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28 Jan 2011
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Urban, ecosystems, pollution
Urban ecosystem analysis
Cities as complex ecosystem
- Complex organisms with metabolic processes
- Huge inputs and outputs, structured by metabolic processes of production, delivery,
- Input & output can be measured and where necessary can be influenced by public
Critical to understand nature of inputs and outputs
Cutting down outputs, such as recycling, is important
Water inputs & outputs
Huge urban input
Ensuring quality water supply is important to health
Polluted water is huge urban output
Successful 19th to 20th century water treatment policies, public water supply
Primary waste treatment, secondary , and tertiary treatment systems were installed
to prevent people from down the stream of the big cities getting sick
Current water challenges
Arise from the way we built our sewage system
Combined sanitary and storm water sewer systems used on pipes in cities, which in
reality needs to be treated in different ways
Works in dry weather, but heavy rain overloaded the systems, and water was
released into lake, river
The reason is because it caused too much to build two sewage systems
Cities are rebuilding systems to separate them
Storage for storm water surges
Point sources and non-point sources
Point sources are those where is a clear point of discharge (factories, sewers)
Relatively easy to monitor, and progress to cleanup
Non-point source pollution is everything else (pesticide, dog feces, antifreeze,
Rain water is a big source of pollution, carrying road pollution into the sewage and
into treatment facilities (stuff that are coated on the roads such as antifreeze, tire
rubber, mechanical oil)
Non-point source include waste that cannot be identified
Sewage sludge were turned into fertilizer because of alternative to landfill and
Problem with pharmaceutical drugs is that 70 90% are not metabolized, endocrine
Water treatment systems are just starting to catch up on our knowledge of the
problems related to water pollution
Major investments in retention ponds, buffers along streams, green roofs, etc
Developing countries
Water management is in short supply in poorer countries
Basic water treatment technologies are still only partially disseminated
Advanced technologies are less widely used
Air pollution
Just as big of a problem, point source and non-point source
Smokestacks, factories are increasingly well regulated since 1970s
Success in cleaning up factory emissions of SO2No
All are point source pollution
Except in developing countries such as China and India where air pollution is a
Also some non-point sources such as pesticides, deodorants, building material
Current air pollution challenges
Even though pollution of cars have been cut down, it is still a serious issue
In Toronto, it causes 1000 premature death each year
Most air pollution growth is due to car and trucks
Asthma is big in children, it is a crisis
Also cause autoimmune diseases such as arthritis, eczema, lupus
Exotic toxins (PCBs, pesticides)
Japan was a major producer of dioxins because they burnt everything
Unregulated industrial waste incineration
Eating food contaminated by air pollution is the main way humans ingest them
Final exam
Monday, December 13, 2 4pm, in the gym
10 short answer questions, weighted equally
There are 10 sections in the course, each with 2 questions, only
answer one of each
Cover main content of lectures and readings
Think about the main themes of each lecture