Materials Included In Kit

Additional Materials Required

Safety Precautions

Phosphate TesTabs contain chemicals that may irritate skin or be harmful if swallowed. The TesTab reagents used in this kit were designed with safety in mind. The single-use, foil-packaged TesTabs are easy to dispense. Store TesTabs in a cool, dry place and only open when ready to use the tablet. A single tablet, either alone or reacted with a sample, is a very low health hazard; however, TesTabs should not be ingested. Wear chemical splash goggles and chemical-resistant gloves. Please review current Safety Data Sheets for additional safety, handling and disposal information.

Disposal

Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. All resulting solutions may be disposed of according to Flinn Suggested Disposal Method #26b.

Teacher Tips

• There are enough materials for 30 students working in pairs.
• Using scissors, cut the supplied plastic tubing into 2" pieces for use in Part II, Experiment B.
• Some of the tests require an outdoor environment. Read the lab all the way through ahead of time and plan class time accordingly.
• Encourage students to place their slides for Part I in a variety of locations. Allow students to take their slides out of the classroom to sample the total particulates in or around their homes. Compile class data and compare individual results.
• Extra slides and labels are given for additional tests for Part I.
• The main components of the matches used in Experiment A of Part II are red phosphorus and other phosphorous compounds, sulfur and potassium compounds. The fumes from the match are comparible to the fumes emitted by some types of factories.
• Extra bromthymol blue is given to perform multiple tests for Part II, Experiment B. Bromthymol blue is a blue color. If it has turned green or yellow, add 0.1 M sodium hydroxide dropwise until a blue color is achieved.
• Be sure to use distilled or deionized water in experiment B, Part II.
• It’s a good idea to collect several water samples from each site that is tested. It is also wise to test the samples within one hour of collection if possible.
• pH Wide Range TesTabs contain a mixture of pH indicators that are sensitive to pH and undergo specific color changes with variation in pH.
• Positive pH results will be seen in the range of 4–11.
• Phosphate TesTabs contain ammonium molybdate which reacts with phosphate to form a phosphomolybdate complex. This complex is reduced to a blue complex by ascorbic acid.
• The range of the phosphate TesTab test is between 0 to 4 ppm.
• Ammonia #1 TesTabs and Ammonia #2 TesTabs contain lithium hypochlorite and sodium salicylate. Ammonia reacts with salicylate at high pH in the presence of a chlorine donor and an iron catalyst to form an indophenol dye in proportion to the amount of ammonia in the sample.
• The range of the ammonia TesTab test is between 0 and 4 ppm.
• TesTabs are a vendor product of the LaMotte Company. SDSs are available through the manufacturer website. Links to the specific TesTabs used in this kit are listed: 
  Phosphate — http://www.lamotte.com/pages/common/pdf/msds/5422.PDF
  Wide Range — http://www.lamotte.com/pages/common/pdf/msds/6459.PDF

Further Extensions

• Have students write reports on certain pollutants and their sources and effects. Encourage students to use the Internet and local libraries to explore the wide range of information available.
• Contact local manufacturing companies and see if you could take a tour of their plant. Discuss the steps that the company takes to reduce the amount of pollution coming from their facility.
• Visit the United States Environmental Protection Agency’s (EPA) website at www.epa.gov for further information on air and water pollution.

Sample Data

Part I. Particulates in the Air

Part II. Smoke and Acidic Gases in Air Experiment

A. Smoke from Match

Experiment B. Outside Air

Parts III, IV, V. Water Testing

Answers to Questions

Part I. Particulates in the Air

1. Did your test area have low or high particle pollution? Give examples of possible sources of particle pollution in your test area. Compare your results with your classmates.

My test area has a low amount of particle pollution. Particles may have come from clothes, natural fibers, etc., from an open window or ventilation ducts.

2. Which location had the highest number of particulates?

The highest number of particulates come from a slide placed in an open field.

3. Which location had the largest particulates? the smallest?

The largest particles came from a slide placed near a grain elevator. The smallest particles came from the slides in the classroom.

4. Which location had the most variable types of particulates?

A slide that was placed on a tree branch had the most variable types of pollutants.

Part II. Smoke and Acidic Gases in Air

5. What effect does the pH of smoke have on water in the atmosphere?

The pH of smoke may alter the overall pH of atmospheric water and cause acid rain.

6. What are some possible sources of acidic gases in air?

Acidic gases in air may be present from volcanoes, sea spray, dust from dry soils, smog and the burning of fossil fuels to name a few.

7. Discuss possible outcomes of high levels of acidic gases in the atmosphere.

Acidic gases in the atmosphere may lead to acid rain and smog, which presents increased health hazards to humans, causes soils to become very acidic, causes harm to seeds and plants and damages statues and buildings.

Part III. pH of Water

8. What could cause the pH of water to be acidic? basic?

Water can become acidic from nitrogen and sulfur oxides in the air (which causes acid rain). Water with abundant algae and vegetation generally has a very high pH.

9. What are the possible consequences of acidic water? basic water?

In acidic water, the larval stages of insects and other small aquatic organisms may die. In basic water, aquatic organisms have a difficult time excreting ammonia from their bodies.

10. Was the pH value of your water acceptable? If not, what could be done to correct the pH?

Answers will vary.

Part IV. Phosphate in Water

11. Did your water sample have a high or low amount of phosphate?

Answers will vary.

12. Name and describe a possible outcome of high phosphate levels in lakes.

Natural waters high in phosphate may undergo high algae blooms and eutrophication.

13. What could be done to help minimize the amount of phosphate ions in water?

Answers will vary.

Part V. Ammonia in Water

14. What happens when ammonia is placed in water?

When ammonia is introduced in water it is converted to nitrates by the process of nitrification (the process in which nitrifying bacteria convert toxic ammonia to less harmful nitrates).

15. According to the values given in the Background section, did your water contain a high amount of ammonia?

Answers will vary.

16. What effect do pH and temperature have on the amount of ammonia aquatic organisms can tolerate?

As pH and temperature decrease, more total ammonia can be tolerated by aquatic organisms. As pH and temperature increase less, ammonia can be tolerated.

Discussion

Alignment with AP^® Environmental Science Topics and Scoring Components

Topic: Pollution. Air pollution (Sources—primary and secondary; major air pollutants; measurement units; smog; acid deposition—causes and effects; heat islands and temperature inversions; indoor air pollution; remediation and reduction strategies; Clean Air Act and other relevant laws). Water pollution (Types; sources, causes, and effects; cultural eutrophication; ground-water pollution; maintaining water quality; water purification; sewage treatment/septic systems; Clean Water Act and other relevant laws).

Scoring Component: 9-Pollution, Air and Water.

References

Cunningham, W. P.; Woodworth, S. B. Environmental Science: A Global Concern; William C. Brown: Dubuque, IA, 1997; pp 385–390.

U.S. Environmental Protection Agency. Ambient Water Quality Criteria for Ammonia. (EPA 440/5–85–001) January 1985.

Introduction

How clean is the air and water around us? How does the air and water look, taste, feel and smell in your local community? In this laboratory activity, several tests will be performed to determine the quality of air and water in your area.

Concepts

• Air quality
• Acid rain
• Smoke pollution
• Phosphate concentration
• Particulates
• Ammonia concentration
• pH

Background

Air Pollution

The major components of pollution-free, dry air are nitrogen (78%), oxygen (20.95%), argon (0.934%) and carbon dioxide (0.0314%). Air also contains trace quantities of neon, ammonia, helium, methane and krypton. If any other substances are added to the atmosphere, an imbalance occurs that leads to the degradation of the air. The air in your area is probably polluted to some extent. Air pollution is considered as the most widespread and noticeable type of pollution. Each year in the United States, 147 million metric tons of air pollution are released into the air as a result of human activity. Worldwide, nearly 2 billion tons of air pollutants are released into the atmosphere every year.

There are five major classes of air pollutants—particulate materials, sulfur oxides, nitrogen oxides, carbon monoxide and volatile organic compounds.

Particulate materials, also known as aerosols, are defined as any group of liquid droplets or solid materials suspended in air. Particulate materials include substances such as dust, lint, smoke, pollen and ash, as well as many other suspended materials. Particulate material is often the most visible and noticeable type of air pollution and can be harmful to many organisms. World-wide, natural sources of particulate material in the air account for more than ten times the pollution of human sources; although in many cities, more than 90% of suspended particulate matter is due to human activity.

Sulfur oxides occur in air from both natural and human sources. Natural sources such as volcanoes, sea spray, and dust from dry soils, all account for sulfur compounds in the atmosphere. The major source of sulfur in the air caused by humans is sulfur dioxide (which comes from the combustion of coal and oil, and smelting of ores). Sulfur dioxide is a corrosive, colorless gas that is a major constituent of smog. It is very toxic by inhalation and poses a strong health hazard to humans. Sulfur oxides are also one of the two major classes of gases that lead to acid rain (nitrogen oxide is the other).

Nitrogen oxides are present in the atmosphere mainly from the burning of fossil fuels. Many fossil fuels contain small amounts of nitrogen-containing compounds that produce nitrogen oxides upon combustion. Nitrogen oxides combine with the water in the atmosphere to produce acid precipitation. Rain and other forms of precipitation generally do not have a pH of 7. Dissolved carbon dioxide in the atmosphere generally lowers the pH of rainwater to about 5.5. In contrast, nitrogen oxide and sulfur oxides can cause the pH of rainwater to be as low as 2.5. This is called acid rain and causes damage in many ways. Acid rain may cause high amounts of stress on aquatic life in bodies of water. In fact, many lakes in the United States have become so acidic that organisms that used to flourish have disappeared. Acid rain causes soils to become very acidic and also washes away essential nutrients from the soil. The acidity of the rain can also cause direct harm to plants by damaging leaves and preventing the germination of seeds. On a more visible, although less life-threatening level, acids released into our atmosphere can severely damage statues and erode artwork and buildings.

Carbon monoxide is a colorless, odorless gas that is highly toxic to humans and other organisms. It is present in the atmosphere mainly from the incomplete combustion of fossil fuels. If an internal combustion engine does not have the proper mix of fuel and air, carbon monoxide is formed instead of carbon dioxide. Carbon monoxide actually inhibits the respiratory system in animals by competing with oxygen for the binding sites on hemoglobin. Every year, about one billion metric tons of carbon monoxide are released into the air from the exhaust vapors of cars, trucks and other vehicles.

Volatile organic compounds are organic chemicals that persist in the atmosphere as gases. Plants are considered the largest source of volatile organic compound production. In addition to natural sources of these compounds, a high number of man-made synthetic organic chemicals such as toluene, benzene, phenols and chloroform are also released into the atmosphere. The major source of manmade, volatile organic pollution is the evaporation of gasoline from gas stations when customers are refueling.

Water Pollution

Water is an essential resource for all life forms. In fact, water is the main component in cells and it composes up 60 to 70 percent of the weight of living organisms. It is used for almost every activity in today’s world. Some examples are seen in agricultural and industrial applications, drinking, transportation and recreation. Water often seems to be available in an almost endless supply, but as human populations rise and our world becomes increasingly industrialized, more and more water is being used. With this extensive use of water, a problem arises: the water becomes polluted and contaminated. This pollution leads to a strain on water’s ability to recycle and cleanse itself of contaminants. The amount of water available, its distribution, and its quality are critical issues to all life. An increasing awareness of the need to monitor the quality of water and to locate the sources of pollution is becoming more prevalent in today’s society.

In this activity, three types of water tests will be performed: pH, phosphate and chlorine.

The pH test is a standard test used during water analysis. pH is a measure of the relative abundance of hydrogen ions in a water sample. In pure water, the hydrogen ion concentration [H⁺] is equal to 1.0 x 10^–7 moles per liter. Equation 1 shows how the pH value of a sample is calculated from the hydrogen ion concentration.

As water becomes more acidic, the pH value decrease from 7 to 6 to 5 to 4 and so on. As the solution becomes more basic, the pH values increase from 7 to 8 to 9, etc. (see Figure 1). The pH scale for water has a range of 0 to 14. Most aquatic organisms require a pH range between 6.5 and 8.2. At pH levels below 5 larval stages of insects and other small aquatic organisms may die off rapidly. Water with abundant algae and vegetation growth usually has a significantly high pH. This is due to the fact that rapidly growing algae and vegetation remove carbon dioxide from the water during photosynthesis. At pH levels above 9, fish may have a difficult time excreting ammonia from their bodies.

Phosphorus is a vital element of life and occurs naturally in water in the form of phosphate ions. Phosphate originates from fertilizers, wastewater of domestic origin, such as human, animal and plant residue, and from wastewater of industrial origin. Phosphates are also added to farm and city water systems to control water hardness. Phosphates also come from some laundry detergents. Excess phosphates can result in overgrowth of algae (also known as algae blooms), which in turn will cause the algae to die at a high rate and undergo decomposition. This decomposition process depletes oxygen from the water and results in increased fish kill. Lakes that have high phosphate levels undergo a process called eutrophication. There are two types of eutrophication: cultural eutrophication and natural eutrophication. Cultural eutrophication is water pollution caused by excessive amounts of phosphates introduced by human activities. The rapid growth and die-off of plants causes lakes to “fill-in” and age more rapidly (see Figure 2). In contrast, natural eutrophication, which is the process where lakes age gradually and become more productive, requires thousands of years to come to completion. Phosphate levels greater than 0.1 parts per million may lead to an overgrowth of aquatic plants.

When ammonia is introduced into water it is converted to nitrates by the process of nitrification. Nitrification is the process during which nitrifying bacteria convert toxic ammonia to less harmful nitrates. By way of nitrification, ammonia is often the primary or secondary source of nitrates for plants. Ammonia is found in water from excretions of aquatic organisms and from bacterial decomposition of organic waste. Ammonia is generally found in very low amounts in water that is non-polluted and in water that contains a high amount of oxygen.

The amount of ammonia aquatic life can withstand depends on the pH and temperature of the water. As pH and temperature decrease, more total ammonia can be tolerated. Table 1 shows an example of how pH and ammonia can affect aquatic life (specifically salmon in this study). Lethal concentrations were derived from levels at which half of the exposed organisms died.


Water that contains 5 to 10 parts per million of ammonia indicates that there is a high amount of decaying matter and low dissolved oxygen in the water. Ammonia is an essential nutrient for life but high levels may also cause changes in the metabolism and pH levels of organisms.

Materials

Safety Precautions

Phosphate TesTabs^® contain chemicals that may irritate skin or be harmful if swallowed. The TesTab reagents used in this kit were designed with safety in mind. Store TesTabs in a cool, dry place and only open when ready to use. A single tablet, either alone or reacted with a sample, is a very low health hazard; however, TesTabs should not be ingested. Wear chemical splash goggles and chemical-resistant gloves. Please review current Safety Data Sheets for additional safety, handling and disposal information.

Procedure

Part I. Particulates in the Air

1. Place a label, sticky side up, on your microscope slide. This may be done by curling two of the outside edges of the label down so the label will stick to the slide.
2. Choose a location, inside or outside, to place your slide. Be sure to choose a different location than other classmates (i.e., inside a classroom by a window, in a tree, near the corner of the school building). Choose an area that is exposed to the air, elevated off the ground and, if possible, sheltered from rain. Be sure to describe where the slide was placed. Record placement in Part I of the data table.
3. Leave the slide in the same location for seven days.
4. At the end of the seven days, collect the sample.
5. Using a magnifying glass, look at the label and record observations in the data table. Measure and draw two 1-cm squares on your label. Count or estimate how many particles are in each of the squares (look for white as well as dark specks) and record these values in the data table. Average the two counts to obtain the overall particles per square centimeter. Record this value in the data table. Total particle counts between 100 to 500 per square centimeter indicate slight particle pollution. Values over 500 particles per square centimeter correspond to high particle air pollution.

Part II. Smoke and Acidic Gases in Air

Experiment A. Smoke from Match

1. Fill the plastic jar to the 10-mL line with distilled water. Using a Beral-type pipet, add 5 drops of bromthymol blue indicator solution.
2. Swirl the solution in the plastic jar and record the initial color of the solution in Part II of the data table.
3. Light a match and place it in the solution in the sampling container and immediately close the lid. Try to capture all of the smoke from the match in the plastic jar.
4. Swirl the solution in the plastic jar so it can interact with the fumes. Record all observations and the pH of the resulting solution. (Note: At a pH below 6.0 bromthymol blue is yellow, at a pH of 7.0 it is green, and at a pH above 7.6 it is blue.)
5. Rinse the plastic jar with distilled water for use in the next experiment.

Experiment B. Outside Air

1. Fill the plastic jar to the 10-mL line with distilled water. Using a Beral-type pipet, add 5 drops of bromthymol blue indicator solution.
2. Swirl the plastic jar and record the color of the solution in the data table.
3. Attach a 2-inch piece of tubing to the end of a syringe as seen in Figure 3. Fill the syringe with outside air.
4. Force the air out of the syringe through the tubing and into the bromthymol blue/water solution by depressing the plunger.
5. Repeat Steps 3 and 4 ten times and record all observations in the data table. Note: If the bromthymol blue/water solution does not change color, the air in your area has a fairly low amount of acidic gases. If the solution changes to a yellow color, your local air supply contains a high concentration of acidic gases.
6. Rinse the syringe, tubing and plastic jar with distilled water.

Part III. pH of Water

1. Fill the water sample tube to the 10-mL line with a water sample.
2. Add one pH Wide Range TesTab to the tube.
3. Cap the tube and mix until the tablet has dissolved.
4. Compare the color of the sample to the pH color comparison chart.
5. Dispose of the reacted sample according to the instructor and rinse the water sample tube twice.

Part IV. Phosphate in Water

1. Fill the water sample tube to the 5-mL line with a water sample.
2. Add one Phosphorus TesTab to the tube.
3. Cap the tube and mix until the tablet has dissolved.
4. Wait for five minutes.
5. Compare the color of the sample to the Phosphate color comparison chart.
6. Dispose of the reacted sample according to your instructor and rinse the water sample tube twice with the water sample for the next test.

Part V. Ammonia in Water

1. Fill the water sample tube to the 5-mL line with the water sample.
2. Add one Ammonia #1 TesTab to the tube.
3. Cap the tube and mix the solution until the tablet has dissolved.
4. Add one Ammonia #2 TesTab to the tube.
5. Cap the tube once again and mix the solution until the tablet has dissolved.
6. Wait for five minutes.
7. Compare the color of the water sample to the Ammonia color comparison chart.
8. Dispose of the reacted sample according to the wishes of your instructor.

Student Worksheet PDF

10362_Student1.pdf