3. SOURCES OF WATER POLLUTION
Point Source: Any single identifiable source of
pollution from which pollutants are discharged
Non point Source: Sources of pollution are
scattered or diffuse and can not be readily identified
5. POINT SOURCE
• Pollution occurs from a single
• Discharge of effluents occurs at
• Effect is high
• Easier to manage and control
• Ex. Industries, faulty treatment
plant, oil tank spills, sewer
NON POINT SOURCE
• Pollution occurs through many
• Caused by discharge of
pollutants over a wide area
• Effect is low
• Very difficult to manage and
• Ex. Farming pesticides and
fertilizers, road salt runoff etc.
6. CLASSIFICATION OF WATER POLLUTANTS
On the basis of their source
(a) Natural Pollutants : The pollutants released in
environment due to natural activities like Volcanic
eruption, forest fire, storms, decomposition etc.
(a) Man-made (anthropogenic) Pollutant : The
pollutants produced by different human activities like,
Industrialisation, urbanisation, deforestation, mining, use
of fertilizers and pesticides etc.
7. CLASSIFICATION OF WATER POLLUTANTS
On the basis of nature of material
(a) Biodegradable : The pollutants which are
Ex. Sewage, wood, paper, garbage, cardboard etc.
(a) Non-biodegradable : The pollutants which can not
be decomposed naturally or degrade at very slow rate
Ex. DDT, Plastic, glass, E-waste etc
8. CLASSIFICATION OF WATER POLLUTANTS
On the basis of their concentration in nature
(a) Quantitative pollutants : The pollutants which
normally occur in environment but become pollutants if
their concentration increases than allowable limit.
Ex. CO2 in atmosphere
(a) Qualitative pollutants : The pollutants which do
not occur naturally in environment and added by human
Ex. Pesticides, Insecticides etc.
9. CLASSIFICATION OF WATER POLLUTANTS
On the basis of form of pollutant
(a) Primary pollutants : The substance which remain in
same form in environment
- Also, called as direct pollutants
Ex. Smoke, dust, ash, hydrocarbon etc
(a) Secondary pollutants : The substance which are
formed from primary pollutants.
- Considered more toxic than primary pollutants
Ex. SO3 , Ketones, Ozone, aldehydes, PAN (Peroxyacyle
10. WATER QUALITY STANDARDS
• The water quality is physical , chemical and
biological properties of water.
• The water quality defines on the basis of its
• Different type of water use require different level
of water purity like, drinking water requires
highest standards of purity while irrigation and
hydropower generation requires lower quality
11. WATER QUALITY STANDARDS
1. Physical Parameters:
- The parameters which respond to the sense of
sight, taste and smell.
- The user can judge water quality by its physical
2. Chemical Parameters:
3. Biological Parameters:
13. WATER QUALITY STANDARDS
1. Indian Standard Institution (ISI)
2. World Health Organization (WHO)
3. Indian Council of Medical Research (ICMR)
4. United States Public Health Services (USPHS)
14. Physical Parameters
• Pure water is colorless. Therefore any types of color appearance in water
indicates water pollution.
• Natural water system is often colored by foreign material. If color is due to
suspended material, it is called as apparent color. Color given by dissolved
material that remains even after removal of suspended material is called
true color or real color
• Materials decayed from organic matter, namely, vegetation and inorganic
matter such as soil, stones, and rocks impart color to water, which is
objectionable for esthetic reasons, not for health reason.
• Color is measured by Tintometer. Permissible limit is 15 Hazen units.
15. Physical Parameters
Taste & Odour
• Pure water is always tasteless and odorless. Therefore if any types of taste and
odor is present, it indicates water pollution.
• Water taste and odor may develops due to natural or artificial regions.
• Artificial region for taste and odor in water is due to (chlorination). Some natural
impurities dissolved in water can also give taste and odor.
• Inorganic salts such as NaCl, KCl etc dissolve in water give taste whereas
compounds like H2S can give both taste and odor.
• Compounds giving taste and odor to water may be toxic to consumer, so drinking
water should be taste less and odour less.
16. Physical Parameters
• Total Suspended Solids (TSS) are solids in water that can be trapped by a
filter. TSS can include a wide variety of material, such as silt, decaying plant
and animal matter, industrial wastes, and sewage.
• High concentrations of suspended solids can cause many problems for
stream health and aquatic life.
• Total suspended solids (TSS) are particles that are larger than 2 microns
found in the water column. Anything smaller than 2 microns (average filter
size) is considered a dissolved solid.
17. Physical Parameters
• High TSS can block light from reaching submerged vegetation. As the
amount of light passing through the water is reduced, photosynthesis
slows down. Reduced rates of photosynthesis causes less dissolved
oxygen to be released into the water by plants.
• If light is completely blocked from bottom dwelling plants, the plants will stop
producing oxygen and will die. As the plants are decomposed, bacteria will
use up even more oxygen from the water. Low dissolved oxygen can lead to
• High TSS can also cause an increase in surface water temperature,
because the suspended particles absorb heat from sunlight. This can cause
dissolved oxygen levels to fall even further (because warmer waters can
hold less DO), and can harm aquatic life in many other ways,
18. Physical Parameters
• Pure water is clear and do not absorb light.
• Turbidity is the cloudiness of water. It is a measure of the ability of light to
pass through water.
• It is caused by suspended material such as clay, silt, organic material,
plankton, and other particulate materials in water
• Some materials that give turbidity may be toxic to consumers. Therefore
turbid water is not suitable for drinking purposes.
• Turbidity prevents penetration of light into deeper layer of natural water
system that directly affects photosynthetic organism in bottom.
• Drinking water should have turbidity less than 5 NTU (Naphthalometric
19. Physical Parameters
• Turbidity is measured by an instrument called nephelometric turbidimeter,
which expresses turbidity in terms of NTU or TU.
• Turbidity more than 5 NTU can be visible to the average person while
turbidity in muddy water, it exceeds 100 NTU.
• Groundwater normally has very low turbidity because of the natural filtration
that occurs as the water penetrates through the soil
20. Physical Parameters
• It is one of the important parameter in natural surface water system.
• Desirable limit of temperature for domestic use ranging between 100 C to
• The temperature in water governs the kinds and types of aquatic life that
live in it.
• It regulates the maximum dissolved oxygen concentration of the water.
• Temperature influences the rate of chemical and biological reactions.
• It affects the dissolved oxygen level in water, photosynthesis of aquatic
plants, metabolic rates of aquatic organisms, and the sensitivity of these
organisms to pollution, parasites, and disease.
22. Chemical Parameters
• Organic and inorganic particles dissolved in water
• Sizes varies from 10 -3 µm to 10 -5 µm
• They may impart colour, taste, toxicity and smell in water
• Can be removed by reverse osmosis, electro dialysis, etc.
• Defined as the negative logarithm of H+ ion concentration
• It is measure of degree of acidity or alkalinity of water
• Measured on pH scale, which varies from 0 to 14.
• Potable water should have pH in range of 6.5 to 8.5
23. Chemical Parameters
• Capacity of substance to neutralize OH- ions
• Due to presence of minerals and dissolution of CO2
• Causes the corrosion of metals and pipelines
• Capacity of substance to neutralize H+ ions (acids)
• Due to presence of bicarbonates, carbonates and hydroxides
• It imparts bitter taste to water
24. Chemical Parameters
• Defined as the soap destroying property of water
• Carbonates and bicarbonates of Calcium and magnesium are responsible
of temporary hardness while, sulphates, chlorides and nitrates of
calcium and magnesium are responsible for permanent hardness.
• Causes excessive consumption of soap in laundries
• Forms deposits in boiler
• Ground water have more hardness than surface water
25. Chemical Parameters
• Due to intrusion of sea water, industrial wastes and domestic wastes
• Usually present in form of CaCl, NaCl and MgCl
• Imparts salty taste in water
• Mainly associated with some sedimentary rocks and igneous rocks
• Harmful and toxic for human and other animals if presented in large quantity
while small amount can be beneficial
• Its deficiency can cause dental cavities in children
• Excess amount can cause discoloration of teeth (Fluorosis)
26. Chemical Parameters
• Added to water by mining, industrial or agricultural sources
• Arsenic, Cadmium, Chromium, lead and mercury are some of the toxic
• Excess amount of Sodium cause bitter taste and cause health hazard like
cardiac and kidney
• Iron and Manganese impart colour even if presented in small quantity
Organic matter :
• Utilized DO of water bodies for their degradation and decreased DO level which
affects the aquatic ecosystem
27. Biological Parameters
The combined group of pathogenic and non-pathogenic
bacteria is termed as B-coli group.
Bacteria - Cholera, diarrhea, typhoid, jaundice
Protozoa – Amebic dysentery, giardiasis
Viruses – Hepatitis, meningitis, poliomylitis
28. WATER POLLUTANTS
Oxygen demanding waste ( BOD, COD)
Nutrients ( Eutrophication)
Sediments ( Decreased photosynthesis, lower DO)
Toxic chemicals ( Bio accumulation, Biomagnification, BCF)
Pathogens ( Water borne diseases)
Radioactive materials ( highly harmful)
Thermal Pollutants ( Lower DO, increased biological actitivities, death of
heat sensitivity organisms)
Water bodies with poor concentration of nutrients and very low
productivity of aquatic plants
2. Mesotrophic :
Water bodies with moderate concentration of nutrients and average
productivity of aquatic plants
3. Eutrophic :
Water bodies with very high concentration of nutrients and very high
productivity of aquatic plants
31. Control of Water Pollution
• By proper sewage treatment
• Proper treatment of industrial effluents
• Judiciously using pesticides and chemical fertilizers
• Encourage reuse of water
• By preventing discharges from nuclear power plant
• By prohibiting direct washing of clothes and animals in water
bodies used for drinking water supply
• Reducing oil spills
• Increasing vegetation cover to reduce soil erosion
• Public awareness