This document discusses various types and sources of water pollution. It defines water pollution as changes in water quality from physical, chemical, or biological factors that harm living organisms. The main types of water pollutants discussed are infectious agents, oxygen-demanding wastes, inorganic pollutants, organic chemicals, sediment, and thermal pollution. Agricultural runoff, industrial waste, and mining are identified as leading causes of water pollution. Prevention and treatment of sewage as well as regulation are discussed as ways to reduce water pollution.

1. 1
Water Pollution

2. 2
Definition = physical, chemical, biological changes in
water quality that adversely affect living organisms.
(i.e., degradation)
Types:
Infectious Agents
Oxygen-Demanding Wastes
Inorganic Pollutants
Organic Chemicals
Sediment (Particulates)
Thermal Pollution

3. 3
Infectious Agents
Infectious Agents = pathogenic organisms. Water-borne diseases
from infectious agents include typhoid, cholera, bacterial and
amoebic dysentery, polio, infectious hepatitis, guinea worm
and schistosomiasis. Due to lack of sanitation.
Analyze coliform
bacteria (E. coli).
Presume if coliform
bacteria are present,
infectious pathogens are
also present.

4. 4
Key Concepts
 Types, sources, and effects of water pollutants
 Major pollution problems of surface water
 Major pollution problems of groundwater
 Reduction and prevention of water pollution
 Drinking water quality

5. 5
Types, Effects, and Sources of Water
Pollution
• Water is polluted by infectious bacteria, inorganic
and organic chemicals, and excess heat.
• Water pollution is any chemical, biological, or
physical change in water quality that has a harmful
effect on living organisms.
• The WHO estimates that 3.4 million people die
prematurely each year from waterborne diseases.
• In the U.S., an estimated 1.5 million people a year
become ill from infectious agents.

6. 6
• Scientists monitor water quality by using bacterial
counts, chemical analysis, and indicator organisms.
• One method of measuring water quality involves
measuring the number of colonies of fecal coliform
bacteria present in a water sample.
• Drinking water should not contain any colonies/100
milliliters,
• Chemical analysis includes checking inorganic and
organic chemicals present, sediment content, and
turbidity of water.
• Indicator species are living organisms that are
monitored to determine levels of pollution.

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Sources of Water Pollution
Point sources
Nonpoint sources
Water quality

8. Supply of Water Resources
Freshwater Readily accessible freshwater
Biota
0.0001%
Rivers
0.0001%
Atmospheric
water vapor
0.0001%
Lakes
0.0007%
Soil
moisture
0.0005%
Groundwater
0.592%
Ice caps
and glaciers
0.592%
0.014%

9. 9
Inorganic Pollutants
Nonmetallic Salts:
Arsenic from mining or drainage of desert soils
Causes: - anemia
- cancer
- death.
Sodium Chloride: Salinization
Acids:
Sulfur and nitrogen compounds from coal.
Causes: - pH changes which affect species
- leaches aluminum

10. Evaporation and transpiration
Evaporation
Stream
Infiltration
Water tableInfiltration
Unconfined aquifer
Lake
Well requiring a pump
Flowing
artesian well
Runoff
Precipitation
Confined
Recharge Area
Aquifer
Ground Water
Fig. 15-3 p. 308

11. Use of Water Resources
 Humans use about 54% of reliable runoff
 Agriculture
 Industry
 Domestic
 Power plants
Industry 11%
Public 10%
Power
cooling
38%
Agriculture
38%

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Point and Nonpoint Sources
NONPOINT SOURCES
Urban streets
Suburban
development
Wastewater
treatment
plant
Rural homes
Cropland
Factory
Animal feedlot
POINT
SOURCES

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Sources of water pollution
The leading sources of water pollution are
agriculture, industries, and mining.
1. Agricultural activities are the leading cause of
water pollution from
erosion, overgrazing, fertilizers and
pesticides, and excess salt from irrigated soils.
2. Industrial facilities are another large source of
water pollution, and mining is a third source.

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• One of every five people in the world lacks access
to safe drinking water.
• Ninety-five percent of people in developed
countries and 74% of people in developing
countries have access to clean drinking water.
• In a warmer world, too much rain and too little
rain can increase water pollution.

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Pollution of Freshwater Streams
Streams can recover from moderate levels of
degradable water pollutants if the flows are not
reduced.
1. A combination of dilution and biodegradation can
allow recovery of stream pollution
2. The breakdown of pollutants by bacteria creates
an oxygen sag curve. Organisms that have a high
oxygen demand can’t survive in the curve.
3. Volume of the stream, volume of wastes
entering, flow rate, temperature, and pH levels all
affect how great a sag curve is produced.

16. 16
Oxygen Sag Curve

17. 17
Water Pollution: Now
Most developed countries have reduced point source
pollution, but toxic chemicals and pollution from
non-point sources are still problems.
Stream pollution in most developing countries is a
serious and growing problem. Half of the world’s
500 major rivers are heavily polluted, and most of
them run through developing countries where
waste treatment is minimal or nonexistent.
For example: Religious beliefs, cultural traditions,
poverty, little economic development, and a large
population interact to cause severe pollution of the
Ganges River in India.

18. 18
Pollution of Lakes

19. 19
Groundwater Pollution: Causes
 Low flow rates  Few bacteria
 Cold temperatures
Coal strip
mine runoff
Pumping
well
Waste lagoon
Accidental
spills
Groundwater
flow
Confined aquifer
Discharge
Leakage from faulty
casing
Hazardous waste injection well
Pesticides
Gasoline
station
Buried gasoline
and solvent tank
Sewer
Cesspool
septic tank
De-icing
road salt
Water pumping
well Landfill
 Low oxygen

20. 20
Pollution of Groundwater
Experts rate groundwater pollution as a low-risk
ecological problem; it is rated as a high-risk
health problem.
The extent of groundwater contamination is
generally unknown
Prevention is the most effective and affordable way
to protect groundwater from pollutants.

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Ocean Pollution
Fig. 22-11 p. 504

22. Problems with Using Groundwater
 Water lable lowering
 Depletion
 Subsidence
 Saltwater intrusion
Chemical contamination
 Reduced stream flows

23. Groundwater Pollution
• >70,000 chemicals are used not; effects of
many are not known
• Each year another 700-800 new chemicals are
produced
• 55 million tons of hazardous chemical wastes are
produced in the US each year
• The 20 most abundant compounds in
groundwater at industrial waste disposal sites
include TCE, benzene, vinyl chloride…all are
carcinogens, and also affect liver, brain, and
nervous system

24. Kinds of Water Pollution
• Inorganic Pollutants
• Organic Pollutants
• Biologic Pollutants

25. Inorganic Pollutants
• Examples:
• Pb in gasoline
• Radionuclides
• Phosphorus, nitrogen (Great Lakes)
• Other heavy metals

26. Inorganic Pollutants
• 3 groups
• 1) Produce no health effects until a threshold
concentration is exceeded—e.g., NO3 at
, 50mg/liter; at higher levels:
methaemoglobinaemia
• 2) No threshold—e.g.—genotoxic substances:
some natural and synthetic organic
compounds, microorganic compunds, some
pesticides, arsenic
• 3) Essential to diets: F, I, Se—absence causes
problems, but too much also causes problems

27. Inorganic Trace Contaminants
• Mercury—methyl Hg and dimethyl Hg in
fish—probably most significant path to
humans—Minamata Bay, Japan, 1950’s
• Rhine River drains 185,000 sq km—heavily
polluted by 1970’s
• Lead—toxicity has been known for a long
time
– 1859 book
– Tetraethyl lead—anti-knowck additive for
gas, 1930-1966

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Oil Spills
Sources: offshore wells,
tankers, pipelines and
storage tanks
Effects: death of organisms, loss
of animal insulation and
buoyancy
Significant economic impacts
Mechanical cleanup methods: skimmers and blotters
Chemical cleanup methods: coagulants and dispersing
agents

30. 30
Solutions: Preventing and Reducing
Surface Water Pollution
Nonpoint Sources Point Sources
Reduce runoff
Buffer zone vegetation
Reduce soil erosion
Clean Water Act
Water Quality Act

31. Reducing Water Pollution through
Sewage Treatment
• Primary and Secondary sewage treatment.
Figure 20-19