This document discusses various topics related to water pollution and water quality. It addresses the following key points: 1. Water pollution can come from a variety of sources including dissolved gases, agricultural and industrial wastes, sewage, and subsurface geology. 2. Polluted water can pose biological hazards like bacteria, viruses, protozoa, and helminths that can cause diseases. It can also cause other health issues due to chemical imbalances. 3. Water quality is determined by assessing physical, chemical, bacteriological, and radiological characteristics. This includes measuring turbidity, odor, taste, dissolved oxygen, microbiological indicators like E. coli, and radioactive elements. 4. Biochemical oxygen

1. Water Pollution and its Hazards…
By:
SHAHINA BANO
Water to drink.
66% of the human body is made up of water.
At just 2% dehydration your performance decreases by around 20%.
We should drink at least 2 litres of water a day.
Clean Water
The number of people with access to clean water has doubled in the last 20 years.
1.1 billion people in the world still do not have access to safe water. This is nearly 20% of the population.
Water Future
The UN estimates that by 2025, 75% of the world population won’t have reliable, clean water.
Saving Water
Do you leave the tap on when you clean your teeth? You waste 5 litres of water.
You only need ¼ litre!
Water Diseases
80% of all illness in developing countries is caused by water related diseases.
90% of wastewater in developing countries is discharged directly into rivers and streams without treatment.
World Water Uses
22%
8%
70%
0
10
20
30
40
50
60
70
80
Agriculture Domestic Industry
Water uses
%
of
total
water
used

2. Water Pollution- A Glance…
Water Pollution
• 1. Dissolved gases ( CO2, SO2, H2S, NH3)
• 2. Agricultural Pollutants ( Fertilizer )
• 3. Industrial wastes
• 4. Sewage
( decomposing organic water & pathogenic agents)
• 5. Sub – soil geology
Hazards of polluted water
• 1. Biological hazards
• A. Bacterial: Typhoid, Cholera, Bac: Dysent:
• B. Viral: Polio, Hepatitis A & E
• C. Protozoal: Amoebiasis, Giardiasis
• D. Helminthic: Round worm, Whip worm,
Hydrated disease
• E. Leptospiral : Weil’s Disease
• F. Cyclops : Guinea worm
• 2. Other hazards:
• GIT disturbances ( due to Na, Mg & Ca ions)
E.g:- MgSo4, Lead to Diarrhoea
• Lead poisoning
• Iodine Deficiency
• Fluorine Deficiency

3. • Hardness of water
• Infant met haemoglobinemia
Criteria for water Quality
• 1. Physical Qualities
• 2. Chemical Qualities
• 3. Bacteriological Indicators
• 4. Radiological standards
1. Physical Qualities
Turbidity : Must be free from turbidity
Color : Must be free from color
Odour : Disagreeable odour ( No odor)
Taste : Must be palatable
Turbidity measurement
Nephelometric Turbidity Units (NTU’s)?
2. Chemical Qualities
Ammonia: Free / up to 0.05 mg / L
Nitrites : Zero
Nitrates: up to 1 mg / L
Dissolve O2: Not less than 5 mg / L
Cl : standard 200 mg / L
O2 absorbed : at 370C in 3 hours
Hardness: not exceeding 300mg / L

4. 3. Bacteriological Indicators
• E. coli and coli form group must not be detected in 100 ml sample of water
• Fecal streptococci presence shows recent contamination of water
• Clostridium perfringens presence in water suggests that Fecal contamination has been occurred
at some remote time
E. coli are bacteria, full name is Escherichia Coli
4. Radiological standards
• Gross alpha activity 0.1 Bq / L ( upper limit )
• Gross Beta activity 1 Bq / L ( upper limit )
Dissolved oxygen as an indicator of oxygen content in water …
• Animals and plants that live in an aquatic habitat depend on oxygen dissolved in the water for
their survival. Oxygen is not very soluble in water, and the amount that does dissolve also
depends on the temperature of the water.
• Dissolved oxygen (often abbreviated DO) is used as an indicator of oxygen content in water. It is
measured as percentage saturation of oxygen.
Biochemical Oxygen Demand (BOD)
• This is the amount of oxygen required to break down the organic matter present in the water
sample.
• The oxygen is required by microorganisms, such as many forms of bacteria, to break down the
organic matter that constitutes their food.
Biochemical Oxygen Demand (BOD) as an indicator of the extent of water pollution
• Ultimately, given near normal condition ad enough time, the micro-organisms will convert huge
quantities of organic matter into the following end products like carbon dioxide, water,
nitrogen, etc.

5. BOD can thus be used as an indicator of the extent of organic pollution. If water has a high BOD,
it indicates that a lot of organic waste is present and a lot of oxygen is required to break down
the waste. A low BOD indicates the presence of small amount of organic matter and there is a
little organic pollution.
Have a nice day...