Download WATER POLLUTION

•Water is a ubiquitous chemical substance that is
composed of hydrogen and oxygen and is vital for all
known forms of life.
•In typical usage, water refers only to its liquid form or
state, but the substance also has a solid state, ice, and a
gaseous state, water vapor or steam.
•Water on Earth moves continually through a cycle of
evaporation
or
transpiration
(evapotranspiration),
precipitation, and runoff, usually reaching the sea. Over
land, evaporation and transpiration contribute to the
precipitation over land.
 Water is used for drinking, washing , bathing ,
etc.
 It is also used for irrigation purpose.
 A lot of water is used to make food.
 Almost every food contains water
SCARCE OF DRINKING WATER
•This natural resource is becoming scarcer in certain places, and its availability
is a major social and economic concern. Currently, about a billion people
around the world routinely drink unhealthy water.
• Poor water quality and bad sanitation are deadly; some five million deaths a
year are caused by polluted drinking water. The World Health Organization
estimates that safe water could prevent 1.4 million child deaths from diarrhea
each year.
•It is, rather, the distribution of potable and irrigation water which is scarce,
rather than the actual amount of it that exists on the earth.
WATER POLLUTION
 Water pollution is the contamination of water bodies (e.g.
lakes, rivers, oceans, groundwater).
 Water pollution affects plants and organisms living in these
bodies of water and in almost all cases the effect is damaging
either to individual species and populations, but also to the
natural biological communities.
 Water pollution occurs when pollutants are discharged
directly or indirectly into water bodies without adequate
treatment to remove harmful compounds.
SOURCES OF WATER
POLLUTION.
1) INDUSTRY
 Industry is a huge source of water pollution, it produces pollutants
that are extremely harmful to people and the environment.
 Many industrial facilities use freshwater to carry away waste from the
plant and into rivers, lakes and oceans.
 Pollutants from industrial sources include:
 Asbestos – This pollutant is a serious health hazard . Asbestos
fibres can be inhaled and cause illnesses such as asbestosis, lung
cancer, intestinal cancer and liver cancer.
 Lead – This is a metallic element and can cause health and
environmental problems. It is a non-biodegradable substance so is
hard to clean up once the environment is contaminated. Lead is
harmful to the health of many animals, including humans, as it can
inhibit the action of bodily enzymes.
2) OIL POLLUTION IN WATER
 Oceans are polluted by oil on a daily basis from oil spills, routine
shipping, run-offs and dumping.
 Oil spills make up about 12% of the oil that enters the ocean. The rest
come from shipping travel, drains and dumping.
 An oil spill from a tanker is a severe problem because there is such a
huge quantity of oil being spilt into one place.
 Oil cannot dissolve in water and forms a thick sludge in the water. This
suffocates fish, gets caught in the feathers of marine birds stopping
them from flying and blocks light from photosynthetic aquatic plants.
3) RADIO ACTIVE WASTE
 Nuclear waste is produced from industrial, medical and scientific
processes that use radioactive material. Nuclear waste can have
deterimental effects on marine habitats. Nuclear waste comes
from a number of sources:
 Operations conducted by nuclear power stations produce
radioactive waste. Nuclear-fuel reprocessing plants in northern
Europe are the biggest sources of man-made nuclear waste in the
surrounding ocean. Radioactive traces from these plants have been
found as far away as Greenland.
 Mining and refining of uranium and thorium are also causes of
marine nuclear waste.
4.Mining and Agricultural Wastes
Mines, especially gold and coal mines, are responsible for large
quantities of acid water. Agricultural pesticides, fertilizers and
herbicides may wash into rivers and stagnant water bodies.
5. Sewage Disposal and Domestic Wastes
Sewage as well as domestic and farm wastes were often allowed to
pollute rivers and dams.
6.Human activities:
Human activities such as bathing , washing clothes etc in towns and
villages lead to water pollution
7.Customs and Traditions: Disposal of dead bodies and
immersion of idols of gods and goddess into water bodies during
various festivals in India degrade the quality of water.Plaster of Paris
which is used generally used to make the idols contain gypsum ,
sulphur and magnesium and idols are decorated using chemical paints
that contain magnesium , cadimium and lead. All these increase the
acidity of water and concentration of heavy metals in it. Such water
pollution can damage the ecosystem by killing aquatic plants and
organism and other living creatures dependent on water.
Garbage Polluted Stream
Water Pollution by Mining
Water Pollution by Slums
Water Quality Standards:
 Water is usually colourless, tasteless and odourless in its pure
form. Due to addition of a number of substances due to natural
or artificial reasons it loses its pure character and quality.
Therefore several impurities are always associated with it.
 Water quality standards are the foundation of the water quality
based pollution control programs mandated by the clean water
act.
 Water quality standards define the goals for a water body by
designating its uses, setting criteria to protect those uses and
establishing provisions such as anti degradation policies to
protect water bodies from pollutants.
Impurities in water
 Physical Impurities: These impurities are mainly caused
due to soil erosion including soil particles, pollens
microorganisms etc. Generally these impurities are
separated by filtration.
 Minerals Impurities: These are mainly the minerals present
in soil which get dissolved in ground water or surface water.
These are also known as total dissolved solid (TDS) .In
many parts of India water gets contaminated due to the
presence of fluorides , arsenic and iron which causes fatal
diseases.
 Organic Impurities: Surface water is subjected to these
organic impurities comprising both plant and animal
residuals and microorganisms, which are found on the
surface of earth. Fertilizers and pesticides are the chief
organic contaminants found in water.
Mandatory Requirements for water testing
 Testing water samples of ground water is a mandatory
requirement to keep a check on its quality. Most of
the authorities which supply drinking water are
equipped with water testing facilities. The strict
enforcement of pollution control laws has resulted in
an increase in demand for lab facilities for the proper
testing of water quality standards.
 There are many private agencies which provide wide
spectrum of water testing services. The results of
labs. Accredited Board for testing and calibration
laboratories are accepted by the Pollution Control
Board and other government authorities.
EFFECTS OF WATER POLLUTION
 Virtually all types of water pollution are harmful to the health of humans
and animals. Water pollution may not damage our health immediately
but can be harmful after long term exposure. Different forms of
pollutants affect the health of animals in different ways:
 Heavy metals from industrial processes can accumulate in nearby
lakes and rivers. These are toxic to marine life such as fish and
shellfish, and subsequently to the humans who eat them.
 Industrial waste often contains many toxic compounds that damage the
health of aquatic animals and those who eat them. Some of the toxins
in industrial waste may only have a mild effect whereas other can be
fatal. They can cause immune suppression, acute poisoning.
 Microbial pollutants from sewage often result in infectious diseases
that infect aquatic life and terrestrial life through drinking water.
Microbial water pollution is a major problem in the developing world,
with diseases such as cholera and typhoid fever being the primary
cause of infant mortality.
EFFECTS OF WATER POLLUTION--- Organic matter and nutrients causes an increase in aerobic
algae and depletes oxygen from the water column. This causes
the suffocation of fish and other aquatic organisms.
 Sulphate particles from acid rain can cause harm to the health of
marine life in the rivers and lakes it contaminates, and can result
in mortality.
 Suspended particles in freshwater reduces the quality of drinking
water for humans and the aquatic environment for marine life.
Suspended particles can often reduce the amount of sunlight
penetrating the water, disrupting the growth of photosynthetic
plants and micro-organisms.
EFFECTS OF WATER POLLUTION ON PLANTS
:Eutrophication
Definition
 Eutrophication is a process whereby water bodies, such as
lakes, or slow-moving streams receive excess nutrients that
stimulate excessive plant growth (algae, periphyton attached
algae, and nuisance plants weeds).
 This enhanced plant growth, often called an algal bloom,
reduces dissolved oxygen in the water when dead plant
material decomposes and can cause other organisms to die.
Nutrients can come from many sources, such as fertilizers
applied to agricultural fields, golf courses, and lawns;
deposition of nitrogen from the atmosphere; erosion of soil
containing nutrients; and sewage treatment plant discharges.
Water with a low concentration of dissolved oxygen is called
hypoxic.
Eutrophication
Eutrophication
Process of Eutrophication
Eutrophication is a natural process!
However, humans in their everyday activities can exacerbate
the process:
Point sources (can locate the cause)
 Sewage treatment plant discharges
 Storm sewer discharges
 Industrial discharges
Non-point sources (can’t locate the cause, it’s everywhere)
 Atmospheric deposition
 Agricultural runoff (fertilizer, soil erosion)
 Septic systems
Eutrophication process in 6 stages
ADDITION OF NITRATES
GROWTH OF PLANTS
DEATH OF PLANTS
GROWTH OF BACTERIA
LACK OF OXYGEN
SUFFOCATION
Before increases in nutrients:
Acceleration of eutrophication :
Results of eutrophication :
Photo 1: Algal bloom in a lake.
Photo 1: Algal bloom in a lake.
Photo 2: Overgrowth of floating aquatic plants.
Lake Biwa, the largest lake in Japan during summer time showing
overgrowth of aquatic plants.
Algae
Algae
Impact of Eutrophication
Include death of aerobic organisms,
increased turbidity,
reduction in length of food chains
and loss of species diversity.
Efeects of water polltion on
animals:Biomagnification
Biomagnification
 Definition:
 Biomagnification,
also
known
as
bioamplification, or biological magnification is
the increase in concentration of a substance, such
as the pesticide DDT, that occurs in a food chain
Biomagnification Through the Food Chain
Effects of Water Pollution on Animals:
 The organisms that live in aquatic habitats are directly affected
by water pollution. The presence of harmful chemicals and
pollutants in water makes the survival of aquatic organisms
extremely difficult. Owing to the increasing amounts of
pollutants in water a large no. of known and unknown aquatic
plant and animal species become extinct.
 Drinking polluted water causes the toxins present in the water
to enter the body of the organisms , this poisoning may lead to
serious health disorders and may even cause death.
Control of Water Pollution
 Judicious use of agrochemicals like pesticides and fertilizers
which will reduce surface run off .Avoid their usaage of these
on slope lands.
 Use of nitrogen fixing plants to supplement the use of
fertilizers.
 Adopting integrated pest management to reduce reliance on
pesticides.
 Prevent run off manure. Divert such run off to basin for
settlement .
Control of Water Pollution
 Separate drainage of sewage and rain water should be provided
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to prevent overflow of sewage with rain water.
Planting trees would reduce pollution by sediments and will
also prevent soil erosion.
Waste water should be treated by primary and secondary
treatment to reduce BOD,COD levels upto permissible levels
of discharge.
Industrial effluents and wastes must be treated in order to
reduce their toxity.
Non biodegradable waste materials such as plastics should not
be dumped in water bodies .These not only increase the levels
of toxins in water but also choke the aquatic organisms to death.
Control of Water Pollution
 Human activities such as bathing and washing in the rivers ,
ponds and lakes , washing animals, immersing of idols must
be stopped.
Marine Pollution
 The contamination of the marine
environment due to the presence of
various undesirable materials that
have been added directly or
indirectly by humans is known as
marine pollution. This pollution has
adversely
affects
biological
resources and human health.
Marine pollution: Another definition
The introduction by man of substances or
energy into the marine environment, which
results in harm to marine life, hazards to
human health, hindrance to marine activities,
including fishing and other legitimate uses of
the sea, impairment of quality for use of sea
water and reduction of amenities.
Causes of Marine Pollution:
 Oil
and petroleum
leakage of oil from
discharge in the sea.
threatened as it lies
shipping routes.
spillage: It includes
oil tankers, accidental
South Africa is greatly
on one of the busiest
 Toxic Chemicals: Industrial wastes containing toxic chemicals
and heavy metals pollute marine ecosystem and hence are
considered to be the most lethal pollutants causing marine
pollution. A part from heavy metals substances such as petrol
and grease, oil, pesticides, herbicides and solvents on marine
ecosystem
 Hazardous Wastes: Wastes discharged through nuclear testing,
nuclear power plants, defence explosions are categorised
as
hazardous wastes. These substances poison the ecosystem and
cause a serious form of marine pollution
 Raw Sewage: Oceans receive huge amount of sewage from costal
cities all over the World. Of over 60 licensed pipe lines that discharge
effluents along the South African coast, about 66 million litres per day,
half discharge industrial wastes and mixed effluents.
 Thermal Pollution: In many industries water is used as a
coolant and it becomes hot in the process. This warm water
is discharged into water bodies. The addition of warm water
to oceans causes the temp. Of water to change drastically
and affect the living organisms a lot.
EFFECTS OF MARINE POLLUTION
 Reduction
in Photosynthetic rate: Owing to high
concentration of pollutants, water becomes turbid and
obstruct the penetration of sun light. It reduces the rate of
photosynthesis in marine plants.
 Declines in dissolved oxygen: Due to decrease in rate of
photosynthesis, amount of dissolved oxygen also decreases.
 Toxicity: Due to addition of heavy metals such as mercury,
arsenic, cadmium, cyanide etc into marine ecosystem,
enormous amount of aquatic life is lost.
 Eutophication
 Diseases: Consumption of marine food obtained from such
polluted waters cause a number of fatal diseases such as viral
hepatitis, cholera, typhoid and digestive problems.
 Effect on marine animals: An oil spillage not only affects the
fishes and living organisms that dwell inside water but also the
birds that depend on these aquatic organisms. Oil forms a thin
layer on the surface of water body and the oil pollutants are
absorbed into the feathers of birds and reduce the flying
efficiency.
 Plastic disposed in the water bodies also affects the marine living
organisms and induces a no. Of diseases and abnormalities in
the animals.
Marine pollution: DDT
 DDT was a widely used pesticide that became
concentrated in marine fish
 DDT caused brown pelicans and ospreys to
produce thin egg shells
 Worldwide, DDT has been banned from
agricultural use but is still used in limited
quantities for public health purposes
Marine pollution: Polychlorinated
biphenyl (PCB)
 PCBs are industrial chemicals used as liquid
coolants and insulation in industrial equipment
such as power transformers
 PCBs enter the marine environment through
leaks and from discarded equipment
 PCBs can accumulate in animal tissues and affect
reproduction
Nuclear Radiation
 Caused by leaking of containment structures.
 The severity of this contamination depends on the life of
the radioactive isotopes that would be released if a
meltdown were to occur. Some like iodine 131, would
only affect humans if plants and vegetables were
consumed immediately after contamination because
they quickly degrade. Others, like caesium, are more
dangerous because they remain radioactive for about 28
years.
SOME OTHER POLLUTANTS
Plastic in the marine environment
 Plastic:
 Does not biodegrade
 Floats
 Has high strength
 Is ingested by and
entangles marine
animals
Marine pollution: Petroleum
 Oil spills can be caused
by:
 Tanker accidents
 Intentional dumping
 Drilling/pumping
operations
Marine pollution: Petroleum
 When oil washes up
at a beach, it can
negatively affect the
marine environment
 Oil can coat marine
organisms and render
their insulating fur or
Oil on the beach from the
feathers useless
Exxon Valdez oil spill,
Alaska
Control of Marine Pollution:
 Toxic pollutants from industries and sewage treatment plants
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should not be discharged in coastal waters.
Run offs from where sources should be prevented
Sewer overflows should be prevented to reach coastal areas.
Dumping of toxic , hazardous wastes and sewage should be
banned
Development activities on coastal areas should be minimised
Oil and grease from service stations should not be dumped
rather must be processed for reuse.
Oil blasts should not be dumped into sea.
Oil spillage must be minimised.
 Oil pollution can be controlled by using oleic and stearic acids which
help in concentrating and removing oil pollutants.
 Ships should be maintained properly and serviced regularly to prevent
oil leakage.
 Solid wastes such as plastic, glass, metal, papers should be recycled
for different purpose instead of being discarded as wastes.
 Strategies such as establishment of marine protected areas , adoption
of a bioregional- management approach and negotiation of
international agreements for regulating pressures on marine resources
should be followed.
THERMAL POLLUTION
Chemical industries, fossil fuel and nuclear power plants use water for
cooling purpose and return this water to stream at higher temperature.
The rise in water temperature due to warm water discharged after
cooling the machines in factories and in nuclear and thermal power
plants is called thermal pollution. The addition of warm water causes
the temperature of water body to rise and adversely affects the
aquatic plants and animals in it and this is called thermal pollution.
Causes:
 The major sources of thermal pollution are electric power plants
and industries. They contribute to thermal pollution in the following
ways:
 In most of electric power plants, a large amount of heat is released
when coal, oil, or natural gas is burned or nuclear fuels under go
fission. This heat energy is used to turn water to steam, which in
turns spins turbines to produce electricity. For the condensation of
this steam and for cooling the machines in factories and in nuclear
power plants a large quantity of water is required. As a result
temperature of water is increased by 5-10oC .
 Deforestation is another major cause of thermal pollution.Removal
of vegetation to grow crops or to construct buildings , roads and
other structures warms the water by 10oC
Effects of Thermal Pollution
•The mixing of waste hot water into water bodies raises the average
temperature of the water and also affects the concentration of dissolved
oxygen. Warm water contains lower concentration of dissolved oxygen
compared to cold water hence affects the survival of the aquatic floura and
fauna.
•The increase in water temperature may cause the activities of certain
pathogenic microorganisms to accelerate. There may be changes in the
microbial population due to increased water temperature that may affect
the quality of water and the general production of aquatic ecosystem.
•The heated industrial effluents may contain toxic pollutants such as
cadmium, copper and arsenic that may make the water unstable for any
purpose. Thermal pollution may also result in Change in the physical and
chemical properties of water.
Control of Thermal Pollution
•Establishment of cooling towers.
•Constructing ponds for collecting hot water.
•Artificial lakes can be made for the hot effluents from where the cool water can
be recycled.
•The cold water or air showers may be used in the industries to check hot
gases, at the source.
•The excess heat energy that is produced in the generation of electricity may
be utilized in another industry where this energy may be required. This process
is called cogeneration.
•In places where residential or commercial buildings are located near the
industrial plants the waste hot water may be used for heating purpose.
Radiation Pollution : Nuclear Hazards
 Radiation refers to the energy emitted by an atom
while transforming from a high energy state to a low
energy state .The elements that continuously emit
radiations are known as radioactive elements. In
nuclear reactors radioactive elements such as
uranium, plutonium etc are used as fuels.
The products of the reaction may also be
radioactive in nature and form nuclear wastes. If
these wastes are not properly disposed they may
cause serious poisoning of the environment. This is
known as radioactive pollution or radiation pollution.
Causes of Radioactive or Radiation
Pollution
 Natural Causes: High energy protons and electrons
released from sun are contained in cosmic rays
.Prolonged exposure to these rays may cause skin
cancer in humans and animals.
 Radioactive wastes from nuclear power plants: There is
no reliable method of storing radioactive waste generated
from power plants as a result some radioactivity is bound
to leak from wastes which causes severe poisoning of
the environment.
 Nuclear Explosion: Atomic explosions release a large
amount of radiations. Sometimes radioactive elements in
small traces passed on to humans via food chain.
 Medical Use: Most of the man made ionising radiations
come from the X rays for examination of teeth, bones,
lungs and other organs. Diagnostic X-rays in pregnant
women may increase the risk of cancer in the unborn
child. In addition the lab technicians who are constantly
exposed to these radiations as an occupational hazard
are also at great risk of developing various types of
cancers.
 Radiation from other sources: Radiations from luminous
watches, clock dials , cell phones, microwave ovens etc
constitute smaller sources of exposure.
Effects of Radiation Pollution
 Somatic Effects: Different parts of the body have different
levels of sensitivity. Tissues of intestine , bone etc are highly
sensitive to radiations. Radiations can cause skin cancer, bone
cancer, premature ageing, cardiovascular disorders etc and
hence reduce life span.
 Genetic Effects: Radiations emitted from natural and
anthropogenic sources can lead to changes in the genetic
framework of an individual and cause certain genetic defects.
Such defects are caused mainly because of changes in the DNA
which may lead to an increase in the no.of children born with
abnormalities and cause infant motality.
Control Measures
 Amount of radiations can be reduced by plantation of dense
trees around the atomic power plants.
 Proper management of radioactive waste should be ensured.
Suitable waste disposal methods and better technology for
nuclear power plants should be developed to protect radiation
health hazards.
 Diagnostic procedures involving X-rays examination should be
avoided as much as possible. Workers and technicians
associated with X-ray procedures should regularly use lead
rubber aprons to reduce effect of exposure.
 For setting the nuclear power plants various efforts including the
process of site selection its design , construction , operation and
short and long term effects should be seriously considered to
control radiation.