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Lecture 4

Lecture 4 - Pollution & Clean Up.pdf

Earth Sciences
Course Code
Luc Bernier

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Pollution & Clean Up
1) Which BC mining company has recently admitted in Court polluting the Columbia River
in Washington State for more than a century?
a. Teck Resources Ltd [*]
b. Taseko Mines Limited
c. Barrick Gold Corporation
d. Thompson Creek Metals
Part 1 - Water Quality Standards
Water Pollution: a global problem
This map illustrates the impact of water pollution on rivers shared by two or more
Red = severe impact
The problem of water pollution is distributed worldwide and has grown during the 20th
This is attributed to population growth, expansion of industry, use of fertilizers and
pesticides in agriculture
Water use has increased six fold and there is more waste in the water
This is a concern in 1/5 of the United Nations Environmental program Regions
The major drainage basins Mississippi river, Islands of Caribbean, Indian ocean, and the
coral sea
Water Pollution and Health Impacts
Water quality standards have been developed to protect human populations from
These standards have been developed with a strict focus on medical issues
They are based on known medical effects
They relate to drinking water for human consumption without considering the
environmental context
These standards need to be constantly revised in the face of new knowledge

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Pollution & Clean Up
Water quality standards have not been developed with the protection of wildlife in mind
The effects of water pollutants on wildlife is more poorly understood
The resistance of one species to a specific pollutant compared to another species varies
The impact of pollutants on behavior need to be taken into account
Water Quality Testing
Another problem relies with the monitoring of water quality
It is not practical to test water quality on a continuous basis
Therefore only spot checks tend to be made
Sometimes they are too infrequent to pick up a specific pollution event
Critical peaks of pollution may be missed
Sampling may be arranged to miss critical peaks in pollution on purpose
For example direct release of sewage into the environment stemming from treatment
being bypassed in a wastewater treatment facility are predictable
Fecal pollution tends to be highest after rain events
Sampling could be devised to miss these days giving the false impression that the water
being released meets environmental standards
Part 2 - Agriculture and Water Quality
Water Pollution and Agriculture
Agriculture is the greatest source of water pollution in developed countries
Largely because of inadequate legislation
Environmental protection agencies tend to focus on point discharges from industries
For instance a specific pipe discharging a pollutant in a body of water
Pollution from agriculture is harder to pinpoint because it's distributed over a larger area
(e.g. multiple fields)
In developing countries water pollution from agriculture has intensifies with the adoption
of the practices of green revolution n the 1960's and 1970's
For instance the use of pesticides
Nitrates: an increasing threat
Nitrates derived from agricultural fertilizers have been affecting water quality due to a
major increase in their use over the last 50 years
They now prohibit the phosphorus in certain countries as the fertilizer of choice for
instance England
WHO limit: 45 mg/L
Much above the concentrations depicted on this map that illustrates the flow of nitrates in
major bodies of water between 1991-2000
The increased levels in major river systems in the world is problematic and leads to
additional environmental consequences downstream for instance eutrophication

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Pollution & Clean Up
Pollution by Nitrates and Health
Well water and “blue baby syndrome”
There are specific health concerns due to the exposure of nitrates that can be found in the
drinking water supply
This chart illustrated the increasing levels of nitrate in ground water in various European
countries (France, Great Britain, Denmark) since the 1980's
The concentration index has been increasing ever since
Since 1945 there is increasing evidence of a link between blue baby syndrome and well
water contaminated by nitrates
The main symptom is blue coloration of the skin
o Lack of oxygen in the blood
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