This document contains lecture notes on environmental science from Dr. R. Buamah. It defines environmental science as an interdisciplinary field involving both scientific and social aspects of human impact on the world. It also discusses concepts like ecosystems, which involve the movement of energy and materials through communities of organisms and their environment.

1. Environmental Science
Environmental Science
(CE 155)
(CE 155)
LECTURE NOTES
LECTURE NOTES
R. BUAMAH (PhD)
R. BUAMAH (PhD)

2. Environmental Science
Environmental Science
An interdisciplinary field that includes both scientific and
An interdisciplinary field that includes both scientific and
social aspects of human impact on the world. It involves an
social aspects of human impact on the world. It involves an
understanding of the scientific principles and impacts,
understanding of the scientific principles and impacts,
economic influences and political actions.
economic influences and political actions.
A common adage by the naturalist John Muir
A common adage by the naturalist John Muir –
– ‘
‘Tug on
Tug on
anything at all and you will find it connected to everything els
anything at all and you will find it connected to everything else
e
on the universe
on the universe’
’.
.
Eg
Eg. In the forest behind the college of Engineering laboratories
. In the forest behind the college of Engineering laboratories
formerly used to harbour a number of trees, shrubs, biennials,
formerly used to harbour a number of trees, shrubs, biennials,
etc with reptiles like snakes
etc with reptiles like snakes –
– python, cobras etc, mice, frogs,
python, cobras etc, mice, frogs,
insects, different species of the birds, squirrels, etc. Since
insects, different species of the birds, squirrels, etc. Since the
the
start of the development of new structures to house business.
start of the development of new structures to house business.

3. Environmental Science
Environmental Science
school certain reptiles like the python have either been
school certain reptiles like the python have either been
killed or chased away. In addition small scale farmers
killed or chased away. In addition small scale farmers
have been cultivating vegetables in some portions of the
have been cultivating vegetables in some portions of the
land.
land.
This development have led to increase in population
This development have led to increase in population
of mice in the forest thereby attracting animals like owls
of mice in the forest thereby attracting animals like owls
and hawks to the area, a situation which hitherto was not
and hawks to the area, a situation which hitherto was not
existing.
existing.
The water in the stream in the valley is
The water in the stream in the valley is
gradually decreasing in the volume because of the felling
gradually decreasing in the volume because of the felling
of the trees and exposition of the stream surface to the
of the trees and exposition of the stream surface to the
harsh dry climatic conditions thus increasing the rate of
harsh dry climatic conditions thus increasing the rate of
the evaporation.
the evaporation.

4. Environmental Ethics
Environmental Ethics
The Ethics is a branch of philosophy that seeks to define
The Ethics is a branch of philosophy that seeks to define
what is right and what is wrong. Most of the issues discussed
what is right and what is wrong. Most of the issues discussed
in this course will involve much of ethical dimensions.
in this course will involve much of ethical dimensions.
The laws of any nation should match the ethical commitment
The laws of any nation should match the ethical commitment
of those living there. Not every action that is ethically right
of those living there. Not every action that is ethically right
can have a law supporting it. E.g. 1) There is no law that you
can have a law supporting it. E.g. 1) There is no law that you
have to help your elderly neighbour to unload her groceries
have to help your elderly neighbour to unload her groceries
from the car. But even without a law this still must be the
from the car. But even without a law this still must be the
ethical right thing to do. 2) It is ethically right that after
ethical right thing to do. 2) It is ethically right that after
Eating snack you do not throw or litter around with the
Eating snack you do not throw or litter around with the
Polythene bag that was used to bag your snack.
Polythene bag that was used to bag your snack.
The goal of environmental ethics is not just to convince us to
The goal of environmental ethics is not just to convince us to
be concerned about the environment but rather to focus on
be concerned about the environment but rather to focus on

5. Environmental Ethics
Environmental Ethics
the moral foundation of environmental responsibility and
the moral foundation of environmental responsibility and
how far this responsibility extends. Three primary theories
how far this responsibility extends. Three primary theories
have been put forward on moral responsibility regarding the
have been put forward on moral responsibility regarding the
environment. They include:
environment. They include:
1)
1) Anthropocentrism or human centred ethics
Anthropocentrism or human centred ethics
2)
2) Biocentrism or life centred environmental ethics
Biocentrism or life centred environmental ethics
3)
3) Ecocentrism
Ecocentrism
Anthropocentrism
Anthropocentrism has the view that all environmental
has the view that all environmental
responsibility is derived from human interest alone. It
responsibility is derived from human interest alone. It
assumes that only humans are morally significant and have
assumes that only humans are morally significant and have
direct moral standing. In this view the adage is
direct moral standing. In this view the adage is ‘
‘protect when
protect when
it benefits humans
it benefits humans’
’. This view is flawed in the sense that
. This view is flawed in the sense that
we must ensure that the Earth remains environmentally
we must ensure that the Earth remains environmentally
hospitable for supporting human life and even that it remains
hospitable for supporting human life and even that it remains

6. Environmental Ethics
Environmental Ethics
a pleasant place for humans to live now and for the future.
a pleasant place for humans to live now and for the future.
Biocentrism
Biocentrism or life centred environmental ethics
or life centred environmental ethics
According to this theory all forms of life (humans, animals,
According to this theory all forms of life (humans, animals,
Plants, microorganisms etc.) have an inherent right to life.
Plants, microorganisms etc.) have an inherent right to life.
Ecocentrism
Ecocentrism
This approach / theory maintains that the entire
This approach / theory maintains that the entire
environment deserves direct moral consideration and
environment deserves direct moral consideration and
not consideration that is derived merely from human or
not consideration that is derived merely from human or
animal interests. In this regard everything existing on
animal interests. In this regard everything existing on
the Earth or mother Earth should have the same right to
the Earth or mother Earth should have the same right to
life as any other mother.
life as any other mother.

7. Environmental Ethics and Sustainable
Environmental Ethics and Sustainable
Development
Development
Generally our attitudes or approaches to the environment
Generally our attitudes or approaches to the environment
must evolve round development, preservation and
must evolve round development, preservation and
conservation.
conservation.
In order to preserve and conserve our environment, our
In order to preserve and conserve our environment, our
development should be sustainable. Sustainable development
development should be sustainable. Sustainable development
(SD) is often defined as
(SD) is often defined as ‘
‘meeting the needs of current
meeting the needs of current
generations without compromising the ability of future
generations without compromising the ability of future
generations to meet theirs
generations to meet theirs’
’. SD focuses on the promotion of
. SD focuses on the promotion of
appropriate development to alleviate poverty while still
appropriate development to alleviate poverty while still
preserving the ecological health of the landscape. SD hinges
preserving the ecological health of the landscape. SD hinges
on three pillars namely: economic development, social
on three pillars namely: economic development, social
development and environmental protection. At times
development and environmental protection. At times
consideration is given to cultural development as well.
consideration is given to cultural development as well.

8. Ecosystems
Ecosystems
The United Nations Conference on Environment and
The United Nations Conference on Environment and
Development in 1992 in Rio de
Development in 1992 in Rio de Janerio
Janerio, Brazil set out a
, Brazil set out a
roadmap for sustainable development. In a follow up
roadmap for sustainable development. In a follow up
conference in South Africa in 2002, many observers
conference in South Africa in 2002, many observers
questioned why there had been such a lack of
questioned why there had been such a lack of
international progress in alleviating poverty and
international progress in alleviating poverty and
protecting the environment.
protecting the environment.
Stnble
Stnble –
– Sustainable
Sustainable’
’
Social
Bearable
Equitable
Stnble
Viable
Environment Economic

9. ENVIRONMENTAL SCIENCE AND
ENVIRONMENTAL SCIENCE AND
ENERGY PRINCIPLES
ENERGY PRINCIPLES
In environmental science
In environmental science
information is provided on the
information is provided on the
environment especially the
environment especially the
resources occurring within our
resources occurring within our
environment and how human
environment and how human
activities affect the quality,
activities affect the quality,
composition, constitution of these
composition, constitution of these
resources.
resources.
What is a resource?
What is a resource?

10. Resource
Resource
Any physical or virtual entity of limited
Any physical or virtual entity of limited
availability or anything used to help one
availability or anything used to help one
earn a living.
earn a living.
There are two broad divisions of
There are two broad divisions of
resources
resources
Natural Resources
Natural Resources
Human Resources
Human Resources
Natural Resources
Natural Resources
These are basically derived from the
These are basically derived from the
environment.
environment.

11. Natural Resources
Natural Resources
Natural resources may be classified
Natural resources may be classified
based upon
based upon
Origin
Origin
Stage of development
Stage of development
Renewability
Renewability

12. Origin
Origin
Biotic and
Biotic and Abiotic
Abiotic
Biotic
Biotic –
– living e.g. Forest, animals,
living e.g. Forest, animals,
birds and their products
birds and their products
Abiotic
Abiotic –
– land, water, air, minerals
land, water, air, minerals
etc.
etc.

13. Stage of development
Stage of development
Potential resources
Potential resources
Actual resources
Actual resources
Potential resources are those that exist and
Potential resources are those that exist and
may be used in the future
may be used in the future
Actual resources are the type of resources
Actual resources are the type of resources
that have been surveyed. Their quantity and
that have been surveyed. Their quantity and
quality have been determined and are being
quality have been determined and are being
put to use in the present times.
put to use in the present times.

14. Renewability
Renewability
Renewable and the non
Renewable and the non-
-renewable resources
renewable resources
Renewable
Renewable –
– are inexhaustible resources e.g..
are inexhaustible resources e.g..
the sun, plants and animals, fresh air, fertile
the sun, plants and animals, fresh air, fertile
soil, fresh water, energy from the sun and
soil, fresh water, energy from the sun and
wind tides.
wind tides.
Non renewable sources:
Non renewable sources:
Can be depleted after a period of time of
Can be depleted after a period of time of
exploitation. Recovery may be expensive and
exploitation. Recovery may be expensive and
may be impossible e.g..
may be impossible e.g..
metallic
metallic minerals e.g. gold, iron, copper, tin
minerals e.g. gold, iron, copper, tin
etc.
etc.
Non
Non-
-metallic e.g. fossil fuel, clay, sand,
metallic e.g. fossil fuel, clay, sand,
salt phosphates etc.
salt phosphates etc.

15. Renewable and Non
Renewable and Non-
-renewable
renewable
Renewable resources can become non
Renewable resources can become non -
-
renewable resources if they are used at a faster
renewable resources if they are used at a faster
rate than they can be replenished. Some
rate than they can be replenished. Some
animal and plant spp. have become extinct
animal and plant spp. have become extinct
because the rate at which they are being
because the rate at which they are being
utilised is faster than what the sedentary
utilised is faster than what the sedentary
phosphorus cycle can maintain.
phosphorus cycle can maintain.
The world is running out of resources e.g..
The world is running out of resources e.g..
Fossil fuels
Fossil fuels -
- 50 yrs
50 yrs
Pb
Pb,
, Sn
Sn, Cu, Ag, Hg
, Cu, Ag, Hg –
– 2000
2000 –
– 2040. etc
2040. etc

16. Mitigation Measures
Mitigation Measures
Recycle
Recycle
Reuse
Reuse
Reduction in consumption
Reduction in consumption
Recovery
Recovery
More devised technologies to recover more
More devised technologies to recover more
minerals from used ores; alternative method or
minerals from used ores; alternative method or
alternative materials for same purpose that a
alternative materials for same purpose that a
mineral or a particular resource is used.
mineral or a particular resource is used.

17. THE ENVIRONMENT
THE ENVIRONMENT
The sum total of external conditions and influences
The sum total of external conditions and influences
affecting the development and life of an organism. In
affecting the development and life of an organism. In
addition it is the aggregate of all natural and operational
addition it is the aggregate of all natural and operational
conditions that affects the performance of an equipment
conditions that affects the performance of an equipment
or its components and determine the behaviour of a
or its components and determine the behaviour of a
physical system.
physical system.
The Environmental setting
The Environmental setting:
:
Physico
Physico-
-chemical: Water, air, soil, noise, radiations
chemical: Water, air, soil, noise, radiations
Biological: terrestrial and aquatic lives
Biological: terrestrial and aquatic lives
Cultural: history (beliefs), attitudes and practices,
Cultural: history (beliefs), attitudes and practices,
Socio
Socio-
-economic: population, economy, infrastructure
economic: population, economy, infrastructure

18. Environmental Engineering
Environmental Engineering
Basically the application of theories of science
Basically the application of theories of science
and material forces to confront ecological and
and material forces to confront ecological and
socio
socio-
-economic problems so as to reduce
economic problems so as to reduce
pollution, contamination and deterioration of
pollution, contamination and deterioration of
the surroundings in which humans live.
the surroundings in which humans live.
Environmental Engineering involves control of
Environmental Engineering involves control of
water, soil and atmospheric pollution and the
water, soil and atmospheric pollution and the
social and environmental impact of planned
social and environmental impact of planned
projects.
projects.

19. Ecological Concepts
Ecological Concepts
Ecology
Ecology –
– study of the relationship between
study of the relationship between
living organisms and with their environment.
living organisms and with their environment.
Ecosystem is a self
Ecosystem is a self-
-sustaining and self
sustaining and self
regulating community of organisms with their
regulating community of organisms with their
environment.
environment.
Population is a group of plant or animal
Population is a group of plant or animal
species in a given locality.
species in a given locality.
Community is a group of plant and animal
Community is a group of plant and animal
populations living and interacting in a given
populations living and interacting in a given
locality
locality

20. Ecosystems
Ecosystems
Ecosystem does not only include the community of organisms
Ecosystem does not only include the community of organisms
but also organisms and their biotic environment, which
but also organisms and their biotic environment, which
involves the movement of energy and materials through the
involves the movement of energy and materials through the
communities. Ecosystems have no definite boundaries. They
communities. Ecosystems have no definite boundaries. They
are self regulating and normally have a continuous input of
are self regulating and normally have a continuous input of
energy to retain its stability. The only significant source of
energy to retain its stability. The only significant source of
energy for most ecosystems is sunlight. Producers in an
energy for most ecosystems is sunlight. Producers in an
ecosystem are the only animals that could trap the sun
ecosystem are the only animals that could trap the sun’
’s
s
energy through the process of photosynthesis and make it
energy through the process of photosynthesis and make it
available to the ecosystem
available to the ecosystem
The ecosystem functions through the operation of some
The ecosystem functions through the operation of some
natural laws. It operates through the recycling of matter in
natural laws. It operates through the recycling of matter in
accordance with the law of conservation of matter and the one
accordance with the law of conservation of matter and the one
way energy flow is in accordance with the first and second law
way energy flow is in accordance with the first and second law
of energy.
of energy.

21. HABITAT AND NICHE
HABITAT AND NICHE
Organisms interact with their surroundings in many ways.
Organisms interact with their surroundings in many ways.
Certain factors may be critical for the existence of a particula
Certain factors may be critical for the existence of a particular
r
species. A shortage or absence of a particular factor can
species. A shortage or absence of a particular factor can
restrict the success of the species. Such factors are known as
restrict the success of the species. Such factors are known as
limiting factors. The factors could be biotic or
limiting factors. The factors could be biotic or abiotic
abiotic. E.g.
. E.g.
Many plants are limited by scarcity of water, light, specific so
Many plants are limited by scarcity of water, light, specific soil
il
nutrients such as nitrogen, phosphorus etc. Climatic factors
nutrients such as nitrogen, phosphorus etc. Climatic factors
such as temperature range, humidity, periods of drought or
such as temperature range, humidity, periods of drought or
length of winter are often limiting factors.
length of winter are often limiting factors.
It is impossible to understand an organism apart from its
It is impossible to understand an organism apart from its
environment. The habitat of an organism is the space that
environment. The habitat of an organism is the space that
the organism inhabits, the place where it lives.
the organism inhabits, the place where it lives.

22. The Niche of an organism is the functional role it has in
The Niche of an organism is the functional role it has in
its surroundings (its profession). An organism s niche
its surroundings (its profession). An organism s niche
includes all the ways it affects the organisms with which
includes all the ways it affects the organisms with which
it interacts as well as how it modifies its physical
it interacts as well as how it modifies its physical
surroundings. In addition the description of a niche
surroundings. In addition the description of a niche
includes all of the things that happens to the organism.
includes all of the things that happens to the organism.

23. KINDS OF ORGANISM INTERACTIONS
KINDS OF ORGANISM INTERACTIONS
Predation
Predation: a kind of interaction where one organism
: a kind of interaction where one organism –
– the
the
predator, kills and eats another (known as prey). To succeed
predator, kills and eats another (known as prey). To succeed
many predators employ several strategies including strength,
many predators employ several strategies including strength,
speed and snares to overpower their prey. Obviously for the
speed and snares to overpower their prey. Obviously for the
prey to survive, they need to and do breed more else they
prey to survive, they need to and do breed more else they
become extinct. Normally the prey that is healthier, quicker
become extinct. Normally the prey that is healthier, quicker
and better
and better –
– adapted are likely to survive.
adapted are likely to survive.
Competition
Competition: in this kind of interaction two organisms strive to
: in this kind of interaction two organisms strive to
obtain the same limited resource. Two kinds of competition
obtain the same limited resource. Two kinds of competition
exist
exist –
– Intraspecific
Intraspecific and
and Interspecific
Interspecific competition. Competition
competition. Competition
among members of the same species is
among members of the same species is intraspecific
intraspecific while
while
competition between members of different species is referred
competition between members of different species is referred
to as
to as interspecific
interspecific competition
competition.
.

24. KINDS OF ORGANISM INTERACTIONS
KINDS OF ORGANISM INTERACTIONS
Competition among members of the same spp. is a major force
Competition among members of the same spp. is a major force
in shaping the evolution of a specie. When resources are
in shaping the evolution of a specie. When resources are
limited, less well
limited, less well –
–adapted individuals are more likely to die or
adapted individuals are more likely to die or
be denied mating privileges. Because the most successful
be denied mating privileges. Because the most successful
organisms are likely to have larger numbers of offspring, each
organisms are likely to have larger numbers of offspring, each
succeeding generation will contain more of the genetic
succeeding generation will contain more of the genetic
characteristics that are favourable for survival of the species
characteristics that are favourable for survival of the species in
in
that particular environment. Since individuals of the same
that particular environment. Since individuals of the same
species have similar needs, competition among them is usually
species have similar needs, competition among them is usually
very intense. A slight advantage on the part of the individual
very intense. A slight advantage on the part of the individual
may mean the difference between survival and death.
may mean the difference between survival and death.
Competitive Exclusion Principle
Competitive Exclusion Principle
Is the concept that no two species can occupy the same
Is the concept that no two species can occupy the same
ecological niche in the same place at the same time. The more
ecological niche in the same place at the same time. The more

25. similar two species are, the more intense will be the
similar two species are, the more intense will be the
competition between them. If one of the two is better adapted
competition between them. If one of the two is better adapted
to live in the area than the other, the less
to live in the area than the other, the less –
–fit species must
fit species must
evolve into a slightly different niche, migrate to a different
evolve into a slightly different niche, migrate to a different
geographic area or become extinct.
geographic area or become extinct.
Symbiosis
Symbiosis is a close long lasting physical relationship between
is a close long lasting physical relationship between
two different species where at least one of them derives some
two different species where at least one of them derives some
sort of benefits from the contact / interaction. Three types of
sort of benefits from the contact / interaction. Three types of
symbiotic relationships exist: Parasitism, Commensalism and
symbiotic relationships exist: Parasitism, Commensalism and
mutualism.
mutualism.
Parasitism:
Parasitism:-
- a relationship in which one organism known as the
a relationship in which one organism known as the
parasite lives in or on another organism known as the host
parasite lives in or on another organism known as the host
from which it derives some form of benefit e.g. Nourishment.
from which it derives some form of benefit e.g. Nourishment.
Parasites are normally smaller than the host. The host
Parasites are normally smaller than the host. The host
generally is harmed, it is generally not killed immediately.
generally is harmed, it is generally not killed immediately.

26. KINDS OF ORGANISM INTERACTIONS
KINDS OF ORGANISM INTERACTIONS
Two kinds of parasites occur
Two kinds of parasites occur –
– endoparasites
endoparasites and
and ectoparasites
ectoparasites
Commensalism:
Commensalism:-
- a relationship between two organisms in
a relationship between two organisms in
which one organism benefits while the other is not affected.
which one organism benefits while the other is not affected.
Many
Many commensal
commensal relationships are rather opportunistic and
relationships are rather opportunistic and
may not involve a long
may not involve a long-
-term physical contact.
term physical contact.
Mutualism:
Mutualism:-
- a relationship that benefits both specie involved.
a relationship that benefits both specie involved.
In most
In most mutualistic
mutualistic relationships the relationship is obligatory;
relationships the relationship is obligatory;
the species cannot live without each other. In others the
the species cannot live without each other. In others the
species can exist separately but are more successful when
species can exist separately but are more successful when
they are involved in a
they are involved in a mutualistic
mutualistic relationship. E.g. Many kinds
relationship. E.g. Many kinds
of plants such as legumes (beans, peanuts, clover etc) have
of plants such as legumes (beans, peanuts, clover etc) have
bacteria that live in their roots in little nodules. The roots
bacteria that live in their roots in little nodules. The roots for
for
nodules when they are infected with certain kinds of bacteria.
nodules when they are infected with certain kinds of bacteria.
The bacteria do not cause disease but provide the plants with
The bacteria do not cause disease but provide the plants with

27. KINDS OF ORGANISM INTERACTIONS
KINDS OF ORGANISM INTERACTIONS
nitrogen
nitrogen-
-containing molecules that the plant can use for
containing molecules that the plant can use for
growth. Similarly, many kinds of fungi form an association
growth. Similarly, many kinds of fungi form an association
with the roots of plants. The root
with the roots of plants. The root-
-fungus associations are
fungus associations are
called
called mycorrhizae
mycorrhizae.
.

28. ROLES OF ORGANISMS IN ECOSYSTEMSS
ROLES OF ORGANISMS IN ECOSYSTEMSS
Producers
Producers: are organisms that are able to use simple inorganic
: are organisms that are able to use simple inorganic
substances in their environment together with sunlight to
substances in their environment together with sunlight to
produce / make complex organic molecules.
produce / make complex organic molecules.
Consumers
Consumers: are organisms that require organic matter as a
: are organisms that require organic matter as a
source of food. They consume the organic matter to provide
source of food. They consume the organic matter to provide
themselves with energy and the organic molecules necessary
themselves with energy and the organic molecules necessary
to build their own bodies. They break down the organic matter
to build their own bodies. They break down the organic matter
to simple inorganic molecules through the process of
to simple inorganic molecules through the process of
respiration. Based upon the way they obtain their food and the
respiration. Based upon the way they obtain their food and the
kinds of things they eat, consumers can be classified as either
kinds of things they eat, consumers can be classified as either
primary consumers or secondary consumers
primary consumers or secondary consumers
Primary consumers (herbivores) are animals that eat
Primary consumers (herbivores) are animals that eat
producers (plants and
producers (plants and phytoplanktons
phytoplanktons) as a source of food.
) as a source of food.
Secondary Consumers (carnivore) are animals that eat other
Secondary Consumers (carnivore) are animals that eat other

29. animals.
animals.
Omnivores :
Omnivores :-
- Animals that eat both plants and other animals.
Animals that eat both plants and other animals.
Decomposers:
Decomposers:-
- organisms that use non
organisms that use non-
-living organic matter
living organic matter
as a source of energy and raw materials to build their bodies.
as a source of energy and raw materials to build their bodies.
Whenever an organism sheds a part of itself, excretes waste
Whenever an organism sheds a part of itself, excretes waste
products or dies, it provides a source of food for decomposers.
products or dies, it provides a source of food for decomposers.
Decomposers are extremely important in recycling matter by
Decomposers are extremely important in recycling matter by
converting organic matter to inorganic material.
converting organic matter to inorganic material.
Scavengers:
Scavengers:-
- these animals eat carcasses.
these animals eat carcasses.

30. Trophic
Trophic Levels and energy flow in Ecosystems
Levels and energy flow in Ecosystems
Each step in the flow of energy through an ecosystem is known
Each step in the flow of energy through an ecosystem is known
as a
as a trophic
trophic level. Producers normally constitute the first
level. Producers normally constitute the first
trophic
trophic level and herbivores for the second
level and herbivores for the second trophic
trophic level.
level.
Carnivores that eat herbivores are the third
Carnivores that eat herbivores are the third trophic
trophic level
level
followed by carnivores that eat other carnivores as occupants
followed by carnivores that eat other carnivores as occupants
of the fourth
of the fourth trophic
trophic level. Omnivores, parasites and
level. Omnivores, parasites and
scavengers occupy different
scavengers occupy different trophic
trophic levels depending upon
levels depending upon
what they happen to be eating at the time.
what they happen to be eating at the time.
In ecosystems there is always the transfer of energy. The
In ecosystems there is always the transfer of energy. The
transfer occurs in accordance with the second law of
transfer occurs in accordance with the second law of
thermodynamics. As energy flows through an ecosystem, it
thermodynamics. As energy flows through an ecosystem, it
passes through several levels know as
passes through several levels know as trophic
trophic levels. Each
levels. Each
trophic
trophic level contains a certain amount of energy. Each time
level contains a certain amount of energy. Each time

31. Trophic
Trophic Levels and energy flow in Ecosystems
Levels and energy flow in Ecosystems
useful energy is lost, usually as heat to the surroundings.
useful energy is lost, usually as heat to the surroundings.
Therefore, in most ecosystems useful energy is lost, usually as
Therefore, in most ecosystems useful energy is lost, usually as
heat to the surroundings. Therefore, in most ecosystems
heat to the surroundings. Therefore, in most ecosystems
higher
higher trophic
trophic levels contain less energy and fewer organisms.
levels contain less energy and fewer organisms.
It is normally difficult to actually measure the amount of
It is normally difficult to actually measure the amount of
energy contained in each
energy contained in each trophic
trophic level. One of the ways to
level. One of the ways to
estimate the amount of energy is to quantify the biomass. The
estimate the amount of energy is to quantify the biomass. The
biomass is the weight of living material in a
biomass is the weight of living material in a trophic
trophic level. For
level. For
a simple ecosystem it is often easy to collect and weigh all the
a simple ecosystem it is often easy to collect and weigh all the
producers, herbivores and carnivores. The weights often show
producers, herbivores and carnivores. The weights often show
the same 90% loss from one
the same 90% loss from one trophic
trophic level to the next as
level to the next as
happens with the amount of energy.
happens with the amount of energy.

32. FOOD CHAINS AND FOOD WEBS
FOOD CHAINS AND FOOD WEBS
Food Chain:
Food Chain:-
- a series of organisms occupying different
a series of organisms occupying different trophic
trophic
levels through which energy passes as a result of one
levels through which energy passes as a result of one
organism consuming another. Some food chains rely on a
organism consuming another. Some food chains rely on a
constant supply of small pieces of dead organic material
constant supply of small pieces of dead organic material
coming from situations where photosynthesis is taking place.
coming from situations where photosynthesis is taking place.
The small bits of non
The small bits of non-
-living
living orgainc
orgainc materials are called
materials are called
detritus. The floor of a forest can be a perfect example of a
detritus. The floor of a forest can be a perfect example of a
detritus food chain.
detritus food chain.
The forest floor receives fallen leaves that serve as detritus
The forest floor receives fallen leaves that serve as detritus
food chain. Initially the leaves will be colonized by bacteria
food chain. Initially the leaves will be colonized by bacteria
and fungi. If an earthworm is eaten by a bird, it becomes part
and fungi. If an earthworm is eaten by a bird, it becomes part
of a larger food chain that includes material from both a
of a larger food chain that includes material from both a
detritus food chain and a photosynthesis
detritus food chain and a photosynthesis –
– driven food chain.
driven food chain.
When several food chains overlap and intersect, they make up
When several food chains overlap and intersect, they make up
a food web.
a food web.

33. 1
1st
st
and 2
and 2nd
nd
Laws of Energy
Laws of Energy
1.
1. Energy is neither created nor destroyed but merely
Energy is neither created nor destroyed but merely
changed from one form into another.
changed from one form into another.
2.
2. This law states that whenever energy is changed
This law states that whenever energy is changed
from one form to the other, some of the useful
from one form to the other, some of the useful
energy is lost. The energy that cannot be used to
energy is lost. The energy that cannot be used to
do useful work is called entropy. The entropy of the
do useful work is called entropy. The entropy of the
universe is increasing. Normally the quality of the
universe is increasing. Normally the quality of the
energy available for useful work will always be lower
energy available for useful work will always be lower
in quality than the initial energy. We can recycle
in quality than the initial energy. We can recycle
matter but we cannot recycle energy for all practical
matter but we cannot recycle energy for all practical
purposes
purposes.
.

34. 1
1st
st
and 2
and 2nd
nd
Laws of Energy
Laws of Energy
All machines and living things that manipulate energy release
All machines and living things that manipulate energy release
heat. Organized matter tends to become more disordered
heat. Organized matter tends to become more disordered
unless an external source of energy is available to maintain
unless an external source of energy is available to maintain
the ordered arrangement. The chemical reaction that causes
the ordered arrangement. The chemical reaction that causes
rust release heat. The chemical reaction that causes rust
rust release heat. The chemical reaction that causes rust
releases heat. Ultimately, orderly arrangements of matter,
releases heat. Ultimately, orderly arrangements of matter,
such as clothing automobiles, or living organisms, become
such as clothing automobiles, or living organisms, become
disordered. There is an increase in entropy.
disordered. There is an increase in entropy.
Eventually, nonliving objects wear out and living things die
Eventually, nonliving objects wear out and living things die
and decompose. This process of becoming more disordered
and decompose. This process of becoming more disordered
coincides with the constant flow of energy toward a dilute
coincides with the constant flow of energy toward a dilute
form of heat. This dissipated, low quality heat has little valu
form of heat. This dissipated, low quality heat has little value
e
to us, since we are unable to use it.
to us, since we are unable to use it.

35. It is important to understand that energy that is of low
It is important to understand that energy that is of low
quality from our point of view may still have significance
quality from our point of view may still have significance
to the world in which we live. For example the
to the world in which we live. For example the
distribution of heat energy in the ocean tends to
distribution of heat energy in the ocean tends to
moderate the temperature of the coastal climates. It is
moderate the temperature of the coastal climates. It is
important to recognize that we can sometimes figure new
important to recognize that we can sometimes figure new
ways to convert low quality energy to high quality
ways to convert low quality energy to high quality
energy.
energy. Eg
Eg. Low quality wind energy to high quality
. Low quality wind energy to high quality
electricity.
electricity.
An unfortunate consequence of energy conversion is
An unfortunate consequence of energy conversion is
pollution. The heat lost from most energy conversions is
pollution. The heat lost from most energy conversions is
a pollutant. The wear of the brakes used to stop cars
a pollutant. The wear of the brakes used to stop cars
results in pollution. The emissions from power plants
results in pollution. The emissions from power plants
pollutes.
pollutes.

36. Environmental Crisis
Environmental Crisis
The laws of energy give keys to understanding the
The laws of energy give keys to understanding the
environmental crisis currently challenging the world.
environmental crisis currently challenging the world.
Environmental Crisis
Environmental Crisis
Global warming,
Global warming, Ozone layer depletion
Ozone layer depletion
Floods
Floods Air pollution
Air pollution
Polluted water supply
Polluted water supply Waste disposal
Waste disposal
Land degradation
Land degradation Destruction of rainforest
Destruction of rainforest
Desertification
Desertification Rapid population growth etc
Rapid population growth etc

37. Environmental Crisis
Environmental Crisis
Structure of Earth
Structure of Earth’
’s atmosphere
s atmosphere
The thin film of gas that surrounds the earth varies in structur
The thin film of gas that surrounds the earth varies in structure as
e as
the distance increases outward from the surface. The earth
the distance increases outward from the surface. The earth’
’s
s
atmosphere is divided into regions based primarily on
atmosphere is divided into regions based primarily on
considerations of temperature as shown in the figure on the next
considerations of temperature as shown in the figure on the next
slide. The temperature at the earth
slide. The temperature at the earth’
’s surface varies from sub
s surface varies from sub-
-
zero
zero °
°C (i.e. temperatures beneath zero; so it is a term normally
C (i.e. temperatures beneath zero; so it is a term normally
used for negative number
used for negative number –
– temperature) in the polar regions and
temperature) in the polar regions and
high mountains areas to highs of about 70
high mountains areas to highs of about 70°
°C in the arid desert
C in the arid desert
regions.
regions.
The corresponding air temperatures close to the earth
The corresponding air temperatures close to the earth’
’s surface
s surface
(within a few metres) are lows of sub
(within a few metres) are lows of sub-
-zero and highs of about 50
zero and highs of about 50°
°C.
C.
In very warm areas, the air temperature is typically 10 to 20
In very warm areas, the air temperature is typically 10 to 20°
°C
C
cooler than the hot surface temperatures. Typically, at mid lati
cooler than the hot surface temperatures. Typically, at mid latitudes
tudes
the temperature falls with increasing altitude in the tropospher
the temperature falls with increasing altitude in the troposphere.
e.
This is known as positive lapse rate.
This is known as positive lapse rate.

38. The increase continues to an altitude known as the
The increase continues to an altitude known as the tropopause
tropopause,
,
above which the temperature increases again in the region known
above which the temperature increases again in the region known as
as
stratosphere. The height of the troposphere is about 10km above
stratosphere. The height of the troposphere is about 10km above
the earth
the earth’
’s surface, while the stratosphere extends a further 20 to 30
s surface, while the stratosphere extends a further 20 to 30
km.
km.
The lower 0 to 2 km of the troposphere can be further divided in
The lower 0 to 2 km of the troposphere can be further divided into
to
several regions. This entire region (0 to 2 km) is called the
several regions. This entire region (0 to 2 km) is called the
atmospheric boundary layer (ABL). The ABL is that region where
atmospheric boundary layer (ABL). The ABL is that region where
the wind velocity is affected by the shear resistance of the ear
the wind velocity is affected by the shear resistance of the earth
th’
’s
s
surface. The ABL is shallowest over oceans or large inland
surface. The ABL is shallowest over oceans or large inland
waterways, where its height is about 500 m.
waterways, where its height is about 500 m.
The depth of the ABL may be up to 2 km in urban areas with many
The depth of the ABL may be up to 2 km in urban areas with many
tall structures. In typical rural areas, the ABL depth is about
tall structures. In typical rural areas, the ABL depth is about 1 km.
1 km.
At the earth
At the earth’
’s surface, the wind velocity is lowest, and increases
s surface, the wind velocity is lowest, and increases
gradually (non linearly) to the top of the ABL.
gradually (non linearly) to the top of the ABL.

39. 10
30
100
300
H
(km)
T (°
K)
300 600
Tropopause
Troposphere
Thermosphere
Mesopause
Mesosphere
Stratopause
Temperature
Stratosphere

40. Above the ABL, the wind velocity is approximately constant, bein
Above the ABL, the wind velocity is approximately constant, being
g
unaffected by the shear resistance of the earth
unaffected by the shear resistance of the earth’
’s surface. The
s surface. The
region of most interest for atmospheric pollution is that within
region of most interest for atmospheric pollution is that within the
the
ABL, though higher regions within the troposphere are of interes
ABL, though higher regions within the troposphere are of interest
t
to large scale air circulation behaviour and global climate
to large scale air circulation behaviour and global climate
circulation modelling. A region close to the earth
circulation modelling. A region close to the earth’
’s surface, called
s surface, called
the sub
the sub-
-layer of the ABL, is affected by local roughness and is
layer of the ABL, is affected by local roughness and is
characterized by high turbulence and strong mixing.
characterized by high turbulence and strong mixing.

41. Within the ABL the average percentage chemical composition of
Within the ABL the average percentage chemical composition of
the air is as follows:
the air is as follows:
%
%
Nitrogen (N
Nitrogen (N2
2)
) 78
78
Oxygen (O
Oxygen (O2
2)
) 21
21
Argon
Argon (
(Ar
Ar)
) 0.9
0.9
Carbon dioxide (CO
Carbon dioxide (CO2
2)
) 0.03
0.03
Neon (Ne)
Neon (Ne) 0.0018
0.0018
Helium (He)
Helium (He) 0.00052
0.00052
CH
CH4
4 0.00022
0.00022
Krypton (Kr)
Krypton (Kr) 0.0001
0.0001
Di
Di-
-nitrogen oxide (N
nitrogen oxide (N2
2O)
O) 0.0001
0.0001
Hydrogen (H
Hydrogen (H2
2)
) 5.0 x 10
5.0 x 10-
-5
5
Xenon
Xenon (
(Xe
Xe)
) 8.0 x 10
8.0 x 10-
-6
6
Ozone
Ozone (O
(O3
3)
) 2.0 x 10
2.0 x 10-
-6
6
Ammonia (NH
Ammonia (NH3
3)
) 6.0 x 10
6.0 x 10-
-7
7
Nitrogen dioxide (NO
Nitrogen dioxide (NO2
2)
) 1.0 x 10
1.0 x 10-
-7
7
Nitrous oxide
Nitrous oxide (NO)
(NO) 6.0 x 10
6.0 x 10-
-8
8
Sulphur dioxide (SO
Sulphur dioxide (SO2
2)
) 2.0 x 10
2.0 x 10-
-8
8
Hydrogen sulphide (H
Hydrogen sulphide (H2
2S)
S) 2.0 x 10
2.0 x 10-
-8
8

42. OZONE
OZONE
The proliferation of ozone is one of the most widespread
The proliferation of ozone is one of the most widespread
environmental problems and one of the most difficult to manage.
environmental problems and one of the most difficult to manage.
Just about every major urban area of the country exceeds the
Just about every major urban area of the country exceeds the
health protective limits for ozone established by the various EP
health protective limits for ozone established by the various EPA.
A.
Ozone is a
Ozone is a colorless
colorless gas with a pungent
gas with a pungent odor
odor, and the chief
, and the chief
component of smog. Chemically it is a form of oxygen with three
component of smog. Chemically it is a form of oxygen with three
oxygen atoms instead of the two normally found in oxygen. It is
oxygen atoms instead of the two normally found in oxygen. It is
very reactive. Ozone levels high enough to cause health proble
very reactive. Ozone levels high enough to cause health problems
ms
for people are also high enough to damage crops and vegetation.
for people are also high enough to damage crops and vegetation.
Ozone can also damage the lungs of man, building materials and
Ozone can also damage the lungs of man, building materials and
cultural treasures (monuments). Ozone could exist in the
cultural treasures (monuments). Ozone could exist in the
troposphere or the stratosphere.
troposphere or the stratosphere.
Ozone is produced in the atmosphere (troposphere) when sunlight
Ozone is produced in the atmosphere (troposphere) when sunlight
triggers certain chemical reactions. The
triggers certain chemical reactions. The precurssors
precurssors, or chemicals
, or chemicals
that are initially needed for this reaction to take place includ
that are initially needed for this reaction to take place include
e
volatile organic compounds (
volatile organic compounds (VOCs
VOCs) and nitrogen oxides (
) and nitrogen oxides (NOx
NOx).
).
VOCs
VOCs are released into the air when petroleum products are
are released into the air when petroleum products are
combusted, handled or processed.
combusted, handled or processed. NOx
NOx are also produced by
are also produced by
combustion. Sunlight provide energy to fuel the reactions betwe
combustion. Sunlight provide energy to fuel the reactions between
en
the
the VOCs
VOCs and the
and the NOx
NOx and naturally occurring atmospheric
and naturally occurring atmospheric

43. gases, resulting in the production of ozone and eventual generat
gases, resulting in the production of ozone and eventual generation of smog.
ion of smog.
Recent findings indicate that some pollutants especially ozone a
Recent findings indicate that some pollutants especially ozone are more
re more
harmful in lower concentrations than previously thought because
harmful in lower concentrations than previously thought because they could
they could
cause life long, permanent health damage. Ozone is the most ser
cause life long, permanent health damage. Ozone is the most serious threat
ious threat
to vegetation. It attacks leaves causing them to yellow, develo
to vegetation. It attacks leaves causing them to yellow, develop dead spots
p dead spots
and drop early. It can reduce plant
and drop early. It can reduce plant’
’s growth, fruit yield and increase
s growth, fruit yield and increase
susceptibility to insect attack and interferes with photosynthes
susceptibility to insect attack and interferes with photosynthesis.
is.
OZONE IN STRATOSPHERE
OZONE IN STRATOSPHERE
The ozone layer in the stratosphere filters out some of the
The ozone layer in the stratosphere filters out some of the u.v
u.v. light from the
. light from the
sun. Destruction of the ozone layer allows more of the sun
sun. Destruction of the ozone layer allows more of the sun’
’s UV rays to
s UV rays to
penetrate to us. Increased UV can lead to greater incidence of
penetrate to us. Increased UV can lead to greater incidence of skin cancer,
skin cancer,
Cataracts, reduction in populations of certain fish larvae and p
Cataracts, reduction in populations of certain fish larvae and plankton. It also
lankton. It also
reduces the useful life of outdoor paints and plastics.
reduces the useful life of outdoor paints and plastics. Chlorofluoro
Chlorofluoro-
-carbons
carbons
(CFC) are compounds that consist of
(CFC) are compounds that consist of Cl
Cl, F and C and used as coolants for
, F and C and used as coolants for
refrigerators, air conditions, propellants for aerosol sprays ag
refrigerators, air conditions, propellants for aerosol sprays agents for
ents for
producing plastic foam and cleansers for electrical parts. CFCs
producing plastic foam and cleansers for electrical parts. CFCs do not
do not
degrade easily in the first layer of the atmosphere (troposphere
degrade easily in the first layer of the atmosphere (troposphere) and so rises
) and so rises
into the stratosphere. CFCs are broken down by UV light in the
into the stratosphere. CFCs are broken down by UV light in the stratosphere.
stratosphere.
The chlorine atoms released react with the ozone layer to conver
The chlorine atoms released react with the ozone layer to convert it into two
t it into two
molecules of oxygen and chloride.
molecules of oxygen and chloride.

44. OZONE
OZONE
UV
UV
F
F Cl
Cl F
F Cl
Cl
C
C →
→ C
C + O
+ O3
3 →
→ O
O2
2 +
+ Cl
Cl-
-O
O →
→
Cl
Cl F
F Cl
Cl F
F
O +
O + Cl
Cl-
-O
O →
→ O
O2
2 +
+ Cl
Cl

45. The
The Halons
Halons are also industrially produced group of
are also industrially produced group of
chemicals that contain bromine.
chemicals that contain bromine. Halons
Halons destroy ozone in
destroy ozone in
a manner similar to chlorine.
a manner similar to chlorine. Halons
Halons are used primarily
are used primarily
in fire extinguishing foam.
in fire extinguishing foam.
Green house gases and Global warming
Green house gases and Global warming
Green house effect is a natural phenomenon caused
Green house effect is a natural phenomenon caused
predominantly by water vapour, NO
predominantly by water vapour, NO2
2, O
, O3
3, CO
, CO2
2 and CH
and CH4
4
(methane) and other gases in the atmosphere. Their
(methane) and other gases in the atmosphere. Their
effect on the earth is comparable to that of the glass in a
effect on the earth is comparable to that of the glass in a
green house.
green house. Greenhouse gases greatly affect the
Greenhouse gases greatly affect the
temperature of the Earth; without them, Earth's surface
temperature of the Earth; without them, Earth's surface
would be on average about 33
would be on average about 33 °
°C (59
C (59 °
°F) colder than at
F) colder than at
present.
present.
OZONE
OZONE

46. Visible light passes through the atmosphere to the earth
Visible light passes through the atmosphere to the earth’
’s surface.
s surface.
When the light is absorbed by the earth, it is converted to heat
When the light is absorbed by the earth, it is converted to heat.
.
Some heat escapes, CO
Some heat escapes, CO2
2 and other gases in the troposphere trap the
and other gases in the troposphere trap the
rest, warming the earth. This allows the earth to maintain a wa
rest, warming the earth. This allows the earth to maintain a warm
rm
temperature and support life. If there is no green house effect
temperature and support life. If there is no green house effect, the
, the
earth will be much colder. In recent years, activities of man h
earth will be much colder. In recent years, activities of man have
ave
generated a lot of CO
generated a lot of CO2
2 and many people have become concerned
and many people have become concerned
about human activity causing the earth to become too warm. It i
about human activity causing the earth to become too warm. It is
s
important to recognize that there is a great deal of disagreemen
important to recognize that there is a great deal of disagreement
t
among scientists about weather global warming is actually occurr
among scientists about weather global warming is actually occurring.
ing.
Causes of global warming
Causes of global warming
Certain types of air pollutants may be producing long
Certain types of air pollutants may be producing long-
-term and
term and
perhaps irreversible changes to the global atmosphere.
perhaps irreversible changes to the global atmosphere.
Industrial growth since the mid
Industrial growth since the mid-
-nineteenth century has released
nineteenth century has released
large amounts of CO
large amounts of CO2
2 into the troposphere.
into the troposphere.
Global Warming
Global Warming

47. Acid Rain
Acid Rain
Acid rains is mainly attributable to the strong mineral acids
Acid rains is mainly attributable to the strong mineral acids –
–
Sulphuric and nitric acids that are derived from oxidation of SO
Sulphuric and nitric acids that are derived from oxidation of SO2
2 and
and
NOx
NOx respectively. Pollutant emission of the strong acids
respectively. Pollutant emission of the strong acids -
- nitric and
nitric and
sulphuric are slight but atmospheric oxidation NO
sulphuric are slight but atmospheric oxidation NO2
2 and SO
and SO2
2 causes
causes
formation of these acids. They are removed from the air in rain
formation of these acids. They are removed from the air in rainfall
fall
then known as acid rain (acid fog, acid snow and acid dust). Wi
then known as acid rain (acid fog, acid snow and acid dust). Winds
nds
carry air pollutants hundreds of miles from their points of orig
carry air pollutants hundreds of miles from their points of origin.
in.
These transported air pollutants can damage aquatic ecosystems,
These transported air pollutants can damage aquatic ecosystems,
crops and forest and may pose risks to human health. One of the
crops and forest and may pose risks to human health. One of the
pollutants is called acid deposition (or more commonly
pollutants is called acid deposition (or more commonly –
– acid rain).
acid rain).
Acid rain, which results from the reaction of pollutant gases an
Acid rain, which results from the reaction of pollutant gases and
d
moisture in the atmosphere has irreversibly damaged the
moisture in the atmosphere has irreversibly damaged the
environment in many parts of the world. The process of acid
environment in many parts of the world. The process of acid
deposition begins with emissions of
deposition begins with emissions of sulfur
sulfur dioxide (primarily form coal
dioxide (primarily form coal
burning power plants) and nitrogen oxides (primarily from motor
burning power plants) and nitrogen oxides (primarily from motor

48. Acid Rain
Acid Rain
vehicles and coal burning power plants). These
vehicles and coal burning power plants). These
pollutants interact with sunlight and water
pollutants interact with sunlight and water vapor
vapor in the
in the
upper atmosphere to form acidic compounds (
upper atmosphere to form acidic compounds (sulfuric
sulfuric
acid and nitric acid). These compounds often fall to earth
acid and nitric acid). These compounds often fall to earth
as acid rain or snow but the compounds can also join
as acid rain or snow but the compounds can also join
dust or other dry airborne particles and fall as dry
dust or other dry airborne particles and fall as dry
deposition.
deposition.
Effects:
Effects:
The extent of damage caused by acid rain depends on
The extent of damage caused by acid rain depends on
the total acidity deposited in a particular area and the
the total acidity deposited in a particular area and the
sensitivity of the area receiving it. Areas with acid
sensitivity of the area receiving it. Areas with acid
neutralising compounds in the soil can experience
neutralising compounds in the soil can experience
years of acid deposition without problems.
years of acid deposition without problems.
Since surface waters have less buffering capacity than
Since surface waters have less buffering capacity than
soils, acid precipitation problems are usually noticed in
soils, acid precipitation problems are usually noticed in
aquatic ecosystems before they are noticed in
aquatic ecosystems before they are noticed in
terrestrial ecosystems.
terrestrial ecosystems.

49. Burning fossil fuels such as coal, oil and natural gas also rele
Burning fossil fuels such as coal, oil and natural gas also release
ase
large amounts of CO
large amounts of CO2
2.
.
Clearing of rain forests by burning the wood contributes CO
Clearing of rain forests by burning the wood contributes CO2
2 and
and
other green house gases to the atmosphere. Also the clearing
other green house gases to the atmosphere. Also the clearing
means less CO
means less CO2
2 is removed from the air by plants.
is removed from the air by plants.
EFFECTS
EFFECTS
Recent studies and computer models indicate that by increasing
Recent studies and computer models indicate that by increasing
the amount of CO
the amount of CO2
2 in the atmosphere, we may have initiated a
in the atmosphere, we may have initiated a
warming trend that may raise, average global temperature
warming trend that may raise, average global temperature
between 2
between 2°
°F (
F (-
-16.7
16.7°
°C) to 8
C) to 8°
°F (
F (-
-13.3
13.3°
°C) by the year 2050.
C) by the year 2050.
Global warming may change weather patterns and regional
Global warming may change weather patterns and regional
climates
climates
Natural important agricultural areas could become less productiv
Natural important agricultural areas could become less productive
e
Natural ecosystems would also be affected.
Natural ecosystems would also be affected.
Leads to rising sea levels of one foot in the next 30 to 40 year
Leads to rising sea levels of one foot in the next 30 to 40 years
s
and two to seven feet by the year 2100. This inundate 50 to 80%
and two to seven feet by the year 2100. This inundate 50 to 80%
of the US, coastal wetlands, erode all recreational beached and
of the US, coastal wetlands, erode all recreational beached and
increase salinity of estuaries and groundwater.
increase salinity of estuaries and groundwater.

50. Acid Rain
Acid Rain
Increased acidity of surface waters so much that it
Increased acidity of surface waters so much that it
reduces or eliminates their ability to sustain aquatic
reduces or eliminates their ability to sustain aquatic
life.
life.
Forest and agricultural crops are vulnerable because
Forest and agricultural crops are vulnerable because
acid deposition can leach nutrients from the ground
acid deposition can leach nutrients from the ground
Can hamper micro
Can hamper micro-
-organisms that nourish plants
organisms that nourish plants
(
(rhizobium
rhizobium, etc)
, etc)
Release toxic metals that would normally be tied up in
Release toxic metals that would normally be tied up in
the soil at higher pH.
the soil at higher pH.
The pollutants that cause acid rain can also make the
The pollutants that cause acid rain can also make the
air hazy or foggy affecting the enjoyable views of
air hazy or foggy affecting the enjoyable views of
vacationers and potentially affecting communication
vacationers and potentially affecting communication
and navigation.
and navigation.

51. Acid Rain
Acid Rain
Control:
Control:
Power plants burning coal with high
Power plants burning coal with high sulfur
sulfur content are considered
content are considered
major cause of acid rain. Coal from e.g. Midwest (U.S.A) has a
major cause of acid rain. Coal from e.g. Midwest (U.S.A) has a
much higher sulphur content than Western coal. These oxides of
much higher sulphur content than Western coal. These oxides of
N and S released from Midwestern power plants, are carried by
N and S released from Midwestern power plants, are carried by
winds toward the eastern seaboard and Canada.
winds toward the eastern seaboard and Canada.
Power plants have to reduce release of SO
Power plants have to reduce release of SO2
2. Total SO
. Total SO2
2 released
released
should be permanently limited to the low levels set.
should be permanently limited to the low levels set.
Stiff penalties for plants that release more pollution
Stiff penalties for plants that release more pollution
Bonus allowance to be given to power plants that install clean c
Bonus allowance to be given to power plants that install clean coal
oal
technology designed to reduce SO
technology designed to reduce SO2
2 release or for using renewable
release or for using renewable
energy sources such as solar or wind.
energy sources such as solar or wind.
New cars and utility boilers that releases lesser
New cars and utility boilers that releases lesser NO
NOx
x emmissions
emmissions to
to
be designed.
be designed.

52. POLLUTION
POLLUTION
Pollution can be defined as an undesirable change in the physic
Pollution can be defined as an undesirable change in the physical,
al,
chemical or biological characteristics of the air, water or land
chemical or biological characteristics of the air, water or land that
that
can harmfully affect health, survival, or activities of humans o
can harmfully affect health, survival, or activities of humans or
r
other living organisms. Under this definition, pollution does n
other living organisms. Under this definition, pollution does not
ot
necessarily have to cause physical harm. It may merely interfer
necessarily have to cause physical harm. It may merely interfere
e
with human activities, e.g. a lake may be considered polluted if
with human activities, e.g. a lake may be considered polluted if it
it
cannot be used for boating activities.
cannot be used for boating activities.
The term
The term ‘
‘undesirable change
undesirable change’
’, requires value judgements. An
, requires value judgements. An
alteration may be judged favourable by some; or the undesirable
alteration may be judged favourable by some; or the undesirable
effect may be considered acceptable when compared with the
effect may be considered acceptable when compared with the
favourable effect e.g. an affluent country may ban the use of DD
favourable effect e.g. an affluent country may ban the use of DDT
T
as a pesticide because of a judgement that the risks (especially
as a pesticide because of a judgement that the risks (especially to
to
non
non-
-human organisms) outweigh the benefits. At the same time,
human organisms) outweigh the benefits. At the same time,
a country with insufficient food production or a country where
a country with insufficient food production or a country where
malaria affects much of the population may decide that the
malaria affects much of the population may decide that the
advantages of using DDT to kill crop pests or malaria
advantages of using DDT to kill crop pests or malaria-
-carrying
carrying
mosquitoes outweigh the risks of its undesirable effects.
mosquitoes outweigh the risks of its undesirable effects.

53. Types of Pollution
Types of Pollution
Classification of pollutants
Classification of pollutants
One classification of pollutants put pollutants into three divis
One classification of pollutants put pollutants into three divisions.
ions.
The first type of pollutants include those substances that occu
The first type of pollutants include those substances that occur in
r in
nature, but as a result of human activity are found in unusually
nature, but as a result of human activity are found in unusually large
large
concentrations e.g. CO
concentrations e.g. CO2
2.
.
The second type of pollutants are the toxic compounds that relea
The second type of pollutants are the toxic compounds that released
sed
into the environment as a result of anthropogenic activities. T
into the environment as a result of anthropogenic activities. These
hese
compounds are not found naturally in the environment e.g. mercur
compounds are not found naturally in the environment e.g. mercury,
y,
zinc, arsenic, selenium etc.
zinc, arsenic, selenium etc.
The third type of pollutants occur when substances which are no
The third type of pollutants occur when substances which are not
t
themselves toxic but are released into the environment as a resu
themselves toxic but are released into the environment as a result of
lt of
human activity.
human activity.

54. Types of Pollution
Types of Pollution
Another classification of the pollutants is given based upon
Another classification of the pollutants is given based upon
the pollutants susceptibility to degradation.
the pollutants susceptibility to degradation.
Two Types of pollutants
Two Types of pollutants
Degradable Pollutants
Degradable Pollutants
Non
Non-
-degradable Pollutants
degradable Pollutants
Degradable Pollutants
Degradable Pollutants
These are the pollutants that can be decomposed, removed,
These are the pollutants that can be decomposed, removed,
consumed and thus reduced to acceptable levels either by natural
consumed and thus reduced to acceptable levels either by natural
processes or by human
processes or by human-
-engineered systems.
engineered systems.
Two classes of degradable pollutants
Two classes of degradable pollutants
Rapidly degradable pollutants
Rapidly degradable pollutants –
– decomposes faster e.g.
decomposes faster e.g.
human sewage, animal and crop wastes.
human sewage, animal and crop wastes.
Slowly degradable pollutants
Slowly degradable pollutants –
– decompose slowly but
decompose slowly but
eventually are either broken down completely or reduced
eventually are either broken down completely or reduced
to harmless levels, e.g. DDT, radioactive materials
to harmless levels, e.g. DDT, radioactive materials
(strontium
(strontium-
-90, plutonium
90, plutonium-
-239 etc.).
239 etc.).

55. Non
Non-
-degradable Pollutants
degradable Pollutants
These are pollutants not broken down by natural
These are pollutants not broken down by natural
processes. E.g. lead, mercury, some plastics etc.
processes. E.g. lead, mercury, some plastics etc.

56. Air Pollution
Air Pollution
Air pollution
Air pollution refers to the accumulation of substances in the atmosphere that
refers to the accumulation of substances in the atmosphere that can
can
cause harmful health effects to living things or can negatively
cause harmful health effects to living things or can negatively affect the public
affect the public
welfare. Negative effects of public welfare include the economi
welfare. Negative effects of public welfare include the economic impact of damage
c impact of damage
to crops or property, such as buildings or works of arts. Air p
to crops or property, such as buildings or works of arts. Air pollution is the result
ollution is the result
of human activities as well as naturally occurring phenomenon.
of human activities as well as naturally occurring phenomenon. Transportation,
Transportation,
power and heat generation, industrial processes and the burning
power and heat generation, industrial processes and the burning of solid wastes are
of solid wastes are
the major sources of pollution due to human activities. Volcan
the major sources of pollution due to human activities. Volcanic eruptions and
ic eruptions and
naturally occurring fires such as those caused by lightning stor
naturally occurring fires such as those caused by lightning storms are natural
ms are natural
causes of air pollution.
causes of air pollution.
For anyone living in a crowed city it
For anyone living in a crowed city it’
’s hard to envision a world without smog. The
s hard to envision a world without smog. The
word smog is a relatively recent term describing a type of pollu
word smog is a relatively recent term describing a type of pollution associated with
tion associated with
urban settings and smokestack industries. Smog is a blend of t
urban settings and smokestack industries. Smog is a blend of the two words
he two words
smoke and fog and it was first used by the French physician, Dr.
smoke and fog and it was first used by the French physician, Dr. H. A. des
H. A. des Voeux
Voeux.
.
One of the greatest risk to human health and the environment is
One of the greatest risk to human health and the environment is air pollution. The list
air pollution. The list
of health problems brought on or aggravated by air pollution in
of health problems brought on or aggravated by air pollution includes: lung
cludes: lung
diseases, such as chronic bronchitis and pulmonary
diseases, such as chronic bronchitis and pulmonary enphysema
enphysema; cancer,
; cancer,
particularly lung cancer; neural disorders including brain damag
particularly lung cancer; neural disorders including brain damage; bronchial asthma
e; bronchial asthma
and the common cold which are most persistent in places with hi
and the common cold which are most persistent in places with highly polluted air
ghly polluted air
and eye irritation.
and eye irritation.
Environmental problems range from damage to crops and vegetatio
Environmental problems range from damage to crops and vegetation to acid rain
n to acid rain
which eventually increases the acidity of some lakes and making
which eventually increases the acidity of some lakes and making them not
them not
conducive for the survival of fish and other aquatic life to glo
conducive for the survival of fish and other aquatic life to global warming and
bal warming and
destruction of the stratospheric ozone layer which can potenti
destruction of the stratospheric ozone layer which can potentially have
ally have
devastating effects on our planet.
devastating effects on our planet.

57. Air Pollution
Air Pollution
In addition to ozone, common pollutants that were among the firs
In addition to ozone, common pollutants that were among the first
t
to be regulated throughout the country include: carbon monoxide,
to be regulated throughout the country include: carbon monoxide,
airborne particulates,
airborne particulates, sulfur
sulfur dioxide, lead, nitrogen oxides,
dioxide, lead, nitrogen oxides,
asbestos, beryllium, mercury, vinyl chloride, arsenic,
asbestos, beryllium, mercury, vinyl chloride, arsenic,
radionuclides
radionuclides, benzene and coke oven emissions.
, benzene and coke oven emissions.
Carbon monoxide
Carbon monoxide –
– ordorless
ordorless gas produced from incomplete
gas produced from incomplete
combustions
combustions
Sulfur
Sulfur dioxide
dioxide –
– produced from combustion of coal, fuel oil and diesel
produced from combustion of coal, fuel oil and diesel
fuel.
fuel.
Nitrogen dioxide
Nitrogen dioxide –
– Produced from combustions, motor vehicles,
Produced from combustions, motor vehicles,
industrial boilers and heaters.
industrial boilers and heaters.
Particulate matter
Particulate matter –
– produced from diesel soot and smoke produced
produced from diesel soot and smoke produced
from wood burning. Can also be produced from photochemical
from wood burning. Can also be produced from photochemical
reactions among polluting gases, primarily
reactions among polluting gases, primarily sulfur
sulfur oxides and
oxides and
nitrogen oxides resulting in corrosive
nitrogen oxides resulting in corrosive sulfate
sulfate or nitrate ions.
or nitrate ions.

58. Common Air Pollutants
Common Air Pollutants Health concern
Health concern
Ozone (0.12
Ozone (0.12 ppm
ppm)
) Respiratory tract problems, asthma, eye irritation,
Respiratory tract problems, asthma, eye irritation,
nasal congestion, premature aging of lung tissue
nasal congestion, premature aging of lung tissue
Particulate matter (150
Particulate matter (150 µ
µg/m
g/m3
3
)
) Eye and throat irritation, bronchitis, lung damage
Eye and throat irritation, bronchitis, lung damage
Carbon monoxide (10
Carbon monoxide (10 mg/m
mg/m3
3
)
) Cardiovascular, nervous and pulmonary problems,
Cardiovascular, nervous and pulmonary problems,
Sulfur
Sulfur Dioxide (0.03
Dioxide (0.03 ppm
ppm)
) Respiratory tract problems, permanent lung
Respiratory tract problems, permanent lung
damage
damage
Lead (1.5
Lead (1.5 µ
µg/m
g/m3
3
)
) Retardation and brain damage
Retardation and brain damage
Nitrogen Dioxide (100
Nitrogen Dioxide (100 µ
µg/m
g/m3
3
)
) Respiratory illness and lung damage
Respiratory illness and lung damage
Hazardous Air Pollutants
Hazardous Air Pollutants
Asbestos (
Asbestos ( -
- )
) Variety of lung disease especially lung cancer
Variety of lung disease especially lung cancer
Beryllium
Beryllium Primary lung disease; affects liver, spleen, etc.
Primary lung disease; affects liver, spleen, etc.
Mercury
Mercury Damages brain, kidneys and bowels
Damages brain, kidneys and bowels
Vinyl chloride (26
Vinyl chloride (26 µ
µg/m
g/m3
3
)*
)* Lung and liver cancer
Lung and liver cancer
Arsenic
Arsenic Causes cancer
Causes cancer
Radionuclides
Radionuclides Causes cancer
Causes cancer
Benzene
Benzene Leukemia
Leukemia
Coke Oven Emissions
Coke Oven Emissions Respiratory Cancer
Respiratory Cancer
Values quoted in the brackets represent the guideline values
Values quoted in the brackets represent the guideline values –
– California, USA
California, USA

59. SOIL FORMATION, PROPERTIES AND
SOIL FORMATION, PROPERTIES AND
PROFILE
PROFILE
OBJECTIVES
OBJECTIVES
a.) Geologic process
a.) Geologic process
b). physical, chemical and biological factors involved in
b). physical, chemical and biological factors involved in
soil formation
soil formation
c). Soil texture and structure
c). Soil texture and structure
d). Layers in the soil profile
d). Layers in the soil profile
e). Human activities and impact on soil
e). Human activities and impact on soil

60. Geologic Processes
Geologic Processes
Formerly the earth was thought of to be a stable
Formerly the earth was thought of to be a stable
unchanging mass but recent findings and research has
unchanging mass but recent findings and research has
shown that activities such as earthquakes, floods, tsunamis,
shown that activities such as earthquakes, floods, tsunamis,
volcanic eruptions and windstorms have been changing the
volcanic eruptions and windstorms have been changing the
surface of the places we live. Much of these activities cause
surface of the places we live. Much of these activities cause
large portions of the Earth surface (known as plates) to
large portions of the Earth surface (known as plates) to
shift. The Earth comprise the crust, the mantle, inner and
shift. The Earth comprise the crust, the mantle, inner and
outer core. The crust is the outermost and superficial less
outer core. The crust is the outermost and superficial less
dense but thin layer that covers a thick underlying layer
dense but thin layer that covers a thick underlying layer
called the mantle.
called the mantle.
The mantle consist of an inner part and an outer portion
The mantle consist of an inner part and an outer portion
that is adjacent to the crust. The crust together with the
that is adjacent to the crust. The crust together with the
outer mantle is referred to as lithosphere. The inner mantle
outer mantle is referred to as lithosphere. The inner mantle
portion is a relatively thin layer known as
portion is a relatively thin layer known as asthenosphere
asthenosphere.
.
The
The asthenosphere
asthenosphere is capable of plastic flow. Below the
is capable of plastic flow. Below the
asthenosphere
asthenosphere is a solid mass that forms the remaining part
is a solid mass that forms the remaining part

61. of the mantle. The central core consists primarily of iron and
of the mantle. The central core consists primarily of iron and
nickel and has a solid centre and liquid outer region.
nickel and has a solid centre and liquid outer region.

62. Picture
Picture

63. Plate Tectonics
Plate Tectonics
The concept of plate tectonics indicates that the outer
The concept of plate tectonics indicates that the outer
surface of the Earth consist of large plates composed of
surface of the Earth consist of large plates composed of
the crust the outer portion of the mantle and that these
the crust the outer portion of the mantle and that these
plates are slowly moving over the surface of the liquid
plates are slowly moving over the surface of the liquid
outer mantle. The movements of the plates on the
outer mantle. The movements of the plates on the
plastic outer layer of the mantle are independent of each
plastic outer layer of the mantle are independent of each
other. Therefore, some of the plates are pulling apart
other. Therefore, some of the plates are pulling apart
from one another, while others are colliding. Where the
from one another, while others are colliding. Where the
plates are pulling apart form one another, the liquid
plates are pulling apart form one another, the liquid
mantle moves upward to fill the gap and solidifies. Thus
mantle moves upward to fill the gap and solidifies. Thus
new crust is formed from the liquid mantle.
new crust is formed from the liquid mantle.
Approximately half of the Earth surface has been formed
Approximately half of the Earth surface has been formed
in this way in the past 200 million years. The bottom of
in this way in the past 200 million years. The bottom of
the Atlantic and Pacific Oceans and Rift Valley and Red
the Atlantic and Pacific Oceans and Rift Valley and Red
Sea of Africa are areas where this is occurring. Where
Sea of Africa are areas where this is occurring. Where

64. Picture
Picture

65. plates are pulling apart on one portion of the Earth, they must
plates are pulling apart on one portion of the Earth, they must
be colliding elsewhere. Where plates collide, several other
be colliding elsewhere. Where plates collide, several other
things can happen. Often one of the plates slide under the
things can happen. Often one of the plates slide under the
other and is melted. Often when this occurs, some of the liquid
other and is melted. Often when this occurs, some of the liquid
mantle makes its way to the surface and volcanoes are formed
mantle makes its way to the surface and volcanoes are formed
that results in the formation of mountains. Volcanic activities
that results in the formation of mountains. Volcanic activities
add new material to the crust. When a collision occurs
add new material to the crust. When a collision occurs
between two plates under the ocean, the volcanoes may
between two plates under the ocean, the volcanoes may
eventually reach the surface and form a chain of volcanic
eventually reach the surface and form a chain of volcanic
islands, such as can be seen in the Caribbean Islands. Most of
islands, such as can be seen in the Caribbean Islands. Most of
these movements are associated with earthquakes. The
these movements are associated with earthquakes. The
movements of the plates are not slow and steady sliding
movements of the plates are not slow and steady sliding
movements but tend to occur in small jumps.
movements but tend to occur in small jumps.
These building processes are counteracted by processes that
These building processes are counteracted by processes that
tend to make the elevated surfaces lower. Gravity provides a
tend to make the elevated surfaces lower. Gravity provides a
force that tends to wear down the high places.
force that tends to wear down the high places.

66. Moving water, ice and wind assist in the process, however
Moving water, ice and wind assist in the process, however
their effectiveness is related to the size of the rock particles
their effectiveness is related to the size of the rock particles.
.
Mechanical weathering results from physical forces that reduce
Mechanical weathering results from physical forces that reduce
the size or rock particles without changing the chemical nature
the size or rock particles without changing the chemical nature
of the rock. Common causes of mechanical weathering are
of the rock. Common causes of mechanical weathering are
changes in temperature that tend to result in fractures in rock,
changes in temperature that tend to result in fractures in rock,
the freezing of water into ice that expands and tends to split
the freezing of water into ice that expands and tends to split
larger pieces of rock into smaller ones, and the actions of
larger pieces of rock into smaller ones, and the actions of
plants and animals. Because rock does not expand evenly,
plants and animals. Because rock does not expand evenly,
heating a large rock can cause it to fracture so that pieces of
heating a large rock can cause it to fracture so that pieces of
the rock flake off. These pieces can be further reduced in size
the rock flake off. These pieces can be further reduced in size
by other processes, such as the repeated freezing of water and
by other processes, such as the repeated freezing of water and
thawing of ice. Water that has seeped into rock cracks and
thawing of ice. Water that has seeped into rock cracks and
crevices expands as it freezes, causing the cracks to widen.
crevices expands as it freezes, causing the cracks to widen.
Subsequent thawing allows more water to fill the widened
Subsequent thawing allows more water to fill the widened
cracks, which are enlarged further by another period of
cracks, which are enlarged further by another period of
freezing. Alternating freezing and thawing breaks large rock
freezing. Alternating freezing and thawing breaks large rock
pieces into smaller ones. Other activities that bring about the
pieces into smaller ones. Other activities that bring about the
breaking of rocks include the following:
breaking of rocks include the following:

67. The roots of plants growing
The roots of plants growing
Wind and moving water
Wind and moving water
Activities of organism like worms and rats burrowing
Activities of organism like worms and rats burrowing
Chemical weathering
Chemical weathering

68. Picture
Picture

69. Chemical weathering
Chemical weathering
The chemical alteration of rock
The chemical alteration of rock eg
eg when rocks are
when rocks are
exposed to the atmosphere they may undergo oxidation
exposed to the atmosphere they may undergo oxidation
or hydrolysis by combining with atmospheric oxygen
or hydrolysis by combining with atmospheric oxygen
and/or water (acid rain), in so doing get chemically
and/or water (acid rain), in so doing get chemically
changed into different compounds.
changed into different compounds.
A combination of physical, chemical and biological events
A combination of physical, chemical and biological events
acting over time is responsible for the formation of soil.
acting over time is responsible for the formation of soil.

70. LAND AND SOIL
LAND AND SOIL
Land is the part of the world not covered by the oceans. Soil is the thin
covering over the land consisting of a mixture of minerals, organic material,
living organisms, air and water that together support the growth of plant
life. The proportions of the soil components vary with different types of
soils, but a typical ‘good’ agricultural soil is about 45% mineral, 25% air,
25% water and 5% organic matter. This combination provides good
drainage, aeration and organic matter. The organic material resulting from
the decay of plant and animal remains is known as humus.
Humus accumulates on the surface and ultimately becomes mixed with the
top layers of mineral particles. This material contains nutrients that are
taken up by plants from the soil. Humus also increases the water holding
capacity and the acidity of the soil so that inorganic nutrients which are
more soluble under acidic conditions, become available to plants. Humus
also tends to stick other soil particles together and helps to create a loose,
crumbly soil that allows water to soak in and permits air to be incorporated
into the soil. Compact soils have few pore spaces, so they are poorly
aerated and water has difficulty penetrating, so it runs off.

71. SOIL PROPERTIES
SOIL PROPERTIES
Soil properties include soil texture, structure,
Soil properties include soil texture, structure,
atmosphere, moisture, biotic content and chemical
atmosphere, moisture, biotic content and chemical
composition. Soil texture is determined by the size of
composition. Soil texture is determined by the size of
the mineral particles within the soil. The largest soil
the mineral particles within the soil. The largest soil
particles are
particles are gravl
gravl, which consists of fragments larger
, which consists of fragments larger
than 2.0
than 2.0 millimeters
millimeters in diameter. Particles between
in diameter. Particles between
0.05
0.05 adn
adn 2 mm are classified as sand. Silt particles
2 mm are classified as sand. Silt particles
range from 0.002 to 0.05mm in diameter
range from 0.002 to 0.05mm in diameter adn
adn the
the
smallest particles are clay particles, which are less than
smallest particles are clay particles, which are less than
0.002 mm in diameter. Clay particles tend to be flat and
0.002 mm in diameter. Clay particles tend to be flat and
are easily packed together to form layers that greatly
are easily packed together to form layers that greatly
reduce the movement of water through them. Such
reduce the movement of water through them. Such
soils are poorly aerated and do not drain well. Clay soils
soils are poorly aerated and do not drain well. Clay soils
ten stay moist for longer periods of time and do not
ten stay moist for longer periods of time and do not
easily lose minerals to percolating water.
easily lose minerals to percolating water.

72. Soil Properties
Soil Properties
An ideal soil for agriculture use is a loam, which combines
An ideal soil for agriculture use is a loam, which combines
the good aeration and drainage properties of large
the good aeration and drainage properties of large
particles of large particles with the nutrient
particles of large particles with the nutrient –
– retention
retention
and water holding ability of clay particles.
and water holding ability of clay particles.
Soil structure is different from its texture. Soil structure
Soil structure is different from its texture. Soil structure
refers to the way various soil particles clump together.
refers to the way various soil particles clump together.
The particles in sandy soils do not attach to one another;
The particles in sandy soils do not attach to one another;
therefore, sandy soils have a granular structure. The
therefore, sandy soils have a granular structure. The
particles in clay soils tend to stick to one another to form
particles in clay soils tend to stick to one another to form
large aggregates. Other soils that have a mixture of
large aggregates. Other soils that have a mixture of
particle sizes tend to form smaller aggregates. A good
particle sizes tend to form smaller aggregates. A good
soil is friable, which means that it crumbles easily. The
soil is friable, which means that it crumbles easily. The
soil structure and its moisture content determine how
soil structure and its moisture content determine how
friable a soil is.
friable a soil is.

73. Soil Profile
Soil Profile
The soil profile is a series of horizontal layers in the soil th
The soil profile is a series of horizontal layers in the soil that differ in
at differ in
chemical composition, physical properties, particle size and amo
chemical composition, physical properties, particle size and amount
unt
of organic matter. Each recognizable layer is known as a horiz
of organic matter. Each recognizable layer is known as a horizon.
on.
Several systems exist for describing and classifying the horizon
Several systems exist for describing and classifying the horizons in
s in
soils. The uppermost layer of the soil contains more nutrients
soils. The uppermost layer of the soil contains more nutrients and
and
organic matter than do the deeper layers. The top layer is know
organic matter than do the deeper layers. The top layer is known as
n as
the A horizon and consist of small mineral particles mixed with
the A horizon and consist of small mineral particles mixed with
orgnaic
orgnaic matter. It
matter. It’
’s usually dark in
s usually dark in color
color because of the high content
because of the high content
of organic matter. If there is a layer of litter (
of organic matter. If there is a layer of litter ( undecomposed
undecomposed or
or
partially decomposed organic matter) on the surface, it is known
partially decomposed organic matter) on the surface, it is known as
as
the O
the O-
- horizon. Forest soils typically have an O
horizon. Forest soils typically have an O-
- horizon. Many
horizon. Many
agricultural soils do not, since the soil is worked to incorpora
agricultural soils do not, since the soil is worked to incorporate
te
surface crop residue. As the organic matter decomposes, it beco
surface crop residue. As the organic matter decomposes, it becomes
mes
incorporated into the A horizon. The thickness of the A horizon
incorporated into the A horizon. The thickness of the A horizon may
may
vary from less than one cm on steep mountain slopes to over a
vary from less than one cm on steep mountain slopes to over a
meter deep. Most of the living organisms and nutrients are foun
meter deep. Most of the living organisms and nutrients are found in
d in
the A
the A –
– horizon. As water moves down through the A
horizon. As water moves down through the A –
– horizon, it
horizon, it
carries dissolved organic matter and minerals to lower layers in
carries dissolved organic matter and minerals to lower layers in a
a
process called leaching. Below the A horizon is a lighter colou
process called leaching. Below the A horizon is a lighter coloured
red

74. Layer known as the B
Layer known as the B –
– horizon. The B
horizon. The B-
-horizon, often
horizon, often
called the subsoil contains less organic material and
called the subsoil contains less organic material and
fewer organisms than the A
fewer organisms than the A –
– horizon. However it
horizon. However it
contains accumulations of nutrients that were leached
contains accumulations of nutrients that were leached
from higher levels. B
from higher levels. B –
– horizon is a valuable source of
horizon is a valuable source of
nutrients for plants and it normally support a well
nutrients for plants and it normally support a well
developed root system. The area below the B
developed root system. The area below the B-
-horizon is
horizon is
known as the C
known as the C-
-horizon and it consists of weathered
horizon and it consists of weathered
parent material. The chemical composition of the
parent material. The chemical composition of the
minerals of the C
minerals of the C-
- horizon helps to determine the pH of
horizon helps to determine the pH of
the soil. The characteristics of the parent material in
the soil. The characteristics of the parent material in
the C horizon may also influence the soil
the C horizon may also influence the soil’
’s rate of water
s rate of water
absorption and retention.
absorption and retention.

75. Picture
Picture

76. Picture
Picture

77. Land Pollution
Land Pollution
Historically, land has been the recipient of most wastes includi
Historically, land has been the recipient of most wastes including
ng
those removed from the air and water. Pollution of the land / s
those removed from the air and water. Pollution of the land / soil
oil
not only threaten the future use of the land but also the qualit
not only threaten the future use of the land but also the quality of
y of
the
the surronding
surronding air, surface water and groundwater. Pollutants on
air, surface water and groundwater. Pollutants on
the surface of the land or in the soil
the surface of the land or in the soil frequaently
frequaently move to the
move to the
surrounding air and water, particularly groundwater. Sometimes
surrounding air and water, particularly groundwater. Sometimes
this contamination is the result of a direct application, say of
this contamination is the result of a direct application, say of
pesticides or fertilizers, onto the land; improper storage, hand
pesticides or fertilizers, onto the land; improper storage, handling
ling
or disposal of toxic substances.
or disposal of toxic substances.
Industrial waste, if not properly treated and handled can imperi
Industrial waste, if not properly treated and handled can imperil both
l both
public health and the environment. Leaks from underground
public health and the environment. Leaks from underground
storage tanks and chemical spills also contribute to contaminati
storage tanks and chemical spills also contribute to contamination
on
of the land and groundwater.
of the land and groundwater.
If not properly disposed, common household wastes can cause
If not properly disposed, common household wastes can cause
environmental problems ranging from foul
environmental problems ranging from foul-
-smelling smoke from
smelling smoke from
burning trash to breeding grounds for rats, flies and mosquitoes
burning trash to breeding grounds for rats, flies and mosquitoes.
.
Even at properly run disposal sites, land contamination can
Even at properly run disposal sites, land contamination can
contribute to air and water pollution because small quantities o
contribute to air and water pollution because small quantities of
f
toxic substances may be dumped with other household wastes.
toxic substances may be dumped with other household wastes.

78. Land Pollution
Land Pollution
Rain water seeping through these buried wastes may form
Rain water seeping through these buried wastes may form leachate
leachate.
.
Leachate
Leachate is the liquid that results when water moves through any
is the liquid that results when water moves through any
non
non-
-water media and collects contaminants. Examples would
water media and collects contaminants. Examples would
include water as it trickles through either wastes or soils wher
include water as it trickles through either wastes or soils where
e
agricultural pesticides or fertilizers have been applied. This
agricultural pesticides or fertilizers have been applied. This
leachate
leachate can then percolate down through the soil and may result
can then percolate down through the soil and may result
in contamination of the groundwater.
in contamination of the groundwater.
Other organic wastes such as garbage and paper products
Other organic wastes such as garbage and paper products
decompose and can form explosive methane gas which, because it
decompose and can form explosive methane gas which, because it
is lighter than air, tends to rise through the soil and into the
is lighter than air, tends to rise through the soil and into the
atmosphere. Instances of houses near municipal landfills
atmosphere. Instances of houses near municipal landfills
collecting explosive levels of methane gas in crawl spaces or
collecting explosive levels of methane gas in crawl spaces or
basements have been documented.
basements have been documented.
The main sources of land pollution are municipal waste disposal,
The main sources of land pollution are municipal waste disposal,
illegal hazardous waste disposal, abandoned hazardous waste site
illegal hazardous waste disposal, abandoned hazardous waste sites
s
and underground tanks.
and underground tanks.

80. Environmental Impact Assessment
Environmental Impact Assessment
EIA is a process of assessing environmental impact of
EIA is a process of assessing environmental impact of
a development project to improve decision making
a development project to improve decision making
on its implementation
on its implementation
Brief History (Before the concept of EIA)
Brief History (Before the concept of EIA)
-
- Project evaluation
Project evaluation –
– formerly prior after the
formerly prior after the
execution of a major project there used to be project
execution of a major project there used to be project
evaluation. This was based on technical studies
evaluation. This was based on technical studies
valued in monetary terms (cost benefit analysis).
valued in monetary terms (cost benefit analysis).
-
- Rough evaluation
Rough evaluation –
– full of shortcomings and failures
full of shortcomings and failures
-
- Efforts to develop new evaluation approach led to
Efforts to develop new evaluation approach led to
EIA. In this Technical, Financial, Economic and
EIA. In this Technical, Financial, Economic and
Environmental aspects were given their proper
Environmental aspects were given their proper
weight in the decision making process.
weight in the decision making process.

81. ENVIRONMENTAL IMPACT ASSESSMENT
ENVIRONMENTAL IMPACT ASSESSMENT
1960 in the USA
1960 in the USA
1962
1962 -
- First evidence of local application of
First evidence of local application of
insecticides had far reaching ecological
insecticides had far reaching ecological
impacts
impacts
Environmental aspects of projects became a
Environmental aspects of projects became a
requirement for decision making
requirement for decision making
National Environmental Policy Act / Law
National Environmental Policy Act / Law
(NEPA) published in 1970. EIS should be
(NEPA) published in 1970. EIS should be
published for major actions significantly
published for major actions significantly
affecting quality of human environment.
affecting quality of human environment.

82. Some common targets
Some common targets
EIA seeks to identify probable alternatives for project
EIA seeks to identify probable alternatives for project
with little or no adverse impacts on the community or
with little or no adverse impacts on the community or
environment.
environment.
EIS is the assessment report produced after the
EIS is the assessment report produced after the
assessment exercise; it details both the beneficial and
assessment exercise; it details both the beneficial and
adverse impacts anticipated upon completion of a
adverse impacts anticipated upon completion of a
project and the probable impacts that would be
project and the probable impacts that would be
experienced during the operational phase of the
experienced during the operational phase of the
project.
project.
To perform an EIA about 5 major parties are involved:
To perform an EIA about 5 major parties are involved:
The Proponent or the Initiator e.g.
The Proponent or the Initiator e.g. Gov
Gov’
’t
t agency,
agency,
private personnel, company etc.
private personnel, company etc.
Decision makers
Decision makers –
– Central or Local
Central or Local gov
gov’
’t
t agency,
agency,
provincial official (EPA
provincial official (EPA –
– Gh
Gh)
)
Review Commission
Review Commission –
– EPA, EIA committee
EPA, EIA committee –
–
management committee
management committee

83. Interest group
Interest group –
– NGO, General (Univ. staff, Local
NGO, General (Univ. staff, Local
people, Chiefs, District Assemblies)
people, Chiefs, District Assemblies)
Consultant / Consultancy companies
Consultant / Consultancy companies

84. Purpose of the EIA
Purpose of the EIA
It enables financier/ client to take environmental
It enables financier/ client to take environmental
issues into account
issues into account
It seeks to compare the various alternatives which
It seeks to compare the various alternatives which
are available for any project. Each alternative will
are available for any project. Each alternative will
have economic cost and benefit as well as
have economic cost and benefit as well as
environmental impact. Adverse impacts may be
environmental impact. Adverse impacts may be
reduced at higher project cost whilst environmental
reduced at higher project cost whilst environmental
benefits may be enhanced at environmental cost.
benefits may be enhanced at environmental cost.
It attempts to weigh the environmental effects on a
It attempts to weigh the environmental effects on a
common basis with economic cost and benefit in the
common basis with economic cost and benefit in the
overall project evaluation
overall project evaluation
It identifies and forecasts the possible positive and
It identifies and forecasts the possible positive and
negative impacts to the environment resulting from
negative impacts to the environment resulting from
a proposed project.
a proposed project.
It helps to avoid costs and delays in implementation.
It helps to avoid costs and delays in implementation.

85. It provides a formal mechanism for direct agency co
It provides a formal mechanism for direct agency co-
-
ordination to deal with concerns.
ordination to deal with concerns.
It measures the level of plan implementation and the
It measures the level of plan implementation and the
degree of effectiveness of the above environmental
degree of effectiveness of the above environmental
protection provision.
protection provision.

86. Basic Water microbiology and Public Health
Basic Water microbiology and Public Health
Introduction
Introduction: The constituents of wastewater and natural untreated
: The constituents of wastewater and natural untreated
water that often impair the quality and thus make water unwholes
water that often impair the quality and thus make water unwholesome for
ome for
human consumption include micro
human consumption include micro-
-organisms (e.g. bacteria, viruses,
organisms (e.g. bacteria, viruses,
algae, fungi etc) and hazardous chemical constituents
algae, fungi etc) and hazardous chemical constituents e.g
e.g heavy metals
heavy metals
like As,
like As, Cd
Cd, Hg, etc; some poly
, Hg, etc; some poly-
-aromatic hydrocarbons like pesticides
aromatic hydrocarbons like pesticides –
–
DDT,
DDT, lindane
lindane etc. These contaminants has the capacity of adversely
etc. These contaminants has the capacity of adversely
affecting the health of consumers. The most important aspect of
affecting the health of consumers. The most important aspect of drinking
drinking
water is its micro
water is its micro-
-biological quality. Very important is the types of
biological quality. Very important is the types of
microoganisms
microoganisms that are pathogenic.
that are pathogenic.
Microbiological contaminants
Microbiological contaminants:
:
Bacteria
Bacteria -
- Several types of bacteria including
Several types of bacteria including coccus
coccus, bacillus,
, bacillus, vibrio
vibrio and
and
spirillum
spirillum exist and are sized between 0.5 and 5
exist and are sized between 0.5 and 5 µ
µm. Bacteria are single
m. Bacteria are single-
-cell
cell
organism consisting of a protoplasm enclosed by a unit cell memb
organism consisting of a protoplasm enclosed by a unit cell membrane.
rane.
Within the protoplasm is centrally positioned nuclear region whi
Within the protoplasm is centrally positioned nuclear region which bears the
ch bears the
genetic material known as chromatin. Also present in the cytopl
genetic material known as chromatin. Also present in the cytoplasm are
asm are
other organelles like mitochondria,
other organelles like mitochondria, ribosomes
ribosomes and vacuoles. The
and vacuoles. The
mitochondria helps with the respiration and metabolic activities
mitochondria helps with the respiration and metabolic activities of the cell to
of the cell to
produce chemical energy required for multiplication and other ac
produce chemical energy required for multiplication and other activities. The
tivities. The
ribosomes
ribosomes are needed for the production of proteins whiles the vacuoles
are needed for the production of proteins whiles the vacuoles
engage in excretory processes. Most bacteria multiply by binary
engage in excretory processes. Most bacteria multiply by binary fission.
fission.

87. Bacteria
Bacteria
Bacteria are the cause of most sanitary problems, because some o
Bacteria are the cause of most sanitary problems, because some of
f
them are pathogenic, so they can cause diseases. Their generati
them are pathogenic, so they can cause diseases. Their generation
on
time is very short e.g. as short as 20 minutes. In sewage treat
time is very short e.g. as short as 20 minutes. In sewage treatment
ment
and in some cases of water treatment process (nitrification
and in some cases of water treatment process (nitrification –
–
nitrosomonas
nitrosomonas and
and nitrobacter
nitrobacter), some bacteria are advantageous
), some bacteria are advantageous
because they can stabilize organic matter.
because they can stabilize organic matter.
C
C5
5H
H7
7O
O2
2N + 5 O
N + 5 O2
2 →
→ H
H2
2O + 4 CO
O + 4 CO2
2 + NH
+ NH4
4
+
+
+ HCO
+ HCO3
3
-
-
Bacteria cells can combine to form chains. As in a capsule bact
Bacteria cells can combine to form chains. As in a capsule bacteria cells can
eria cells can
be found surrounded by a slime layer consisting of degradation p
be found surrounded by a slime layer consisting of degradation products of
roducts of
the cell wall (polysaccharides). Some have flagella for locomot
the cell wall (polysaccharides). Some have flagella for locomotion.
ion.
The major source for pathogenic organisms is
The major source for pathogenic organisms is fecal
fecal matter originating from
matter originating from
domestic sewage. The number of organisms, that is present in se
domestic sewage. The number of organisms, that is present in sewage
wage
varies enormously. Normally you don
varies enormously. Normally you don’
’t find in water quality surveys
t find in water quality surveys
quantitative values for the pathogenic organisms mentioned. We
quantitative values for the pathogenic organisms mentioned. We often find
often find
values for faecal
values for faecal coliforms
coliforms, e.g. Escherichia coli or E. coli, sometimes
, e.g. Escherichia coli or E. coli, sometimes
streptococcus
streptococcus faecalis
faecalis and spores of Clostridium
and spores of Clostridium perfringens
perfringens. Next to these
. Next to these
we find values for bacterial counts at 20 and 37
we find values for bacterial counts at 20 and 37°
°C representing the
C representing the
temperature at which these bacterial / pathogens are cultured.
temperature at which these bacterial / pathogens are cultured.

88. COLIFORMS AND FECAL COLIFORMS
COLIFORMS AND FECAL COLIFORMS
The organisms which are used as indicators of water pollution ar
The organisms which are used as indicators of water pollution are:
e:
Coliform
Coliform bacteria
bacteria
Coliform
Coliform species are regularly found in unpolluted soils and water. The
species are regularly found in unpolluted soils and water. The
standard test for
standard test for coliforms
coliforms cannot be said to indicate specific faecal pollution.
cannot be said to indicate specific faecal pollution.
Especially in warm polluted waters the
Especially in warm polluted waters the coliform
coliform number in water can increase
number in water can increase
quite significantly. The
quite significantly. The coliforms
coliforms are commonly rod
are commonly rod-
-shaped bacterium, not
shaped bacterium, not
thought of as disease causing bacteria. Pathogenic bacteria in
thought of as disease causing bacteria. Pathogenic bacteria in wastes and
wastes and
polluted waters are usually much lower in numbers and much more
polluted waters are usually much lower in numbers and much more harder
harder
to isolate and identify than
to isolate and identify than coliforms
coliforms which are usually in high numbers in
which are usually in high numbers in
polluted waters. Many
polluted waters. Many coliform
coliform bacteria live in the soil and these organisms
bacteria live in the soil and these organisms
may be the source of those that appear in water especially surfa
may be the source of those that appear in water especially surface water.
ce water.
In recent years
In recent years coliform
coliform bacteria are replaced in water analysis by faecal
bacteria are replaced in water analysis by faecal
coliform
coliform.
. Fecal
Fecal coliforms
coliforms are more specific and live in the intestinal track of
are more specific and live in the intestinal track of
humans and many other animals. E. Coli is exclusively faecal and
humans and many other animals. E. Coli is exclusively faecal and constitutes
constitutes
over 90% of the
over 90% of the coliform
coliform flora of human intestine. E. coli are the main part
flora of human intestine. E. coli are the main part
of faecal
of faecal coliform
coliform; more time
; more time-
- consuming to detect. The faecal
consuming to detect. The faecal coliforms
coliforms e.g.
e.g.
the
the E.coli
E.coli must still be taken as the most sensitive and specific indicato
must still be taken as the most sensitive and specific indicator of
r of
faecal pollution at present available. Faecal Streptococci are
faecal pollution at present available. Faecal Streptococci are occassionally
occassionally
used as indicator organisms especially when confirmation of dub
used as indicator organisms especially when confirmation of dubious
ious E.coli
E.coli
results is required. Animals generally excrete much more high
results is required. Animals generally excrete much more high numbers of
numbers of
faecal streptococci than human, hence the ratio of faecal
faecal streptococci than human, hence the ratio of faecal coliforms
coliforms to
to

89. faecal streptococci, can indicate whether pollution is derived f
faecal streptococci, can indicate whether pollution is derived from animal or
rom animal or
human source (ratio of more than 4 = human source pollution).
human source (ratio of more than 4 = human source pollution).
Spores of Clostridium
Spores of Clostridium perfringens
perfringens :
: -
- spore of C.
spore of C. perfringens
perfringens is some
is some
times used for detection of intermittent pollution. Indicator o
times used for detection of intermittent pollution. Indicator organisms are
rganisms are
present in large numbers in the faeces of man. The presence of
present in large numbers in the faeces of man. The presence of these
these
organism in water may be interpreted to mean that such a water
organism in water may be interpreted to mean that such a water has
has
been contaminated with faecal matter, possibly coming from carri
been contaminated with faecal matter, possibly coming from carriers of
ers of
diseases / pathogenic organisms.
diseases / pathogenic organisms.
-
- E.coli
E.coli 10
105
5 –
– 10
106
6 / ml
/ ml
-
- Streptococcus
Streptococcus faecalis
faecalis 10
103
3 –
– 10
105
5 / ml
/ ml
-
- Spores of clostridium
Spores of clostridium perfringens
perfringens 10
102
2 –
– 10
104
4 / ml
/ ml
Organisms which might be injurious to health are in general alwa
Organisms which might be injurious to health are in general always present
ys present
in smaller numbers than E. coli. This implies that
in smaller numbers than E. coli. This implies that E.coli
E.coli (and faecal
(and faecal
coliforms
coliforms) is a good indicator for the probable presence of harmful
) is a good indicator for the probable presence of harmful
organisms. Organisms which are a hazard to health mostly origin
organisms. Organisms which are a hazard to health mostly originate from
ate from
excrements.
excrements.
E. Coli itself belongs to the
E. Coli itself belongs to the coliform
coliform group and is harmless. Besides
group and is harmless. Besides E.coli
E.coli,
,
the bacteria of the
the bacteria of the coliform
coliform group are used as well in order to simplify the
group are used as well in order to simplify the
examinations in the laboratory.
examinations in the laboratory.

90. Fungi
Fungi
Fungi are microscopic plants,
Fungi are microscopic plants, multicellular
multicellular, lacking in chlorophyll,
, lacking in chlorophyll,
which is a photosynthetic
which is a photosynthetic pigmen
pigmen which permits the conversion of
which permits the conversion of
sunlight energy into chemical energy. Fungi are found in biolog
sunlight energy into chemical energy. Fungi are found in biological
ical
treatment plants and polluted water utilizing organic matter. T
treatment plants and polluted water utilizing organic matter. They
hey
can be responsible for tastes and odours in water.
can be responsible for tastes and odours in water.
Algae
Algae
Algae are microscopic plants,
Algae are microscopic plants, multicellular
multicellular, lacking definite stems and
, lacking definite stems and
leaves as is the case of higher plants. They are present normal
leaves as is the case of higher plants. They are present normally
ly
in surface water (river, lake, reservoirs) because they need
in surface water (river, lake, reservoirs) because they need
sunlight. Algae utilize CO
sunlight. Algae utilize CO2
2 (HCO
(HCO3
3
-
-
), NH
), NH4
4 (NO
(NO2
2
-
-
, NO
, NO3
3
-
-
), PO
), PO4
4
3
3-
-
and
and
elements in minor amounts to produce cells and oxygen.
elements in minor amounts to produce cells and oxygen.
Algae can carry out photosynthesis (utilization of sunlight ener
Algae can carry out photosynthesis (utilization of sunlight energy)
gy)
and don
and don’
’t depend on oxidation of organic matter to survive. Algae
t depend on oxidation of organic matter to survive. Algae
produce oxygen in the presence of light converting inorganic
produce oxygen in the presence of light converting inorganic
materials in water into organic matter.
materials in water into organic matter.
In absence of light the algae exert oxygen demand.
In absence of light the algae exert oxygen demand.

91. Different Classes Of Algae
Different Classes Of Algae
Blue
Blue-
-green algae
green algae –
– (
(cyanophyceae
cyanophyceae or
or myxophyceae
myxophyceae)
)
e.g.
e.g. microcystis
microcystis anabaena,
anabaena, aphanizomenon
aphanizomenon,
, oscilatoria
oscilatoria.
.
Green algae (
Green algae (chlorophyceae
chlorophyceae) e.g. chlorella,
) e.g. chlorella, palmella
palmella,
,
scenedesmus
scenedesmus.
.
Diatoms (
Diatoms (bacillariophyceae
bacillariophyceae) e.g.
) e.g. asterionella
asterionella,
, melosira
melosira,
, synedra
synedra,
,
tabellaria
tabellaria.
.
Flagellates (
Flagellates (chrysophyceae
chrysophyceae,
, euglenophyceae
euglenophyceae) e.g.
) e.g.
chlamydomonas
chlamydomonas, euglena,
, euglena, pandorina
pandorina,
,
The importance of algae for water quality is large because of
The importance of algae for water quality is large because of
Their formation of taste and odour compounds, toxic substances
Their formation of taste and odour compounds, toxic substances
Their influence on the oxygen balance of the water
Their influence on the oxygen balance of the water
(
(supersaturation
supersaturation of O
of O2
2; anaerobic conditions)
; anaerobic conditions)
Their contribution to the organic matter content of the water an
Their contribution to the organic matter content of the water and
d
the turbidity (clogging of filters).
the turbidity (clogging of filters).

92. Virus
Virus
A virus particle (
A virus particle (viron
viron) consists of nucleic acid, DNA or RNA covered by
) consists of nucleic acid, DNA or RNA covered by
a protein coat called a
a protein coat called a capsid
capsid. The combined nucleic acid and
. The combined nucleic acid and capsid
capsid
called the
called the nucleocapsid
nucleocapsid can either be naked and enclosed by a
can either be naked and enclosed by a
membrane. Among the enclosed virus are the influenza virus and
membrane. Among the enclosed virus are the influenza virus and
herpes. Virus are extremely host
herpes. Virus are extremely host-
-specific and within a given host also
specific and within a given host also
tissue
tissue –
– and cell
and cell-
-specific. The virus differ from micro
specific. The virus differ from micro-
-organisms in the
organisms in the
ff properties.
ff properties.
1.
1. They may contain only one kind of nucleic acid RNA or DNA (note:
They may contain only one kind of nucleic acid RNA or DNA (note: there
there
has been discovered however
has been discovered however virons
virons with both nucleic acid).
with both nucleic acid).
2.
2. Only the nucleic acid is necessary (but not sufficient) for the
Only the nucleic acid is necessary (but not sufficient) for their
ir
reproduction.
reproduction.
3.
3. They are unable to reproduce outside living cells. Reproduction
They are unable to reproduce outside living cells. Reproduction occurs
occurs
within the host cell since they depend on the host cell for the
within the host cell since they depend on the host cell for the replication
replication
of its nucleic acid and synthesis of its protein coat. This pro
of its nucleic acid and synthesis of its protein coat. This process usually
cess usually
leads to the death of the host cell. Plants, animals and micro
leads to the death of the host cell. Plants, animals and micro-
-organism
organism
e.g. bacteria are host for viruses size about 100 nm in length.
e.g. bacteria are host for viruses size about 100 nm in length. In using
In using
a bacteria as a host the virus is known as phage
a bacteria as a host the virus is known as phage
Reproduction:
Reproduction: -
- Following adsorption, the phage injects its DNA into the host
Following adsorption, the phage injects its DNA into the host
cell. In phage T2, the nucleic acid penetrates the host cell, t
cell. In phage T2, the nucleic acid penetrates the host cell, the protein
he protein
coat remaining on the exterior. The injected phage DNA causes a
coat remaining on the exterior. The injected phage DNA causes an
n
immediate change in metabolism of infected cell.
immediate change in metabolism of infected cell.

93. The synthesis of bacteria DNA ceases but the total protein
The synthesis of bacteria DNA ceases but the total protein
content continues to increase and DNA synthesis is resumed at
content continues to increase and DNA synthesis is resumed at
higher rate. Phage DNA is synthesised at the expense of
higher rate. Phage DNA is synthesised at the expense of
degraded bacterial DNA. New protein coat are then
degraded bacterial DNA. New protein coat are then
synthesised for the new
synthesised for the new phages
phages. Matured
. Matured phages
phages then cause
then cause
the bacterial cell to
the bacterial cell to lyse
lyse through secretion of
through secretion of lysozyme
lysozyme to
to
release the new
release the new phages
phages. Viral infections in general are
. Viral infections in general are
currently among the most prominent infectious diseases. This
currently among the most prominent infectious diseases. This
is easily explained by the fact that bacteria offer a variety of
is easily explained by the fact that bacteria offer a variety of
targets for therapeutic agents to inhibit their growth.
targets for therapeutic agents to inhibit their growth.
The multiplication of viruses on the other hand is intimate
The multiplication of viruses on the other hand is intimate
coupled to essential metabolic processes of the host cell, such
coupled to essential metabolic processes of the host cell, such
as nucleic acid synthesis. It is therefore extremely difficult
as nucleic acid synthesis. It is therefore extremely difficult to
to
inhibit intracellular viral growth without serious damage to th
inhibit intracellular viral growth without serious damage to the
e
host cell metabolism. The development of anti
host cell metabolism. The development of anti-
-viral
viral
therapeutics has therefore met with little success so far and
therapeutics has therefore met with little success so far and
the old
the old-
- fashioned methods for dealing with the common cold
fashioned methods for dealing with the common cold
for instance still seems the best.
for instance still seems the best.

94. Public significance of diseases associated with excreta
Public significance of diseases associated with excreta
and water related diseases
and water related diseases
Classification of water and related diseases
Classification of water and related diseases
Disease
Disease
Cholera
Cholera
Infectious hepatitis
Infectious hepatitis
Paratyphoid
Paratyphoid
Typhoid
Typhoid
Waterborne
Waterborne
Disease
Disease
Guinea worm
Guinea worm
Schistosoma
Schistosoma
(
(Bilharzia
Bilharzia)
)
Water
Water-
-based
based
Amoebic dysentery
Amoebic dysentery
Bacillary dysentery
Bacillary dysentery
Gastroenteritis
Gastroenteritis
Waterborne
Waterborne
or water
or water –
–
washed
washed
Malaria
Malaria
Onchocerciasis
Onchocerciasis
Yellow fever
Yellow fever
Sleeping
Sleeping
sickness
sickness
Water related
Water related
insect vector
insect vector
Ascaris
Ascaris
Conjuctivitis
Conjuctivitis
Diarrhoea diseases
Diarrhoea diseases
Leprosy
Leprosy
Scabies
Scabies
Water
Water -
-
washed
washed

95. Water quality and health
Water quality and health
Water washed disease
Water washed disease-
- Water washed diseases are caused by water
Water washed diseases are caused by water
scarcity where people cannot wash themselves, their clothes or h
scarcity where people cannot wash themselves, their clothes or home
ome
regularly.
regularly.
Trachoma
Trachoma is the main cause of preventable blindness in the developing
is the main cause of preventable blindness in the developing
world, with four million sufferers, an estimated 500 million at
world, with four million sufferers, an estimated 500 million at risk and six
risk and six
million permanently blinded. It is common in areas that are hot,
million permanently blinded. It is common in areas that are hot, dry and
dry and
dusty and where there is not enough water for people to wash reg
dusty and where there is not enough water for people to wash regularly.
ularly.
Trachoma is spread, especially among young children, by flies, f
Trachoma is spread, especially among young children, by flies, fingers and
ingers and
clothing coming into contact with infected eyes, spreading the i
clothing coming into contact with infected eyes, spreading the infection to
nfection to
other people's eyes.
other people's eyes.
Effect on health:
Effect on health: The infection causes a sticky eye discharge with soreness
The infection causes a sticky eye discharge with soreness
and swelling of the eyelids. After repeated infections scarring
and swelling of the eyelids. After repeated infections scarring of the inner
of the inner
eyelids occurs which can lead to
eyelids occurs which can lead to trichiasis
trichiasis where the eyelashes turn inwards.
where the eyelashes turn inwards.
These then rub on the eye, scarring the cornea and causing blind
These then rub on the eye, scarring the cornea and causing blindness.
ness.
Prevention:
Prevention: Trachoma can be prevented through regular hand and face
Trachoma can be prevented through regular hand and face
washing with a good supply of clean water, along with hygiene ed
washing with a good supply of clean water, along with hygiene education to
ucation to
help prevent flies from breeding.
help prevent flies from breeding.

96. Water quality and health
Water quality and health
Scabies
Scabies occurs in areas where there is a lack of water
occurs in areas where there is a lack of water
and people are unable to wash themselves,
and people are unable to wash themselves,
their clothes, bedclothes or houses regularly.
their clothes, bedclothes or houses regularly.
It is caused by the scabies mite which infests the surface
It is caused by the scabies mite which infests the surface
layer of the skin. The mite can spread
layer of the skin. The mite can spread
from one person to another through personal contact.
from one person to another through personal contact.
Effect on health:
Effect on health: Scabies causes itchy sores and lesions
Scabies causes itchy sores and lesions
mainly between the fingers, wrists, elbows,
mainly between the fingers, wrists, elbows,
breasts and pubic areas.
breasts and pubic areas.
In younger sufferers more areas, including baby's feet
In younger sufferers more areas, including baby's feet
and the head, can be infected. Because
and the head, can be infected. Because
sufferers often scratch the sores and lesions they become
sufferers often scratch the sores and lesions they become
prone to other infections.
prone to other infections.
Prevention:
Prevention: Washing regularly with soap and keeping
Washing regularly with soap and keeping
clothes, bedclothes and houses clean
clothes, bedclothes and houses clean
prevents scabies.
prevents scabies.

97. Water quality and health
Water quality and health
Waterborne disease
Waterborne disease-
- Diseases spread by contamination of water (or hands)
Diseases spread by contamination of water (or hands)
by human
by human feaces
feaces or urine. With this type of disease, infection occurs in a
or urine. With this type of disease, infection occurs in a
manner as shown in the scheme below:
manner as shown in the scheme below:
Infected person
Infected person →
→ Pathogens in excreta
Pathogens in excreta→
→ contaminated water source
contaminated water source
Susceptible person
Susceptible person consumption of untreated water
consumption of untreated water
Preventive measures
Preventive measures: Improve quality of drinking water. Prevent casual use
: Improve quality of drinking water. Prevent casual use
of untreated or unimproved sources
of untreated or unimproved sources
Water based disease
Water based disease-
- Diseases whose causative pathogen spend part of its
Diseases whose causative pathogen spend part of its
life cycle in aquatic animals such as water snails. The most we
life cycle in aquatic animals such as water snails. The most well known
ll known
example is
example is schistosomiasis
schistosomiasis. Its pattern of disease transmission includes a
. Its pattern of disease transmission includes a
part of the pathogen (worm) life cycle in an intermediate host (
part of the pathogen (worm) life cycle in an intermediate host (as eggs in
as eggs in
snails). After the eggs of the worm have penetrated a snail the
snails). After the eggs of the worm have penetrated a snail the hatch
hatch
inside the snail. These larvae can only survive for 48 hours in
inside the snail. These larvae can only survive for 48 hours in water.
water.
The larvae can however, penetrate the skin of human beings and t
The larvae can however, penetrate the skin of human beings and they can
hey can
then migrate through the body, where they can multiply. It is
then migrate through the body, where they can multiply. It is
unfortunate that
unfortunate that schitosomiasis
schitosomiasis is often spread by irrigation schemes
is often spread by irrigation schemes
which tend to provide suitable habitats for the snail host as we
which tend to provide suitable habitats for the snail host as wells as
lls as
increasing the likelihood of contact with the water by agricultu
increasing the likelihood of contact with the water by agricultural workers.
ral workers.
The scheme of development of the pathogen is given as follows:
The scheme of development of the pathogen is given as follows:

98. Water quality and health
Water quality and health
worm in bladder wall
worm in bladder wall
Eggs in urine
Eggs hatch into
miracidia
Miracidia enter
snail
Cercariae leave
snail
Skin penetration
Cercariae develops and
moves within veins and
arteries
In man
In water
Infectious cycle of schistosomiasis

99. Water quality and health
Water quality and health
Preventive measures: Desist form the use of or contact with any
Preventive measures: Desist form the use of or contact with any
water resource known to have the infection. Control snail
water resource known to have the infection. Control snail
population and prevent people or inhabitants from defecating in
population and prevent people or inhabitants from defecating in
surface waters.
surface waters.
Water
Water –
– related insect vector diseases
related insect vector diseases
Diseases spread by insects that breed or feed near open surface
Diseases spread by insects that breed or feed near open surface
waters
waters eg
eg. malaria.
. malaria.
Preventive measures: include avoiding suitable habitats for inse
Preventive measures: include avoiding suitable habitats for insect like
ct like
shallow stagnant water pools, regions around the edges of lakes
shallow stagnant water pools, regions around the edges of lakes
and irrigation canals. Control by the use of insecticides, alth
and irrigation canals. Control by the use of insecticides, although
ough
this measure has the possibility of creating some water quality
this measure has the possibility of creating some water quality
problems. Biological control measure like the introduction of f
problems. Biological control measure like the introduction of fish
ish
species that prey on the larvae of the insect could be adopted.
species that prey on the larvae of the insect could be adopted.

100. Water Quality
Water Quality
Aim
Aim
To provide you with information on
To provide you with information on
what parameters are considered
what parameters are considered
when defining the quality of water
when defining the quality of water
To offer you a survey of situations
To offer you a survey of situations
and conditions in which the quality
and conditions in which the quality
of water changes
of water changes

101. contents
contents
Water resources, use and
Water resources, use and
consumption
consumption
Water quality parameters
Water quality parameters
Water quality and public health
Water quality and public health
Raw water quality and pollution
Raw water quality and pollution
Raw water quality and application
Raw water quality and application
requirements
requirements

102. Water resources, use and
Water resources, use and
consumption
consumption
Water
Water resouces
resouces
surfaces waters, groundwater, rain
surfaces waters, groundwater, rain
water, sea / ocean, moisture,
water, sea / ocean, moisture,
water reuse
water reuse
Hydrological cycle
Hydrological cycle

103. The Water Cycle
The Water Cycle
Water travels on the surface of the earth,
underground and in the atmosphere in a
cycle – the Water Cycle.
• Clouds provide precipitation in the form of
rain, snow and hail.
•Water runs on the surface. Part is used by
the vegetation; part flows to the water
bodies or infiltrates the soil to form the
underground water bodies.
•Surface water bodies evaporates under the
effect of the sun and finds itself in a gaseous
form in the atmosphere.
•Water vapour condenses in contact with
cold air masses, which then creates clouds
and comes down as rain.
Invisible phenomena
Evaporation, absorption, water
vapour and transport by winds –
sun energy required for process
Visible phenomena –
condensation, precipitation,
snow, runoff, infiltration,
superficial and underground
flow.

104. Water Quality
Water Quality
As precipitated water encounters the
As precipitated water encounters the
atmosphere and the environment, its
atmosphere and the environment, its
quality changes through interactions
quality changes through interactions
with:
with:
-
- Gases in the air
Gases in the air
-
- soil and rock
soil and rock–
– contaminants
contaminants
-
- anthropogenic activities
anthropogenic activities eg
eg mining,
mining,
agriculture and irrigation, industries e.g.
agriculture and irrigation, industries e.g.
dyeing and tannin
dyeing and tannin

105. Water use
Water use
About 66% of the human body is made up of
About 66% of the human body is made up of
water
water
Depending on the human body needs about 3
Depending on the human body needs about 3 –
–
10 litres of water / day is required for normal
10 litres of water / day is required for normal
functioning.
functioning.
Uses
Uses –
– cooking, recreation, laundry, drinking
cooking, recreation, laundry, drinking
gardening, transportation, waste disposal, fire
gardening, transportation, waste disposal, fire
fighting, industrial applications etc.
fighting, industrial applications etc.
Influences
Influences: Cultural habits, pattern and standard
: Cultural habits, pattern and standard
of living, utility fee for water, quality of water,
of living, utility fee for water, quality of water,
proximity of water source.
proximity of water source.
In the selection of the type of water supply /
In the selection of the type of water supply /
source, finance, location, size of community,
source, finance, location, size of community,
geographical conditions and the available water
geographical conditions and the available water
source are normally the major considerations.
source are normally the major considerations.

106. Water consumption
Water consumption
Water use and consumption are
Water use and consumption are
normally expressed in litres per
normally expressed in litres per
capita(head
capita(head) per day (
) per day (l.c.d
l.c.d).
).
l.c.d
l.c.d is useful for making rough
is useful for making rough
estimates of a community
estimates of a community’
’s water
s water
demand
demand

107. Typical Domestic Water Usage
Typical Domestic Water Usage
Type of water supply
Type of water supply Typical water
Typical water Range (
Range (l.c.d
l.c.d)
)
consumption (
consumption (l.c.d
l.c.d)
)
Communal water point
Communal water point
(e.g. village well, public stand
(e.g. village well, public stand-
-post)
post)
-
- at considerable dist. (1000 m)
at considerable dist. (1000 m) 7
7 5
5 -
- 10
10
-
- at medium dist.(500
at medium dist.(500 –
– 1000m)
1000m) 12
12 10
10 -
- 15
15
Village well
Village well
walking distance 250m
walking distance 250m 20
20 15
15 -
- 25
25
Communal standpipe
Communal standpipe
walking distance 250m
walking distance 250m 30
30 20
20 -
- 50
50
Yard connection
Yard connection
(tap placed in house
(tap placed in house-
-yard)
yard) 40
40 20
20 -
- 80
80
House connection
House connection
-
- single tap
single tap 50
50 30
30 -
- 60
60
-
- multiple taps
multiple taps 150
150 70
70 -
- 250
250

108. Water incidence 10
Water incidence 103
3 km
km3
3 Amount of water
Amount of water
% of total water % of fresh water
% of total water % of fresh water
World oceans
World oceans 1 300 000
1 300 000 97 .220
97 .220 -
-
Salt lakes and
Salt lakes and 100
100 0.008
0.008 -
-
inland seas
inland seas
Icebergs and polar ice
Icebergs and polar ice 28 500
28 500 2.136
2.136 77.63
77.63
Water in the atmos.
Water in the atmos. 13
13 0.001
0.001 0.035
0.035
Water in
Water in plts
plts and
and liv.org
liv.org. 1.13
. 1.13 0.0001
0.0001 0.003
0.003
Fresh water lakes
Fresh water lakes 120.3
120.3 0.009
0.009 0.335
0.335
Water courses
Water courses 1.34
1.34 0.0001
0.0001 0.003
0.003
Soil and subsurface water 67
Soil and subsurface water 67 0.005
0.005 0.178
0.178
Groundwater
Groundwater 8290
8290 0.62
0.62 21.800
21.800
Total Fresh water
Total Fresh water 36,700
36,700 2.77
2.77 100
100

110. Water and Wastewater Quality parameters
Water and Wastewater Quality parameters
Important properties of water focused on when
Important properties of water focused on when
considering water quality include, the
considering water quality include, the bpt
bpt.,
.,
Melting pt., vapour pressure, surface tension,
Melting pt., vapour pressure, surface tension,
solvent, density, heat capacity.
solvent, density, heat capacity.
The very notion of water quality is linked to the
The very notion of water quality is linked to the
intended use of the water: swimming, drinking
intended use of the water: swimming, drinking
and cooking, irrigation, industrial process water
and cooking, irrigation, industrial process water
etc. Whatever we use it for, its quality must be
etc. Whatever we use it for, its quality must be
preserved. As the natural content varies
preserved. As the natural content varies
considerably. We must define average conditions
considerably. We must define average conditions
for natural and safe waters. Above a predestined
for natural and safe waters. Above a predestined
threshold, water will be declared polluted.
threshold, water will be declared polluted.

111. Water pollution is a harmful modification of water
Water pollution is a harmful modification of water
caused by the addition of substances likely to
caused by the addition of substances likely to
modify its quality, aesthetic aspect and use for
modify its quality, aesthetic aspect and use for
human purposes. The polluting agent may be
human purposes. The polluting agent may be
physical, chemical or biological in nature and
physical, chemical or biological in nature and
cause discomfort, nuisance or contamination
cause discomfort, nuisance or contamination

112. Water and Waste water Quality parameters
Water and Waste water Quality parameters
Parameter
Parameter WHO
WHO GH std
GH std bd
bd GH EPA
GH EPA
pH
pH 8.5
8.5 5.5
5.5 –
– 8.5
8.5 6.9 (
6.9 (ww
ww)
)
Temperature
Temperature
Turbidity
Turbidity (NTU)
(NTU) 5
5 5
5
DO
DO
Colour (mg Pt/l); (TCU)
Colour (mg Pt/l); (TCU) 15
15 15
15
TSS
TSS 0
0
TDS (mg/l)
TDS (mg/l) 1000
1000 1000
1000
BOD
BOD5
5 50 (
50 (ww
ww)
)
COD
COD
VS
VS
Coliform
Coliform (No. /100ml)
(No. /100ml) 0
0 0
0
Fecal
Fecal coliform(No./100ml) 0
coliform(No./100ml) 0 0
0
Samonella
Samonella 0
0 0
0
Heavy metals
Heavy metals
Fe
Fe (mg/l)
(mg/l) 0.3*
0.3* 0.3
0.3*
*
Mn(mg/l
Mn(mg/l)
) 0.4
0.4
As
As (
(µ
µg/l
g/l)
) 10
10
Ca
Ca (
(mmol/l
mmol/l)
) 2.5(EU)
2.5(EU)
Mg (mg/l)
Mg (mg/l) 30 (EU)
30 (EU)
Cr
Cr (mg/l)
(mg/l) 0.05
0.05
Zn
Zn 5
5
Na
Na 200
200
Pb
Pb (mg/l)
(mg/l) 0.05
0.05
Se (mg/l)
Se (mg/l) 0.01
0.01

113. Water and waste water Quality parameters
Water and waste water Quality parameters
Parameter
Parameter WHO
WHO GH std
GH std bd
bd GH EPA
GH EPA
Pesticides
Pesticides
Chloride (mg/l)
Chloride (mg/l) 250
250 250
Alkalinity
Alkalinity
Total
Total hardness(mmol/l
hardness(mmol/l) 5
) 5
Total
Total hardness(mg/l
hardness(mg/l)
) 500 500
500
(mg/l as CaCO
(mg/l as CaCO3
3)
) 500
500
SO
SO4
4
2
2-
-
250
250
Eutrophic
Eutrophic compds
compds
NH
NH4
4
+
+ (mg/l)
(mg/l) 0.5*(EPA)
0.5*(EPA)
NO
NO3
3
-
- 45
45 10
10
NO
NO2
2
-
- 0.1
0.1
PO
PO4
4
3
3-
-
SiO
SiO2
2
Organic
Organic compds
compds
KMnO
KMnO4
4
PAH
PAH
Odour
Odour
colour
colour

114. Hardness
Hardness
Carbonate hardness (temporal hardness)
Carbonate hardness (temporal hardness)
Non
Non-
- carbonate hardness (permanent hardness)
carbonate hardness (permanent hardness)
The most abundant multivalent metallic ions in natural water
The most abundant multivalent metallic ions in natural water
normally responsible for hardness are Ca and Mg. Other
normally responsible for hardness are Ca and Mg. Other cations
cations like
like
Fe
Fe2+
2+
, Mn
, Mn2+
2+
, Sr
, Sr2+
2+
and Al
and Al3+
3+
also contribute to the hardness but to a
also contribute to the hardness but to a
little extent.
little extent.
The carbonate hardness is sensitive to heat and precipitates rea
The carbonate hardness is sensitive to heat and precipitates readily
dily
Ca(HCO
Ca(HCO3
3)
)2
2 →
→ CaCO
CaCO3
3 + CO
+ CO2
2 + H
+ H2
2O
O
The impact of hardness, is that it wastes soap. In solution the
The impact of hardness, is that it wastes soap. In solution the
lathering does not occur
lathering does not occur untill
untill all of the hardness ions are
all of the hardness ions are
precipitated thereby softening the soap.
precipitated thereby softening the soap.
e.g. 2 NaCOOC
e.g. 2 NaCOOC17
17H
H33
33 + Ca
+ Ca2+
2+
→
→ Ca
Ca2+
2+
(COOC
(COOC17
17H
H33
33)
)2
2 + 2Na
+ 2Na+
+
The precipitate formed adheres and stains dishwashers, clothes,
The precipitate formed adheres and stains dishwashers, clothes,
tubs, dishes and may remain in the pores of the skin making
tubs, dishes and may remain in the pores of the skin making
the skin feel rough and uncomfortable.
the skin feel rough and uncomfortable.

115. Changes in pH in the water distribution may result in
Changes in pH in the water distribution may result in
deposits of precipitates. HCO
deposits of precipitates. HCO3
3 begin to convert to
begin to convert to
the less soluble carbonates at pH above 9.
the less soluble carbonates at pH above 9.
Unit of measurement: mg/L as CaCO
Unit of measurement: mg/L as CaCO3
3
Ranges of hardness
Ranges of hardness
Soft
Soft : 50 mg/l as CaCO
: 50 mg/l as CaCO3
3
Moderately hard
Moderately hard : 50
: 50 –
– 150 mg/L as CaCO
150 mg/L as CaCO3
3
Hard
Hard : 150
: 150 –
– 300 mg/L as CaCO
300 mg/L as CaCO3
3
Very Hard
Very Hard : 300 mg/L as CaCO
: 300 mg/L as CaCO3
3

116. IRON AND MANGANESE
IRON AND MANGANESE
Consumer complaints
Consumer complaints –
– dark brown to black precipitates,
dark brown to black precipitates,
stain laundry and porcelain fixtures
stain laundry and porcelain fixtures
Coating and darkening of filters in treatment plant
Coating and darkening of filters in treatment plant
Concentration as low as 0.02 mg/l could form coating in
Concentration as low as 0.02 mg/l could form coating in
distribution mains, service lines, meters
distribution mains, service lines, meters
chronic exposure to manganese concentration beyond
chronic exposure to manganese concentration beyond
0.5mg/l could give rise to a disease condition similar to
0.5mg/l could give rise to a disease condition similar to
Parkinsonism.
Parkinsonism.
WHO health based guideline for manganese occurrence in
WHO health based guideline for manganese occurrence in
drinking water is pegged at 0.4 mg/l (WHO guideline
drinking water is pegged at 0.4 mg/l (WHO guideline
2004).
2004).
WHO
WHO gu
guideline
ideline value of 0.1 mg/l has been recommended
value of 0.1 mg/l has been recommended
for
for Mn
Mn for drinking water sources
for drinking water sources

117. ARSENIC
ARSENIC
Long term exposure to drinking water with [As]
10 µg/l
Can cause cancer of the skin, lungs, urinary
bladder, kidney, etc
Skin pigmentation,
Hardening, thickening of skin and laceration of
sole of feet.
Retardation in the intelligence of children.
Nausea, vomiting, stomach pain, numbness of
hands and feet etc.
In Ghana – upsurge in the incidence of cancer
especially breast, meanwhile patronage
groundwater as drinking water source is on the
increase.

118. ARSENIC
ARSENIC
Long term exposure to drinking water
with [As] 10 µg/l
Can cause cancer of the skin, lungs,
urinary bladder, kidney, etc
Skin pigmentation,
Hardening and laceration of sole of feet.
Retardation in the intelligence of children.
In Ghana – upsurge in the incidence of
cancer especially breast, meanwhile
patronage groundwater as drinking water
source is on the increase.

119. FLUORIDE
FLUORIDE
Inorganic anion
Inorganic anion
Allerged
Allerged to be impact benefits to humans.
to be impact benefits to humans.
Recent finds
Recent finds –
– controversy
controversy
WHO
WHO –
– Europe
Europe –
– Rate of decrease of cavities in teeth of
Rate of decrease of cavities in teeth of
childn
childn in regions with / without
in regions with / without –
– same.
same.
The claim of F
The claim of F-
-
being beneficial has not held up
being beneficial has not held up
independent scientific scrutiny.
independent scientific scrutiny.
High [F
High [F-
-
]
] →
→ more brittle and fragile bones, increased bone mass
more brittle and fragile bones, increased bone mass
density but reduce strength of the bone at the same time due to
density but reduce strength of the bone at the same time due to
F
F-
- caused defects in the bone structure.
caused defects in the bone structure.
F
F-
- + Al in drinking water
+ Al in drinking water →
→ accumulates in brain
accumulates in brain →
→ neurotoxic
neurotoxic
morphological changes.
morphological changes.
A study in China has shown that even accepted levels in F
A study in China has shown that even accepted levels in F-
- in water
in water
(0.88 mg/l) may affect children
(0.88 mg/l) may affect children’
’s intelligence
s intelligence
High F
High F-
- is also a contributing factor to a bone cancer condition of
is also a contributing factor to a bone cancer condition of
osteosarcoma
osteosarcoma.
.
May cause elevation in blood sugar possibly exacerbating diabete
May cause elevation in blood sugar possibly exacerbating diabetes.
s.

120. Fluoride defects
Fluoride defects

121. Kpugi—Gushegu
Wunjuga—Saboba/Cheriponi

122. LEAD
LEAD
Anaemia, mental retardation,
Anaemia, mental retardation,
SO
SO2
2
Bronchitis
Bronchitis
Acid rain
Acid rain –
– precipitation causes corrosion of monuments
precipitation causes corrosion of monuments
and materials.
and materials.
Changes acidity of water bodies and can cause death of
Changes acidity of water bodies and can cause death of
fish
fish
Impedes photosynthesis
Impedes photosynthesis

123. DISSOLVED OXYGEN
DISSOLVED OXYGEN
1.
1. Biodegradable organic matter, mostly of domestic origin,
Biodegradable organic matter, mostly of domestic origin,
removes DO. This is because the micro
removes DO. This is because the micro-
-organisms present in
organisms present in
water consume the organics as food (substrate) and utilize
water consume the organics as food (substrate) and utilize
oxygen to accomplish respiration. The more the organics
oxygen to accomplish respiration. The more the organics
present, the larger the demand on oxygen.
present, the larger the demand on oxygen.
2.
2. Aquatic animals, including organisms in sediment remove DO.
Aquatic animals, including organisms in sediment remove DO.
3.
3. Plants add DO during the day via photosynthesis but remove it
Plants add DO during the day via photosynthesis but remove it
at night by respiration. Dying and decaying plants diminish
at night by respiration. Dying and decaying plants diminish
Do.
Do.
4.
4. In summer periods in temperate countries and tropical
In summer periods in temperate countries and tropical
countries, the increased water temperature reduces DO
countries, the increased water temperature reduces DO
solubility.
solubility.
5.
5. Tributaries draining into or waste water discharging into a rive
Tributaries draining into or waste water discharging into a river
r
bring their own oxygen supplies that affect DO of the river on
bring their own oxygen supplies that affect DO of the river on
mixing.
mixing.
6.
6. Low river flows slow the rate of oxygen transfer into the water
Low river flows slow the rate of oxygen transfer into the water
from the atmosphere.
from the atmosphere.

124. PUBLIC HEALTH
PUBLIC HEALTH

125. Toxic Chemical compounds and their extent
Toxic Chemical compounds and their extent
of toxicity
of toxicity
In toxicology the adverse effects of chemicals (pollutants)
In toxicology the adverse effects of chemicals (pollutants)
on living organisms is studied and the probability of
on living organisms is studied and the probability of
these effects occurring upon consumption of the
these effects occurring upon consumption of the
pollutant is considered.
pollutant is considered.
The toxicity of a pollutant is described using various
The toxicity of a pollutant is described using various
terminologies:
terminologies:
Lethal dosage, ADI, MAC etc.
Lethal dosage, ADI, MAC etc.
The toxicity of a chemical substance in water depends
The toxicity of a chemical substance in water depends
upon several factors other than the actual
upon several factors other than the actual
concentration. Some substances, which are highly
concentration. Some substances, which are highly
toxic, are unstable in water and break down into
toxic, are unstable in water and break down into
innocuous by
innocuous by-
-products. The degree of toxicity also has
products. The degree of toxicity also has
to be assessed on the daily intake from sources other
to be assessed on the daily intake from sources other
than water, for example lead pollution in air.
than water, for example lead pollution in air.

126. Toxic Chemical compounds and their extent
Toxic Chemical compounds and their extent
of toxicity
of toxicity
Toxicity
Toxicity –
– i) Acute toxicity, ii) Sub
i) Acute toxicity, ii) Sub-
-acute toxicity
acute toxicity iii)
iii)
Chronic toxicity,
Chronic toxicity,
Acute toxicity
Acute toxicity –
– The health effects is expressed within a
The health effects is expressed within a
few days.
few days.
Expressed as LD
Expressed as LD-
-50. LD
50. LD-
-50 is the quantity of a
50 is the quantity of a
compound ingested at once that results in the dead of
compound ingested at once that results in the dead of
50% of the consumers (animals or human beings) in a
50% of the consumers (animals or human beings) in a
few days. Generally the
few days. Generally the measuement
measuement of acute toxicity
of acute toxicity
is determined within 4 days (i.e. 96 hours) of exposure.
is determined within 4 days (i.e. 96 hours) of exposure.

127. Toxic Chemical compounds and their extent of toxicity
Toxic Chemical compounds and their extent of toxicity
100
Time of exposure (hr)
%
mortality
25
Determination of the LD50
50
75
100
200ug/l
150 ug/l
100 ug/l 50
log concentration
100
%
mortality
96 hr LD 50
%
mortality
Concentration (mg/l)

128. Toxic Chemical compounds and their extent
Toxic Chemical compounds and their extent
of toxicity
of toxicity
Class
Class LD 50 range
LD 50 range category
category
1
1 1 mg/kg
1 mg/kg Extremely toxic
Extremely toxic
2
2 1
1 –
– 50 mg/kg
50 mg/kg Very toxic
Very toxic
3
3 50
50 –
– 500 mg/kg
500 mg/kg Moderately toxic
Moderately toxic
4
4 0.5
0.5 –
– 5 g/kg
5 g/kg Slightly toxic
Slightly toxic
5
5 5
5 –
– 15 g/kg
15 g/kg Hardly toxic
Hardly toxic
6
6 15 g/kg
15 g/kg Non
Non –
– toxic
toxic

129. Toxic Chemical compounds and their extent
Toxic Chemical compounds and their extent
of toxicity
of toxicity
Sub
Sub-
-acute toxicity
acute toxicity
This is often expressed using the no observed effect level
This is often expressed using the no observed effect level
or no observed adverse effect level (NOAEL)
or no observed adverse effect level (NOAEL)
The NOAEL is the highest dose or concentration of a
The NOAEL is the highest dose or concentration of a
substance that causes no detectable health effect. (Based
substance that causes no detectable health effect. (Based
on long term studies)
on long term studies)
In some cases LOAEL may be used. LOAEL refers to the
In some cases LOAEL may be used. LOAEL refers to the
lowest observed dose or concentration of a substance at
lowest observed dose or concentration of a substance at
which there is a detectable adverse health effect.
which there is a detectable adverse health effect.

130. Toxic Chemical compounds and their extent of
Toxic Chemical compounds and their extent of
toxicity
toxicity
TDI
TDI –
– is the amount of a substance, expressed on a body
is the amount of a substance, expressed on a body
weight (e.g. mg/kg of body weight of a person) that can
weight (e.g. mg/kg of body weight of a person) that can
be ingested daily with e.g. food, air, water without appreciable
be ingested daily with e.g. food, air, water without appreciable health
health
risk (TDI
risk (TDI –
– Tolerable Daily intake)
Tolerable Daily intake)
The TDI can be derived as follows:
The TDI can be derived as follows:
TDI =
TDI = (C)(GV)
(C)(GV)
(
(bw)(P
bw)(P)
)
GV =
GV = TDI.
TDI. bw
bw. P
. P
C
C
where:
where:
bw
bw = body weight (60 kg for adults, 10 kg for children, 5 kg for
= body weight (60 kg for adults, 10 kg for children, 5 kg for
infants
infants
P = Fraction of the TDI allocated to drinking water
P = Fraction of the TDI allocated to drinking water
C = daily consumption of drinking
C = daily consumption of drinking-
-water (2 L for adults, 1 L for
water (2 L for adults, 1 L for
children, (1.75 for infants)
children, (1.75 for infants)
GV = Guideline value
GV = Guideline value

131. Toxic Chemical compounds and their extent
Toxic Chemical compounds and their extent
of toxicity
of toxicity
Guideline Value
Guideline Value
GV represents the concentration that does not result in any
GV represents the concentration that does not result in any
significant risk to health of the consumer over a lifetime of
significant risk to health of the consumer over a lifetime of
consumption; With GV, the quality parameter defined is suitable
consumption; With GV, the quality parameter defined is suitable for
for
human and for all domestic purposes including personal hygiene
human and for all domestic purposes including personal hygiene
Chronic toxicity
Chronic toxicity
The measurement of chronic toxicity has generally been held as
The measurement of chronic toxicity has generally been held as
monitoring over periods of 30
monitoring over periods of 30 –
– 60 days for which there are no
60 days for which there are no
adverse effects on life. Concerns over potential cancers,
adverse effects on life. Concerns over potential cancers, tumors
tumors and
and
birth defects are real and difficult to quantify into acceptabl
birth defects are real and difficult to quantify into acceptable water
e water
quality criteria.
quality criteria.
Acceptable (ADI)
Acceptable (ADI)
It has been the practice to use
It has been the practice to use ‘
‘safety factors
safety factors’
’ commonly of 100 to
commonly of 100 to
bring down the no
bring down the no-
- effect level to the safe ADI level.
effect level to the safe ADI level.

132. RAW WATER QUALITY AND
RAW WATER QUALITY AND
APPLICATION REQUIRMENTS
APPLICATION REQUIRMENTS

133. Algae
Algae
Gross photosynthesis (limitation)
Gross photosynthesis (limitation)
∑
∑P
Pgross
gross
=
= µ
µmax
max *
* F(i
F(i) *f
) *f * C
* C
E
Ew
w + C *
+ C * E
Ec
c
Where:
Where:
C: algae concentration
C: algae concentration
µ
µmax
max = the maximum photosynthesis rate at optimum light (per unit of
= the maximum photosynthesis rate at optimum light (per unit of
biomass)
biomass)
f: photoperiod of the day
f: photoperiod of the day
E
Ew
w: light extinction coefficient of water
: light extinction coefficient of water
E
Ec
c: specific extinction coefficient (per unit of biomass)
: specific extinction coefficient (per unit of biomass)
F(i
F(i): dimensionless function of light intensity (integrated
): dimensionless function of light intensity (integrated
over depth)
over depth)
Net Growth =
Net Growth = ∑
∑P
Pgross
gross -
- ∑
∑ R
R

134. Adverse effects of algae
Adverse effects of algae
Occurrence of very turbid and coloured water.
Occurrence of very turbid and coloured water.
Give rise unstable oxygen conditions by
Give rise unstable oxygen conditions by
photosynthesis and respiration of algae
photosynthesis and respiration of algae
Can cause overstrained oxygen economy due to
Can cause overstrained oxygen economy due to
degradation of dead algae, leading to anaerobic
degradation of dead algae, leading to anaerobic
conditions at the sediment
conditions at the sediment –
– water interface
water interface
Production of organic compound with chelating
Production of organic compound with chelating
properties. Other algae can for gels which can clog
properties. Other algae can for gels which can clog
rapid sand filters
rapid sand filters
Blue green algae if prevalent are capable of
Blue green algae if prevalent are capable of
forming toxins.
forming toxins.

135. Adverse effects of algae especially for the water
Adverse effects of algae especially for the water
supply
supply
Increase of coagulant demand
Increase of coagulant demand
Flotation of
Flotation of flocs
flocs in settling basins
in settling basins
Clogging and passage of filter
Clogging and passage of filter
Bacterial
Bacterial aftergrowth
aftergrowth in distribution system
in distribution system
Adverse effects of aquatic weeds
•Clogging of intake screens for water supply or
hydropower production
•High evapo-transpiration
•Interferences with transportation
•Interference with fisheries:
fish population and harvesting of fish

136. Eutrophication
Eutrophication
Eutrophication
Eutrophication –
– the enrichment of water bodies (lakes, rivers,
the enrichment of water bodies (lakes, rivers,
reservoirs) with nutrients usually phosphates (mainly) and at
reservoirs) with nutrients usually phosphates (mainly) and at
times nitrogen compounds, (silicates to a lesser extent) resulti
times nitrogen compounds, (silicates to a lesser extent) resulting
ng
in increased plant biomass (algal blooms,
in increased plant biomass (algal blooms, macrophytes
macrophytes or
or
floating aquatic weeds).
floating aquatic weeds).
Eutrophication
Eutrophication is a natural process but can be accelerated by
is a natural process but can be accelerated by
human influence (
human influence ( -
- Cultural
Cultural eutrophication
eutrophication)
)
Degree of
Degree of Eutrophication
Eutrophication Level of nutrients
Level of nutrients
Oligotrophic
Oligotrophic low
low
mesotrophic
mesotrophic moderate
moderate
eutrophic
eutrophic high
high
hypertrophic
hypertrophic very high
very high

137. Eutrophication
Eutrophication
Trophic
Trophic [P]
[P] [
[Chl
Chl]
] secchi
secchi
µ
µg/l
g/l µ
µg/l
g/l m
m
Oligo
Oligo 10
10 2.5
2.5 6
6
Meso
Meso 10
10 –
– 35
35 2.5
2.5 –
– 8
8 3
3 –
– 6
6
Eu
Eu 35
35 –
– 100
100 8
8 –
– 25
25 1.5
1.5 –
– 3
3
Hyper
Hyper 100
100 25
25 1.5
1.5

138. INDUSTRIAL WATER
INDUSTRIAL WATER
Maximum conc. Of constituents in raw waters for various industri
Maximum conc. Of constituents in raw waters for various industrial operations (mg/l)
al operations (mg/l)
Characteristic
Characteristic Boiler
Boiler
water
water
Cooling
Cooling
water
water
Textile
Textile
Plants
Plants
Pulp and
Pulp and
paper
paper
Chemical
Chemical
industry
industry
Petroleum
Petroleum
Silica
Silica 150
150 50
50 -
- 50
50 -
- 85
85
Aluminum
Aluminum 3
3 3
3 -
- -
- -
- -
-
Iron
Iron 80
80 14
14 0.3
0.3 2.6
2.6 10
10 15
15
Manganese
Manganese 10
10 2.5
2.5 1.0
1.0 -
- 2
2 -
-
Calcium
Calcium -
- 500
500 -
- -
- 250
250 220
220
Magnesium
Magnesium -
- -
- -
- -
- 100
100 85
85
Ammonia
Ammonia -
- -
- -
- -
- -
- 40
40
Bicarbonate
Bicarbonate 600
600 600
600 -
- -
- 600
600 480
480
Sulfate
Sulfate 1400
1400 680
680 -
- -
- 850
850 900
900
Chloride
Chloride 19000
19000 600
600 -
- 200
200 500
500 1600
1600
Nitrate
Nitrate -
- -
- -
- -
- -
- 8
8
Dissolved
Dissolved
solids
solids
35000
35000 1000
1000 150
150 1080
1080 2500
2500 3500
3500
Suspended
Suspended
solids
solids
15000
15000 5000
5000 1000
1000 -
- 10000
10000 5000
5000
Hardness
Hardness 5000
5000 850
850 120
120 475
475 1000
1000 900
900
Alkalinity
Alkalinity 500
500 500
500 -
- -
- 500
500 500
500
Color
Color 1200
1200 -
- -
- 360
360 500
500 25
25

139. Agriculture Water
Agriculture Water
Water Quality for irrigation (tropical conditions)
Water Quality for irrigation (tropical conditions)
TDS
TDS
-
- 400 mg/l
400 mg/l –
– poor drainage
poor drainage
saline soil
saline soil
inadequate water supply
inadequate water supply
1000 mg/l
1000 mg/l –
– good drainage
good drainage
-
- proper irrigation management
proper irrigation management
2000 mg/l
2000 mg/l –
– salt resistant crops
salt resistant crops
-
- good drainage
good drainage
-
- low sodium adsorption ration (S.A.R.)
low sodium adsorption ration (S.A.R.)
E.C.
E.C. 100
100 mS/m
mS/m (25
(25˚
˚C)
C)
SAR 10
SAR 10 -
- poor drainage
poor drainage
18
18 -
- good drainage
good drainage

140. Agriculture Water
Agriculture Water
Water Quality for irrigation (tropical conditions)
Water Quality for irrigation (tropical conditions)
Boron
Boron 1.25 mg/l
1.25 mg/l -
- sensitive crops
sensitive crops
4 mg/l
4 mg/l –
– tolerant crops
tolerant crops
Coliforms
Coliforms 100 per 100 ml if water is to be used for
100 per 100 ml if water is to be used for
unrestricted irrigation
unrestricted irrigation
SAR (
SAR (meq/l
meq/l)=
)= [Na
[Na+
+]
]
[Ca
[Ca2+
2+] + [Mg
] + [Mg2+
2+]
]
2
2
The porosity of Na
The porosity of Na –
– clay is lower than for Ca
clay is lower than for Ca –
– clay. This
clay. This
means that the permeability for air and water is lower.
means that the permeability for air and water is lower.

141. Quality requirements for fishing in tropical
Quality requirements for fishing in tropical
streams
streams
CO
CO2
2 12
12 mg/l
mg/l
pH
pH 6.5
6.5 –
– 8.5
8.5
NH
NH3
3 1
1
Heavy metals
Heavy metals 1
1
Copper
Copper 0.02
0.02
As
As 1
1
Pb
Pb 0.1
0.1
Selenium
Selenium 0.1
0.1
Hg
Hg 0.01
0.01
Cyanides
Cyanides 0.012
0.012
Detergents
Detergents 0.2
0.2
DO
DO 2
2
Pesticides
Pesticides
DDT
DDT 0.002
0.002
Endrin
Endrin 0.004
0.004
Methylparathion
Methylparathion 0.21
0.21
Malathion
Malathion 0.16
0.16

142. CATTLE BREEDING
CATTLE BREEDING
Purposes of water use
Purposes of water use
Consumption (drinking, fodder preparation etc)
Consumption (drinking, fodder preparation etc)
Washing cleaning and waste transport
Washing cleaning and waste transport
For processing dairy products at the farm (cheese,
For processing dairy products at the farm (cheese,
cleaning
cleaning equipment
equipment
Water demand for livestock and poultry breeding
Water demand for livestock and poultry breeding

143. Species
Species Average Water
Average Water
requirement
requirement
Max.
Max.
requirment
requirment
Excrement
Excrement –
–
liquid(l
liquid(l/day
/day
Livestock under
Livestock under
fattening
fattening
10
10 -
- 40
40 60
60 10
10
Milk cows
Milk cows 15
15 –
– 60
60 140
140 20
20
Calves
Calves 15
15 20
20 2
2
Horses
Horses 48
48 60
60
Sheep
Sheep 8
8 10
10
lambs
lambs 4
4 6
6
Poultry and
Poultry and
small animals
small animals
Hens
Hens 0.23
0.23 –
– 2.75
2.75 1.5
1.5
Turkeys
Turkeys 0.5
0.5 0.9
0.9
Rabbits
Rabbits 3
3 5
5

144. The Facts
Global water: 97% seawater, 3% freshwater. Of the
freshwater 87% not accessible, 13% accessible (0.4%
of total).
Today more than 2 billion people are affected by water
shortages in over 40 countries.
263 river basins are shared by two or more nations;
2 million tonnes per day of human waste are deposited
in water courses
Half the population of the developing world are
exposed to polluted sources of water that increase
disease incidence.
90% of natural disasters in the 1990s were water
related.
The increase in numbers of people from 6 billion to 9
billion will be the main driver of water resources
management for the next 50 years.

145. Integrated Water Resource
Management
Integrated management means that all the different
users of Water resources are considered together.
Water allocations and management decisions consider
the effects of each use on the others. They are able to
take account of overall social and economic goals,
including the achievement of sustainable development.

146. Within this IWRM principle, it is vital to recognise
first the basic right of all human beings to have
access to clean water and sanitation at an
affordable price.
Water has a value as an economic good as well
as a social good.
Many past failures in water resources management
are attributable to the fact that the full value of
water has not been recognised and has led to
wasteful and environmentally damaging uses of the
resource.
Allocation
Treating water as an economic good is an important
means for decision making on the allocation of
water. This is particularly important when extending
supply is no longer a feasible option.

147. Agriculture
Water supply wastewater
Mining, industry
Environment
Fisheries
Tourism
Energy
Transport
Each of the water uses identified above has valuable
positive impacts.
Most also have negative impacts which may be made
worse by poor management practices, lack of regulation
or lack of motivation due to the water governance
regimes in place. Water management within government
structures is distributed across many agencies and tends
to be dominated by sectoral interests.

148. Fresh water is a finite and vulnerable resource, essential to sustain
life, development and the environment.
Water development and management should be based on a
participatory approach, involving users, planners and
policymakers at all levels.
Women play a central part in the provision, management and
safeguarding of water.
Water has an economic value in all its competing uses and should
be recognised as an economic good.
The participatory approach involves raising awareness of the importance
of water among policy-makers and the general public. It means that
decisions are taken at the lowest appropriate level, with full public
consultation and involvement of users in the planning and implementation
of water projects

149. SOME ACTIVITIES TO EMBARK UPON FOR
SOME ACTIVITIES TO EMBARK UPON FOR
INTEGRATED ENVIRONMENTAL RESOURCES
INTEGRATED ENVIRONMENTAL RESOURCES
MANAGEMENT
MANAGEMENT
1.
1. Awareness creation
Awareness creation
2.
2. Solid and Liquid Waste management
Solid and Liquid Waste management
3.
3. Creation of buffer zones for water bodies
Creation of buffer zones for water bodies
4.
4. Development of woodlots
Development of woodlots
5.
5. Appropriate farming (both crops, fishing and
Appropriate farming (both crops, fishing and
animal farming) practices
animal farming) practices
6.
6. Water Abstraction, Use and Drilling license
Water Abstraction, Use and Drilling license
7.
7. Creation of Game reserves
Creation of Game reserves

150. MILLENIUM DEVELOPMENT GOALS
MILLENIUM DEVELOPMENT GOALS
1.
1. Eradicate extreme poverty and hunger
Eradicate extreme poverty and hunger
2.
2. Achieve universal primary education for all
Achieve universal primary education for all
3.
3. Gender equality
Gender equality
4.
4. Child health
Child health
5.
5. Maternal health
Maternal health
6.
6. Combat HIV/AIDS
Combat HIV/AIDS
7.
7. Ensure environmental sustainability
Ensure environmental sustainability
8.
8. Global partnership
Global partnership

151. GOAL 7
GOAL 7
ENSURE ENVIRONMENTAL SUSTAINABILITY
ENSURE ENVIRONMENTAL SUSTAINABILITY
Target 1
Target 1
Integrate the principles of sustainable development into
Integrate the principles of sustainable development into
country policies and programmes and reverse the loss of
country policies and programmes and reverse the loss of
environmental resources.
environmental resources.
Target 2
Target 2
Reduce biodiversity loss; achieving by 2010, a significant
Reduce biodiversity loss; achieving by 2010, a significant
reduction in the rate of loss
reduction in the rate of loss
Target 3
Target 3
Halve, by 2015, the proportion of the population without
Halve, by 2015, the proportion of the population without
sustainable access to safe drinking water and basic
sustainable access to safe drinking water and basic
sanitation
sanitation
Target 4
Target 4
By 2020 to have achieved a significant improvement in
By 2020 to have achieved a significant improvement in
the lives of at least 100 million slum dwellers
the lives of at least 100 million slum dwellers

152. Target 1
Target 1
Integrate the principles of sustainable development
Integrate the principles of sustainable development
into country policies and programmes and reverse
into country policies and programmes and reverse
the loss of environmental resources.
the loss of environmental resources.
Immediate action is needed to contain rising green
Immediate action is needed to contain rising green
house gas emission.
house gas emission.
Success in limiting ozone depleting substances is also
Success in limiting ozone depleting substances is also
helping to mitigate climate change
helping to mitigate climate change

153. Target 2
Target 2
Reduce biodiversity loss; achieving by 2010,
Reduce biodiversity loss; achieving by 2010,
a significant reduction in the rate of loss
a significant reduction in the rate of loss
Marine areas and land conservation need greater
Marine areas and land conservation need greater
attention
attention
Deforestation slows and more forests are designated
Deforestation slows and more forests are designated
for biodiversity conservation
for biodiversity conservation
The number of species threatened with extinction is
The number of species threatened with extinction is
rising rapidly
rising rapidly
Fish stocks require improved fisheries management to
Fish stocks require improved fisheries management to
reduce depletion
reduce depletion

154. Target 3
Target 3
Halve, by 2015, the proportion of the population
Halve, by 2015, the proportion of the population
without sustainable access to safe drinking water
without sustainable access to safe drinking water
and basic sanitation
and basic sanitation
Almost half of the world
Almost half of the world’
’s population face a scarcity of water
s population face a scarcity of water
More people are using improved sanitation facilities, but meetin
More people are using improved sanitation facilities, but meeting
g
the target will acquire a redoubling of efforts
the target will acquire a redoubling of efforts
In developing regions, nearly one in four uses no form of
In developing regions, nearly one in four uses no form of
sanitation
sanitation
Though access to improved drinking water has expanded, nearly
Though access to improved drinking water has expanded, nearly
one billion people do without
one billion people do without
Women shoulder the largest burden in collecting water
Women shoulder the largest burden in collecting water

155. Target 4
Target 4
By 2020 to have achieved a significant improvement
By 2020 to have achieved a significant improvement
in the lives of at least 100 million slum dwellers
in the lives of at least 100 million slum dwellers
Simple, low
Simple, low –
– cost interventions could significantly
cost interventions could significantly
improve the lives of many slum dwellers
improve the lives of many slum dwellers