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Lecture 4

Week 4 Lecture


Department
Environmental Science
Course Code
EESA10H3
Professor
Jovan Stefanovic
Lecture
4

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Waterborne Hazards and Human Health
Liquid natural capitol
l The Earth is water planet
l Water covers 71% of Earth surface
l Mostly salt water
l No species can do without waterall living things like water
l Sculpting the Earths surface
l Moderating climate
l Removing and diluting wastes and pollutants
Worlds problems
l Quantity of water
l Quality of water
Ganges River
l Withdrawal- total amount of water removed from a river, lake or aquifer for any purpose.
l Some may be returned to the source for reuse
l Use about 54 % of the world's reliable runoff of surface water and could be using 70-90% by
2025 (more and more water will be used)
Quantity of water
How much fresh water is available? Not much!
Stress on the worlds major river basins (how much is used in comparison to how much is available)
Water stress <1700 cubic meters/year/person
Water scarcity <1000 cubic meters/year/person
Worlds problems
l Some areas have lots of water but the largest rivers are far from agricultural and population
centers
oLot of investments, transport
l Lots of precipitation arrives during short period but cannot be collected and stored
l Lakes and rivers shrinks
The satellite images show the Aral Sea in (A) 1976 and (B) 1997. As water was diverted for irrigation, the
sea level subsided
How do we use the worlds fresh water?
85% of water use for irrigation is consumed and not returned to its water basin
Average water use in Canadian homes (Environment Canada, 2005)
Hydrological poverty – lack of clean water, no safe drinking water, travel long distances for water source
l One out of six people do not have regular access to clean water
l Diarrheal deaths kill over 2 million children annually
Water and Your health
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l Drinking water
l Swimming water
Desperate for help
DRINKING WATER
l Annual reports on local drinking water quality
Tap water & b o t tl ed water
l Naturally p ure water & distilled water
l Natural co n tent of minerals in water
l Surfa c e water - In u rban are a s mostly from rivers, lakes and reservoirs
l Grou n d water- In rural are a s (wells)
How d evelo p ment chan g e the n atural flow of water
Quality of water
Sourc e s of water co n taminatio n
Con taminants in Drinking Wa ter
1. Microb es
2. Radio n u clides
3. Inorganic Contaminants
l Arsenic
l Fluoride
l Le a d
l Nitrates
4. Ind u strial Organic Contaminants
l Pesticides an d Herbicides
l Volatil e Organic Comp o u n d s (VOC)
5. Disinfe c tio n by pro d u cts
Point so urc e pollutio n: Ind u strial ru n off po urs into a waste pit in the Ama zo n River
basin. Natural g as b urns from an adjac e nt pipe.
1. Microb es all of these dise a ses result in diarrhe al illnes s es
l Fec al Coliform an d E. coli b a c teria co n tamination wit h hu man and animal
wastes, diarr he a , cramps, n ause a , h e a da c hes, renal failure, coag ulatio n
disorders
l Salmo n ell a ty p hi typhoid fever (high fever, ab d o minal p ain, co n stipation)
l Shigella sp.- more severe ab d o minal cramping with bloo d and mucus in the
stool
l Vibrio ch olera e life thre a tenin g, ric e-water sto ols
l Norwalk viruses, enteroviruses, aden oviruses - diarrhe al illnes s
l Hepati t es A- liver inflam m atio n (no n-diarrhe al illnes s)
l Cryp tosp oridium p arasit e that enters lake an d rivers thro u g h sewage an d
animal wastes
l Giardia lambli a - enters lake and rivers through sewage an d animal wastes,
diarrhe a , vo mi ti n g, cramps
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Fecal colifor m test: This test indicates the likely presence of disease-causing agents
in water. A sample is first passed through a filtering apparatus.
A. The filter disk is then placed on a medium that support coliform bacteria for
24hours.
B. After incubation, the nu mber of bacterial colonies is counted. Each colony of
E.coli arose from a single coliform bacterium in the original water sample
Case Study:
Walkerton example (E.coli) 6 people died; many got sick because water was
contaminated with Ecoli
Young girl and an elderly died; can affect anyone
Figures illustrate a pipe containing biofilm and a scanning electron micrograph
(below) of the surface of a pipe containing bacteria, isolated from Walkerton during
the investigation in 2000.
2. Radionuclides
l Alpha emitters
l Beta/photon emit ters
l Combined Radium 226/228
l Radon gas
l Damage to DNA, Increase risk of getting cancer
Radon
Radon: a colourless and odourless gas
Produced by the radioactive decay of uranium, in particular Uranium-238 with a
half life of 4.5 billion years, and other radioactive minerals
Radium-226 with a half life of 1,602 years decays to Radium-222 with a half life of
3.8 days
Radon decays radioactive isotopes Polonium-218 and Polonium-214 which also
produces alpha particles that if breathed or swallowed can cause several types of
cancer
Uranium is found in several types of minerals associated with granites,
metamorphic gneiss, and sedimentary rock derived from weathering and erosion of
granite
Radon can build up in the basement of a home constructed on soils with high
radon levels or if the basement walls are built of granite
Uraninite is the main uranium ore. This sample is from the Burnt Hill mine in
northern Saskatchewan.
Radium Hot Springs, as it appeared shortly af ter opening (early 1900s)
Radium Hot Springs (2000s)
These are beneficial to us
3. Inorganic Contaminants: Arsenic (not beneficial)
High concentration of arsenic are poisonous and lower concentrations can
cause skin cancer and melanosis (dark pigmentation of the skin)
After many years of drinking, possibility of skin damage, problems with
circulatory system
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