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Deadly
Water: The Lessons of Walkerton |
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The Basic Facts of E.coli |
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| Since
Walkerton became the worst case of E.coli poisoning in Canadian history
many Canadians are now acutely aware that E.coli can be a killer. This section
presents some of the basic vocabulary of the Walkerton tragedy and will
help you gain a deeper understanding of the facts and a broader awareness.
What is E.coli? E.coli is short for Escherichia coli. It is a type of bacteria found in the intestines of animals and humans. There are hundreds of different kinds, or strains, of E.coli, some of which are harmful, but most of which are not. The variety that struck Walkerton is known as E.coli 0157:H7. This type produces a powerful toxin, or poison, and can cause severe illness and even death. E.coli 0157:H7 was first identified in 1982 in the United States when 47 people developed severe stomach disorders. The cause of these disorders was traced to ground beef patties that were contaminated with the harmful variety of E.coli. Because E.coli can be caught from eating undercooked contaminated ground beef it has been called the hamburger disease. However, the bacteria can also be caught from consuming unpasteurized milk and apple cider, ham, turkey, roast beef, sandwich meats, raw vegetables, cheese, and of course water. Once infected, people do not necessarily die. Some people develop mild diarrhea. You may even have had a mild strain of E.coli yourself and never realized it! In more serious cases there is severe diarrhea, which is often bloody, as well as very painful stomach cramps. The most severe cases tend to be with young children and elderly people because their immune systems are not as able to fight the infection. In children the infection causes red blood cells to be destroyed, and the kidneys can fail. Even if a child recovers from such a serious illness they may have permanently damaged kidneys and other serious health problems for the rest of their lives. In an elderly patient E.coli can cause strokes, which may kill. However, in most cases people recover with the help of antibiotics after five to 10 days of treatment. E.coli and Water Contamination If E.coli comes from hamburger meat, how does it get into water, you may ask? The answer is through human and animal waste. During heavy rains E.coli in the form of animal manure from farms may be washed into creeks, rivers, streams, lakes, or even groundwater (underground sources of water). Human sewage can do the same thing if it comes into contact with the water sources just listed. When this polluted water is used as a source of drinking water and the water is not treated properly, E.coli may end up in the drinking water as it did in Walkerton. The more manure in the area of water sources, the greater the likelihood that water may become contaminated during flooding. This is why factory farming, as it is called, has been blamed for the water contamination at Walkerton. The good news is that by testing water samples we can find out if water is contaminated with E.coli and then treat the water with chlorine or other substances to destroy the bacteria. The bad news is that the water in Walkerton was not properly treated with chlorine. Follow-up Questions and Activities 1. Are all types of E.coli bacterial harmful? Explain your answer carefully. 2. When E.coli 0157:H7 was first discovered, what was the source of the contamination? Was it water as in the Walkerton situation? Why is this question so important? 3. What food products can E.coli contamination be found in? What implications does this have for all of us in our daily lives? Consider where, how, and when you buy, prepare, and serve food. Why is proper hygiene far more than the lessons our parents teach us? Why is science a critical area of expertise in terms of the production, supply and delivery, and preparation of food? 4. How does E.coli get into the water supply? Can the water be treated? What sciences and what career fields are directly related to water supply systems? In small groups, make a list of jobs and special fields of knowledge that are directly related to water supplies. Task Forces Form three groups or "task forces" to research and study various aspects of water. Initially, brainstorm thoughts and ideas using the information below and then, using encyclopedias, dictionaries, atlases, and the Internet, prepare an overview presentation for the class. 1. Water: The Source of Life: What is the "continuous hydrologic cycle" of water? What does the Earth's atmosphere have to do with our water? What is the importance of evaporation and water supplies? What is "water yield?" What is "runoff" and in what parts of Canada can this be a serious problem? What do fishing, navigation, recreation, and wildlife habitats have to do with water? Why is Canada's history directly and closely linked to water? What is irrigation and what is its importance to Canadians? Why are most cities and industries in Canada river- and lake-oriented? 2. Water Distribution Systems: Why do we need systems? What systems exist? What are those systems composed of? What keeps them running? How does the fact that 80 per cent of Canada's population is urban affect these systems? What are the implications for Canadians who are not urban? What do the terms inter-governmental co-operation and water management have to do with this issue? How is water obtained and distributed throughout Canada? How do rising costs and public opposition to land-use changes affect water supplies and distribution? What does "efficiency" have to do with water distribution? 3. Water Treatment: Why have humans always had to treat water even in the most simple ways? What is the importance of the words quality and minimum standards to water treatment? What is the importance of the following in water treatment: temperature, colour, turbidity, odour and taste/palatability, micro-organisms, chemical treatments, screening, flocculation, sedimentation, filtration and adsorption, distillation and reverse osmosis, aeration, coagulation, softening, pH adjustment, ion exchange, disinfection? |
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Comprehensive
News in Review Study Modules Using both
the print and non-print material from various issues of News in Review,
teachers and students can create comprehensive, thematic modules that
are excellent for research purposes, independent assignments, and small
group study. We recommend the stories indicated below for the universal
issues they represent and for the archival and historic material they
contain. |
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Other Related Videos Available from CBC Non-Broadcast Sales Does Your Resource Collection Include These CBC Videos? Water: To The Last Drop Howe Sound: Poisoned Waters Canada's Water Supply (series) Watershed |
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Using both
the print and non-print material from various issues of News in Review,
teachers and students can create comprehensive, thematic modules that
are excellent for research purposes, independent assignments, and small
group study. We recommend the stories indicated below for the universal
issues they represent and for the archival and historic material they
contain. |
| Other Related Videos Available from CBC Non-Broadcast Sales Does Your Resource Collection Include These CBC Videos? Water: To The Last Drop Howe Sound: Poisoned Waters Canada's Water Supply (series) Watershed |