGS AND FENS

Swamps, marshes, bogs, fens are all examples of wetlands that are important to our ecological system.

Swamps are forested wetlands which are near large lakes and rivers. They have slow-moving waters and support

woody plants, such as mangroves or cypress trees.

Marshes on the other hand have the same water source but have softer, non-woody plants.

Bogs are characterized by peats, left overs of dead plant material. Their water source is mainly from precipitation

and no external runoff or river. The water in bogs has mostly a lower pH limiting survival of plants and animals as

compared to marshes that have a neutral pH making them rich with plants and animals.

Fens also have peat. They are high in nutrients and usually also pH neutrals. Fens near each other can form bogs.




Types of Graphical Representation

1, Bar Chart

A bar chart is a graphic display of categorical variables that uses bars to represent the frequency of the

count in each category. The reason why the bars are separated by spaces is to emphasize the fact that they

are categories and not continuous numbers.

2. Histogram

A histogram is a display that indicates the frequency of specified ranges of continuous data values on a

graph in the form of immediately adjacent bars.

3. Box- and- Whisker plot

A boxplot (also known as a box and whiskers plot) is another way to display quantitative data. It displays

the five 5 number summary (minimum, Q1, median, Q3, maximum). The box can either be vertically or

horizontally displayed depending on the labeling of the axis. The box does not need to be perfectly

symmetrical because it represents data that might not be perfectly symmetrical.




REMOTE SENSING

Remote Sensing: Remote sensing is the science and art of obtaining information about objects,

areas or a phenomenon from a distance, typically from aircraft or satellites using sensors. (Lillesand et

al. 2004)

7 processes of Remote Sensing:

Energy Source: provides EM Energy to the target of interest.

Radiation and Atmosphere: deviation of EM Radiations.

Interaction with Target: reflections from the surfaces of the

targets.

Recording of Energy by Sensors: records reflected EM

radiations

Transmission, Reception and Processing

Interpretation and Analysis

Application

History of Remote Sensing:

Remote sensing began in the 1840s as balloonists took pictures of the ground using the newly invented

photo-camera. Perhaps the most novel platform at the end of the last century is the famed pigeon fleet that operated

as a novelty in Europe.

Segments and Components of Remote Sensing:

PLATFORM: a carrier for remote sensor

a. Ground based: upto 50 m from surface

b. Air-borne: from 1 km to 30 kms

c. Space-borne: more than 250 kms

Polar Satellite: low height; 700 km

Geostationary: high; 36765 kms




SENSORS: a device that gathers/collects reflected EM Radiations and converts it into digital signal.

1. Passive: Receives solar EM energy reflected from the surface or the energy emitted by the

surface itself. These sensors does not have own sources and hence cant be used at night.

2. Active: Have its own source of energy to first emit and then captures data. It can work

during night.

Based on data output, we have 2 types:

a. Photographic (Analog): it records image of an object at an instance of exposure

b. Non-photographic (Digital): it obtains images of an object bit-by-bit. They are known as

‘scanners.’

Multi-spectral Scanners:

Whish-Broom Scanners: rotating mirror and single detector. Scanning is done from left to right or

vice-versa.

Push-Broom Scanners: Larger no of detectors and no rotating mirror..

No of Detectors is obtained by dividing swath of sensor by size of spatial resolution, i.e.,

No of Detectors = Swath of Sensor

Size of spatial resolution

Spatial Resolution:

It is the geographical area covered by a pixel in a satellite image. Generally, the higher the spatial

resolution, the less area is covered by a single pixel.

Temporal Resolution:

Revisit period of a satellite. It is the time which satellites takes to revisit the same spot second time.




Law of thermodynamics

Thermodynamics: The branch of physical science that deals with the relations between heat and other forms of

energy (such as mechanical, electrical, or chemical energy. It describes how thermal energy is converted to and

from other forms of energy and how it affects matter.

When we are discussing thermodynamics, the particular item or collection of items that we’re interested in

is called the system, while everything that's not included in the system we’ve defined is called the

surroundings. For example, if the system is one mole of a gas in a container, then the boundary is simply

the inner wall of the container itself. Everything outside of the boundary is considered the surroundings,

which would include the container itself.

There are three types of systems in thermodynamics: open, closed, and isolated.

An open system can exchange both energy and matter with its surroundings. The stovetop example would

be an open system, because heat and water vapor can be lost to the air.

A closed system, on the other hand, can exchange only energy with its surroundings, not matter. If we put

a very tightly fitting lid on the pot, it would approximate a closed system.

An isolated system is one that cannot exchange either matter or energy with its surroundings. A perfect

isolated system is hard to come by, but an insulated drink cooler with a lid is conceptually similar to a true

isolated system. The items inside can exchange energy with each other, which is why the drinks get cold

and the ice melts a little, but they exchange very little energy (heat) with the outside environment.




El Nino

A recurring (again and again) characteristic of the climate is called Climatic Pattern. The gap between two

recurrences may be from one year to as long as tens of thousands of years. Some of the events are in regular cycle,

while some are not. When they recur in the form of regular cycles of fluctuations in climate parameters, they are

called climate oscillations. The term oscillation is used because such fluctuations are not perfectly periodic. For

example, we say that El Nino returns every four and half years. But actually it may or may not return. Or it may

return too early or too late.

El Niño

El Niño was originally recognized by fisherman off the coast of Peru in South America. The ocean off the

coast of Peru is one of the world’s richest fisheries regions.

In most years trade winds flow from the southeast push warm surface water away from the coast. In its

place, the cold water comes up on the surface due to upwelling. This cold water is full of nutrients and

provides nourishments to planktons.

These planktons serve as food for fishes. Fishes in turn provide food to the sea birds. Due to all this, not

only there is a good catch of fishes but also good collection of the Guano, the bird excreta, used as a

valuable fertilizer. This is what that made Peru number one fishing nation in the world by the early 1970s.

However, every few years, there is a change in the pattern of air circulation. It changes in such a way that

the trade winds reverse direction, blowing from west to east. Due to this reversal, the upwelling of the cold

water gets weakened. The surface water is warm.

This lowers the nutrients available to fish and thus poses problems to the economics of fisheries. The

problems don’t end here. The accumulation of large mass of warm water allows formation of more and

more clouds and this would bring destructive rains that occur in normally dry areas of Peru and Chile.




The above mentioned reversal of the winds occurred during Christmas times (Please note that India have

Christmas in winter, but Peruvians have in summer, because they are in southern hemisphere), so they

named it El Niño or “Christ Child” or “The Little Boy” in their own language. Before, you read further,

please understand the location of Eastern, Central and Western Pacific on the map, otherwise it would be

too confusing (earth is round…after all)




Due to this warm water, the air gets up and surface air pressure above Eastern Pacific gets down. On the

other hand, the waters cool off in western pacific and off Asia. This leads to rise in surface pressure over the

Indian Ocean, Indonesia, and Australia

So, while there is raining (read flooding) in Eastern Pacific; the drought sets in over Asia as high pressure

builds over the cooler ocean waters.

The net result is:

Normal or high rainfall in eastern / central pacific.

Drought or scant rainfall in western pacific / Asia.

Heavy rains in Ecuador and Peru.

Heavy rains in southern Brazil but drought in north East Brazil

Drought in Zimbabwe, Mozambique, South Africa, Ethiopia

Warm winter in the northern half of the United States and southern Canada

Drought, Scant rains off Asia including India, Indonesia, and Philippines etc.

Coral bleaching worldwide

La Niña

La Niña, which means “The Little Girl” or “El Viejo” or “anti-El Niño” or simply “a cold event” or “a cold episode

is the cooling of water in the Eastern Pacific Ocean. Here is what happens in La Niña.

The water in Eastern Pacific, which is otherwise cool; gets colder than normal. There is no reversal of the

trade winds but it causes strong high pressure over the eastern equatorial Pacific.

On the other hand, low pressure is caused over Western Pacific and Off Asia.

This has so far caused the following major effects:

o Drought in Ecuador and Peru. Low temperature, High Pressure in Eastern Pacific

o Heavy floods in Australia; High Temperature in Western Pacific, Indian Ocean, Off coast Somalia

and good rains in India.




Drainage Systems

The typical shape of a river course as it completes its erosional cycle is referred to as the drainage pattern of

a stream.

A drainage pattern reflects the structure of basal rocks, resistance and strength, cracks or joints and tectonic

irregularity, if any.

1. Dendritic or Pinnate

This is an irregular tree branch shaped

Examples: Indus, Godavari, Mahanadi, Cauvery, Krishna.

2. Rectangular

The main stream bends at right angles and the tributaries join at right angles creating rectangular patterns.

This pattern has a subsequent origin (subsequent drainage – you will study this in Indian drainage systems).

Example: Colorado river (USA).

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