Class Notes (835,294)
Canada (509,074)
EESA10H3 (501)
Lecture 3

Lecture 3.docx

6 Pages
59 Views
Unlock Document

Department
Environmental Science
Course
EESA10H3
Professor
Jovan Stefanovic
Semester
Summer

Description
Week 3 – Lecture 3 Water Hazards and Human Health Liquid Capitol - The earth is composed of 71% water – mostly saltwater - Moderates climate, dilutes and removes pollutants and wastes - Every living creature needs water – Human body is 60% water World’s Water Problem Quantity - Withdrawal – the amount of water removed from a river, lake, or aquifer. - Some may be returned to the source for reuse - Fresh water = 2.6% of all water available o Mostly in glaciers, ice caps, and groundwater o Readily accessible freshwater can be found in lakes, rivers, soil moisture - Stress on the World’s river basins? o Water stress = <1700 cubic meters/year/person o Water Scarcity = <1000 cubic meters/year/person - Some areas have lots of water – some are too far from population and agriculture – not distributed to key areas properly - Precipitation cannot be collected and stored effectively - As a result, lakes and rivers shrink eg. Aral Sea - How do we use water? o 85% is used for irrigation and not returned to the water basin o Canada = mainly used to cool power plants  In homes = showering, toiler, laundry, drinking, cleaning o China = agriculture o USA = both o All = mainly delivered to the public and industries - Hydrological Poverty – not enough water eg. Asia/Africa (1 out of 6 don’t have access to clean water) o People in these areas need to walk and get water = increased chances of contracting diseases/death eg. Diarrhea – kills 2 million children annually (dehydration) o Bad hygiene at home and body = host to diseases and parasites - Water and your health o Drinking water  Let the water system go for a few minutes in the morning because the water in the system has been idle overnight and might have higher traces of minerals and chemicals  Annual reports of water quality  Tap water – checked everyday o Hot water accumulates more lead o Acidic waters dissolves more metal and lead o Soft water attracts more metals o Surface water – mostly in urban areas – come from lakes, basins, rivers o Ground water – mostly in rural areas – come from wells, underground  Bottled water - not checked everyday o Plastic use may be a danger – strip some essential minerals eg. Calcium and Magnesium  Mineral water – higher salt level o Sources of water  Runoff from the mountain reaches the soil and lakes  Ground water is naturally purified in rocks and sand  Unconfined aquifer  Easier to contaminate  Less often used  Confined Aquifer  Cleaner and harder to get  Need to drill to get access o Effects of Urbanization  Surface runoff is smaller in urbanized areas because of concrete  In rural areas, there is more soil = more ground water, runoff is also slow due to vegetation Quality How is drinking water treated? - Water from rivers, lakes, streams o In settling tanks – treated with coagulants so dirt and contaminants settle at the bottom of the tank. o It is then filtered and particles are removed o Chemical filtration – reverse osmosis, chlorination, resins, charcoal  Chlorination – important in the process as it makes the water safe for drinking  prolonged effect of disinfection - Groundwater o Naturally filtered through rocks, sand o Has less organic matter and is fine without any treatment o Problem arises when there is contamination of the soil as it can leak to these sources Contaminants in drinking water Overview - Pesticides and fertilizers o Used in agriculture o Produced nitrates and contaminates water  can be washed off by runoffs and be fed into streams/rivers/lakes - Underground storage tanks o Age of these tanks  old tank can start leaking chemicals and contaminate ground water eg. Septic tanks o Sewers and lagoons can leak nitrogen - Landfills/Factories o Lead leak from plastic liners 1) Microbes – causes poop disorders (except for Hepatitis A) - Fecal Coliform and E. coli bacteria o Human and animal wastes contamination – causes diarrhea, n/v, headaches, renal failure, coagulation disorders o Fecal Coliform test  Sample in filtering apparatus  filter disk for 24 hours  after incubation, count the number of colonies present.  Each colony of E.coli came from a single coliform bacterium o Case study  Walkerton (May 2001)  6 deaths d/t contaminated water  Arose from manure used in agriculture  rains assisted the bacteria to seep through the soil  contaminate water  Officials failed to inform the public  budget cuts = no testers  after incident = more water testers - Salmonella typhi o Typhoid fever – fever, constipation, abdo pain - Shigella – abdo cramps with blood in stool/mucous - Vibrio cholera (Cholera) – rice-water stools, life threat - Norwalk virus, enterovirus, adenovirus – diarrhea - Hepatitis A – liver inflammation - Parasites– enters lakes and rivers through sewages and animal wastes o Cryptosporidium o Giardia lamblia  diarrhea, cramps, vomiting 2) Radionuclides – damage DNA  increased risk of cancers - Alpha emitters, beta/photon emitters - Radium 226/228 - Radon gas – colourless and odourless o From radioactive decay of Uranium 238 (half-life of 4.5 billion
More Less

Related notes for EESA10H3

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit