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Lecture

ENVS 3410 Lecture Notes - Disinfectant, Water Cycle, Aquifer


Department
Environmental Studies
Course Code
ENVS 3410
Professor
all

Page:
of 4
Lecture 3
Water (Liquid Natural Capitol)
Water is in the air and in our body (60% of our body)
Earth is a water planet and is 71% percent of it is covered with water
However this water is mostly salt water and this limits its usages and more expensive to use the
limited fresh water.
To convert salt water to drinking water is expensive, corrosive and difficult to do.
No species can exist without water
Water changes the surfaces of the Earth (e.g. hill, valley, canyons) due to erosion of the soil,
rain, weathering
Water moderates climates
It is also used to remove and dilute wastes and pollutants
Human usage: withdrawal total amount of water removed from a river, lake or aquifer for any
purpose. Some of this water can be returned to its source.
o Water cycle is one of the most important cycles on the Earth and reuses and renews
water the supply on Earth
o Humans use 54% of the world’s reliable run-off (surface water). In 2025, humans would
have consumed 70%-90% of available surface water.
o Raises two questions: 1) how much water is available and 2) what is the quality of
available reliable water.
Globally, there is a very low amount of fresh water available. 2.6% of all
available water is fresh water and only 0.14% is readily accessible water.
Some areas of the planet lack a good amount of water (less than 1700 cubic
meters/year/person) (e.g. USA, Africa, and lower Asia). Under water stress.
Canada has 20% of all freshwater in the world.
o Some World’s Problems:
Some areas have a lot of water but the largest rivers are far from agricultural
and population centres. It is very expensive to transport to where it is needed.
Lot of precipitation arrives during short periods which cannot and stored
because it is very expensive
Lakes and rivers are shrinking due to climate change
o How do we use our water?
64% of available water is used for industrial purposes such as power plant
cooling
A lot of water is being used in the agricultural centers of the USA, not so much
in Canada. In China, most of the water is used for agriculture purposes (87%).
85% of water available is consumed and not returned to its water basin
(source).
In Canada, one household would use for showering (35%) and flushing the
toilet.
Majority of world lives in hydrological poverty. 1 of 6 people doesn’t have
access to clean water.
Poor quality water can lead to diarrhea and kills 2 million children annually.
Water and Your Health
Drinking Water
Municipal government reports annually on local drinking water quality
Is there any naturally pure water? No, all water contains other minerals like potassium, sodium
and magnesium. These minerals are good for one’s health.
Distillate water is a not good for drinking because it is lacking minerals.
Water percolates with the soil and then rocks and then minerals dilute within the water.
However, some minerals are not good, such as arsenic.
Surface water (e.g. rivers, lakes, and reservoirs) are sources of water for urban areas. Ground
water in rural areas (e.g. wells and water below ground reservoir) is used to attain water.
Ground water is fed from the ground and moves slowly and thus it is hard to contaminate.
However, once contaminated, it is harder to clean it of impurities. Ground water can be either
deep or shallow.
Water found in different sources undergoes different process and treatments.
Mechanical Aspect
o Mechanical impurities are removed (e.g. organic material, plant parts) put in tanks to
let water settle.
o Some compounds are added to clump impurities and allow settling at the bottom of the
water basin.
o Water undergoes filtration.
Chemical Aspect
o Water undergoes chemical disinfection.
o Chlorination is a popular technique in disinfecting water.
o Before the chlorination technique, in the end of 19th century, many people in England
died from cholera because of microbes in water. When chlorination of water became a
practice, water quality improved greatly.
o Research found out that a special type of coal can remove many type of organic
materials but cannot remove inorganic materials from water. However, they are only in
use when necessary. For example, used if water is contaminated with metals and no
water supply is around, these treatments may be used.
Ground Water is naturally filtered water and contains less organic matter. It often does not need
any treatment.
Contaminants in Drinking Water:
o Contaminants vs. Pollutants
Contaminants are any agents that can be found in water, soil or other mediums
but does not necessarily hurt an individual but may cause health effects in high
concentrations (e.g. microbes). Calcium can be a contaminant if it is in extreme
concentrations and it is not desired.
Pollutants always hurt individuals and cause human health effects.
o EPA (Environmental Protection Agency) provides a list of possible drinking water
contaminants. CECA (Canadian one).
Microbes: Viruses, Bacteria, Protostomes
SOME BACTERIA
Fecal Coli form and E.Coli bacteria contamination with human and
animal wastes. It can cause diarrhea, cramps, nausea, headaches, renal
failure, and coagulation disorders.
Salmonella typhi can cause typhoid fever, abdominal pain and
constipation
Shigella sp. severe diarrhea, more severe abdominal cramping with
blood and mucus
Cholera is life threatening, common in the 19th century, and caused
rice-water stools
Some VIRUSE
Norwalk viruses, anteroviruses, adenoviruses cause diarrheal illness
Hepatitis A doesn’t result in diarrhea but liver inflammation and is
transferred from water to person.
Radionuclei: Radioactive elements
Inorganic Elements: arsenic, lead
Industrial organic contaminant: pesticides and herbicides
Volatile organic compounds
Disinfection by-products
o PART OF THE LECTURE IS MISSING!!! TECHNICAL PROBLEM
INORGANIC CONTAMINANTS
Arsenic
If arsenic is in high concentration in water, it can cause health effects
Main source is from industrial pollution
If arsenic is consumed with water for many years, it can possibly cause skin damage (e.g.
discoloration), problems with the circulatory system and cancer.
Fluorides
Fluorides in water (has dental purposes) promotes dental health. It doesn’t cause harm if it is in
low concentrations and controlled. However, if used heavily it can cause bone diseases.
Lead
Lead is an important source to water pollution; however, not as much because it is banned from
being used in water pipes.
Concentration of lead is higher in hot water and in water with more acidic water.
Nitrates
Come from manure and fertilizer.
When nitrites enter our stomach, the bacteria in our stomach convert nitrites into nitrates.
Nitrates are harmful and can starve the body of oxygen. The hemoglobin does not bind with
oxygen and bind to nitrates and this inhibits the hemoglobin function. Some symptoms is
cyanosis (bluish anatomy) and can interfere with reproduction (e.g. spontaneous abortion or
neural tube defection).
Case Studies:
Walkerton (E.coli): too much precipitation over flooded the wells which mixed with the surface
water. This mixed water contained fecal matter and this water was distributed to different
homes in Walkerton. Many got sick and a few died.
India and China natural occurring fluoride
Bangladesh, India, China natural occurring arsenic
o For 30 years the populations used arsenic
Pesticides
DDT:
o very chemically persistent
o biochemically accumulating and biomagnifying: build up over time