An environmental hazard is a substance, a state or an event which has the potential to threaten the surrounding natural environment/ adversely affect people’s health, including pollution and natural disasters such as storms and earthquakes. The environmental hazards deals with the concept that are caused by air, water, soil and radioisotopes. Air pollution occurs when the air contains gases, dust, fumes or odor in harmful amounts. Water pollution is the contamination of water bodies. Contamination of soil by human and natural activities which may cause harmful effects on living beings.
3. INTRODUCTION
• An environmental hazard is a substance, a state or an event
which has the potential to threaten the surrounding natural
environment/ adversely affect people’s health, including
pollution and natural disasters such as storms and earthquakes.
• Any undesirable change in the physical, chemical or biological
features of air, land and water is called pollution.
• Any physical, chemical or biotic component/ agent or non-
living substance that is responsible to bring about an
undesirable change in the environment is called pollutant.
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4. AIR POLLUTION
Definition: Any atmospheric condition in which substances
are present at concentrations high enough above their normal
ambient levels to produce a measurable effect on man,
animals, vegetation or materials is called air pollution.
• It is when concentrated gases exceed safe limits.
• Air pollutant: It is a substance or effect dwelling
temporarily or permanently in the air , which adversely
alters the environment by interfering with the health, the
comfort, or the food chain, or by interfering with the
property values of people.
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6. SOURCES OF AIR POLLUTION
• Air Pollution may originate from a natural or anthropogenic
source or from both sources.
• natural source – an erupting volcano, accidental fire etc.
• Man- made- industrial units, thermal power plants,
automobile exhausts, fossil fuel burning, mining, nuclear
explosions.
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7. CAUSES OF AIR POLLUTION
Carbon monoxide
• colorless,
odorless,
tasteless gas.
• Volcanoes, natural
gas emissions, seed
germination
contribute to CO
carbon dioxide
• Fossil fuel
combustion
• Effect on
climate,
increase
global temp
Oxides of
nitrogen
• Fuel
combustion
in
automobiles
and
industries
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Primary air pollutants
8. • Secondary air pollutants
o Smog: Air pollution in urban and industrial areas.
o Photochemical smog: a noxious mixture of gases and particles, is
produced when strong sunlight triggers photochemical reactions in
the atmosphere.
o The major component of photochemical smog is ozone.
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9. EFFECTS OF AIR POLLUTION
• Human effects: eg: diseases
• Environmental Effects
o Acid rain
o Ozone Depletion
o Global Climate Change
a. Green- house effect
b. Global warming
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10. WATER POLLUTION
• Water pollution is defined as alteration in physical, chemical or
biological characteristics of water, making it unsuitable for
designating best use in its natural states.
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11. CAUSES OF WATER POLLUTION
1. Industrial wastes: All the industries discharge the waste by-
products from the manufacturing processes into rivers or other
water bodies.
2. Domestic sewage: It consists of water borne wastes of the human
community. Mostly it is disposed off as such in treated, partly or
untreated form in nearby lakes, rivers or sea, where it causes
pollution.
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12. 3. Thermal and Radioactive Waste: Different industries and
nuclear power plants use water and discharge the heated water into
nearby water bodies.
4.Biodegradable and Non-Biodegradable Waste:
Biodegradable pollutants consist mainly of organic matter from
domestic sewage.
Non-biodegradable wastes includes plastic bags, long chain
detergents, aluminium cans, glass etc.
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13. EFFECTS OF WATER POLLUTION
• Physical effects:
o Settled particles may slowly accumulate on vegetation foliage and
produce a deposit on the river bed.
o Small suspended particles make water turbid and reduces light
penetration, reduces photosynthesis and restricts plant growth.
• Chemical toxic wastes:
a. Toxic metals: Heavy metals eg: Iron, lead, mercury, cadmium,
zinc etc
b. Acid and alkali toxins: These may be regarded as hazardous
because they lower or raise the pH value of water.
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14. c. Pesticide toxins: Hazardous pesticides are the organochloride
compounds because of their stability and persistence in the
environment.
• Chemical nutrient effects: In water pollution, the two most
important nutrients are nitrogen and phosphorous usually present
in nitrates and phosphates.
• Microorganism effect: Wastes that are discharged into water
contain pathogenic organisms that are capable of causing human
diseases. Eg: cholera, typhoid fever, bacillary dysentery etc
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15. CONTROL MEASURES FOR WATER POLLUTION
• Prevent or minimize the mixing of pollutants into water
bodies.
• Maintenance and restoration of water of all types, such as
surface water and ground water.
• Industries should treat their effluents before they dispose it
into water bodies.
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16. SOIL POLLUTION
• Contamination of soil by human and natural activities
which may cause harmful effects on living beings.
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17. CAUSES FOR SOIL POLLUTION
• Natural causes: Landslides, Hurricanes
• Man-made causes
o Urbanization: Contamination of soil due to waste water. Unfit
for agricultural land due to construction of dams , project in
near by places.
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18. • Industrial wastes: Discharge of large quantities of toxic,
flammable, non-biodegradable substances on land results in soil
pollution.
• Mining: Mining refers to process by which nonrenewable
substances and valuable minerals are extracted from earth. It leads
to change in composition of soil.
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19. • Domestic waste: It includes wastes such as food wastes, paper,
glass, plastic materials. Contribute to soil pollution.
• Radioactive waste: Nuclear power plants, nuclear testing, and
explosion.
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20. EFFECTS OF SOIL POLLUTION
• Disposal of industries wastes on fertile lands degrades the
quality of soil.
• Urban waste slowly poison the soil, damaging its fertility.
• Radioactive elements that present in polluted soil enter food
chain through plants.
Causes
• Planting of trees must be encouraged.
• Solid waste can also be used for electricity generation.
• Use of chemical fertilizers and pesticides should be minimized.
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21. METHODS TO CONTROL SOIL POLLUTION
• Reducing chemical fertilizer and pesticide use.
• Recycling is another way to reduce and control soil
pollution.
• Reusing of materials
• De-forestation, the cutting down of trees, causes erosion,
pollution and the loss of fertility in the topsoil.
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23. SOURCES OF RADIOACTIVE POLLUTION
• Natural sources
o Cosmic Radiation
o Terrestrial Radiation
o Internal Radiation
• Man-made sources
o Production and research of nuclear weapons
o Mining of radioactive ore
o Medical waste
o Nuclear power plants
o Industrial radiography
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24. • Production of nuclear weapons: Radioactive materials used in
this production have high health risks and release a small
amount of radioactive pollution.
• Mining of radioactive ore: Mining of these involves crushing
and processing of the radioactive ores and this generates
radioactive waste which emits alpha particles.
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25. • Medical waste: A number of radioactive isotopes are used in
medicine, either for treatment or diagnostics.
• Nuclear power plants: Nuclear power plants under current
standards produce little radioactive pollution due to safety
precautions that must be adhered.
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26. CONTROL OF RADIOACTIVE POLLUTION
• Prevention of leakage of radioactive elements from the nuclear
reactor.
• Proper storage and disposal of nuclear wastes.
• Regular monitoring and high risk analysis.
• Global understanding about nuclear exposure.
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27. CONCLUSION
• A hazard is a situation that poses a level of threat to life,
health, property, or environment.
• 'Environmental hazard' is the state of events which has the
potential to threaten the surrounding natural environment
and adversely affect people's health.
• Air pollution has long been a serious problem in the world.
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28. REFERENCE
• https://www.ncbi.nlm.nih.gov/pmc/articles (accessed on 6
march 2019)
• https://www.jacionline.org/article (accessed on 5 march
2019)
• https://www.pharmatutor.org/articles/discussion-
radiosotope-radiopharmaceutical-uses (accessed on 7
march 2019)
• https://www.omicsonline.org/scholarly/water-pollution-
journals-articles-ppts-list.php (accessed on 6 march 2019)
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29. • Dr. M.K Gupta, Dr. Manish Jaimini, Vikas Pandey,
Environmental Science, Nirali Prakashan, 1st edition, P:
3.1-3.23
• Dr. Kishore R. Pawar, Dr. Sachin B. Narkhede,
environmental sciences, Vandana publications, 2nd edition,
P: 3.1-3.3
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