Lincoln University College
MASTERS IN PUBLIC HEALTH
&
health management
PRINCIPLES OF ENVIRONMENTAL HEALTH SCIENCES
LECTURE BY
MR. ABDULWAKIL DAUDI (Msc., BED (Sc)
MODULES AND UNITS
Module Title
1
2
3
4
Environment and Environmental Health
Unit 1: Environment
Unit 2: Health and Environment
Unit 3: Environment and health protection policies
End of units Assignments
Concepts of Environmental Pollution
Unit 1: Water Pollution
Unit 2: Noise Pollution
Unit 3: Soil Pollution
Unit 4: Food Hygiene and Food Pollution
Unit 5: Radiation Pollution
End of units Assignments
Concepts of Disease Causing Agents in the Environment
Unit 1: Arthropods and Zoonosis
Unit 2: Air borne Diseases
Unit 3: Food borne, Water Borne and Vector borne Diseases
Unit 4: Life-style Related Diseases
End of units Assignments
Concepts in Waste Management
Unit 1: Dry Refuse or Solid Waste
Unit 2: Methods of Final Disposal of Solid Waste
Unit 3: Wet Refuse or Liquid Waste
Unit 4: Emerging issues in environmental health science
End of units Assignments
Module 2
Concepts of Environmental Pollution
and Food Hygiene
Mode: Evening Programme
UNIT 1: CONCEPT OF ENVIRONMENTAL
POLLUTION AND AIR POLLUTION
OBJECTIVES
• By the end of this unit, the students should be able to:
1.Define environmental pollution.
2.Identify measures for controlling pollution.
3.Identify the agencies for pollution control in Nigeria.
4.Define air pollution.
5.State the types and sources of air pollution.
6.Discuss the effects of air pollution.
Concept of Environmental Pollution
• Increase in technological development and population pressure due to
urbanization results to stress to the ecological system.
• `Pollution' means contamination, or the process of making something dirty,
impure, or poisonous by adding a chemical, waste, or infection,
• Pollution is caused by the introduction of a harmful substance into the air,
water or soil that prevents the functioning of natural process, and
produces undesirable environmental and health effects due to its chemical
composition or quantity.
• Environmental pollution is the contamination of air, water or food in such a
manner as to cause real or potential harm to human health or well- being or
damage to non-human nature without justification.
• Environmental pollution is also defined as the introduction by man into the
environment of substances or energy/radiations in such concentration as
may be or tend to be hazardous/injurious/harmful to human health, living
organisms, and ecological systems, damage to structures or interference
with the legitimate use of the environment.
Concept of Environmental Pollution
• From the above definitions, some basic facts can be deduced.
1.
2.
3.
4.
That pollution is caused by substances
That man is the major cause of sources of pollution.
That pollution has effects on man, resources and ecological systems.
Environmental pollution could be man-made pollution it could also be natural
pollution.
5. Man-made is caused by human activities while natural pollution is caused by
natural sources.
Concept of Environmental Pollution
The terms used in Environmental Pollution
1. Source: This is the place from where the pollutants originate A source increases the
level of pollution. For example, cooking and heating (combustion) are the sources of
carbon monoxide, nitric oxides, and Volatile Organic Compounds.
2. Sink: Sink is an area or part of the environment in which, or a process by which,
pollutant(s) is removed from the medium in which it is dispersed. A sink decreases
the level of pollution, For example, the sink for atmospheric nitrous oxide is
destruction in the stratosphere by photolysis to nitrogen and oxygen.
3. Receptor/ Ecological receptors : Receptors comprise any living organism other than
humans, or the habitat that supports such organisms, or natural resources that could
be adversely affected by environmental contaminations. Plants, soil insects, and
marine animals are examples of receptors.
4. Transport: Transport is the means by which pollution travels from a source to a
receptor, For example, transport through the media of air and water.
5. Dispersion: It is the process of spreading out of the pollution in the environment
during the process of transport. For example, pollutants from vehicular or factory
emissions are dispersed into the atmosphere are removed from the transport
medium (air) through deposition due to rain.
Types of Environmental Pollution
• There are three types of pollution, based on the source of pollutants.
• 1) Point source pollution and
• 2) Non-point source pollution.
• 3) Fugitive emissions.
Types of Environmental Pollution
1. Point source pollution:
• According to the United States Environmental Protection Agency
(UNEPA), point source pollution is `any single identifiable source of
pollution from which pollutants are discharged'.
• Emission of contaminants into the environment from a single,
identifiable location is called point source pollution.
• Some examples of point source pollution include the following:
a)
b)
c)
d)
Emissions from waste treatment plants like incinerators
Toxic effluents from industries, such as tanneries
Sewage effluents
Exhaust from vehicles
Types of Environmental Pollution
2. Non-point source pollution:
• Emission of contaminants into the environment from more than one location
over a wide area is called non-point source pollution.
• No specific area of source can be identified in this case; instead the pollution
originates from several unidentifiable areas, Some examples of non-point source
pollution include the following:
a) Toxic chemicals, which have not been properly disposed off
b) Harmful bacteria and micro organisms from cattle wastes
c) Pesticides, fungicides and nutrients from agricultural fields and residences
d) Oil, grease, metals and cleaning agents washed from roads and workshops
e) Sediments from construction sites, forests and agricultural fields
f) Leaching and emissions from garbage dumps
Types of Environmental Pollution
3. Fugitive emissions:
• In addition to the point source and non-point source pollution
sources, there is another source of pollution, which is called fugitive
emissions.
• The pollutants released into the atmosphere from leaks in equipment,
pipe lines, seals, valves etc., but not from the usual sources,
constitute fugitive emissions.
Pollutants
• These are substances causing damage to living and non-living things
in the environment.
• Some chemical elements such as Carbon, Nitrogen, Oxygen, Sodium,
Manganese, Iron, Bromide, Zinc, Calcium, and so on when they occur
in single or in combined form may be essential in the environment
and they may be toxic to the environment at a certain level.
• For instance, Carbon and Nitrogen are essential to plant but they are
toxic to animals particularly when carbon combines with Oxygen to
form Carbon-monoxide.
• Secondly, the effects of pollutants on the environment could depend
on formulation or on concentration of the substances e.g., the
organic combination of Mercury particularly methyl mercury pose a
greater risk or hazard than its inorganic salt.
Types of Environmental Pollutants
1. Local Pollutants:
• These are those substances, the concentrations of which cross the threshold
concentration levels within a small area or volume of air, soil or water.
• The local concentration (e.g., within home, place of work, parts of the city
and around, areas of industrial activities) can vary temporarily above the
threshold concentrations.
• For example, the presence of oxides of nitrogen (N0d, Volatile Organic
Compounds (VOCs) and aerosols in air belong to this class of pollutants.
2. Global Pollutants:
• These are those substances whose concentration levels have been built up in
air, water or soil over years.
• For example, global warming and stratospheric ozone depletion is due to an
increase in the levels of carbon dioxide (CO2) and chlorofluorocarbons (CFCs),
respectively.
Control of Environmental Pollution
• Site Selection and Zoning - planning of industrial estates, highways, residential
should be done.
• Process change or Equipment Modification - e.g. the use of tall chimneys to
spread pollution and reduce concentration, wet process of cement manufacturing
instead of dry process etc.
• Fuel Selection and utilization - e.g. use of diesel fuel with less chemical pollutions
instead of gasoline wih pollutants like sulphur dioxide, Good burning efficiency of
fuel for complete combustion and less CO .
• Legislation - Enactment of laws and regulatory agencies that will help regulate the
generation of poisonous substances in the environment.
• Health Education – Public awareness and research on the effect and matters of
environmental pollution
• Involving members of the public – Members of the public should be involved in
actions or programme regarding environmental pollution.
• Sensitizing and stimulating the workers of Environmental Sanitation or Task Forcethis is a body or group established by the government to ensure a clean, pollution
free and healthy environment. They usually operate at the Local Government level.
Air Pollution
• Air pollutant: Any substance added/present in the air which may harm the
natural environment, plants, animals and human beings.
• Air pollution is the presence in the out air atmosphere of substances or
contaminants which emanates from anthropogenic activities in quantities
and duration to cause any discomfort to substantial number of inhabitants
of a locality or which are injurious to public health, plant or animal life or
property or which interferes with the reasonable or comfortable
enjoyment of life in an area.
• According (WHO), air pollution may be defined as `Substances put into air
by the activity of mankind at concentrations sufficient to cause harmful
effect to his health, vegetables, property or to interfere with the enjoyment
of his property.
• The (USEPA) defines air pollution as the presence of contaminants or
pollutants, such as noxious gases, particles of solid and particulates of
liquid matter in high concentrations that interfere with human health or
welfare, or produce other harmful environmental effects.
Air Pollution
Types and Source of Air Pollution
a)
b)
c)
d)
e)
Nitrogen oxides which emanate from natural and anthropogenic
activities such as burning, lighting, microbial activities, biological
processes, high temperature, combustion, power station etc.
Sulphur dioxide which results from domestic fuel, diesel etc.
Carbon monoxide - From combustion of fossil fuels or organic materials,
motor vehicle etc.
Chlorofluorocarbons (CFCs) - This arise from refrigerator manufacturing
process, aerosol spray cans, air conditioners, plastic, foams and
solvents.
Particulate matter- such as dust, fume, mist, smoke, spray and lead.
These are being generated from motor vehicle using leaded petrol,
demolition of structures, excavation of soil, wood materials, etc.
Types and Source of Air Pollution
f) Asbestos - This emanate from asbestos mining, construction, refining,
fabrication, demolition, remodelling and replacement of pipes and
furnaces.
g) Mercury - From Chloralkali manufacturing, battery manufacturing
and solid waste incineration.
h) Hydrogen Sulphide - From craft paper manufacturing, oil refining
and pipeline transformation.
i) Benzene – From pharmaceutical manufacturing petrochemical
manufacturing, industrial solvents.
j) Fluoride – From primary aluminium smelting and phosphate fertilizer
manufacturing,
Effects of Air Pollution
(a) Effects on man
1. It aggravates respiratory and cardiovascular diseases
2. Causes chronic pulmonary fibrosis especially the gaseous
pollutants
3. Causes bronchitis in 2 -3 years old children
4. If concentrated can cause kidney inflammation
5. Impairs visibility at very high concentration causing even vehicle
accidents and sever loss to live and property.
6. Impairs mental functions in case of carbon monoxide exposure.
7. Carbon monoxide (CO) at a very high level may cause unconsciousness
and death.
Effects of Air Pollution
8. Causes headaches, nausea, and loss of coordination.
9. Long exposure to volatile organic compounds (VOCs) can lead to liver
problem.
10. Some dangerous substances such as lead can cause impaired
growth of bone and nervous systems in children and
11. Causes congenital deficits in children
12. In adult, it can cause damage to the brain, kidney, liver and
reproductive system.
13. Dust and other poisonous substances can lead to asthma and other
cardiovascular diseases.
14. Some may be carcinogenic; it can penetrate deeply into the lungs.
Effects of Air Pollution
(b) Effects on Animals
• The damage caused to animals depends on size and respiratory rate.
• Many animals die from inhaling toxic gas, at a lower intake than will kill man.
• Chronic poisoning results from ingesting forage contaminated by particulates from organic, lead
etc.
(c) Effects on Vegetation or Plant
• The types of injuries caused by various pollutants to plants differ from one another. Air
pollution affects vegetation in three ways namely:
i. Necrosis- collapse of the leaf tissue
ii.Chlorosis - bleaching or other colour changes
iii.Alterations in growth.
(d) Effects on Materials
• The soiling of building surfaces, clothing and other articles partly from deposition of smoke
overtime and partly from Acidic precipitation and pollutants like sulphur dioxide.
• Fabrics and dye also bleach as a result of particulate matter such as dust.
• Nitric acid causes corrosion on metal surfaces.
SELF-ASSESSMENT EXERCISE
• Define the following terms:
• (i) Environmental Pollution
• (ii) Pollutants
• Describe any four measures for controlling environmental
pollution.
• Discuss the effects of air pollution on the following:
a) Man
b) Vegetations and plants.
• Identify any five sources of air pollution.
Unit 2: Water Pollution
OBJECTIVES
By the end of this unit, the students should be able to:
• Identify the sources of water and the assurance of safe water
• State the principles of safe water
• Enumerate the sources of water pollution
• Discuss water purification/water treatment
Sources of Water Pollution
• Water pollution can be defined as the introduction of substances into
water levels which at the end may cause a deleterious or harmful effect on
human health, or on aquatic creatures, or on structures and materials.
• Surface water is more liable to pollution because of its water shade.
Ground water can be polluted by septic tank and by oil fields (Strong
solution of salt in water).
• Almost every human activity results to water pollution but the main
sources through which water is being polluted are:
1. Waste from natural sources
2. Agricultural waste
3. Domestic and municipal sewage
4. Commercial or industrial wastes
Sources of Water Pollution
1. Waste from Natural Sources
• These include dead organic matters arising from plants (leaves, branches,
twigs etc) and animals (molluscs, fishes, rabbits, rats, crustacean etc) that fall or
die inside water source and decay in them. They are natural impurities and the
decaying plant materials give rise to fungal micro-organisms while the decaying
animals yield bacterial. These micro-organisms in-turn pollute the water
sources.
2. Agricultural Wastes
• Eroded materials from farmlands, plant nutrients vegetation, in organic salts and
minerals resulting from irrigation, herbicides and pesticides give rise to water
pollution. Presently, farmers use fertilizers to improve crop growth and yield.
Fertilizers contain nitrogen and phosphorus, when they are not properly used and
are dumped in every part of the farms; they are leached off from the land into
rivers and lakes to cause excessive nutrient enrichment in water leading to
propagation of weeds and rich green algae in water bodies.
Sources of Water Pollution
3. Domestic Sewage
• These are human feaces and urine plus sullage. Domestic sewage have
odour and are hazardous in content because of the pathogenic
organisms they contain. This sewage when emptied into water body causes
pollution to the water. Because sewage and sullage contain large floating or
suspended solids like feaces, rags, grease, vegetable peels and so on, they
pollute water bodies in three ways,
i. It adds organic matter, organic forms of pathogen and phosphorus to
water which stimulates the growth of organisms which in- turn uses up
the available oxygen in water,
ii. It adds intestinal bacteria (coliform) along with other pathogens to
water.
iii. It can add hard detergents such as Alkyl benzene sulphonate (ABS) which
causes rivers to foam. This situation fastens the deterioration of water.
Sources of Water Pollution
4. Commercial or Industrial Wastes
• These wastes contain large quantities of raw materials, processing
chemicals and by products such as solvents, detergents, cyanide,
heavy metals, minerals, organic acids, nitrogenous substances, fats,
salts, bleaching agent, dyes, pigments, sulphide etc.
Types of Water Pollution
1. Ground Water Pollution:
• Groundwater is the water present beneath Earth's surface in rock and soil
pore spaces and in the fractures of rock formations.
• This is contamination of ground water. Mainly effluents from industries
containing high levels of contaminants are disposed to the environment.
• Other sources include seepage from sewerage, Leachate from solid waste
dump yards and run offs from agricultural fields and residential areas.
2. Surface Water Pollution:
• Surface water includes water in the oceans, seas, lakes, rivers and streams.
• The main source of surface water pollution is discharge of untreated
effluents from factories and sewerage from homes hence contaminating
water.
Sources of Water Pollution
Types of Water Pollutants
Basically there are five types of water pollutants. These are:
1. Organic pollutants: include oil and organic wastes, such as sewage,
animal manure etc.
2. Inorganic pollutants: comprise nitrates, phosphates, acids, salts, toxic
heavy metals, gasoline, pesticides, dyes, paints, plastics, cleaning
solvents and detergents.
3. Sediments: include suspended solids or insoluble particles of soil, silt,
organic materials etc, Physical agents include heat.
4. Thermal pollutant:- Release of hot water used for cooling in industries.
5. Radioactive pollutants: Radioisotope nuclides in the water may enter
the food chain via aquatic organisms and bio-magnify in the food chain
causing cancer and affect life.
Types of Water Pollutants
1. Organic pollutants: - Includes the following:
a) Oxygen Demanding Wastes:• Present in water from domestic and municipal sewage, industrial effluents
and biomass accumulation in various forms degrade and are decomposed
by bacterial activity in the process they consume the dissolved oxygen
available in the water body. A level of dissolved oxygen below 4.0 mg/L
indicates water pollution. This causes Eutrophication
• The amount of oxygen required to break down the organic waste present
biologically or chemically is measured as biochemical oxygen demand
(BOD). A high BOD indicates a greater depletion of oxygen which results in
killing of fish and shellfish.
• Organic wastes and inorganic wastes (e.g., nitrate and phosphates) cause
the increase in the nutrient contents of that water body. The nutrients act
as a fertiliser and cause overgrowth of water microscopic plants, such as
abundant growth of algae (algal bloom), duck weed, water hyacinth (longer
plants) etc causes in depletion of dissolved oxygen levels causes suffocation
to the aquatic life. This is called Eutrophication.
Types of Water Pollutants
b) Synthetic Organic Compounds
• Synthetic organic compounds enter and pollute the water system through
various human activities, such as manufacturing, and accidental spillage during
transportation. They could form huge foams and volatile substances, which may
cause explosion. Many are toxic in nature and resistant to microbial degradation.
c) Pathogens
• Pathogens that are water pollutants include a large number of disease causing
bacteria, virus and parasitic micro-organisms from sewage effluents, tanning
industries, slaughter houses.
• These pathogens in the contaminated water cause cholera, typhoid, dysentery,
polio, salmonellosis and infectious hepatitis.
d) Nutrients
• Nutrient pollution is a non-point pollution source from agriculture fields and feed
lots, fertiliser industry, and sewage water.
• The nutrient elements, such as nitrogen and phosphorous that stimulate
undesirable growth of plants like algae and other aquatic weeds, Eutrophication
which reduce the dissolved oxygen, thus becoming pollutants.
Types of Water Pollutants
2. Inorganic Pollutants
• Water soluble inorganic pollutants, such as heavy metals, inorganic salts,
trace elements, complexes of metals with organic compounds, cyanides,
sulphates, acids from mine drainage, and acid precipitation contaminate
water.
• Many of these compounds are toxic at low concentrations and nonbiodegradable in nature. These cause an adverse effect on aquatic life.
3. Sediments
• Sand, silt, clay and humus together constitute sediments. Sediments enter
the water bodies from municipal sewers; through the surface runoff during
rainy season; and by erosion from farms, deforested slopes, construction
sites and river banks.
• These sediments make the water muddy and block the sunlight penetrating
the water thereby reducing the photosynthesis. It also increases the bed
load which in turn reduces storage capacities of reservoirs, and kills the
aquatic life.
Types of Water Pollutants
2. Inorganic Pollutants
• Water soluble inorganic pollutants, such as heavy metals, inorganic salts,
trace elements, complexes of metals with organic compounds, cyanides,
sulphates, acids from mine drainage, and acid precipitation contaminate
water.
• Many of these compounds are toxic at low concentrations and nonbiodegradable in nature. These cause an adverse effect on aquatic life.
3. Sediments
• Sand, silt, clay and humus together constitute sediments. Sediments enter
the water bodies from municipal sewers; through the surface runoff during
rainy season; and by erosion from farms, deforested slopes, construction
sites and river banks.
• These sediments make the water muddy and block the sunlight penetrating
the water thereby reducing the photosynthesis. It also increases the bed
load which in turn reduces storage capacities of reservoirs, and kills the
aquatic life.
Types of Water Pollutants
4. Thermal Pollution
• Water is an ideal cooling medium because it has high heat capacity
hence used for cooling purposes in many industrial operations.
• This heated water when reaches the water body, raises the
temperature of the aquatic environment causing thermal pollution.
• It causes adversities that affect the life forms. These include: lowering
of dissolved oxygen (DO), acceleration in metabolic reactions of
organism that do not have constant body temperature; death of heat
sensitive organisms, and growth in the number of certain undesirable
micro-organisms.
Types of Water Pollutants
5. Radioactive Pollutants
• Radioactive isotopes, such as Iodine-131, Phosphorus-32, Carbon-14,
Plutonium-248 and Uranium-235, in the form of unstable radioactive
nuclides are used in the research, agriculture, medical and industrial
activities.
• Radioactive substances are released into water bodies from
processing of uranium ore, wastes from research laboratories,
hospitals using isotopes, effluents from nuclear power plant and
fallout generated by nuclear weapon testing.
• Radio-nuclides in the water enter the food chain via aquatic
organisms and bio-magnify in the food chain. If the concentration of
these radioactive nuclides exceed the WHO recommended levels (0.5
Biqa.) in the water, it may cause cancer in humans and have adverse
effect aquatic life.
Sources of Water
• Water is essential to life because it is the major component of the body
tissue. It also serves as solvents. It is a major components of blood.
• Despite water being a blessing, it can be a hazard, when contaminated and
introduced into the body.
• A water supply system has been identified as a domiciliary water supply, in
which water is supplied for part of a larger system of water storage and
water distribution. On the other hand, a locality without water is brought
to the homes from streams, river, carnal and other similar sources.
• Water is usually served by private owned or individually. However, all water
supplies have its origin in rainfall. We have:
a)Surface water which include lakes, ponds, stream etc.
b)Ground water which include spring, borehole and deep wells.
Assurance of Safe Water
1. Mechanical and physical protection of the sources of surface water
e.g. stream, lake, etc
2. Co-agulation and sedimentation by addition of alum, which is a chemical
co-agulate (aluminium sulphate).
3. Filtration and straining with gauze or mechanized screen or tunnel
sand bed. This process removes a large particles but Cyclops bust
cannot be removed.
4. Use of Chlorination which is equal to chemical disinfection. (Addition of
chlorine which kills micro organisms.)
5. Addition of fluoride – This helps in protecting dental carriers.
6. Proper observation of personal hygiene since some of the
organisms needs human begins for some aspect of their development
e.g., guinea warm.
Uses of Water
1. Water is social amenity used to improve quality of health and living.
2. Safe water is the primary necessity existence specifically for social,
economic and industrial existence of people
3. For body function
4. Domestic services
5. Social recreations
6. Transportation
7. Agricultural purposes
Principles of Safe Water
1. Physical qualities
• Freedom from chemical and biological hazards.
• Adequate quantity, which has been estimated at 25-50 litres per person, per day
• Has a ph of 7.0.
• It is colourless.
• It is turbid.
2. Social quality
• It should be palatable and acceptable in taste.
• It is odourless.
• Water is soft (Soap leathers easily)
3. Biological quality/ Bacteriological
•
•
•
•
Absence of algae and protozoa
Absence of coliform organisms.
Absence of E-coli (Escherichia coli)
Absence of forceful streptococci organ
Water Purification/Treatment at Home
• Water from sources such as pond, rain water, shallow well, stream and river
may require purification to make it safe for drinking. This is because water
from the above sources could be polluted by pathogenic organisms.
Objectives of Water Purification
• To remove facial matter present in the water
• To restore the taste of the water
• To prevent fluorosis of the teeth and dental caries
• To remove unpleasant odour from the water
• To destroy pathogenic organisms present in the water
• To remove water turbidity
• To make the water fit to be stored for a long time.
Method of Water Purification at Home
1.Boiling:
• It involves boiling water to kill pathogens and allowing it to cool before
drinking.
• For water drawn from well, it should be filtered after cooling before drinking.
2. Filtration:
• It uses the correct multimedia filters to remove solid unnecessary elements
from the water.
• Chemical and physical absolution processes are used to purify water and it
removes both large and small compounds from the water.
• Filtration retains necessary mineral salts in water after filtration. This may
locally involve sand filter, simple domestic cloth filter, and thick linen filter.
• These filter devices need thorough cleanliness otherwise, they become
source of pollution to the water-
Method of Water Purification at Home
3. Distillation:
• Involves heating to boiling of water and collect pure water in the form of
vapour.
• The vapour from the boiling water is channelled into a container
condensed and then cooled to safe drinking water.
• The advantage: it removes bacteria germs, salts and other heavy metals
such as arsenic, lead, and mercy from the water and it is simple to
practice.
• The disadvantages: It is a slow purification process and it requires much
heat and hence costly
Method of Water Purification at Home
4. Chlorination:
• This is adding chlorine into water to kills parasites, germs, and other
organisms that cause infection in water.
• Liquid or tablet chlorine could be used and both are cheap and effective.
People with thyroid problems are not advised to treat their water with
chlorine.
• Chlorine tablet is better used in heated water since it dissolves easily.
5. Sedimentation:
• This involves the addition of aluminium sulphate to water flocculate all
suspended matter in the water.
• It allows after particles to settle fast leaving the water very clean and safe
for drinking.
Method of Water Purification at Home
• PH correction: Lime is introduced into a filtered water to minimize
corrosion in the water liquid iodine and iodine tablet. To purify water, little
amount of liquid iodine and iodine tablet could be used. This method is
used in filtered water to be used for a very short term because iodine could
become harmful to the body if the water is kept for a long time.
• Non-chemical stabilized oxygen: Adding drops of stabilized oxygen in the
water. It is a natural antibiotic that can be bought from the market as a
tablet.
• Solar Disinfection: It involves heating the polluted water under the sun.
Get a bottle and fill it up to three quarters. Shake the water for about 2030 seconds before filling it up with water. Close the bottle tightly and put in
the direct sun’s rays for minimum of 6-8 hours before
SELF-ASSESSMENT EXERCISE
1.Discuss the principles of safe water.
2 List and discuss the sources of water pollution.
3. Discuss any three methods of water purification at home
4. What are the objectives of water purification?
UNIT 3
NOISE POLLUTION
OBJECTIVES
By the end of this unit, the student should be able to:
1. Define noise pollution and state the factors that influence
individual’s reaction to noise.
2. Describe the measurement of noise.
3. State the sources of noise.
4. Identify the health effects of noise.
5. List the benefits of noise.
6. Discuss the measures for controlling noise pollution.
Definition of Noise Pollution
• Noise pollution is an unwanted or extraneous sound made by such
products of civilization as trucks, air-planes, industrial machinery
and so on.
• Sound which is acceptable to an individual may not be acceptable to
another and sound which is acceptable in the morning may not be
acceptable in the evening.
• Noise is being measured in decibels. It may adversely affect human
being physiologically and psychologically and because it is an insidious
pollutant, damage is usually long range and permanent.
Definition of Noise Pollution
Factors that Influencing Reactions to Noise
1. Frequency - The higher the frequency the greater the annoyance.
2. Loudness - The louder the noise, the greater the nuisance. It has been
found that there is a general dislike to noise related to loudness than any
other factor.
3. Unexpectedness - Noise which is not expected is annoying.
4. Uncertainty of direction and Unfamiliarity - It is always normal and
natural to experience a sense of unrest until the direction and source of
noise is established.
5. Irregularity and Duration - Noise which is not regular and smooth is
annoying.
6. Necessity - if the noise is thought to be unnecessary, it is annoying.
7. General State of Health - Poor health or emotional instability lowers the
tolerance level of acceptability.
8. Level of background Noise - The difference between a noise and
the background noise is very important. The greater the difference the
greater is the annoyance likely to be.
Measurement of Noise
The figure 2: Scale for measure
sound
• Sound is measured in decibel (DB)
• The higher the value of sound the
higher the noise and vice versa.
• In some countries, the environmental
authorities have banned heavy
sounds in public.
Sources of Noise
1. Construction Noise - All the activities that involve the sitting and
use of temporary static equipment and of mobile plant.
2. Road Traffic Noise
3. Air Craft Noise
4. Train Noise
5. Occupational Noise
Health Effects of Noise
• In the human ear , the sound pressure waves caused by vibrations the ,
physically amplified in the meddle and transmit into the inner ear.
• Prolonged exposure to noise of a certain frequency pattern may cause:
Temporary hearing loss or permanent loss ..
1. Repeated noise over a long period of time results to
permanent threshold shift. This happens most in industrial
environment where people are subjected to noise of a certain frequency.
2. Noise also affects the functioning of the cardiovascular system.
3. It alters the rhythm of the heartbeat
4. It makes the blood to thicken and it dilates blood vessels.
Health Effects of Noise
5.
6.
7.
8.
It affects the focusing of the eyes
Excessive noise also causes headache and irritability.
It delays recovery from illness
It interferes with concentration making the individual unable to
achieve his or her goal.
9. It can arouse fear or insecurity.
Benefits of Noise
1. It can help in stimulating someone who is drowsy
2. It can be used to attract attention
3. It can serve as an indicator that something is going to
happen
Control of Noise
1. A code of practice has to be issued for the guidance of industries and
authority and on operation and construction site for industries.
2. Health educating the masses on the effects of noise.
3. Motivating community actions against noise related problems.
4. To mount programme, campaign and conduct researches on noise
related issues.
5. Removal of noise source from areas where people live to a lonely zone.
6. The Environmental Health Department should co-operate with the
Town Planning in the control of development to avoid noise pollution in
the environment.
SELF-ASSESSMENT EXERCISE
1. Define noise pollution
2. List and describe any four factors that can influence individual’s
reaction to noise
3. Describe the measurement of noise in decibel (DB)
4. Identify the sources of noise
5. What are the health effects of noise?
6. What measures could be adopted to control noise?
UNIT 4: SOIL POLLUTION CONTENTS
OBJECTIVES
By the end of this unit, the students should be able to:
1. Define soil pollution and state the causes of soil pollution
2. Discuss the effects of soil pollution
3. Discuss the measures for controlling soil pollution
Concept of Soil Pollution
• Soil pollution is also called land pollution.
• Soil is part of the environment that is essential to man. It is on the
soil that plants grow what man eats and that is where we live and
conduct all our activities. Aesthetic lack of the soil also enhances the
beauty of nature.
• Soil suffers pollution due to the activities of man like agricultural and
industrial activities are producing toxic chemicals; and that of nature
like dead plants and carcasses of animals which can fertilize and
enrich the soil but also produce toxins that pollute the soil.
Concept of Soil Pollution
Causes of Soil pollutions
1. Waste disposal/Landfills:
• Waste originates from two sources: man-made waste and natural waste.
Man-made domestic wastes and industrial wastes.
• Domestic wastes like urine and feaces are dumped directly into landfills and
not channeled to central sewage treatment centre. These contain toxic and
chemicals which cause soil pollution.
• Industrial activities: This is has caused great problems to the soil due to the
proliferation of manufacturing industries in the environment.
• The extraction industries for coal and iron mining extract minerals and
dumped into the landfill or sometimes leave on the soil surface by-products
causing soil pollution.
• Most of garbage disposed in landfills including metals, plastic, paper, cloth,
wood, containers, discarded manufactured products, chemical fertilisers,
dried sludge and sewage cannot be recycled- Non-biodegradable.
Causes of Soil pollutions
2. Agricultural activities:
• Production of varieties of pesticides, fungicidesand fertilizers with chemicals that
are hostile to the soil and the soil cannot break them down or absorb them. They
mix with rain water and seep into the soil and gradually destroy the fertility of the
soil.
• Irrigation practices may lead to water logging, closing the air passages in the soil
and stops the growth of the soil organisms which makes the soil barren.
3. Acid rain:
• Pollutants present in the atmosphere mix up with rain and fall on the ground and
results to acid rain. This acid rain water dissolve soil nutrients and can change the
soil structure.
• Soil microbes are unable to adapt to the low pH and are killed. Acid rain also
mobilises toxins, and leaches the essential nutrients and minerals, such as
magnesium deep into the ground.
4. Oils spills:
• Oil spills affect soil around oil industries and fuel stations due to chemicals which
contaminate the quality of soil and destroying the chemistry of the soil.
Causes of Soil pollutions
5. Deforestation:
• Deforestation is the permanent removal of a forest or trees. Due to this, the soil is
left exposed and the topsoil becomes saturated with water, loosens and slides off
leading to soil erosion and lacking nutrients.
6. Overgrasing:
• Overgrasing disturbs the ecosystem, reduces biodiversity, alters the feeding and
breeding patterns of birds, mammals, reptiles and insects. Subsequent
encroachment by desert plants makes the soil barren.
7. Mining activities:
• The mining process involves digging of the ground to extract minerals.
• Metal toxicants get deposited during this process, which contaminates the mining
land and makes it barren.
8. Other factors:
• Some other causes of soil pollution are seepage from landfills, discharge of
industrial effluents, transportation and storage of oil, percolation of
contaminated water in to the soil, and leakage of underground storage tanks,
pipe lines etc.
Effects of Soil Pollution
Almost all aspects of our daily lives are dependent on the soil and when the soil is
polluted, man bears the greatest brunt:
1. Polluted soil affects the plants that supply man food, the ability of plants to
produce seeds, leading to hunger and famines
2. Crops and plants that are grown on polluted soil absorb the pollution
from the soil and pass it to man, resulting to acute and chronic illnesses.
3. Man’s exposure to a polluted soil for a long period of time can cause change in
his genetic make-up.
4. Polluted soil emits some poisonous substances into the air which causes
serious respiratory health problems to man when inhaled
5. Polluted soil can affect livestock, if exposed for a long time and it can lead to
food poisoning.
6. Methane production: Organic wastes in the landfills undergo anaerobic
decomposition and produce biogas that consists of methane, hydrogen and
carbon dioxide, which is a highly flammable mixture. This can cause fire
accidents.
Effects of Soil Pollution
7. Fungi and bacteria that line in the soil and bind the soil together. The
pollutant changes the chemistry of the soil which affects the organisms
and hence the fertility of the soil, unfavorable for plants to grow.
8. Toxic chemicals pollutants in the soil reduces soil fertility. This makes fruits
and vegetables produced in such soil hazardous, lack required nutrients
and it may cause illnesses to the consumers.
9. Many soil organisms die as a result of toxic chemicals in the soil.
10. Soil erosion: It leads to the loss of top soil and humus and makes it less fertile
for agriculture. The area becomes deserted. The eroding soils enter into the
streams and rivers, killing fish and damaging the ecosystems.
11. This can result to change in the soil structure.
12. The toxins in polluted soil can percolate gradually and continuously
into the water table and poison the underground water.
13. Biomagnification: The toxins in the contaminated soil, which are consumed
by the animals and plants, make their way into the ecosystem. With each
higher trophic level the concentration of the toxins increases, This process is
known as biomagnification and is a serious threat to the environment,
Control Measures for Soil Pollution
• Reduced use of chemical fertilizers.: Excess use of fertilizer pollutes the soil and
destroys the pH level of the soil and the needed microorganisms in the soil. It is
therefore necessary that the soil be nurtured naturally to improve its fertility
and quality.
• Use of natural manure: Natural manure should be advocated for in place of
fertilizer which provides the soil with the required nutrients and does not
produce toxins to the soil.
• Proper waste management: waste products from homes and industries should
be properly managed. Obnoxious methods such as burning of refuse, and open
dumping should be discouraged
• Involve community members in controlling soil pollution: This will help
proffer solutions and adopt suggestions for controlling the soil pollution.
• Avoid deforestation: There is need for the environment to go green.
Deforestation leads to soil erosion and wasting away of soil nutrients. There is
need for reforestation of deforested land and aforestation for barren land.
Control Measures for Soil Pollution
Advanced Measures for Control
1. Bioremediation:
• Polluted soil could be reclaimed by treating it with micro-organisms, such as
fungi, yeast and bacteria. This process breaks down the hazardous substances
into less toxic substances, such as carbon dioxide and water.
2. Integrated Solid Waste Management:
• It is a complete waste reduction, collection, composting, recycling, and disposal
system. This system should be implemented for the industrial and municipal solid
waste.
3. Pyrolysis:
• This is process that decomposes organic compounds using heat. It could be used
in place of incineration for burning the solid waste.
4. Phytoremediation:
• In this process plants are used to immobilise, convert, or remove industrial
contaminants. Plantation prevent wind erosion, leaching, surface water runoff
and erosion, which break or weaken pollutant linkages between contamination
source and receptor.
SELF- ASSESSMENT EXERCISE(S)
1.
2.
3.
4.
What is soil pollution?
Discuss the causes of soil pollution.
Identify any 3 measures for controlling soil pollution.
Discuss the effects of soil pollution.
UNIT 5: RADIATION POLLUTION
OBJECTIVES
By the end of this unit, the students should be able to:
• Define radioactive pollution and state the sources of radioactive
pollution
• Explain the uses of radioactive materials
• Discuss the effects of radioactive pollution
• Discuss the measures for controlling radioactive pollution
Concept of Radioactive Radiation
• Radiation is the phenomenon of propagation of energy in the form of
particles or waves through matter or space.
• The energy of the radiation from any source is related to its
wavelength. The shorter the wavelength, the higher the energy and
the longer the wavelength, the lesser is the energy.
• The schematic representation below enable understanding of the
entire electromagnetic spectrum.
• The energy of radiation in UV or X-ray region will be much more than
the energy of radiation in the visible and radio-wave region.
Concept of Radioactive Radiation
Figure 1: Electromagnetic spectrum
Definition of Radioactive Radiation Pollution
• Radioactive materials are certain substances in nature that have a
tendency of emitting radiations (alpha, beta, gamma, electron, proton
and neutron).
• Gamma rays are highly ionization energy radiations without charge but
and are more penetrating than X-rays and travel very far through the
medium.
• X-rays are high energy ionising radiations not emitted by a radio isotope.
• Radioactive contamination/pollution, is the deposition of, or presence of
radioactive substances in the environment (including the human body),
where their presence is unintended or undesirable/harmful to organisms.
Sources of Radioactive Pollution
• There are two main sources of radiation pollution are:
a) Natural sources of radiation:
• These include atomic radioactive minerals, cosmic rays and radioactive
elements. Rocks, sediments and soils containing minerals, such as uranium emit
radioactive rays.
• Cosmic rays are high energy ionising electromagnetic radiation.
• Radioactive isotopes of elements occurs in the lithosphere in the lithosphere
(rocks).
• Water contamination occurs when it encounters soils and rocks containing
radioactive minerals.
b) Authropogenic Sources of Radiation:
• These are human activities, which cause radiation pollution.
• These include radiations used for diagnostic applications,
industrial/pharmaceutical tests, nuclear explosion tests, leaks from nuclear
reactors, and nuclear weapons.
Effect of Radiation on the Human Body
The two types of effects are:
• Genetic Effects: Radiations cause genetic damage- alters the genes
and chromosomes . The effect may become visible as deformations in
the offspring . These changes and alterations in DNA (the molecule
containing genetic information), is called mutation.
• Non-genetic Effects: These are seen as birth defects, bums, several
types of leukemia, miscarriages, tumors, cancer of one or more
organs, and fertility problems. The effect of a few types of particles
and radiation on humans is presented in Table 4.1
The Use of Radioactive Materials in Medicine
• The radiation and radio-isotopes are used for diagnosis and treating
disease, test new drugs and conduct research for cures for disease.
• Radiology X-rays are used to diagnose bone fractures under
Radiology. Radiology includes specialised areas like mammography,
computerised tomography (CT), and nuclear medicine.
• Nuclear medicine uses radiation to provide diagnostic information
about the functioning of a person's specific organs, or to treat them
e.g. cancer.
• The medical procedures which use radioactive material generate
radioactive waste with varying level of radioactivity.
Control of Radiation Pollution
The following measures could reduce the effects from radiations:
1. Atomic explosions should not be carried out in the atmosphere.
2. It should be ensured that no radiation leakage through nuclear
reactor coolant occurs.
3. Radioactive wastes from nuclear reactors or Industrial wastes
should be disposed off in specially built tanks or permanently
stored in deep mines until it decays to the same radioactivity level
as that of a natural uranium mine.
4. Production and use of radioisotopes should be minimum and only
for very essential purposes.
Control of Radiation Pollution
5. The number of nuclear installations should be minimized so as to
limit the emission of radio-pollutants.
6. Fission reactions should be minimized.
7. Nuclear mines should be protected for radiation leakage.
8. Working places at radioactive emissions sites should have high
chimneys and good ventilation systems.
9. Radon leakage should be monitored and protection measures can
be installed in buildings and residences.
UNIT 5 FOOD HYGIENE AND POLLUTION
OBJECTIVE
By the end of this unit, the student should be able to:
1. Discuss the term food hygiene
2. Identify the causes of food pollution
3. Mention the effects of food pollution
Description of Food Hygiene
• Food is any substance either in liquid or solid form which when taken
into the body system, nourishes the body, promote growth and
development and sustains life.
• Food hygiene refers to all sanitary measures, including principles and
procedures adopted to ensure that food is free from agents of
contamination or pollutants causing diseases or illnesses.
• Food hygiene practice is a sure means of protecting the food from
pollutants or infective agents in order to promote health and wellbeing.
Aim of Food Hygiene
• The major aim of food hygiene is to avoid pollution of food and
prevent diseases caused by polluted food.
• To affect this, the environmental health officers are professionally
trained to carry out the duties of ensuring that food is safe for
consumption.
• They carry out the following roles in order to achieve the aim of food
hygiene:
1. Enforcement of good hygiene rules and regulations.
2. Advice on the required standard to be achieved regarding the
rules and regulation guiding food hygiene.
3. Caring out health education on food hygiene to food handlers.
Principles of Food Hygiene
a)
• (i)
• (ii)
• (iii)
• (iii)
• (v)
• (vi)
Overall personal hygiene;
Washing of hands
Wearing protective cloth
Covering one cuts or boils in the body
Cutting the finger nails
Avoid sneezing or coupling over food
Avoid touching the mouth, nose and face.
Principles of Food Hygiene
b) Growing of foods:
• Crops, fruits and vegetables should not be planted in a polluted soil or
near polluted wear table.
• The use of pesticides, and herbicides should be avoided.
• Polluted water should not be used for the irrigation of growing plants.
• Use of fertilizer should be discouraged.
c) Storage:
•
•
•
•
•
Food stores must be well ventilated.
The temperature should be below 10oc.
Stored items and the storing items must be checked regularly.
Good and quality storing system should be adopted.
Good packaging
Principles of Food Hygiene
d) Preparation:
• Wear apron and cover your hair, mouth and nose while preparing food.
• Food utensils should be properly cleaned and sterilized before use.
• Environment (kitchen) where food is being prepared should be kept
clean.
• Wash your hands before cooking packing food.
• Do not touch your face while you cook or package food.
• Wash your vegetables and fruits in clean running water.
Principles of Food Hygiene
e)
Serving:
• Wear apron and cover hair.
• Do not cough or sneeze when serving food.
• Food being served should be properly covered and served in a tray and not
bare hands.
• Do not serve in absentia.
• Cutleries should be wrapped with serviette and kept on the tray.
g)
Eating:
• Wash your hands properly before eating.
• Sit in a relaxed position to eat your meal.
• Do not talk when you are eating.
• Do not sneeze or rob your face as you eat.
• Eat in a clean environment.
Food Pollution
Food pollution
• This is the presence of toxic chemicals or biological contaminants in food which
were either not naturally present in the food or were present but above the
natural background levels.
• This implies that some food contain toxic chemical in their natural form but
when it is present in the food above its normal level, it in-turn pollutes the food
e.g. cassava.
• Cassava contains cyanogenic glycosides, which can result in fatal cyanide
poisoning if not properly detoxified by soaking, drying, and scraping before
being consumed.
• Aflatoxins are a family of toxins produced by certain fungi of genus Aspergillus.
They are found on agricultural crops such as maize (corn), peanuts,
cottonseed, and tree nuts, which are abundant in warm and humid regions of
the world
Food Pollution
Fig 5: Uncovered food allows contamination with pollutants
Causes of Food pollution
• A lot of factors cause food pollution any alteration in the principles of
hygiene leads to food pollution.
• Growing of food (e.g. crops, fruits, vegetables) in polluted soils, solid
wastes (e.g. mine tailings) or areas with polluted groundwater;
• Irrigation of grown food (e.g. vegetables, fruits, crops) with
• Growing of food (e.g. crops, fruits, vegetables) in areas with polluted air;
• Agricultural treatments with pesticides;
• Agricultural application of sewage sludge and/or polluted fertilizers
(which contain ash from power plants);
• Consumption of polluted water and/or food by fish or other animals;
• Food processing, packaging, and handling;
• Propagation and concentration of pollutants through the food chain.
Effects of food pollution
• It causes mild to severe food illnesses and could result to serious
health problems such as hormonal and mental health problems in
the body system of the consumer.
• It can induce problem of the nervous system when the food is
polluted by pesticides.
• Consumption of highly polluted food leads to food poisoning and
death, which occurs instantly.
• Consumption of polluted food can trigger other health-related
problem in the body and this could sometime be life-treating
diseases.
SELF-ASSESSMENT EXERCISES
1. List the principles of food hygiene
2. Discuss the effects of food pollution
3. Define the following terms:
a) Food hygiene.
b) Food pollution.
3. What are the aims of food hygiene?
The End Of Module 2
Thank You