Assignment three

Adapted from Chemical Heritage Foundation's Webquest # 6.

Create a google doc at docs.dunmorestudents.net. Change the title to "MTBE" and share it with me (bennettj@dunmorestudents.net).

The Great MTBE Controversy

Introduction

Until recently, methyl tert-butyl ether was used as an additive in gasoline. We call it MTBE for short, and it helped make automobile exhaust cleaner. But there was a problem. As you may know, gasoline is often stored in huge tanks underground. When you're filling up at the gas station you're most likely parked right above a huge underground tank. In a perfect world, these tanks would never leak and no gasoline would ever seep out of them. But as some of you may have figured out, this world is far from perfect, and sometimes gasoline leaks out of these tanks and seeps into the groundwater. This was especially a problem in California, and in some parts of the state unusually high levels of MTBE were showing up in drinking water. While MTBE was great for keeping car exhaust clean, but it wasn't the sort of thing you'd want to drink. The use of MTBE became very controversial.

The long and short of the matter is that in 2000, the U.S. government banned adding MTBE to gasoline. This was a controversial move. The case pitted our need for clean air against our need for clean drinking water. In this activity you are going to research this case and draw your own conclusions. Was the government right or wrong to ban MTBE from use in gasoline? That's the question you're going to be exploring.

Your Task

Your challenge is simply to investigate the benefits and risks associated with using MTBE, and to formulate an opinion on whether the U.S. government was right to ban its use.

Resources

Here are a few websites to get you started in your quest. These are not the only useful websites out there, just a jumping off place for you to begin.

• MTBE (methyl tertiary butyl ether) and Underground Storage Tanks � from the U.S. Environmental Protection Agency.

The Process

Research MTBE and what its benefits are. Answer the following questions in a google document and share it with me (bennettj@dunmorestudents.net):

1. What kinds of compounds are the major components of gasoline?
2. If the gasoline burns completely in an automobile engine, what would the products of the reaction be? That is, what would the exhaust of the car be?
3. What kinds of reaction products are produced when gasoline does not burn completely?
4. Which of these compounds can be partially eliminated from automobile exhaust by adding MTBE to gasoline?
1. Consider the compounds that MTBE partially eliminates from automobile exhaust. What kinds of health problems can these compounds cause if they are released into the air?

Answer the following questions about the risks of using MTBE in your google document :

1. How is MTBE detected in drinking water? How is the concentration of MTBE measured?
2. What is the EPA concentration limit for MTBE in drinking water?
3. What concentrations of MTBE have been found in drinking water in California?
4. What kinds of health problems can be caused by drinking water contaminated with MTBE?
1. What were the incidences of MTBE-related health problems in areas with the highest MTBE concentration in drinking water?

Conclusion

Once you have answered the questions, write a summary based on your opinions concerning the banning of MTBE for use in gasoline. Whatever your opinion is, you should include your own analysis of the relative risks of using MTBE versus not using MTBE. If you feel that the government was right to ban MTBE, please include your ideas on how to keep automobile exhaust as clean as it was when MTBE was used. If you feel that banning MTBE was the wrong decision, please include your ideas on how to protect people from the dangers of MTBE-contaminated drinking water.

Copyright ©2001 The Chemical Heritage Foundation