The Trouble At Bender Lake

Description of Activity:

Overview

A scenario will be given to the students. In this scenario, a river near a community is believed to have contaminants which are lethal to the fish population. Students will acquire skills necessary to analyze a sample of polluted water (synthesized by the teacher) to determine the cause of the fish kill. This activity will lead to an option of two student investigations that incorporate the lab skills acquired in the simulation activity. Students will design and perform investigations to purify polluted water and/or test local water quality samples.

Duration

One week or this could be continued throughout the year if desired.

Materials:

• Water testing kit - Water testing kits vary in the range of sophistication and cost. If resources are limited, swimming pool water test kits, which are relatively inexpensive may be used in this activity. Some classrooms will have more materials available than others, but this investigation may be adapted to the resources of the teacher. (The table belows indicates the materials you will need to complete this activity.)

• Polluted water sample (for scenario)
  • 60 ml instant coffee crystals
  • 100 ml of grass clippings
  • 15 ml garlic powder
  • 15 ml sand or soil
  • 1 liter water

To various test tubes, add one of the following to simulate contaminates found in the water sample.

1. Acid from the electroplating plant found upstream.
• Add 1.5 ml of 6 .M HCl (pH 2.5).
2. Ammonia from a window cleaner bottling company.
• Add 30 ml. ammonia per 1 liter water sample (pH 10)
3. Biological contamination from a local feedlot.
• Add a small amount of commercial protozoan.
4. Phosphates from the surrounding agricultural area.
   • Add 100 ml phosphate per liter of water.
   • Allow to dissolve.
   • Discard any phosphate not dissolved (pH of 5).

Background Information:

The following scenario information may be given to the students as needed during the course of their research:

1. The Electroplating plant uses large amounts of water each day from the river. The water is used to wash metal that has been electroplated with gold or chromium. After the water is used, it is returned to the river.
2. There is a local bottling company which receives large bulk quantities of window cleaner. The company stores and then bottles the product into small 24 oz. spray bottles. Although there are no byproducts, the equipment must be maintained periodically.
3. The feedlot has been in operation for two generations. It is near the river, in fact some of the runoff may reach the river. The manure is stockpiled and spread over the adjacent agricultural land. It is rumored that some disease causing organisms from the feedlot seep into the river.
4. The town of Lakeshore is located in an agricultural area. It is a large exporter of alfalfa hay. Commercial fertilizers are used and irrigation is done by a method called flood irrigation. Some farms exist above Lakeshore and some are located below the town.

Teaching and Learning Strategies:

Ensure inquiry

Tell the students that because water is so necessary to all life on this planet, it is very important that they are aware of personal and industrial uses and misuses of the water system. In this activity they will gain knowledge and skills necessary to become "Hydrologists". They will become familiar with water testing methods, and use those skills as scientists in an investigation.

• Allow students the latitude to pursue a variety of problem solving methods.
• Promote the students as scientists. It is very important that they choose the course of their investigation (e.g., Allow the students to select appropriate water tests based on the water source collected). The teacher should be a facilitator of this activity. Successful strategies might include answering questions with questions, etc.

Classroom strategies

• Adapt the scenario to fit the abilities of the students.
• Allow students to work in cooperative learning groups.

Prerequisite instruction

The following information may be given during the course of this investigation depending on the time and the abilities of the students, or students may research to determine such information.

• Utah is the second driest state in the nation.
• As a nation we consume 1.8 trillion liters of water every day.
• Simple things that many people do without thinking of the consequences can drastically harm water resources. (Example: one quart of motor oil dumped in the backyard can seep into the ground and contaminate one million liters of drinking water.)
• All drinking water in the U.S. is not safe even though it is treated and chlorine is added to eliminate disease causing organisms.
• One out of five people in the United States drink water that is contaminated.
• Drinking water has been discovered that contains lead, radiation, and feces.
• One thousand people in the United States die each year from drinking contaminated water.
• The municipality with the most polluted drinking water is New York City.
• All living things on Earth depend on water. Water quality is determined by the kinds and amounts of dissolved and suspended materials, temperature, degree of alkalinity oracidity, taste, odor, and the presence of microorganisms.
• All natural water on the planet contains dissolved organic and inorganic materials. Total dissolved solids in rivers are usually between 20 and 2,000 parts per million The primary dissolved solids in water are calcium, sodium, magnesium, potassium, sulfate, chloride, carbonate, bicarbonate, and silica.
• Many pollutants can also be found in water. These pollutants vary in toxicity and may be materials not naturally found in water such as pesticides, or increased amounts of substances usually present, such as phosphates, nitrates, and metals.
• The pH of water - a measure of acidic or alkaline it is, is important in determining water quality. River water normally has a pH of 6.5 to pH 8.5. Precipitation usually has a pH of approximately 5.6, but it is becoming more acidic (pH 4 to 5) in some areas, by pollutants in the atmosphere.
• Phosphates and nitrates can also affect the quality of water. These chemicals are often used in agriculture as fertilizers. When found in larger than normal concentrations, they can cause an increase in aquatic plant growth which causes an unsuitable environment for aquatic animals.
• Organisms that live in water need dissolved oxygen for life functions. Ranges of dissolved oxygen are from 14.5 ppm at 0o C to 7.7 ppm at 30o C. The amount present is determined by the balance of Earth systems such as the atmosphere, plant photosynthesis, and the decay and respiration of living things.
• Another important factor in water quality is the amount of sediments suspended in water. The sediments affect light penetration, smothers aquatic life, and fill in lakes. Sediment is also linked to other water-quality factors because pesticides, phosphates, and bacteria may attach to sediment particles. Average sediment concentrations in streams is 100 ppm or less to 100,000 ppm depending on the location of the water body. Concentrations increase as the stream flow increases.
• Fecal-coliform bacteria from the intestines of mammals (including humans) sometimes found in water, are important to determining water quality. They indicate the possibility of the presence of disease organisms.
• Water temperature influences the metabolic rate of aquatic life and the rates of chemical reactions. Increases of temperature caused by industry may be harmful to aquatic life, this condition is called thermal pollution.

Development of Lab Skills and Tools:

After the scenario has been given to the students, demonstrate water testing laboratory skills. Many students have previously been introduced to some methods of testing water (e.g., testing pH and using microscopes), but a review might be necessary to ensure mastery. Be sure to encourage student participation during the demonstration. Also include general and specific laboratory safety procedures as described in the water testing kit and/or the "Standard Operating Procedures Form". Water testing may include but not be limited to the following:

1. Microscopes (Bacterial Growth)
• Review with the students the proper way to handle a microscope, focus, and adjust it. The student will need to know the proper way to mount a slide in preparation to look at a sample under the lens.
2. If a water testing kit is available, demonstrate the procedural and safety instructions of the kit that is being used for any of the following tests:
• pH
• Dissolved Oxygen
• Nitrates
• Alkalinity
• Chlorine
• Phosphates
If no water testing kit is available, the following tests may be performed using materials obtainable in most school science departments.
• pH
  1. There are many ways to test the pH of water. These include litmus, indicator paper, indicator solution ,and a pH meter. With student participation, model to the student the method that will be used to test the water.
• Phosphates
  1. Filter any solid particulate from the water so the precipitate is visible. Place 4 drops of the water sample into a test tube. Add three drops of silver nitrate. A yellow precipitate of Ag³PO⁴f HNO3. If the precipitate dissolves, it is a confirmed test 3Ag + PO4&shyp&shyp> Ag3PO3 (yellow). Collect all water that has been tested for phosphate. Mix with table salt and filter. Wash liquid down the drain. The solid AgCl can be disposed of in a landfill. (It should be noted, that when using this test, some impurities in the water may not allow the phosphate to form a precipitate. Do a trial run first.)

Invitation to Learn:

Problem: Give the following scenario to the students:

The people of Lakeside (see map) have recently been stunned by the number of dead fish that have been floating near the banks of the Bender River and the shores of Bender Lake. The Environmental Protection Agency has determined that an investigation should be conducted to determine the cause of the fish kill. The EPA has assigned your group to assess the quality of the water and determine the cause of the decimated fish population in the river and lake.

Activity

1. Relate the Background Information as stated above to the students.
2. Assign students into groups of three or four.
3. Distribute the map and explain the scenario to the students. Encourage questions about the scenario from students but limit the information given to clarification of the map.
4. Allow students time to design their experiments using the guidelines below. Individually check the proposed experiment of each group.
5. Allow the students time to conduct and record (using above guidelines) their investigations. If tests are inconclusive, they may revise their investigation, get approval, and start over.
6. Instruct each team to present their findings to the class.

Student Designed Experiment:

Review the guidelines and procedures as outlined below:

1. Observations - Study the map to determine possible sources of pollution that would cause the fish kill. .
2. Formulate a question - How, why, what if etc. (Why are the fish of the area dying?)
3. Form a hypothesis - Predict an answer to the question based on the observations.
4. Include a list of resource materials needed for the experiment.
5. Test the hypothesis - Make sure that the test will answer the question. Test only one thing at a time, determine ways to measure the results. Be sure to include a control sample, a dependent variable (that which is measured and changes) and independent variable. (that which is varied).
6. Test the hypothesis - Perform the experiment. Accurately collect the data.
7. Analyze the results - Graph the data, compare and contrast the results.
8. Draw conclusions - Using the results, relate the information back to the hypothesis to prove or disprove it.
9. Report the Experiment - Write up the experiment and discuss it with the appropriate individuals. (The class)
10. Verify the conclusion - Did other scientists (classmates) come up with the same findings?

Summary of Learning:

Multiple choice questions

1. 1. All of the following are tools of a hydrologist except
   1. Thermometer
   2. Seismograph
   3. pH indicators
   4. Silver nitrate
      
2. Suppose that pollution in a local water source was the cause of illness. Which of the following would be the most logical first step?
   1. Treating the water with chlorine and other chemicals to kill bacteria.
   2. Locating the source of pollutant and containing it.
   3. Notifying local news agencies to make a statewide public alert.
   4. Neutralizing the acidity of the water by adding lime.
      
3. Suppose you were testing water for impurities. You filtered the polluted water and added equal amounts of Silver Nitrate. A yellow precipitate formed on the bottom of the test tube. What would be a logical inference about the water.
   1. It has traces of living organisms
   2. It has traces of phosphates
   3. It is basic
   4. It is acidic

Extensions:

Extension #1

1. Challenge the students to design an experiment to purify the polluted water on a small scale. Students should follow the student experiment guidelines as stated above. Wait until after the students have completed their experiments to discuss water purification methods.
2. Make sure that the students have written and discussed proper safety procedures for this activity before approving their experiment. Have them list all safety precautions that should be taken, especially if the students will be using chlorine.
3. Allow students time to design their experiment.
4. Individually approve each group's experiment and safety plan. Advise groups that if they need to revise their experiment, they will need to get it approved once again.
5. Allow time for the groups to perform their experiment. Be sure that students have determined a way to test and compare the water quality of their treated sample with other groups (e.g., pH, Chlorine level, clarity).
6. Allow the students to communicate their findings by discussing the results of the students' experiments. Compare the feasibility of their methods with water purification on a large scale.

Extension #2

1. Discuss with students local water resources and possible pollution sources (e.g., streams near agricultural areas or feedlots, water bodies near industries such as Geneva Steel or Kennecott)
2. Collect water from predetermined sites for analysis.
3. Follow student guidelines to perform water quality tests on the samples.
4. This activity may be ongoing investigation through the school year.

Standard Operating Procedures Form