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“George Byron” Private Language School
Varna
Bulgaria
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I. Aims of the lesson
II. Theory
1. Water pollution
2. Water pollutants
Radioactive pollution
Inorganic pollutants
Organic pollutants
Microorganisms in water
Thermal pollution
3. World Water day -22 March. Organizations and strategies preserving
water resources
III. Control and evaluating
1. Experiments and research
2. Questions
3. Preparing a leaflet - MS Word
IV. Summary
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To list and differentiate the water pollutants
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To describe the impact of the pollutants upon the environment and their
physiological effect on people
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To analyze the quality of water by conducting several experiments
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To summarise the experiment results and make some conclusions about the
quality of the water samples
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To develop a necessity to act sensibly in using and preserving natural resources
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To know the names of organizations and strategies preserving the water
resources
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* Water pollution
Water is a vital resource, without which our life and industry are unthinkable. It is a
significant resource for agriculture, housework, industry and water transportation and source
for putting down fires and production of energy.
The ecological problems and the sequences are interrelated and can be shown in the
following chain:
overpopulation→ overproduction→ overconsumption→ large amounts of waste→
depletion of natural resources and their pollution→ diminishing biodiversity→worsen
human health
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1. Radioactive pollution- solution of radioactive
isotopes
• Reasons: as a result of nuclear or radioactive damages, improper storage of
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radioactive substances (radioactive substances may be thrown away by nuclear
power stations, uranium mines or radiochemical labs, hospitals, etc.)
Consequences: The results are: dying or mutating organisms. The worst, by the way,
is the fact that the polluted place emits radiation for thousands of years.
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Inorganic pollutants
Pesticides
Herbicides
Mineral fertilizers
Sediments
Inorganic chemicals
Acids
Compounds of heavy metals
Toxic metals
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Pesticides - they keep the crops from parasites or
stimulate the growth of plants. Pesticides are
harmful not only for the parasites, but for humans,
too.
Source of pollution: agriculture
Consequences : Spraying with these substances
pollutes the soil as well as water.
Physiological effect: Living organisms are
poisoned and through underground waters the
pesticides leak into the water basins.
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Physiological effects: People drinking water
which contains higher levels of nitrate suffer
shortage of oxygen that reaches any part of the
human body through the blood system. The
major polluter is agriculture.
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These are: acids, salts, compounds of toxic metals such as mercury and lead
Consequences : The presence of highly concentrated pollutants may make water
impotable, to threaten fish and other water inhabitants, to diminish the crops or worsen
the corrosive stability of materials which are near or within the reach of polluted water.
The main polluter is industry.
Physiological effect: can lead to deposit of heavy metals in blood and inner human
organs.
Symptoms of intoxication
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Insoluble substances (sediments) — These are
insoluble substances in the soil which disperse in
water mainly by erosion.
Consequences : Mud damages water supply systems,
dams, water power plants, clogs irrigation networks,
moreover, its impact on ecosystems is highly
negative (it lessens the penetration of light, which is
necessary for photosynthesis of organisms living
there and thus the soluble oxygen in water decreases
dramatically)
Chemicals
Sources
Health risks
Nitrate
Agriculture / rain water
Risky for new – borns (The
blue baby disease)
Pesticides
Agriculture
Cancerous, mutagenic
effect, affects the nervous
system
Petrol products
Waste disposal, leakage
Cancerous
Arsenic
Geogenetic factors (soil)
Skin disease, cancerous
Copper
Copper pipes
Damages liver
Lead
Lead pipes
Affects the nervous system;
may cause retarding effect
on physical and mental
development of children
and babies.
Cadmium
Galvanic pipes
Kidney disease
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Petrol/
petrol
products
Organic
waste
SWS
detergents
Organic
pollutants
Home
waste and
plastics
Oils
Dioxins
and furans
Sources of organic pollution: transportation,
industry and human habitats, petrol industry,
food industry and pharmaceutical industry
Consequences : Organic pollutants are
oxidised in a natural way by the oxygen
dissolved in the water thus lessening its
concentration and worsening the quality of
water. Waste waters with organic pollutants
usually contain a lot of suspended insoluble
substances which diminish the light
(necessary for photosynthesis of organisms).
Oils and grease form a thin layer on the
surface of water and hinder the natural
solution of oxygen in it.
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Pollution with petrol products is caused by unintentional
spills of petrol products in water or soil.
Consequences : The results may be life destroying for flora,
fauna as well as humans. Petrol spills by damaged tankers
can be environmentally harmful because petrol is lighter
than water and floats on the surface. These spills may cover
thousands of kilometers and stop the oxygen and light for
sea animals; cause poisoning and death of the coastal birds,
fish, crabs etc.
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Consequences: SWS cause serious
environmental problems. Industrial and home
wash waters pollute water basins and produce
destructive effect on river flora and fauna.
They disturb the balance in the system which
results in dead fish and other river inhabitants.
Physiological effect – SWS mainly deoil skin
cause allergic reactions to people with highly
sensitive skin. Same fungal diseases are
observed.
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Sources of pollution: All activities of washing
machines and vehicles produce waste waters with
a lot of oils, grease and other petrol products.
Consequences: Oils and grease form a thin layer
on the water surface which hinders the natural
solution of oxygen in it.
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3.4 Dioxins and furans are sub products of the process of burning or
the industrial production of chlorine. They are toxic, difficult to
decompose and can be stored up in the body. Dioxins and furans can be
transferred by air, water and biological species to great distance and are
accumulated in terrestrial and water ecosystems.
Consequences: In water environment dioxins and furans are hard to
dissolve but they have a very strong ability to deposit and pile in
sediments and living organisms.
3.5 Organic waste (animal waste; waste of canning industry; milk
industry, etc.) are dissolved in water. The process of dissolving of
organic waste uses a great amount of the oxygen in water.
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Pollution with some organic materials may
result in mechanical pollution of water and soil
with insoluble synthetic substances ( for
example: plastic bottles, bags, ,etc.)
Consequences :It causes problems in the
normal development of living organisms.
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There are bacteria, viruses, protozoa, parasitic worms, which
get into water through drain pipes or untreated human and
animal waste. These pollutants cause the death of 14 000
people a day, half of them are children.
Physiological effect: They are disease agents ( malignant
cholera, hepatitis, typhoid fever, tetanus, etc.) They can be
spread by sewage, rivers, atmosphere.
http://savewater.uchenici.bg/content/pollution/bacteriological.html
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It can be natural (because of hot weather) or artificial (of industrial origin).
Sources of pollution: Thermal Power Stations and Nuclear Power stations which release a
lot of hot water in rivers and lakes, used for cooling their systems.
Consequences: Thermal pollution lessens the amount of dissolved oxygen and this may
cause the death of fish and intensive multiplying of pathogenic bacteria; change in the weed
biocenosis and bogging of some river parts. The increasing river water temperatures results
in many negative consequences from a physical point of view – fogs, erosion, evaporation.
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Worlds Water Day was appointed 20 years ago in Rio de Janeiro during a
conference. Organisations have been researching global ecological
problems for 20 years and have been looking for ways and methods to
preserve fresh water. Every year the day is celebrated with a different
motto. In 2016 the topic is “Water and Working places”
http://www.unwater.org/campaigns/world-water-day/en/
http://www.unicef.bg/en/article/Svetoven-den-na-vodata/716? UNICEF
http://www.cap-net.org/world-water-day-2015-learning-pack/
Power Point, quiz, a short video
http://www.un.org/waterforlifedecade/ decade of water in UN
http://waterbridge.info International Water bridge
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1. Analyze the quality of water by conducting experiments.
The students conduct the following experiments, concerning water:
smell, opacity. pH, Acid content, alkaloid content, degree of hardness, presence of
phenol, nitrates and H2S
 The students take some water samples from different water basins and label them.
 The students conduct the experiments and fill the table.
 The students describe the experiments and the changes.
 The students summarize the results and make some conclusions about the quality
of the water samples.
 The students present the results and discuss them.
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Water
samples
Proofs
Opacity
рН
Acid content
Nitrates
Н2S
Phenol
Reactive
substance
Description of
experiment
Change
Conclusions/
Summary
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Experiment 1: Opacity- The opacity of drinking water can be observer
directly. Physical features like opacity can indicate microbiological pollution.
Class vessel (0.3l) is full of water. The student holds it against the light.
Opacity is defined as follows: clear, slightly opaque, average level of opacity,
very opaque. Pay attention to the fact whether hard particles deposit on the
bottom of the vessel.
Experiment 2: рН
pH measures the acid content or alkaloid coutend of water solution (this is also the
symbol of acid or alkaloid coutent) The EU rule for drinking water not lower than
6.5 and not more than 9.5
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To measure pH the water temperature should be about 20°C because pH is
influenced by temperature
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Put a piece of puper in water for 1 – 3 seconds to react and compare it with
the colour scale.
Experiment 3: Nitrates in water. This can be done only by
an experiment, because nitrates are colourless, without any
smell or taste. Nitrates in drinking water are dangerous,
especially for babies and small children.
 To define the concentration of nitrates in water, students
put a piece of test paper in water for a few seconds, take it
out and shake it off.
 A minute later students compare the colour of the paper
against the colour scale.
 Don`t test when the temperature is below15°C.
 Please, have in mind that the test is inappropriate for
drinking water with chlorine.
Experiment 4: Hardness of water (harder water has higher content of minerals - Ca2+
and Mg2+).
 Pour some sample water in a glass and add a piece of soap.
 Leave it for 2 minutes, stirring the content from time to time.
Experiment 5: Phenol in water
 Pour some water in a test tube.
 Add some bromine water.
Experiment 6: H2S in water
 Pour 10ml water in a test tube.
 You can define the content of H2S because of the smell of rotten eggs or if you add
CuSO4
Questions:
 Please list some of the aims of the Millenium, concerning water preservation?
 List the environment pollutants and describe the influence of one of them on
environment and human health.
3. Homework: Prepare a leaflet by Word concerning the
leaflet should be disseminated among relatives and friends.
water pollutants. The
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Human life depends on water sources and their quality of water consequently avoiding
water pollution is our personal responsibility. It’s much easier to avoid water pollution than
fighting the consequences of it.
 If harmful emissions of different productions were caught by special appliances there
wouldn’t be acid rains.
 If cars worked with bio fuels there wouldn’t be any pollution with heavy metals or
poisonous gases.
 If agriculture didn’t use drinking water supplies but rainwater or drop watering we could
save enough fresh water.
 If productions worked with water of a closed cycle the use and pollution would be
reduced.
 If water supply systems were newer and more reliable there wouldn’t be leakages and
damages.
 If the households didn’t use such aggressive washing and cleaning detergents the water
basins wouldn’t be polluted with waste waters.
 If there were more cleaning stations there would be more fresh water.
That’s why we should be responsible and sensible in preserving this precious
natural source. It’s priceless because our life depends on it.