Chapter 3A: Are You Sure It's Good?

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To the teacher

Purpose

To have students understand the concept of water quality, how we measure water quality, and why we need to maintain water quality.

Subject areas

Environmental Studies, Science, Social Studies, Language Arts, Health

Procedure

1. Help the students focus on the topic of water quality by asking some of the following questions:
   
   
   • What does water taste like?
     
     
   • Do you think the water from your taps is good? Why? Who monitors it?
     
     
2. How do we measure water quality? What indicates if water quality is good or bad?
   
   
   • Point out that different uses of water need different water quality. For example, water can be clean enough for swimming or irrigation, but it might not be clean enough for drinking.
     
     
   • Ask: Do we really need water of pure quality to flush our toilets?
     
     
3. Lead a class discussion: "We have an obligation to return water to streams, oceans, and lakes as clean as possible and with the least waste."
   
   
   • Why is water quality important?
   • What is the responsibility of industry and business?
   • What can you do as an individual?
   • What is your responsibility?

Vocabulary contaminate desalinization herbicides irrigate monitor pesticides sanitation sediments stringent toxic

References

• Freshwater Series A-3: Clean Water – Life Depends on It!
• A Primer on Fresh Water: "Water – How good is it?"

Student information

Is this good enough to drink?

Lucky you! It's holiday time and you and your family are going on a vacation to Mexico (or Africa, or India, or China, or Russia, or Asia). Pick a destination.

Whichever country is your destination, one of the first pieces of advice you will be given is, "Whatever you do, don't drink the water!"

You will also be warned against eating any fruit or vegetable that can't be peeled. You will not take water for granted again after this trip.

It's time to count your lucky stars. You live in one of the few countries in the world where you can usually drink water straight from the tap and the water fountain in your school.

What about water quality in Canada?

Because of Canada's stringent guidelines for good drinking water, we can be sure that water quality guidelines are always being monitored so that our health is being protected. At the same time, our water looks good, tastes good, and is generally free from bad smells or colours.

But, it's not easy being pure. Industries and technologies are introducing new chemicals into our water supply every year. Therefore, water quality guidelines have to be continually monitored and revised to keep the water quality we depend upon; and, we have to keep learning about the new chemicals being added to our water.

After your trip abroad you will understand why people from other countries envy us Canadians; we have plenty of water and it is generally safe to use. A scary fact is that in developing nations, 80% of diseases are water-related!

Take a moment to think about this Officials estimate that every day throughout the world 34 000 deaths are caused by contaminated water and poor sanitation – that equals 100 jumbo jets crashing every day!

What do we mean by water quality?

"Water, water everywhere, but not a drop to drink." You've probably been swimming in the ocean and tasted salt water. And you know that salt water doesn't taste good. This doesn't have to mean the ocean is polluted; it might mean that the salt water contains substances making it all right to swim in, but not to drink.

There is no single measure of water quality. Water that is used to irrigate fields may not be suitable to drink; and water that you swim in is a different quality from that needed for industrial use. Water samples are taken all the time to test the quality of water, to see if it contains chemicals that make it unfit for drinking or pollutants that make it unfit for swimming.

What affects water quality?

As mentioned earlier, it's not always easy to keep our water pure. From the introduction of new chemicals to natural causes, water quality can be affected by many factors.

For example, moisture in the atmosphere collects around dust, volcanic and natural gases, or any substances in the air like lead and toxic chemicals, and falls to the earth's surface as precipitation.

Runoff from land surfaces can drain into the water supply carrying all kinds of substances. In farming country this can mean animal wastes or fertilizer and pesticides; in the cities, street debris and chemicals end up in the water. One of the main problems in cities occurs after a storm when wastes from dogs and cats are washed into our storm drains and end up in our lakes and rivers. This is one reason why beaches near cities are closed after a major storm. Wastes from industries, mining, and forestry can also affect the water quality.

We ordinary householders affect water quality as well. We dump many things down our drains and into our toilets without thinking. Some of these substances are toxic, and our treatment plants cannot remove them from the water. We have to remember that everything we toss down the drain finds its way into the water system, and one of these days, you or someone else will be drinking that same water after it has been treated.

How do we measure water quality?

Scientists collect samples of water and living organisms from a lake or stream and analyse them in a laboratory with special instruments. Some of their instruments are so exceptional, they can detect one-thousandth of a teaspoon of salt in an Olympic-size swimming pool.

Did you know? On the prairies, irrigation is the largest consumer of water. Irrigation can affect the quality of water because it runs back to the river, lake, or groundwater source carrying sediments, fertilizer, herbicides, and pesticides.

Learning activities

Activity 1 – Environmental Studies

1. Many people in Canada buy bottled water to drink because they believe it is purer than water from the tap. Tests by the Consumers' Association of Canada and other organizations have found out that bottled water is no healthier than tap water and in some cases is not as good.
   
   Find out the results of tests done on brands of bottled water. Make a graph to show the conclusions.

Note: There is no law to enforce the limit of total bacteria in bottled water in Canada.

2. Find out about additives (chemicals added to our water supply) such as chlorine and/or fluoride in the water.
   
   
   • Why are these additives used? Are they used in your drinking water? Why or why not? (Some communities have voted against adding any chemicals to their water supply.)
     
     
3. Contact your local municipality to find out the types and numbers of chemicals that are monitored in your local drinking water; compare your results with the chemicals that are tested in bottled water.

Activity 2 – Social Studies, Language Arts

Conduct some marketing research.

There are several models and types of water filters that fit on taps and claim to filter out impurities from the water.

• Visit a shop selling these. Investigate the costs and find out how they work and how good they are.
  
  
• Make up a report for your class explaining what water filters do.
  
  
• Include whether or not you recommend them and which model you consider the best. Justify your choice.

Activity 3 – Science

Make a "still."

• Your first task is to find out what the word "distillation" means – and then find out what a "still" is. (You may learn that having a "still" may be illegal – but that's not the kind meant here.)
  
  
• Go to your library and find a book that tells you how to find and make your own apparatus for distilling water.
  
  
• After you have a working model, demonstrate distillation to the class using a sample of water to which you have added salt and a little food colouring.
  
  
• Explain the scientific process of distillation.
  
  
• In which situations does distillation have a practical use as far as drinking water is concerned?
  
  
• Do you think this is an economical way for countries without good water supplies to produce their own water from salt water, a process called desalinization? Explain.

Activity 4 – Environmental Studies

What do you think of the following?

Icebergs are made up of distilled and frozen water. Some business people have suggested that we can break off chunks of northern icebergs and tow them down to the dry California coast where they can be melted and used to irrigate the farmland there.

Can this idea work? Be creative and prepare a report about this project. Pretend you are one of these business people trying to sell your idea to others. Answer some of the following questions:

• What are the benefits?
• How do you "break off a chunk?"
• How will you tow this chunk?
• What are some other questions/problems that others may ask you?
• How will you answer these questions?

Activity 5 – Health

• In most parts of Canada we can get our drinking water samples tested free by the provincial or territorial Department of Health. Invite a speaker to explain this process to your class.
  
  
• Prepare a list of questions for your speaker beforehand about the quality of drinking water in your community.

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