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Environmental Science Lecture 1
Assignments should be put in the boxes of SW-223. Each TA will put the name and
course code. We should put the assignments in our TA’s boxes.
Exam format: Mcq’s (4-5 options) and T-f questions
What is environmental health?
According to the WHO: “In its broadest sense, environmental health comprises
those aspects of human health, disease and injuries that are determined or
influenced by factors in the environment.
This includes the study of both the direct pathological effects of various:
•social environment (housing, urban development, land use and
Environment is everything that affects a living organism:
Effect of environment on human health is so great
•Manmade environment (factories, sewage, swamp, industry etc)
•Human population and consumption
•Human alteration of Earth is substantial and growing: In a couple of decades
the population would exceed the limit. Resources will become scarce.
•Protecting the environment has been a mainstay of public health practices
Environmental factors responsible for 25 % of all preventable diseases
•Diarrhea and respiratory infections heading in the list
•Rich & poor
•Scientist used to compare African Americans & Hispanic & Whites and see the
quality of their lives and number of cases related with the environmental
issues. Health problems. Whites have better quality of lives and less exposed
to the environmental and pollution.
•Developed & developing countries
Types of hazard
•Chemical hazards (chemicals in air, water, soil and food)
•Biological hazards (bacteria, viruses, parasites, allergens, animals such as
bees and poisonous snacks)
•Cultural hazards (unsafe working conditions, poor diet, drugs, drinking,
driving, poverty [number 1 hazard])
•Physical hazards (radiation, fire, tornado, hurricane, volcanic eruption,
Video by “Everyday carcinogens: Acting for Prevention in the Face of Scientific
Featured by Dr. Sandra Steingraber
Lecture 3: Water hazards and Human health
Note: Assignments to be submitted to SW223
Liquid natural capitol
Ø Earth is water planet
Ø Water covers 71% of Earth surface but not all the water is available for our consumption
Not much fresh water
Ø Mostly salt water
Ø No species can do without water
Ø Sculpturing the Earth’s surface: Water change the shape of the planet Earth i.e. water erosion
Ø Moderating climate
Ø Removing and diluting wastes and pollutants
Percentages on how water is used up?
Flushing toilets (30%), Showering (35%), Cleaning (5%), Laundry (20%), Drinking (10%)
Canada has plenty of water available for us.
But some countries don’t have water for basic purposes
Ø One out of six people do not have regular access to clean water
- People are walking miles to get some clean water
Ø Diarrheal deaths kill over 2 million children annually
Water and Your Health
Ø Drinking water: NEED CLEAN WATER!
Ø Swimming water
Ø Annual reports on local drinking water quality
- Our right to know what we are drinking: what are we consuming?
Ø Naturally pure water & distillate water: Never purely 100% - we need some minerals in water. Distilled
water is free of salts. Water we drink is coming from the Lake Ontario from deep inside reservoir.
Ø Natural content of minerals in water
Ø Surface water - In urban areas mostly from rivers, lakes and reservoirs
Ø Ground water- In rural areas (wells). It’s underground.
How is drinking water treated?
Ø Water from rivers, lakes and reservoirs
•Addition of coagulants –dirt and contaminants form clumps that settle to the bottom of the tank
•Chemical treatment (disinfection, granulated activated charcoal (very good for organic
contaminants), ion exchange resins, reverse osmosis)
•Naturally filtered: Soil has different chemicals which purifies water.
•Less organic matter
•Often does not need any treatment
Chemical Treatment of the Drinking Water
Chlorination of Drinking Water: Its Benefits and Risks
Chlorine is widely used to disinfect drinking water. Common disinfectant. All about
chlorination: could be diff chemicals. That chemical react with organic matter in water with