Contaminants in the Water Cycle
Based on the National Geographic Activity
http://www.nationalgeographic.com/xpeditions/lessons/14/g912/tgsouhegan.html
Introduction:
We have learned about the water cycle in class, now let’s look at how contaminants in
the cycle can affect us. You will be working with one other person for this activity, but
you will each have individual roles.
Process:
Step 1: Go to the Environmental Protection Agency Web page about drinking water
standards: http://water.epa.gov/drink/contaminants/index.cfm
Step 2: Write the definitions and three examples for each of the six types of
contaminants listed on this page: microorganisms, disinfectants (used to treat drinking
water), disinfection byproducts, inorganic chemicals, organic chemicals, and
radionuclides (radioactive materials). Each partner will complete this for 3 of the
contaminants.
Step 3: Click on your example contaminants to learn more about them. For each
example, include the following. Each partner will complete this section for their 3
contaminants. This information should be written on attached pages.
1) Describe the example (explain what it is)
2) Explain how it enters the water cycle.
3) Explain what possible health risks are associated with it.
Step 4: Answer the following questions using the website and your information gathered
for Steps 2 and 3. You may work on this together, but each partner will turn in their own
answers.
1) If enteric viruses are found in drinking water, what are their likely source and what
health effects might they have? How do you think these viruses could get into the water
supply?
2) What chemicals are used to disinfect the water supply? What positive and negative
effects can these chemicals have?
3) Is inorganic chemical pollution primarily the result of natural or human-made factors?
Name two inorganic chemicals and their potential impacts on human health.
4) What role can agriculture play in water contamination? What are the primary causes
of agricultural contamination?
5) What level of dioxin does the EPA currently allow in drinking water (MCL)? What is
the goal for dioxin levels in drinking water (MCLG)?
Step 5: Sketch a hypothetical town that lies near a body of water such as rivers, lakes,
or the ocean. Your diagram should include the following: Diagram will be completed
together. Sketch on a separate sheet of paper.
1) The water cycle
2) The names of at least four pollutants next to the places they come from (for example,
a town might have a pulp mill that leaks chromium into a river, which subsequently
contaminates the ocean—students would draw the pulp mill and write "chromium" next
to it)
3) The potential human impacts of these contaminants (students can list these impacts
next to the names of the pollutants or at the bottom of their drawings)
Be creative with your sketch, but be sure to include at least four pollution sources and
show the full water cycle in your sketch. See your notes or the book for ideas.
Step 6: Imagine that some residents of your hypothetical town have formed a group that
aims to improve the area's water quality. Write a paragraph suggesting where this group
should focus its energies. Which pollution source should it tackle first? What should it
attempt to do about this pollution problem? Write this paragraph on a separate sheet of
paper – each person in the group will turn in their own paragraph.
Checklist for Project
Steps 1-4 – This handout completed (1 per student – each student packet has 3
contaminants included, each student should write answers to Step 4) (21 points)
Step 5 – Sketch of town (1 per pair of students) (14 points)
Step 6 – Paragraph on improving water quality (1 per student – stapled to completed
packet) (5 points)
Contaminant: Microorganisms
Definition –
Example 1:
Definition –
How does it enter water cycle?
Possible health risks?
Example 2:
Definition –
How does it enter water cycle?
Possible health risks?
Example 3:
Definition –
How does it enter water cycle?
Possible health risks?
Contaminant: Disinfectants
Definition –
Example 1:
Definition –
How does it enter water cycle?
Possible health risks?
Example 2:
Definition –
How does it enter water cycle?
Possible health risks?
Example 3:
Definition –
How does it enter water cycle?
Possible health risks?
Contaminant: Disinfection Byproducts
Definition –
Example 1:
Definition –
How does it enter water cycle?
Possible health risks?
Example 2:
Definition –
How does it enter water cycle?
Possible health risks?
Example 3:
Definition –
How does it enter water cycle?
Possible health risks?
Contaminant: Inorganic Chemicals
Definition –
Example 1:
Definition –
How does it enter water cycle?
Possible health risks?
Example 2:
Definition –
How does it enter water cycle?
Possible health risks?
Example 3:
Definition –
How does it enter water cycle?
Possible health risks?
Contaminant: Organic Chemicals
Definition –
Example 1:
Definition –
How does it enter water cycle?
Possible health risks?
Example 2:
Definition –
How does it enter water cycle?
Possible health risks?
Example 3:
Definition –
How does it enter water cycle?
Possible health risks?
Contaminant: Radionuclides
Definition –
Example 1:
Definition –
How does it enter water cycle?
Possible health risks?
Example 2:
Definition –
How does it enter water cycle?
Possible health risks?
Example 3:
Definition –
How does it enter water cycle?
Possible health risks?