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Fresh Water
Water is the driving force of all
nature.
Leonardo da Vinci
Fresh water found in glaciers
Ground water resources
Wetlands resources
Canadian water supplies
• Most (89%) Canadians get their water supply
from lakes and rivers
• The Great Lakes particularly are a huge source
of fresh water
• These lakes are particularly vulnerable to
pollution because of where they are situated
Types of Water
pollution
Nutrient water pollution
• Nutrients essential to plant growth are
overloaded into the water systems
• E.g. phosphorous (detergents) and nitrogen
(fertilizers, animal poop)
• Causes eutrophication: excessive growth of
algae chokes out oxygen
Eutrophication
Sediment or suspended-matter
water pollution
• Run-off from ploughed fields, construction
sites, logging sites, and urban areas
• Blocks sunlight from entering the water
• Restricts photosynthesis
• Upsets the ecological balance
Toxic or chemical water pollution
• Examples: herbicides, pesticides, PCBs,
mercury, lead, tritrium from nuclear power
stations
• Can you think of an example from the
environmental disasters project?
Bacterial or biological water pollution
• Contamination by bacteria
• E.g. giardiasis or “beaver fever”
• Contaminated the drinking water in Banff,
Alberta in the 1980s
• More common in developing countries
• E.g. what is the disease in Haiti right now?
Thermal Pollution
• Results when temperatures rise or fall due to
human inputs
• E.g. water used a coolant in thermal electric
generating stations
• Water is used to cool many buildings in
Toronto and then re-circulated into the lake
• Environmentally friendly?
Impacts for Thermal pollution
• Aquatic species can be very sensitive to
changes in temperature
• E.g. can alter the reproductive cycles, growth
patterns and ability to survive
• Warmer coolant water discharged into lakes:
– Decreases oxygen
– Kill fish juveniles
– Disrupts ecosystem composition