Water Pollution
Chapter 19
I. What is water pollution?
 Any chemical, biological, or physical change
in water quality that has a harmful effect on
living organisms or makes water unsuitable
for desired uses.
I. B. Sources of Pollutants
 Point Sources : Factories, Straight Piping,
Mines, Oil Wells, Oil Tankers
– Directly from an identifiable source at a specific
location
 Nonpoint Sources: Acid Deposition, Runoff,
Seepage into Groundwater
– Cannot directly identify or trace the source
– Accounts for majority of water pollution
– Difficult to control
II. CATEGORIES OF
WATER POLLUTION
& SOURCES
& IMPACTS
II.A. DISEASE-CAUSING
AGENTS
SOURCES
- Waterborne Bacteria, Pathogens
Giardia sp.*
IMPACT
- Spreads fast
- Can cause sickness
and death
Escherichia coli
B. OXYGEN DEMANDING
AGENTS
BOD : Oxygen is removed from water when
organic matter is consumed by bacteria
SOURCES
- Natural: bogs, leaf fall, riparian zone
- Human: Pulp/Paper Mills, Wastewater
Treatment Plants , Sewage
- Nonpoint: Runoff from urban,
agricultural areas/manure
IMPACTS
-Creates low oxygen conditions that
organisms in the ecosystem rely on
C. INORGANIC CHEMICALS
SOURCES
- Heavy/Toxic Metals, Acids, Industry,
Burning of Fossil Fuels
IMPACT
- Most are extremely toxic
- Readily absorbs into plant/animal tissue
*Biological Magnification
Water
0.000002 ppm
Phytoplankton
0.0025 ppm
Herring gull
124 ppm
Herring gull eggs
124 ppm
Zooplankton
0.123 ppm
Lake trout
4.83 ppm
Rainbow smelt
1.04 ppm
Bioaccumulation :
Mercury Deposition
D. INORGANIC PLANT
NUTRIENTS
SOURCES
- Nitrogen and Phosphorus
From – waste
- storm water runoff
- soil erosion
- excessive use of fertilizers
- detergents, soaps (phased out)
IMPACTS
-Eutrophication: Rapid increase in plant
life
- Algae Blooms
E. ORGANIC CHEMICALS
SOURCES
- Oil, Pesticides, Detergents
IMPACTS
- Some are Degradable: chemically
decomposed
Photodegradable: broken down by
exposure to light
Biodegradable: decomposed by
biological agents
F. SEDIMENT AND
SUSPENDED MATERIAL
SOURCES
- Erosion, Suspended Soil, Trash
IMPACTS
-Sediment Loading
-Reduced light penetration
- Adsorption of pollutants
- Greater nutrients and BOD
- Interferes with navigation,
recreation, spawning beds
G. THERMAL
SOURCES
- Electric and Nuclear Power Plants
IMPACTS
- Heat reduces
the ability of
water to hold
oxygen
Groundwater pollution
 Sources: storage lagoons, septic tanks,
landfills, hazardous waste dumps, deep
injection wells
 High health risks in drinking water – mainly from
petrochemicals, organic chlorides, pesticides,
arsenic, lead, and fluorine
 Moves very slowly
 Low amount of decomposing bacteria
 Cold temps slow decomposition rate
 Extent is unknown