Lesson 2: DDT and Ethics

Almost every decision in life involves trade-offs. Very rarely do we face clear-cut choices where the answer is clearly the best and only choice. Environmental decisions are no exception to this. Land is needed for a hospital, but the remaining open space is a rare habitat. The best substance for protecting against fire may cause cancer if fragmented and inhaled. Nearly every decision has pros and cons that must be reconciled. So what about DDT, banned in the U.S. over three decades ago? DDT is a chemical created to kill insects, and it did its job very well. DDT is a pesticide used in growing crops. It is an organo-chloride chemical and is a toxin suspected of causing cancer and reproductive disorders. Levels of DDT were so high in the early 1970s that a ban on commercial fishing on Lake Michigan was imposed. Levels have since fallen and are now within safe limits. The United States Environmental Protection Agency has banned or severely restricted the use of pesticides like DDT, aldrin, dieldrin, chlordane, and heptachlor. But what trade-offs were involved in making these decisions?

Time Allotment:
one 45-minute session

Materials:

• journals
• pencils or pens
• access to library and/or Internet

Advanced Preparation and Teacher Notes

This lesson should be conducted in two parts: in part one students will set up the question and conduct research; in part two students will present their research and discuss the ethics of the problem.

Tap Prior Knowledge

Ask the students to describe how they make a decision. For example, they wish to buy something they want (e.g., a video game, new clothes, etc.), but it is very expensive. How would they decide whether or not to buy it? What other factors besides price would be considered (e.g., time, other things they would rather buy, consumer reviews)? How limited family money or an approaching family vacation affect their decision?

Share with Neighbor

After a brief discussion on how decisions are made, ask the students to pair up to make a list of steps they feel are necessary to make a smart decision.

On the board create a master list of decision-making steps.

Engage Students in Hands-on Activity

Explain that the process we use to make decisions on a small scale can also be used on a large scale as well. For example, ask the students whether the United States should have banned DDT. List their reasons on the board.

How did they come to their decisions? Did they follow the same steps they outlined earlier? Are there steps they'd like to add to the decision making process? If so, add them to the list on the board. If they haven't already thought of it, mention that doing your own research is usually a good idea before making any big decision. Is this video game rated well by others? Is this outfit likely to go out of style quickly? Is there another product that will be a better value for the money? In the case of DDT, is the information they are basing their decisions on accurate and complete? Would their opinions change if they knew that while it harmed the peregrine falcon, it saved thousands of lives in Africa by controlling mosquito-borne malaria?

Have the students divide into groups to research on the Internet DDT and the decision to ban its use. One group can research how DDT was developed and used. Encourage this group to try to find out how well DDT met its original purpose and how well its replacements do today. Basically they should focus on what it is and how it works. Another group can research the case for banning DDT. A third group should research the case against the DDT ban. Some possible arguments to pursue: was the ban a result of "bad science," and does the ban result in more harm than good (i.e., human lives lost due to malaria and other insect borne illnesses vs. animal lives saved). A fourth group can research how well species harmed by DDT have recovered since the ban, and how we know this. Encourage the students to evaluate the accuracy of their source material, and mention any doubts in their reports.

Each group should organize their data into a 5-10 minute presentation for the class. Each group should also prepare a poster listing their key points.

Make a for/against chart on the board. Based on the information presented, lists reasons for or against banning DDT. As each item is added, discuss how important a factor it is to the decision-making process. Are their any particular groups or individuals that would place special emphasis on any of the pros or cons?

Did this process cause any students to revise their opinions, why or why not?

Introduce the Scientific Principle/Concept

How we personally feel about the Earth and our relationship to it is called an environmental ethic. An environmental ethic provides a guide to an individual's decisions, functioning as a value system in which to interpret environmental issues. Since our environmental ethic affects the choices we make when dealing with the environment, it is important to give some thought to how we think about natural spaces and how we live. We may, for example, feel strongly that natural spaces must be preserved as they are. This may result in personal choices that will encourage or assist such an outcome as donating time and energy to preserving lands, a "no trace" camping policy, living in a more urban setting to reduce urban sprawl, or going without certain products that would necessitate habitat destruction. You may also feel quite strongly that humans are top priority (for example, if DDT saves lives by the thousands in Africa, it is worth a few birds dying, or development to aid humans is necessary even if it eliminates wetlands or other habitats). You may also fall somewhere in between.

Your environmental ethic may also guide you to different opinions in different situations. Development may not be appropriate when drilling for oil, but may be appropriate to build a hospital. It all depends on what you believe. And because it is a value-based philosophy, it is important to include science and what is known to come to a conclusion.

Whether or not a wetland is really endangered by a development project could effect your decision to support or oppose the project. How deer numbers are reduced when they have over-populated a region may completely change your opinion about hunting. Because some people have very strong beliefs about how we should interact with the environment and their beliefs may not agree with yours, don't just take someone's word for it, find out about the evidence they are using to support their statement. A scientific journal article might carry more weight than an anecdotal story. Does the person or group have a goal that might bias what they have to say? Once you have as much information as possible, and are aware of what biases may exist, you can make a decision.

As with any science-based decision, more studies are conducted over time. These studies may change or even refute information from earlier investigations. This re-testing is part of the scientific method to ensure the validity of our information, but moreover it shows the necessity for being a well-informed citizen when making decisions

Relate Activity and Concept

Based on this project, have the students come up with their own environmental philosophy. How do they feel about their environment? You might want to read from the works of Aldo Leopold, John Muir, or other environmental philosophers to assist them in putting together their own environmental ethic.

Emphasize that there is no "right" answer to this exercise. Environmental ethics are different for different people. Some people may be opposed to hunting, while others see it as necessary. Still others may only see it as needed under very specific circumstances. Guided by an environmental ethic and on based on scientific evidence, environmental decisions can be made that best reflect how we as a people should interact with the Earth.

To get the students started in their projects, here are some Websites about DDT. Please note that students should evaluate them for their usefulness and accuracy as they are not affiliated in any way with the Peggy Notebaert Nature Museum/Chicago Academy of Sciences, and we cannot be responsible for their content. For more on evaluating Web resources, click here.

http://users.cybercity.dk/~ccc12787/misc/beebe01.html http://www.raptor.cvm.umn.edu/ http://www.peregrine-foundation.ca/info/index.htm http://www.inhs.uiuc.edu/chf/pub/ifwis/birds/peregrine-falcon.html http://www.dnr.state.wi.us/org/land/er/factsheets/birds/Falcon.htm http://arnica.csustan.edu/esrpp/pfweb1.htm http://www.fs.fed.us/r3/coronado/grazing_bo/apf.htm http://www.altgreen.com.au/chemicals/ddt.html http://www.junkscience.com/ddtfaq.htm http://international.fws.gov/cop11/peregrin.html http://contaminants.fws.gov/examples/AlaskaPeregrine.cfm

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