Transcript Slide 1
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